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1

Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing  

NASA Technical Reports Server (NTRS)

This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

2010-01-01

2

Residual stresses in weld deposited clad pressure vessels and nozzles  

SciTech Connect

Results of through-thickness residual stress measurements are provided for a variety of samples of weld deposited 308/309L stainless steel and Alloy 600 cladding on low-alloy pressure vessel ferritic steels. Clad thicknesses between 5 and 9mm on samples that vary in thickness from 45 to 200mm were studied. The samples were taken from flat plates, from a spherical head of a pressure vessel, from a ring-segment of a nozzle bore, and from the transition radius between a nozzle and a pressure vessel shell. A layer removal method was used to measure the residual stresses. The effects of uncertainties in elastic constants (Young`s modulus and Poisson`s ratio) as well as experimental error are assessed. All measurements were done at room temperature. The results of this work indicate that curvature plays a significant role in cladding residual stress and that tensile residual stresses as high as the yield stress can be measured in the cladding material. Since the vessel from which the spherical and nozzle corner samples were taken was hydrotested, and the flat plate specimens were taken from specimens used in mechanical fatigue testing, these results suggest that rather high tensile residual stresses can be retained in the cladding material even after some mechanical loading associated with hydrotesting and that higher levels of hydrotest loading would be required to alter the cladding residual stresses.

Jones, D.P.; Mabe, W.R. [Westinghouse Electric Co., West Mifflin, PA (United States); Shadley, J.R.; Rybicki, E.F. [Univ. of Tulsa, OK (United States)

1998-04-01

3

Residual Stress Measurements of Explosively Clad Cylindrical Pressure Vessels  

SciTech Connect

Tantalum refractory liners were explosively clad into cylindrical pressure vessels, some of which had been previously autofrettaged. Using explosive cladding, the refractory liner formed a metallurgical bond with the steel of the pressure vessel at a cost of induced strain. Two techniques were employed to determine the residual stress state of the clad steel cylinders: neutron diffraction and mechanical slitting. Neutron diffraction is typically nondestructive; however, due to attenuation along the beam path, the cylinders had to be sectioned into rings that were nominally 25 mm thick. Slitting is a destructive method, requiring the sectioning of the cylindrical samples. Both techniques provided triaxial stress data and useful information on the effects of explosive cladding. The stress profiles in the hoop and radial directions were similar for an autofrettaged, nonclad vessel and a clad, nonautofrettaged vessel. The stress profiles in the axial direction appeared to be different. Further, the data suggested that residual stresses from the autofrettage and explosive cladding processes were not additive, in part due to evidence of reverse yielding. The residual stress data are presented, compared and discussed.

Taylor, Douglas J [TPL, Inc; Watkins, Thomas R [ORNL; Hubbard, Camden R [ORNL; Hill, M. R. [Hill Engineering; Meith, W. A. [Hill Engineering

2012-01-01

4

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test  

NASA Technical Reports Server (NTRS)

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPV has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. The more aggressive second phase, performed at 160 F was designed to determine if the test article will exceed the 95% confidence interval of the model. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezian, Michael; Varanauski, Don; Yoder, Tommy; Woodworth, Warren

2009-01-01

5

Stress distribution in continuously heterogeneous thick laminated pressure vessels  

SciTech Connect

Stress analysis of multilayered pressure vessels possessing cylindrical anisotropy and under internal, external and interlaminar pressure is given. The special case when the axis of anisotropy coincides with the axis of symmetry Oz and the stresses do not vary long the generator is investigated. In this case there exists a plane of elastic symmetry normal to this axis at every point of the cylinder so that each layer may be considered s orthotropic. However, elastic properties can vary through the thickness of a layer. Exact elasticity solutions are obtained for both open-ended and closed-ended cylinders using a stress function approach. The method of solution allows the forces on the layer interfaces to be taken into account with relative ease. Numerical results are presented for thick cylinders with isotropic and orthotropic layers, and stress distributions across the thickness are given.

Verijenko, V.E.; Adali, S.; Tabakov, P.Y. [Univ. of Natal, Durban (South Africa). Dept. of Mechanical Engineering

1995-11-01

6

Stresses in reactor pressure vessel nozzles -- Calculations and experiments  

SciTech Connect

Reactor pressure vessel nozzles are characterized by a high stress concentration which is critical in their low-cycle fatigue assessment. Program of experimental verification of stress/strain field distribution during elastic-plastic loading of a reactor pressure vessel WWER-1000 primary nozzle model in scale 1:3 is presented. While primary nozzle has an ID equal to 850 mm, the model nozzle has ID equal to 280 mm, and was made from 15Kh2NMFA type of steel. Calculation using analytical methods was performed. Comparison of results using different analytical methods -- Neuber`s, Hardrath-Ohman`s as well as equivalent energy ones, used in different reactor Codes -- is shown. Experimental verification was carried out on model nozzles loaded statically as well as by repeated loading, both in elastic-plastic region. Strain fields were measured using high-strain gauges, which were located in different distances from center of nozzle radius, thus different stress concentration values were reached. Comparison of calculated and experimental data are shown and compared.

Brumovsky, M. [Nuclear Research Institute Rez plc (Czech Republic); Polachova, H. [Nuclear Machinery, Ltd. Plzen (Czech Republic)

1995-11-01

7

ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES  

SciTech Connect

In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperature (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP) Conferences. This work is also relevant to the ongoing efforts of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code, Section XI, Working Group on Operating Plant Criteria (WGOPC) efforts to incorporate nozzle fracture mechanics solutions into a revision to ASME B&PV Code, Section XI, Nonmandatory Appendix G.

Walter, Matthew [Structural Integrity Associates, Inc.; Yin, Shengjun [ORNL; Stevens, Gary [U.S. Nuclear Regulatory Commission; Sommerville, Daniel [Structural Integrity Associates, Inc.; Palm, Nathan [Westinghouse Electric Company, Cranberry Township, PA; Heinecke, Carol [Westinghouse Electric Company, Cranberry Township, PA

2012-01-01

8

Stress and Fracture Mechanics Analyses of Boiling Water Reactor and Pressurized Water Reactor Pressure Vessel Nozzles  

SciTech Connect

This paper describes stress analysis and fracture mechanics work performed to assess boiling water reactor (BWR) and pressurized water reactor (PWR) nozzles located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Various RPV nozzle geometries were investigated: 1. BWR recirculation outlet nozzle; 2. BWR core spray nozzle3 3. PWR inlet nozzle; ; 4. PWR outlet nozzle; and 5. BWR partial penetration instrument nozzle. The above nozzle designs were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-license (EOL) to require evaluation as part of establishing the allowed limits on heatup, cooldown, and hydrotest (leak test) conditions. These nozzles analyzed represent one each of the nozzle types potentially requiring evaluation. The purpose of the analyses performed on these nozzle designs was as follows: To model and understand differences in pressure and thermal stress results using a two-dimensional (2-D) axi-symmetric finite element model (FEM) versus a three-dimensional (3-D) FEM for all nozzle types. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated; To verify the accuracy of a selected linear elastic fracture mechanics (LEFM) hand solution for stress intensity factor for a postulated nozzle corner crack for both thermal and pressure loading for all nozzle types; To assess the significance of attached piping loads on the stresses in the nozzle corner region; and To assess the significance of applying pressure on the crack face with respect to the stress intensity factor for a postulated nozzle corner crack.

Yin, Shengjun [ORNL; Bass, Bennett Richard [ORNL; Stevens, Gary [U.S. Nuclear Regulatory Commission; Kirk, Mark [NRC

2011-01-01

9

The inclusion of weld residual stress in fracture margin assessments of embrittled nuclear reactor pressure vessels  

SciTech Connect

Analyses were performed to determine the impact of weld residual stresses in a reactor pressure vessel (RPV) on (1) the generation of pressure temperature (P-T) curves required for maintaining specified fracture prevention margins during nuclear plant startup and shutdown, and (2) the conditional probability of vessel failure due to pressurized thermal shock (PTS) loading. The through wall residual stress distribution in an axially oriented weld was derived using measurements taken from a shell segment of a canceled RPV and finite element thermal stress analyses. The P-T curve derived from the best estimate load analysis and a t / 8 deep flaw, based on K{sub Ic}, was less limiting than the one derived from the current methodology prescribed in the ASME Boiler and Pressure Vessel Code. The inclusion of the weld residual stresses increased the conditional probability of cleavage fracture due to PTS loading by a factor ranging from 2 to 4.

Dickson, T.L.; Bass, B.R.; McAfee, W.J.

1998-01-01

10

Residual stress analysis of autofrettaged thick-walled spherical pressure vessel M. Maleki a,*, G.H. Farrahi a  

E-print Network

Residual stress analysis of autofrettaged thick-walled spherical pressure vessel M. Maleki a,*, G stress Extended variable material properties method Optimum autofrettage pressure a b s t r a c t In this study, residual stress distributions in autofrettaged homogenous spherical pressure vessels sub- jected

Vaziri, Ashkan

11

Stress condition of pressure welded high-pressure vessels with angularity in the longitudinal weld zone  

Microsoft Academic Search

after manufacture often deviates from the circular. The most characteristic deviations are ovality of the cross-section, angularity, and straightened sections in the longitudinal weld zone. These deviations cause changes in the stress condition of the vessels. The stress condition of the vessels with the above mentioned deviations was investigated by tensometric method at the Barnaul Boiler Plant. The results of

V. G. Tatarinov

1969-01-01

12

Elastic-plastic stress analysis and fatigue lifetime prediction of cross-bores in autofrettaged pressure vessels  

Microsoft Academic Search

Elastic-plastic stress analysis has been performed to evaluate the fatigue life of an autofrettaged pressure vessel containing\\u000a cross-bores subjected to pulsating internal pressure of 200 MPa. Finite element analyses were used to calculate the residual\\u000a and operating stress distributions of the pressure vessel due to the autofrettage process and pulsating internal pressure,\\u000a respectively. Theoretical stress concentration factors of 3.06, 2.58,

Seung-Kee Koh

2000-01-01

13

Composite Overwrapped Pressure Vessels (COPV) Stress Rupture Test: Part 2. Part 2  

NASA Technical Reports Server (NTRS)

One of the major concerns for the aging Space Shuttle fleet is the stress rupture life of composite overwrapped pressure vessels (COPVs). Stress rupture life of a COPY has been defined as the minimum time during which the composite maintains structural integrity considering the combined effects of stress levels and time. To assist in the evaluation of the aging COPVs in the Orbiter fleet an analytical reliability model was developed. The actual data used to construct this model was from testing of COPVs constructed of similar, but not exactly same materials and pressure cycles as used on Orbiter vessels. Since no actual Orbiter COPV stress rupture data exists the Space Shuttle Program decided to run a stress rupture test to compare to model predictions. Due to availability of spares, the testing was unfortunately limited to one 40" vessel. The stress rupture test was performed at maximum operating pressure at an elevated temperature to accelerate aging. The test was performed in two phases. The first phase, 130 F, a moderately accelerated test designed to achieve the midpoint of the model predicted point reliability. A more aggressive second phase, performed at 160 F, was designed to determine if the test article will exceed the 95% confidence interval ofthe model. In phase 3, the vessel pressure was increased to above maximum operating pressure while maintaining the phase 2 temperature. After reaching enough effectives hours to reach the 99.99% confidence level of the model phase 4 testing began when the temperature was increased to greater than 170 F. The vessel was maintained at phase 4 conditions until it failed after over 3 million effect hours. This paper will discuss the results of this test, it's implications and possible follow-on testing.

Russell, Richard; Flynn, Howard; Forth, Scott; Greene, Nathanael; Kezirian, Michael; Varanauski, Don; Leifeste, Mark; Yoder, Tommy; Woodworth, Warren

2010-01-01

14

Caustic stress corrosion cracking of pressure vessel steels in dilute alkaline-sulfide solutions  

Microsoft Academic Search

Conditions leading to stress corrosion cracking (SCC) of A516 Grade 70 and A285 Type C pressure vessel steels and E7018, E6010, and EM12K weld filler-metals in kraft continuous digesters were determined using electrochemical, slow-strain rate and fracture mechanics techniques. The influence on SCC of kraft pulping liquors containing organic constituents was also investigated. SCC was observed in solutions containing less

D. Singbeil; A. Garner

1985-01-01

15

Stress corrosion cracking and corrosion fatigue of nuclear reactor pressure vessel steels in hot water  

Microsoft Academic Search

Stress corrosion cracking of quenched and tempered steels in hot water is a phenomenon which has only recently been observed\\u000a in steels with yield strengths from 230 to 1000 MN\\/m2. In nuclear reactor pressure vessel (RPV) steels with about 430 MN\\/m2 yield strength, SCC is transgranular and has a thresholdK,\\u000a \\u000a Iscc\\u000a of about 20 Mn. m?3\\/2. The maximum crack growth

M. O. Speidel

1987-01-01

16

Caustic stress corrosion cracking of pressure vessel steels in dilute alkaline-sulfide solutions  

SciTech Connect

Conditions leading to stress corrosion cracking (SCC) of A516 Grade 70 and A285 Type C pressure vessel steels and E7018, E6010, and EM12K weld filler-metals in kraft continuous digesters were determined using electrochemical, slow-strain rate and fracture mechanics techniques. The influence on SCC of kraft pulping liquors containing organic constituents was also investigated. SCC was observed in solutions containing less than 30 g/L NaOH at 140 C. The potential range for cracking was determined in two typical digester environments. Crack propagation rates were strongly dependent on applied stress intensity, but relatively independent of metallurgy. Organic-containing liquors were more oxidizing than liquors containing only inorganic species, and in one case, organic components of kraft liquors acted as crack inhibitors. The mechanism of cracking in digestors was presumed to be caustic SCC.

Singbeil, D.; Garner, A.

1985-10-01

17

A Comparison of Various Stress Rupture Life Models for Orbiter Composite Pressure Vessels and Confidence Intervals  

NASA Technical Reports Server (NTRS)

In conjunction with a recent NASA Engineering and Safety Center (NESC) investigation of flight worthiness of Kevlar Ovenvrapped Composite Pressure Vessels (COPVs) on board the Orbiter, two stress rupture life prediction models were proposed independently by Phoenix and by Glaser. In this paper, the use of these models to determine the system reliability of 24 COPVs currently in service on board the Orbiter is discussed. The models are briefly described, compared to each other, and model parameters and parameter error are also reviewed to understand confidence in reliability estimation as well as the sensitivities of these parameters in influencing overall predicted reliability levels. Differences and similarities in the various models will be compared via stress rupture reliability curves (stress ratio vs. lifetime plots). Also outlined will be the differences in the underlying model premises, and predictive outcomes. Sources of error and sensitivities in the models will be examined and discussed based on sensitivity analysis and confidence interval determination. Confidence interval results and their implications will be discussed for the models by Phoenix and Glaser.

Grimes-Ledesma, Lorie; Murthy, Pappu, L. N.; Phoenix, S. Leigh; Glaser, Ronald

2006-01-01

18

Dual shell pressure balanced vessel  

DOEpatents

A dual-wall pressure balanced vessel for processing high viscosity slurries at high temperatures and pressures having an outer pressure vessel and an inner vessel with an annular space between the vessels pressurized at a pressure slightly less than or equivalent to the pressure within the inner vessel.

Fassbender, Alexander G. (West Richland, WA)

1992-01-01

19

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

Kahn, Jon B. (inventor)

1992-01-01

20

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2010 CFR

...5) When pressure tests are conducted on pressure vessels or pressure piping, the test pressure shall be maintained for a period of time...examination of all joints, connections and high stress areas. [CGD 95-028, 62 FR...

2010-10-01

21

Stress corrosion cracking of low-alloy reactor pressure vessel steels under boiling water reactor conditions  

NASA Astrophysics Data System (ADS)

The stress corrosion cracking (SCC) behaviour of different reactor pressure vessel (RPV) steels and weld filler/heat-affected zone materials was characterized under simulated boiling water reactor (BWR) normal water (NWC) and hydrogen water chemistry (HWC) conditions by periodical partial unloading, constant and ripple load tests with pre-cracked fracture mechanics specimens. The experiments were performed in oxygenated or hydrogenated high-purity or sulphate/chloride containing water at temperatures from 150 to 288 °C. In good agreement with field experience, these investigations revealed a very low susceptibility to SCC crack growth and small crack growth rates (<0.6 mm/year) under most BWR/NWC and material conditions. Critical water chemistry, loading and material conditions, which can result in sustained and fast SCC well above the 'BWRVIP-60 SCC disposition lines' were identified, but many of them generally appeared atypical for current optimized BWR power operation practice or modern RPVs. Application of HWC always resulted in a significant reduction of SCC crack growth rates by more than one order of magnitude under these critical system conditions and growth rates dropped well below the 'BWRVIP-60 SCC disposition lines'.

Seifert, H. P.; Ritter, S.

2008-01-01

22

Strain Measurement during Stress Rupture of Composite Over-Wrapped Pressure Vessel with Fiber Bragg Gratings Sensors  

NASA Technical Reports Server (NTRS)

Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPV). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPY liner.

Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

2008-01-01

23

Finite Element Analysis of Pressure Vessels  

Microsoft Academic Search

Pressure vessels are a commonly used device in marine engineering. Until recently the primary analysis method had been hand calculations and empirical curves. New computer advances have made finite element analysis (FEA) a practical tool in the study of pressure vessels, especially in determining stresses in local areas such as penetrations, O-ring grooves and other areas difficult to analyze by

David Heckman

1998-01-01

24

Reactor pressure vessel nozzle  

DOEpatents

A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough. 2 figs.

Challberg, R.C.; Upton, H.A.

1994-10-04

25

Reactor pressure vessel nozzle  

DOEpatents

A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough.

Challberg, Roy C. (Livermore, CA); Upton, Hubert A. (Morgan Hill, CA)

1994-01-01

26

High pressure storage vessel  

DOEpatents

Disclosed herein is a composite pressure vessel with a liner having a polar boss and a blind boss a shell is formed around the liner via one or more filament wrappings continuously disposed around at least a substantial portion of the liner assembly combined the liner and filament wrapping have a support profile. To reduce susceptible to rupture a locally disposed filament fiber is added.

Liu, Qiang

2013-08-27

27

Multilayer Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

A method has been devised to enable the fabrication of lightweight pressure vessels from multilayer composite materials. This method is related to, but not the same as, the method described in gMaking a Metal- Lined Composite-Overwrapped Pressure Vessel h (MFS-31814), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 59. The method is flexible in that it poses no major impediment to changes in tank design and is applicable to a wide range of tank sizes. The figure depicts a finished tank fabricated by this method, showing layers added at various stages of the fabrication process. In the first step of the process, a mandrel that defines the size and shape of the interior of the tank is machined from a polyurethane foam or other suitable lightweight tooling material. The mandrel is outfitted with metallic end fittings on a shaft. Each end fitting includes an outer flange that has a small step to accommodate a thin layer of graphite/epoxy or other suitable composite material. The outer surface of the mandrel (but not the fittings) is covered with a suitable release material. The composite material is filament- wound so as to cover the entire surface of the mandrel from the step on one end fitting to the step on the other end fitting. The composite material is then cured in place. The entire workpiece is cut in half in a plane perpendicular to the axis of symmetry at its mid-length point, yielding two composite-material half shells, each containing half of the foam mandrel. The halves of the mandrel are removed from within the composite shells, then the shells are reassembled and bonded together with a belly band of cured composite material. The resulting composite shell becomes a mandrel for the subsequent steps of the fabrication process and remains inside the final tank. The outer surface of the composite shell is covered with a layer of material designed to be impermeable by the pressurized fluid to be contained in the tank. A second step on the outer flange of each end fitting accommodates this layer. Depending on the application, this layer could be, for example, a layer of rubber, a polymer film, or an electrodeposited layer of metal. If the fluid to be contained in the tank is a gas, then the best permeation barrier is electrodeposited metal (typically copper or nickel), which can be effective at a thickness of as little as 0.005 in (.0.13 mm). The electrodeposited metal becomes molecularly bonded to the second step on each metallic end fitting. The permeation-barrier layer is covered with many layers of filament-wound composite material, which could be the same as, or different from, the composite material of the inner shell. Finally, the filament-wound composite material is cured in an ov

DeLay, Tom

2005-01-01

28

Testing of Carbon Fiber Composite Overwrapped Pressure Vessel Stress-Rupture Lifetime  

NASA Technical Reports Server (NTRS)

This paper contains summaries of testing procedures and analysis of stress rupture life testing for two stress rupture test programs, one for Kevlar COPVs performed at Lawrence Livermore National Laboratory, and the other a joint study between NASA JSC White Sands Test Facility and the Jet Propulsion Laboratory. These will be discussed in detail including test setup and issues encountered during testing. Lessons learned from testing in these two programs will be discussed.

Grimes-Ledesma, Lorie; Phoenix, S. Leigh; Beeson, Harold; Yoder, Tommy; Greene, Nathaniel

2006-01-01

29

A test method to evaluate stress corrosion cracking in pressure vessels  

Microsoft Academic Search

An accelerated laboratory test method was developed to evaluate the stress corrosion cracking (SCC) of kraft continuous digesters. The method uses circular patch test welds made from 38-mm-thick ASTM A516 Grade 70 steel plate. The specimens were exposed to a 110 C solution containing 40 gLNaOH and 20 gLNaâS at a controlled electrochemical potential. Several different welding procedures were evaluated

D. Singbeil; A. Garner

1988-01-01

30

Carbon fiber internal pressure vessels  

NASA Technical Reports Server (NTRS)

Internal pressure vessels were designed; the filament was wound of carbon fibers and epoxy resin and tested to burst. The fibers used were Thornel 400, Thornel 75, and Hercules HTS. Additional vessels with type A fiber were made. Polymeric linears were used, and all burst testing was done at room temperature. The objective was to produce vessels with the highest attainable PbV/W efficiencies. The type A vessels showed the highest average efficiency: 2.56 x 10 to the 6th power cm. Next highest efficiency was with Thornel 400 vessels: 2.21 x 10 to the 6th power cm. These values compare favorably with efficiency values from good quality S-glass vessels, but strains averaged 0.97% or less, which is less than 1/3 the strain of S-glass vessels.

Simon, R. A.

1973-01-01

31

Level indicator for pressure vessels  

DOEpatents

A liquid-level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic-field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal-processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

Not Available

1982-04-28

32

Cuff for Blood-Vessel Pressure Measurements  

NASA Technical Reports Server (NTRS)

Pressure within blood vessel is measured by new cufflike device without penetration of vessel. Device continuously monitors blood pressure for up to 6 months or longer without harming vessel. Is especially useful for vessels smaller than 4 or 5 millimeters in diameter. Invasive methods damage vessel wall, disturb blood flow, and cause clotting. They do not always give reliable pressure measurements over prolonged periods.

Shimizu, M.

1982-01-01

33

Static-stress analysis of dual-axis safety vessel  

NASA Astrophysics Data System (ADS)

An 8 ft diameter safety vessel, made of HSLA-100 steel, is evaluated to determine its ability to contain the quasi-static residual pressure from a high explosive (HE) blast. The safety vessel is designed for use with the Dual-Axis Radiographic Hydrotest (DARHT) facility being developed at Los Alamos National Laboratory. A smaller confinement vessel fits inside the safety vessel and contains the actual explosion, and the safety vessel functions as a second layer of containment in the unlikely case of a confinement vessel leak. The safety vessel is analyzed as a pressure vessel based on the ASME Boiler and Pressure Vessel Code, Section 8, Division 1, and the Welding Research Council Bulletin, WRC107. Combined stresses that result from internal pressure and external loads on nozzles are calculated and compared to the allowable stresses for HSLA-100 steel. Results confirm that the shell and nozzle components are adequately designed for a static pressure of 830 psi, plus the maximum expected external loads. Shell stresses at the 'shell to nozzle' interface, produced from external loads on the nozzles, were less than 700 psi. The maximum combined stress resulting from the internal pressure plus external loads was 17,384 psi, which is significantly less than the allowable stress of 42,375 psi for HSLA-100 steel.

Bultman, D. H.

1992-11-01

34

Development of Residual Stress Improvement for Nuclear Pressure Vessel Instrumentation Nozzle Weld Joint (P-43+P-8) by Means of Induction Heating  

SciTech Connect

As a counter measurement of intergranular stress corrosion cracking (IGSCC) in boiling water reactors, the induction heating stress improvement (IHSI) has been developed as a method to improve the stress factor, especially residual stresses in affected areas of pipe joint welds. In this method, a pipe is heated from the outside by an induction coil and cooled from the inside with water simultaneously. By thermal stresses to produce a temperature differential between the inner and outer pipe surfaces, the residual stress inside the pipe is improved compression. IHSI had been applied to weld joints of austenitic stainless steel pipes (P-8+P-8). However IHSI had not been applied to weld joints of nickel-chromium-iron alloy (P-43) and austenitic stainless steel (P-8). This weld joint (P-43+P-8) is used for instrumentation nozzles in nuclear power plants' reactor pressure vessels. Therefore for the purpose of applying IHSI to this one, we studied the following: Investigation of IHSI conditions (Essential Variables); Residual stresses after IHSI; Mechanical properties after IHSI. This paper explains that IHSI is sufficiently effective in improvement of the residual stresses for this weld joint (P-43+P-8), and that IHSI does not cause negative effects by results of mechanical properties, and IHSI is verified concerning applying it to this kind of weld joint. (authors)

Takuro Terajima; Takashi Hirano [Ishikawajima-Harima Heavy Industies Co., Ltd (Japan)

2006-07-01

35

Cryogenic Pressure Vessel workshop, LLNL, February 15, 2011, p. 1 Cryogenic Pressure Vessels  

E-print Network

Cryogenic Pressure Vessel workshop, LLNL, February 15, 2011, p. 1 Cryogenic Pressure Vessels This presentation does not contain any proprietary or confidential information #12;Cryogenic Pressure Vessel workshop, LLNL, February 15, 2011, p. 2 The cryogenic pressure vessel concept has evolved from

36

Static-stress analysis of dual-axis confinement vessel  

NASA Astrophysics Data System (ADS)

This study evaluates the static-pressure containment capability of a 6-ft-diameter, spherical vessel, made of HSLA-100 steel, to be used for high-explosive (HE) containment. The confinement vessel is designed for use with the Dual-Axis Radiographic Hydrotest Facility (DARHT) being developed at Los Alamos National Laboratory. Two sets of openings in the vessel are covered with x-ray transparent covers to allow radiographic imaging of an explosion as it occurs inside the vessel. The confinement vessel is analyzed as a pressure vessel based on the ASME Boiler and Pressure Vessel Code, Section 8, Division 1, and the Welding Research Council Bulletin, WRC-107. Combined stresses resulting from internal pressure and external loads on nozzles are calculated and compared with the allowable stresses for HSLA-100 steel. Results confirm that the shell and nozzles of the confinement vessel are adequately designed to safely contain the maximum residual pressure of 1675 psi that would result from an HE charge of 24.2 kg detonated in a vacuum. Shell stresses at the shell-to-nozzle interface, produced from external loads on the nozzles, were less than 400 psi. The maximum combined stress resulting from the internal pressure plus external loads was 16,070 psi, which is less than half the allowable stress of 42,375 psi for HSLA-100 steel.

Bultman, D. H.

1992-11-01

37

Fatigue life of organic fiber/epoxy pressure vessels  

NASA Technical Reports Server (NTRS)

The cyclic fatigue life of 10.2-cm-diam cylindrical pressure vessels has been studied. The vessels were made of an organic fiber/epoxy composite. To determine the typical strength distribution of the vessels, 25 of them were internally pressurized until they burst. Twenty-five vessels were then tested under sinusoidal cycling at 1 Hz between 4% and 91% of the mean burst strength. An additional twenty-five vessels were tested between 4% and 91% with a rectangular pressure pulse at 1/3 Hz. A limited number of vessels were tested for stress rupture at the 91% level. Cyclic life was found to depend on time at peak load as well as the number of stress cycles.

Hamstad, M. A.; Chiao, T. T.; Patterson, R. G.

1975-01-01

38

Quantification of Processing Effects on Filament Wound Pressure Vessels. Revision  

NASA Technical Reports Server (NTRS)

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be used to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament wound pressure vessels of all types of shells-of -revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

Aiello, Robert A.; Chamis, Christos C.

2002-01-01

39

Quantification of Processing Effects on Filament Wound Pressure Vessels  

NASA Technical Reports Server (NTRS)

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the C C! end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be sued to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament would pressure vessels of all types of shells-of-revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

Aiello, Robert A.; Chamis, Christos C.

1999-01-01

40

Material Selection for a Pressure Vessel  

NSDL National Science Digital Library

Pressure vessels are designed to contain pressure and withstand the operating mechanical and thermal transients for a specified design life. In addition they are designed to safety to leak before break (LBB). LBB describes the situation in which a leak occurs before a complete double-ended break of a component. Ductile and tough materials are widely used in nuclear pressure vessels, because of their high resistance to catastrophic rupture. The design process involves fatigue analysis to demonstrate that there is insignificant crack growth a postulated surface crack during the entire design life. However in terms of LBB the significant parameter is the elastic-plastic fracture toughness, and the material strength. However based on assessment based on linear elastic fracture mechanics, the candidate materials are carbon steels, low alloy steels and stainless steels, which interestingly are the materials that are used for pressure vessels. In terms of the fatigue crack initiation, the appropriate parameters are the threshold stress intensity factor range and the endurance limit and the material selection is based on these parameters.

Chattopadhyay, Sonnath

2009-09-24

41

Reactor pressure vessel vented head  

DOEpatents

A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

Sawabe, James K. (San Jose, CA)

1994-01-11

42

46 CFR 61.10-5 - Pressure vessels in service.  

Code of Federal Regulations, 2010 CFR

...and all pressure vessels used in refrigeration service. (2) If your vessel's...and all pressure vessels used in refrigeration service. (3) No more than 3 years... (2) Pressure vessels used in refrigeration service. (3) Hydraulic...

2010-10-01

43

Optimization of multilayered composite pressure vessels using exact elasticity solution  

SciTech Connect

An approach for the optimal design of thick laminated cylindrical pressure vessels is given. The maximum burst pressure is computed using an exact elasticity solution and subject to the Tsai-Wu failure criterion. The design method is based on an accurate 3-D stress analysis. Exact elasticity solutions are obtained using the stress function approach where the radial, circumferential and shear stresses are determined taking the closed ends of the cylindrical shell into account. Design optimization of multilayered composite pressure vessels are based on the use of robust multidimensional methods which give fast convergence. Two methods are used to determine the optimum ply angles, namely, iterative and gradient methods. Numerical results are given for optimum fiber orientation of each layer for thick and thin-walled multilayered pressure vessels.

Adali, S.; Verijenko, V.E.; Tabakov, P.Y. [Univ. of Natal, Durban (South Africa). Dept. of Mechanical Engineering; Walker, M. [Technicon Natal, Durban (South Africa)

1995-11-01

44

Lightweight bladder lined pressure vessels  

DOEpatents

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near torispherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film seamed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas mixtures, and oxygen used for vehicles, fuel cells or regenerative fuel cell applications, high altitude solar powered aircraft, hybrid energy storage/propulsion systems, and lunar/Mars space applications, and other applications requiring high cycle life.

Mitlitsky, Fred (1125 Canton Ave., Livermore, CA 94550); Myers, Blake (4650 Almond Cir., Livermore, CA 94550); Magnotta, Frank (1206 Bacon Way, Lafayette, CA 94549)

1998-01-01

45

Possibility of increasing the working pressure in cryogenic vessels  

SciTech Connect

Thermal cycling was carried out on unloaded specimens of austenitic stainless steels. Finds that thermal cycling of a metal leads to a change in the yield stress of the steels. Concludes that after bringing into operation a vessel which is used under pressure under conditions of lowtemperature thermal cycling, after a certain number of cycles in its operation (about 100), it is possible to carry out a recertification of the vessel and establish a higher working pressure, corresponding to the increased yield stress; and in designing vessels one can adopt in the calculations an increased allowable stress, allowing for the increase in yield stress during the operation process, thereupon, during the first 100 cycles the vessel should be operated at a pressure lower than the design pressure, after which recertification for design pressure can be carried out. Indicates that the results obtained make it possible to approach the design of vessels which operate under thermal cycling conditions at cryogenic temperatures in a new way. Notes that use of the results will make it possible to reduce considerably (10-30% for various steels) the metal volume of articles which are made from scarce austenitic stainless steels.

Stepanov, G.A.; Skol'tsov, V.I.

1982-09-01

46

46 CFR 50.30-20 - Class III pressure vessels.  

Code of Federal Regulations, 2010 CFR

...pressure vessels. (a) Class III pressure vessels shall be subject to shop inspection...subchapter. (b) For Class III welded pressure vessels, one inspection shall be made during the welding of the longitudinal joint. If...

2010-10-01

47

Feedthrough Seal For High-Pressure Vessel  

NASA Technical Reports Server (NTRS)

Combination of ceramic and plastic withstands many depressurizations. Stack of washers surrounds leadthrough electrode. Under pressure washers expand to fill leadthrough hole in high-pressure vessel. Seal thus formed withstands 20 or more pressurization/depressurization cycles. Seal composed of neoprene, polytetrafluoroethylene, nylon and high-purity, high-density commercial alumina ceramic.

Williams, R.; Mullins, O.; Smith, D.; Teasley, G.

1984-01-01

48

Composite overwrapped nickel-hydrogen pressure vessels  

NASA Technical Reports Server (NTRS)

The presentation is made in viewgraph format, the first of which states the purpose, which is to stimulate interest in composite overwrapped pressure vessel technology as applied to nickel hydrogen battery pressure vessels. The next viewgraph presents the history of nickel hydrogen pressure vessels over the last 15 years including materials, operating conditions, and market expansion to internationals. Basic materials properties are itemized such as thermal conductivity, corrosion resistance, and strength to weight ratio. The monolithic and composite overwrapped construction approaches are compared. A detailed description is presented of the advantages of composite overwrapped pressure vessels showing weight savings, manufacturing schedule reductions, and improved fatigue life. A discussion is also presented of B-1 application, the wide range of usable materials, and a sketch of a possible optimized design.

Reagan, John; Lewis, Joe

1992-01-01

49

PURE NIOBIUM AS A PRESSURE VESSEL MATERIAL  

SciTech Connect

Physics laboratories around the world are developing niobium superconducting radio frequency (SRF) cavities for use in particle accelerators. These SRF cavities are typically cooled to low temperatures by direct contact with a liquid helium bath, resulting in at least part of the helium container being made from pure niobium. In the U.S., the Code of Federal Regulations allows national laboratories to follow national consensus pressure vessel rules or use of alternative rules which provide a level of safety greater than or equal to that afforded by ASME Boiler and Pressure Vessel Code. Thus, while used for its superconducting properties, niobium ends up also being treated as a material for pressure vessels. This report summarizes what we have learned about the use of niobium as a pressure vessel material, with a focus on issues for compliance with pressure vessel codes. We present results of a literature search for mechanical properties and tests results, as well as a review of ASME pressure vessel code requirements and issues.

Peterson, T. J.; Carter, H. F.; Foley, M. H.; Klebaner, A. L.; Nicol, T. H.; Page, T. M.; Theilacker, J. C.; Wands, R. H.; Wong-Squires, M. L.; Wu, G. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

2010-04-09

50

Lightweight bladder lined pressure vessels  

Microsoft Academic Search

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near

Fred Mitlitsky; Blake Myers; Frank Magnotta

1998-01-01

51

Lightweight bladder lined pressure vessels  

Microsoft Academic Search

A lightweight, low permeability liner is described for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using tori

F. Mitlitsky; B. Myers; F. Magnotta

1998-01-01

52

Fatigue lifetime assessment procedures for welded pressure vessel components  

Microsoft Academic Search

Design against fatigue of welded pressure vessel components is usually based on structural or notch stress approaches. Post weld treatment methods such as grinding or TIG dressing provide significant improvements of the fatigue behaviour by blunting of the weld toe notches and by using materials of higher strength. Although well established on the level of welding technologies, fatigue design rules

Jürgen Rudolph; Carsten Schmitt; Eckart Weiß

2002-01-01

53

Flexible Composite-Material Pressure Vessel  

NASA Technical Reports Server (NTRS)

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

Brown, Glen; Haggard, Roy; Harris, Paul A.

2003-01-01

54

Fatigue life evaluation for reactor pressure vessels  

SciTech Connect

In terms of plant safety, the reactor pressure vessel is one of the most critical pressure boundary components in the nuclear power plant. The primary degradation mechanisms for reactor pressure vessels are irradiation embrittlement and thermal fatigue. The effects of irradiation and fatigue damage should then be considered in determining the overall lifetime of the reactor pressure vessel. For the radiation damage, related issues have been studied. For the case of fatigue resulting from the pressure and temperature changes, however, relatively less attention has been paid. The fatigue damage is generally regarded as one of the limiting factors for the safe operation life of the reactor pressure vessel. In this paper, the simplified fatigue damage evaluation procedures are applied to the commercially operating reactor vessel which is currently subjected to plant lifetime management study. Specifically, fatigue lifetime evaluation procedures for RPV inlet/outlet nozzles, shell and studs are therefore investigated based on the design basis approaches and the evaluation results are presented based on the assumed operating transient occurrences.

Roh, H.Y.; Jin, T.E. [Korea Power Engineering Co., Inc., Seoul (Korea, Republic of). Power Engineering Research Inst.; Jeong, I.S.; Hong, S.Y. [Korea Electric Power Research Inst., Daejon (Korea, Republic of). Nuclear Div.

1996-12-31

55

Nickel hydrogen common pressure vessel battery development  

NASA Technical Reports Server (NTRS)

Our present design for a common pressure vessel (CPV) battery, a nickel hydrogen battery system to combine all of the cells into a common pressure vessel, uses an open disk which allows the cell to be set into a shallow cavity; subsequent cells are stacked on each other with the total number based on the battery voltage required. This approach not only eliminates the assembly error threat, but also more readily assures equal contact pressure to the heat fin between each cell, which further assures balanced heat transfer. These heat fin dishes with their appropriate cell stacks are held together with tie bars which in turn are connected to the pressure vessel weld rings at each end of the tube.

Jones, Kenneth R.; Zagrodnik, Jeffrey P.

1992-01-01

56

Proactive life extension of pressure vessels  

NASA Astrophysics Data System (ADS)

For a company to maintain its competitive edge in today's global market every opportunity to gain an advantage must be exploited. Many companies are strategically focusing on improved utilization of existing equipment as well as regulatory compliance. Abbott Laboratories is no exception. Pharmaceutical companies such as Abbott Laboratories realize that reliability and availability of their production equipment is critical to be successful and competitive. Abbott Laboratories, like many of our competitors, is working to improve safety, minimize downtime and maximize the productivity and efficiency of key production equipment such as the pressure vessels utilized in our processes. The correct strategy in obtaining these objectives is to perform meaningful inspection with prioritization based on hazard analysis and risk. The inspection data gathered in Abbott Laboratories pressure vessel program allows informed decisions leading to improved process control. The results of the program are reduced risks to the corporation and employees when operating pressure retaining equipment. Accurate and meaningful inspection methods become the cornerstone of a program allowing proper preventative maintenance actions to occur. Successful preventative/predictive maintenance programs must utilize meaningful nondestructive evaluation techniques and inspection methods. Nondestructive examination methods require accurate useful tools that allow rapid inspection for the entire pressure vessel. Results from the examination must allow the owner to prove compliance of all applicable regulatory laws and codes. At Abbott Laboratories the use of advanced NDE techniques, primarily B-scan ultrasonics, has provided us with the proper tools allowing us to obtain our objectives. Abbott Laboratories uses B-scan ultrasonics utilizing a pulse echo pitch catch technique to provide essential data on our pressure vessels. Equipment downtime is reduced because the nondestructive examination usually takes place while our vessels are in service. As the inspection takes place we are able to view a real time image of detected discontinuities on a video monitor. The B-scan ultrasonic technique is allowing us to perform fast accurate examinations covering up to 95% of the surface area of each pressure vessel. Receiving data on 95% of a pressure vessel provides us with a lot of useful information. We use this data to determine the condition of each pressure vessel. Once the condition is known the vessels are classed by risk. The risk level is then managed by making decisions related to repair, operating parameters, accepting and monitoring or replacement of the equipment. Inspection schedules are set at maximum intervals and reinspection is minimized for the vessels that are not at risk. The remaining life of each pressure vessel is determined, mechanical integrity is proven and regulatory requirements are met. Abbott Laboratories is taking this proactive approach because we understand that our process equipment is a critical element for successful operation. A run to failure practice would never allow Abbott Laboratories to achieve the corporation's objective of being the world's leading health care company. Nondestructive state of the art technology and the understanding of its capabilities and limitations are key components of a proactive program for life extension of pressure vessels. 26

Mager, Lloyd

1998-03-01

57

A Survey of Pressure Vessel Code Compliance for Superconducting RF Cryomodules  

SciTech Connect

Superconducting radio frequency (SRF) cavities made from niobium and cooled with liquid helium are becoming key components of many particle accelerators. The helium vessels surrounding the RF cavities, portions of the niobium cavities themselves, and also possibly the vacuum vessels containing these assemblies, generally fall under the scope of local and national pressure vessel codes. In the U.S., Department of Energy rules require national laboratories to follow national consensus pressure vessel standards or to show ''a level of safety greater than or equal to'' that of the applicable standard. Thus, while used for its superconducting properties, niobium ends up being treated as a low-temperature pressure vessel material. Niobium material is not a code listed material and therefore requires the designer to understand the mechanical properties for material used in each pressure vessel fabrication; compliance with pressure vessel codes therefore becomes a problem. This report summarizes the approaches that various institutions have taken in order to bring superconducting RF cryomodules into compliance with pressure vessel codes. In Japan, Germany, and the U.S., institutions building superconducting RF cavities integrated in helium vessels or procuring them from vendors have had to deal with pressure vessel requirements being applied to SRF vessels, including the niobium and niobium-titanium components of the vessels. While niobium is not an approved pressure vessel material, data from tests of material samples provide information to set allowable stresses. By means of procedures which include adherence to code welding procedures, maintaining material and fabrication records, and detailed analyses of peak stresses in the vessels, or treatment of the vacuum vessel as the pressure boundary, research laboratories around the world have found methods to demonstrate and document a level of safety equivalent to the applicable pressure vessel codes.

Peterson, Thomas; Klebaner, Arkadiy; Nicol, Tom; Theilacker, Jay; /Fermilab; Hayano, Hitoshi; Kako, Eiji; Nakai, Hirotaka; Yamamoto, Akira; /KEK, Tsukuba; Jensch, Kay; Matheisen, Axel; /DESY; Mammosser, John; /Jefferson Lab

2011-06-07

58

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2013 CFR

...shall be either hydrostatic tests or pneumatic tests. (1) When a hydrostatic test...allowable working pressure. (2) When a pneumatic test is conducted on a pressure vessel...stamped on the nameplate. (3) When a pneumatic test is conducted on piping, the...

2013-10-01

59

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2011 CFR

...shall be either hydrostatic tests or pneumatic tests. (1) When a hydrostatic test...allowable working pressure. (2) When a pneumatic test is conducted on a pressure vessel...stamped on the nameplate. (3) When a pneumatic test is conducted on piping, the...

2011-10-01

60

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2012 CFR

...shall be either hydrostatic tests or pneumatic tests. (1) When a hydrostatic test...allowable working pressure. (2) When a pneumatic test is conducted on a pressure vessel...stamped on the nameplate. (3) When a pneumatic test is conducted on piping, the...

2012-10-01

61

Structural design, analysis, and code evaluation of an odd-shaped pressure vessel  

NASA Astrophysics Data System (ADS)

An effort to design, analyze, and evaluate a rectangular pressure vessel is described. Normally pressure vessels are designed in circular or spherical shapes to prevent stress concentrations. In this case, because of operational limitations, the choice of vessels was limited to a rectangular pressure box with a removable cover plate. The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code is used as a guideline for pressure containments whose width or depth exceeds 15.24 cm (6.0 in.) and where pressures will exceed 103.4 KPa (15.0 lbf/in(sup 2)). This evaluation used Section 8 of this Code, hereafter referred to as the Code. The dimensions and working pressure of the subject vessel fall within the pressure vessel category of the Code. The Code design guidelines and rules do not directly apply to this vessel. Therefore, finite-element methodology was used to analyze the pressure vessel, and the Code then was used in qualifying the vessel to be stamped to the Code. Section 8, Division 1 of the Code was used for evaluation. This action was justified by selecting a material for which fatigue damage would not be a concern. The stress analysis results were then checked against the Code, and the thicknesses adjusted to satisfy Code requirements. Although not directly applicable, the Code design formulas for rectangular vessels were also considered and presented.

Rezvani, M. A.; Ziada, H. H.

1992-12-01

62

High-pressure cryogenic seals for pressure vessels  

NASA Technical Reports Server (NTRS)

This investigation of the problems associated with reliably containing gaseous helium pressurized to 1530 bars (22 500 psi) between 4.2 K and 150 K led to the following conclusions: (1) common seal designs used in existing elevated-temperature pressure vessels are unsuitable for high-pressure cryogenic operation, (2) extrusion seal-ring materials such as Teflon, tin, and lead are not good seal materials for cryogenic high-pressure operation; and (3) several high-pressure cryogenic seal systems suitable for large-pressure vessel applications were developed; two seals required prepressurization, and one seal functioned repeatedly without any prepressurization. These designs used indium seal rings, brass or 304 stainless-steel anvil rings, and two O-rings of silicone rubber or Kel-F.

Buggele, A. E.

1977-01-01

63

(Irradiation embrittlement of reactor pressure vessels)  

SciTech Connect

The traveler served as a member of the two-man US Nuclear Regulatory Commission sponsored team who visited the Prometey Complex in Leningrad to assess the potential for expanded cooperative research concerning integrity of the primary pressure boundary in commercial light-water reactors. The emphasis was on irradiation embrittlement, structural analysis, and fracture mechanics research for reactor pressure vessels. At the irradiation seminar in Cologne, presentations were made by German, French, Finnish, Russian, and US delegations concerning many aspects of irradiation of pressure vessel steels. The traveler made presentations on mechanisms of irradiation embrittlement and on important aspects of the Heavy-Section Steel Irradiation Program results of irradiated fracture mechanics tests.

Corwin, W.R.

1990-09-24

64

Corrosion of steel tendons used in prestressed concrete pressure vessels  

Microsoft Academic Search

The corrosion behavior of a high-strength steel (Specifications for Uncoated Seven-Wire-Stress-Relieved Strand for Prestressed Concrete (ASTM A 416-74, Grade 270)), typical of those used as tensioning tendons in prestressed concrete pressure vessels was measured in several corrosive environments. The protection obtained by coating the steel with two commercial petroleum-base greases or with Portland cement grout was evaluated. The few reported

J. C. Griess; D. J. Naus

1980-01-01

65

Sealing behavior of the HTR-10 pressure vessel flanges  

Microsoft Academic Search

The flanges of 10 MW high temperature gas-cooled reactor (HTR-10) pressure vessel play an important role in sealing the primary coolant of Helium. They are bolt-connected with a metallic O-ring and a welded ?-ring. An elastic–plastic nonlinear analysis was performed to evaluate the stress and deformation of the contact flanges with the finite element software of MSC MARC 2000. The

Suyuan Yu; Junjie Liu; Weidong Zuo; Shuyan He

2002-01-01

66

46 CFR 50.30-15 - Class II pressure vessels.  

Code of Federal Regulations, 2010 CFR

...inspection of Class II welded pressure vessels shall be performed during the welding of the longitudinal joint...inspection of Class II welded pressure vessels shall be made during the welding of the...

2010-10-01

67

Modeling Scala Media as a Pressure Vessel  

NASA Astrophysics Data System (ADS)

The clinical condition known as endolymphatic hydrops is the swelling of scala media and may result in loss in hearing sensitivity consistent with other forms of low-frequency biasing. Because outer hair cells (OHCs) are displacement-sensitive and hearing levels tend to be preserved despite large changes in blood pressure and CSF pressure, it seems unlikely that the OHC respond passively to changes in static pressures in the chambers. This suggests the operation of a major feedback control loop which jointly regulates homeostasis and hearing sensitivity. Therefore the internal forces affecting the cochlear signal processing amplifier cannot be just motile responses. A complete account of the cochlear amplifier must include static pressures. To this end we have added a third, pressure vessel to our 1-D 140-segment, wave-digital filter active model of cochlear mechanics, incorporating the usual nonlinear forward transduction. In each segment the instantaneous pressure is the sum of acoustic pressure and global static pressure. The object of the model is to maintain stable OHC operating point despite any global rise in pressure in the third chamber. Such accumulated pressure is allowed to dissipate exponentially. In this first 3-chamber implementation we explore the possibility that acoustic pressures are rectified. The behavior of the model is critically dependent upon scaling factors and time-constants, yet by initial assumption, the pressure tends to accumulate in proportion to sound level. We further explore setting of the control parameters so that the accumulated pressure either stays within limits or may rise without bound.

Lepage, Eric; Olofsson, A.?Ke

2011-11-01

68

46 CFR 115.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Pressure vessels and boilers. 115.812 Section 115.812 Shipping...Inspections § 115.812 Pressure vessels and boilers. (a) Pressure vessels must be tested...inspection and testing requirements for boilers are contained in § 61.05 in...

2013-10-01

69

46 CFR 115.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Pressure vessels and boilers. 115.812 Section 115.812 Shipping...Inspections § 115.812 Pressure vessels and boilers. (a) Pressure vessels must be tested...inspection and testing requirements for boilers are contained in § 61.05 in...

2012-10-01

70

46 CFR 115.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Pressure vessels and boilers. 115.812 Section 115.812 Shipping...Inspections § 115.812 Pressure vessels and boilers. (a) Pressure vessels must be tested...inspection and testing requirements for boilers are contained in § 61.05 in...

2011-10-01

71

46 CFR 115.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Pressure vessels and boilers. 115.812 Section 115.812 Shipping...Inspections § 115.812 Pressure vessels and boilers. (a) Pressure vessels must be tested...inspection and testing requirements for boilers are contained in § 61.05 in...

2010-10-01

72

Application to Pressure Vessels for Underwater Vehicle of Magnesium Alloys  

Microsoft Academic Search

For studies and investigates about the ocean, various underwater vehicles are used. All these vehicles controlled by electronics. Electronic devices need solid pressure vessel to protect them from seawater and water pressure. For electronic devices using under water, defer from using in the air, they need solid pressure vessel. Particularly, water pressure is increasing according to depth, so the pressure

T. Hyakudome; S. Ishibashi; Y. Watanabe; H. Yoshida; S. Tsukioka; T. Aoki

2008-01-01

73

Glass Fiber Reinforced Metal Pressure Vessel Design Guide  

NASA Technical Reports Server (NTRS)

The Engineering Guide presents curves and general equations for safelife design of lightweight glass fiber reinforced (GFR) metal pressure vessels operating under anticipated Space Shuttle service conditions. The high composite vessel weight efficiency is shown to be relatively insensitive to shape, providing increased flexibility to designers establishing spacecraft configurations. Spheres, oblate speroids, and cylinders constructed of GFR Inconel X-750, 2219-T62 aluminum, and cryoformed 301 stainless steel are covered; design parameters and performance efficiencies for each configuration are compared at ambient and cryogenic temperature for an operating pressure range of 690 to 2760 N/sq cm (1000 to 4000 psi). Design variables are presented as a function of metal shell operating to sizing (proof) stress ratios for use with fracture mechanics data generated under a separate task of this program.

Landes, R. E.

1972-01-01

74

Welded repairs of punctured thin-walled aluminum pressure vessels  

NASA Technical Reports Server (NTRS)

Punctures in thin-walled aluminum pressure vessels are repaired by plugging the hole with an interference-fit disc and welding the unit. The repaired vessels withstood test pressures in excess of vessel ultimate design values for 2-, 4-, and 6-inch holes in 0.202-inch-thick aluminum alloy parent material.

Jones, D. J.

1969-01-01

75

Pool critical assembly pressure vessel facility benchmark  

SciTech Connect

This pool critical assembly (PCA) pressure vessel wall facility benchmark (PCA benchmark) is described and analyzed in this report. Analysis of the PCA benchmark can be used for partial fulfillment of the requirements for the qualification of the methodology for pressure vessel neutron fluence calculations, as required by the US Nuclear Regulatory Commission regulatory guide DG-1053. Section 1 of this report describes the PCA benchmark and provides all data necessary for the benchmark analysis. The measured quantities, to be compared with the calculated values, are the equivalent fission fluxes. In Section 2 the analysis of the PCA benchmark is described. Calculations with the computer code DORT, based on the discrete-ordinates method, were performed for three ENDF/B-VI-based multigroup libraries: BUGLE-93, SAILOR-95, and BUGLE-96. An excellent agreement of the calculated (C) and measures (M) equivalent fission fluxes was obtained. The arithmetic average C/M for all the dosimeters (total of 31) was 0.93 {+-} 0.03 and 0.92 {+-} 0.03 for the SAILOR-95 and BUGLE-96 libraries, respectively. The average C/M ratio, obtained with the BUGLE-93 library, for the 28 measurements was 0.93 {+-} 0.03 (the neptunium measurements in the water and air regions were overpredicted and excluded from the average). No systematic decrease in the C/M ratios with increasing distance from the core was observed for any of the libraries used.

Remec, I.; Kam, F.B.K. [Oak Ridge National Lab., TN (United States)

1997-07-01

76

RIS-M-2186 INTERPRETATIOM OF STRAIN HBASUREMEMTS ON NUCLEAR PRESSURE VESSELS  

E-print Network

, EXPERIMENTAL DATA, GRAPHS, MECHANICAL TESTS, PERFORMANCE TESTING, PRESSURE VESSELS, tMR TYPE REACTORS, STEELS design rules are un- available' [1]. For the designer or the stress analyst, a further advantage turns up et al [2] published the results from measurements on a nozzle in a 1:4 model vessel and compared them

77

Acoustic emission testing of 12-nickel maraging steel pressure vessels  

NASA Technical Reports Server (NTRS)

Acoustic emission data were obtained from three point bend fracture toughness specimens of 12-nickel maraging steel, and two pressure vessels of the same material. One of the pressure vessels contained a prefabricated flaw which was extended and sharpened by fatigue cycling. It is shown that the flawed vessel had similar characteristics to the fracture specimens, thereby allowing estimates to be made of its nearness to failure during a proof test. Both the flawed and unflawed pressure vessel survived the proof pressure and 5 cycles to the working pressure, but it was apparent from the acoustic emission response during the proof cycle and the 5 cycles to the working pressure that the flawed vessel was very near failure. The flawed vessel did not survive a second cycle to the proof pressure before failure due to flaw extension through the wall (causing a leak).

Dunegan, H. L.

1973-01-01

78

Finite element analysis of filament-wound composite pressure vessel under internal pressure  

NASA Astrophysics Data System (ADS)

In this study, finite element analysis (FEA) of composite overwrapped pressure vessel (COPV), using commercial software ABAQUS 6.12 was performed. The study deals with the simulation of aluminum pressure vessel overwrapping by Carbon/Epoxy fiber reinforced polymer (CFRP). Finite element method (FEM) was utilized to investigate the effects of winding angle on filament-wound pressure vessel. Burst pressure, maximum shell displacement and the optimum winding angle of the composite vessel under pure internal pressure were determined. The Laminae were oriented asymmetrically for [00,00]s, [150,-150]s, [300,-300]s, [450,-450]s, [550,-550]s, [600,-600]s, [750,-750]s, [900,-900]s orientations. An exact elastic solution along with the Tsai-Wu, Tsai-Hill and maximum stress failure criteria were employed for analyzing data. Investigations exposed that the optimum winding angle happens at 550 winding angle. Results were compared with the experimental ones and there was a good agreement between them.

Sulaiman, S.; Borazjani, S.; Tang, S. H.

2013-12-01

79

Hydroide Storage Vessel wall stress measurements  

SciTech Connect

Holographic Interferometry and strain gauge measurements were used to determine whether a prototype Hydride Storage Vessel (HSV) swelled while it was loaded in eleven stages with hydrogen. Bed swelling is inferred from deformation of the surface of the HSV. No swelling was detected, even after saturating the hydride material inside the HSV. The large chunky morphology of the titanium is likely responsible for the lack of wall stress. This morphology also implies that decay helium that remains in the titanium hydride (that is, helium that is not released as gas to the free volume) should not cause significant wall stresses when the HSV is used for long-term tritium storage. Holographic interferometry proved to be an extremely sensitive technique to measure swelling, having a detection limit of about 3 microns surface displacement.

Clark, E.A. [Westinghouse Savannah River Company, AIKEN, SC (United States); Pechersky, M.J.

1997-07-31

80

Holographic and acoustic emission evaluation of pressure vessels  

SciTech Connect

Optical holographic interfereometry and acoustic emission monitoring were simultaneously used to evaluate two small, high pressure vessels during pressurization. The techniques provide pressure vessel designers with both quantitative information such as displacement/strain measurements and qualitative information such as flaw detection. The data from the holographic interferograms were analyzed for strain profiles. The acoustic emission signals were monitored for crack growth and vessel quality.

Boyd, D.M.

1980-03-05

81

Use of SMA cladding in pressure vessel repair  

SciTech Connect

Cladding is an important process in repair of pressure vessels. Shielded metal arc (SMA) cladding, though a old technique, still plays important role in repair works due to its great flexibility. The advantages of using this technique include, e.g., (1) the possibility of selecting various electrodes according to the requirement (this applies even for self made electrodes if necessary), (2) cladding components with various sizes and geometries, (3) easy operation, (4) good equipment mobility, and (5) low equipment cost. In this paper, an example is presented to repair stress corrosion cracking failure of a pressure vessel by the SMA cladding process. Serious stress corrosion cracking was developed in the inner wall of a CO heat exchanger head. According to the failure, a duplex stainless steel electrode was designed and produced, which was used as the cladding material for the inner layer surface. The major repair procedures include machining of the failure areas, transition layer and surface layer cladding by the SMA process, and post-weld heat treatment. The repair was proved to be practical. Several years operation after the repair verified that the repair was successful.

Sun, Z. [Metalock Singapore Ltd., Singapore (Singapore); Han, H.Y. [Central Iron and Steel Research Inst., Beijing (China)

1996-12-31

82

Holographic nondestructive evaluation of spherical kevlar\\/epoxy pressure vessels  

Microsoft Academic Search

Three spherical kevlar\\/epoxy pressure vessels were evaluated using holographic interferograms provide information on the failure modes, displacement profile, and possible fiber damage. The holograms show a symmetric anisotropic displacement pattern even though the vessels failed due to a leak in the aluminum mandrels. The presence of a biconvex fringe pattern found during the testing of vessel three is believed to

D. M. Boyd; B. W. Maxfield

1979-01-01

83

Tailoring Topology Optimization to Composite Pressure Vessel Design with Simultaneous  

E-print Network

Mechanics 2011 #12;Introduction � CNG Pressure Vessels Compressed Natural Gas (CNG) Pressure Vessels CNG-2000* Transportation costs: MM$230/ship MM$160/ship Comparison of CNG and LNG (Liquefied Natural Gas) Introduction � More attractive costs for compression, loading and unloading CNG inside cars and buses #12;Size

Paulino, Glaucio H.

84

Thermodynamics of insulated pressure vessels for vehicular hydrogen storage  

SciTech Connect

This paper studies the application of insulated pressure vessels for hydrogen-fueled light-duty vehicles. Insulated pressure vessels can store liquid hydrogen (LH2); low-temperature (90 K) compressed hydrogen (CH2); or ambient temperature CH2. In this analysis, hydrogen temperatures, pressures and venting losses am calculated for insulated pressure vessels fueled with LH2 or with low-temperature CH2, and the results are compared to those obtained in low-pressure LH2 tanks. Hydrogen losses are calculated as a function of daily driving distance during normal operation; as a function of time during long periods of vehicle inactivity; and as a function of initial vessel temperature during fueling. The number of days before any venting losses occur is also calculated as a function of the daily driving distance. The results show that insulated pressure vessels have packaging characteristics comparable to those of conventional, low-pressure LH2 tanks (low weight and volume), with greatly improved dormancy and much lower boil-off. Insulated pressure vessels used in a 17 km/l (40 mpg) car do not lose any hydrogen when the car is driven at least 15 km/day in average. Since almost all cars are driven for longer distances, most cars would never lose any hydrogen. Losses during long periods of parking are also relatively small. Due to their high-pressure capacity, these vessels would retain about a third of their full charge even after a very long dormancy, so that the owner would not risk running out of fuel. If an insulated pressure vessel reaches ambient temperature, it can be cooled down very effectively by fueling it with LH2 with no losses during fueling. The vessel has good thermal performance even when thermally insulated with inexpensive microsphere insulation. In addition, the insulated pressure vessels greatly ease fuel availability and infrastructure requirements, since it would be compatible with both compressed and cryogenic hydrogen reveling.

Aceves, S.M.; Berry, G.D.

1997-06-01

85

Reactor Pressure Vessel Head Packaging & Disposal  

SciTech Connect

Reactor Pressure Vessel (RPV) Head replacements have come to the forefront due to erosion/corrosion and wastage problems resulting from the susceptibility of the RPV Head alloy steel material to water/boric acid corrosion from reactor coolant leakage through the various RPV Head penetrations. A case in point is the recent Davis-Besse RPV Head project, where detailed inspections in early 2002 revealed significant wastage of head material adjacent to one of the Control Rod Drive Mechanism (CRDM) nozzles. In lieu of making ASME weld repairs to the damaged head, Davis-Besse made the decision to replace the RPV Head. The decision was made on the basis that the required weld repair would be too extensive and almost impractical. This paper presents the packaging, transport, and disposal considerations for the damaged Davis-Besse RPV Head. It addresses the requirements necessary to meet Davis Besse needs, as well as the regulatory criteria, for shipping and burial of the head. It focuses on the radiological characterization, shipping/disposal package design, site preparation and packaging, and the transportation and emergency response plans that were developed for the Davis-Besse RPV Head project.

Wheeler, D. M.; Posivak, E.; Freitag, A.; Geddes, B.

2003-02-26

86

LOFT Pressurizer Pressure Relief Piping System Stress Analysis and Fatigue Life Report.  

National Technical Information Service (NTIS)

A stress analysis was performed on the LOFT Pressurizer Pressure Relief System to determine if it met the requirements of the ASME Boiler and Pressure Vessel Code, Section III, 1974 Edition, for Class 1 and Class 2 components. Deadweight, thermal expansio...

J. W. Muffett

1978-01-01

87

Crashworthy Sealed Pressure Vessel for Plutonium Transport.  

National Technical Information Service (NTIS)

A rugged transportation package for the air shipment of radioisotopic materials was recently developed. This package includes a tough, sealed, stainless steel inner containment vessel of 1460 cc capacity. This vessel, intended for a mass load of up to 2 K...

J. A. Andersen

1980-01-01

88

A comparative study on failure pressure estimations of GFRP pressure vessels using Acoustic Emission technique  

Microsoft Academic Search

There is a need of design a reliable light weight composite pressure vessel for a launch vehicle or missile system. The composite pressure vessel acted upon by static internal pressure and dynamic during flight, but for practical structural integrity purposes, consideration of internal pressure is all that is necessary. This paper examines the performance of 6-litre capacity cylindrical Glass fiber

R. Joselin; M. Enamuthu; K. M. Usha; E. S. Vasudev; T. Chelladurai

2010-01-01

89

Subsize specimen testing of nuclear reactor pressure vessel material  

SciTech Connect

A new methodology is proposed to correlate the upper shelf energy (USE) of full size and subsize Charpy specimens of a nuclear reactor pressure vessel plate material, A533B. The methodology appears to be more satisfactory than the methodologies proposed earlier. USE of a notched-only specimen is partitioned into macro-crack initiation and crack propagation energies. USE of a notched and precracked specimen provides the crack propagation energy. {Delta}USE, the difference between the USE`s of notched-only and precracked specimens, is an estimate of the crack initiation energy. {Delta}USE was normalized by a factor involving the dimensions of the Charpy specimen and the stress concentration factor at the notch root. The normalized values of the {Delta}USE were found to be invariant with specimen size.

Kumar, A.S. [Missouri Univ., Rolla, MO (United States). Materials Research Center; Rosinski, S.T. [Sandia National Labs., Albuquerque, NM (United States); Cannon, N.S. [Westinghouse Hanford Co., Richland, WA (United States); Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States)

1991-12-31

90

Firefighter's compressed air breathing system pressure vessel development program  

NASA Technical Reports Server (NTRS)

The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.

Beck, E. J.

1974-01-01

91

Neutron shielding panels for reactor pressure vessels  

DOEpatents

In a nuclear reactor neutron panels varying in thickness in the circumferential direction are disposed at spaced circumferential locations around the reactor core so that the greatest radial thickness is at the point of highest fluence with lesser thicknesses at adjacent locations where the fluence level is lower. The neutron panels are disposed between the core barrel and the interior of the reactor vessel to maintain radiation exposure to the vessel within acceptable limits.

Singleton, Norman R. (Murrysville, PA)

2011-11-22

92

On the optimal pretensioning of cylindrical and spherical pressure vessels  

SciTech Connect

Filament winding of pressure vessels and pipes is always realized with some pretensioning, and some external loads may be applied. It is important to determine such an optimal preload regime that ensures the maximum load-carrying capacity of the vessel subject to internal pressure. In the present study, the optimal preload distribution is analyzed in the filament winding fabrication of the cylindrical or spherical pressure vessels that are treated as growing elastic solids subjected to aging. In the case of cylindrical vessels, the dependence of the optimal preload intensity versus the polar radius is obtained for both nonaging and aging material of the fibers. In the case of spherical pressure vessels, the optimal regime of internal pressure applied during the winding process is obtained. The optimal loading of a spherical vessel at both infinitesimal and finite strains is analyzed. The new solutions obtained and the recommendations formulated are of a special practical importance for the optimal design and fabrication of the composite pressure vessels and pipes.

Kalamkarov, A.L.; Drozdov, A.D. [Technical Univ. of Nova Scotia, Halifax, Nova Scotia (Canada). Dept. of Mechanical Engineering

1995-11-01

93

46 CFR 78.33-1 - Repairs of boiler and pressure vessels.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Repairs of boiler and pressure vessels. 78.33-1...Equipment § 78.33-1 Repairs of boiler and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels,...

2012-10-01

94

46 CFR 97.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Repairs to boilers and pressure vessels. 97.30-1...Equipment § 97.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2013-10-01

95

46 CFR 97.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 false Repairs to boilers and pressure vessels. 97.30-1...Equipment § 97.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2011-10-01

96

46 CFR 167.25-5 - Inspection of boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Inspection of boilers, pressure vessels, piping and appurtenances...Engineering § 167.25-5 Inspection of boilers, pressure vessels, piping and appurtenances. The inspection of boilers, pressure vessels, piping...

2013-10-01

97

46 CFR 97.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Repairs to boilers and pressure vessels. 97.30-1...Equipment § 97.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2010-10-01

98

46 CFR 78.33-1 - Repairs of boiler and pressure vessels.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Repairs of boiler and pressure vessels. 78.33-1...Equipment § 78.33-1 Repairs of boiler and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels,...

2013-10-01

99

46 CFR 196.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Repairs to boilers and pressure vessels. 196.30-1...Equipment § 196.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2012-10-01

100

46 CFR 196.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Repairs to boilers and pressure vessels. 196.30-1...Equipment § 196.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2013-10-01

101

46 CFR 97.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Repairs to boilers and pressure vessels. 97.30-1...Equipment § 97.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2012-10-01

102

46 CFR 196.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 false Repairs to boilers and pressure vessels. 196.30-1...Equipment § 196.30-1 Repairs to boilers and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the...

2011-10-01

103

46 CFR 78.33-1 - Repairs of boiler and pressure vessels.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Repairs of boiler and pressure vessels. 78.33-1...Equipment § 78.33-1 Repairs of boiler and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels,...

2010-10-01

104

46 CFR 78.33-1 - Repairs of boiler and pressure vessels.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 false Repairs of boiler and pressure vessels. 78.33-1...Equipment § 78.33-1 Repairs of boiler and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels,...

2011-10-01

105

30 CFR 57.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2010 CFR

...requirements for boilers and pressure vessels. 57.13001 Section...NONMETAL MINES Compressed Air and Boilers § 57.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2010-07-01

106

30 CFR 57.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2012 CFR

...requirements for boilers and pressure vessels. 57.13001 Section...NONMETAL MINES Compressed Air and Boilers § 57.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2012-07-01

107

30 CFR 57.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2011 CFR

...requirements for boilers and pressure vessels. 57.13001 Section...NONMETAL MINES Compressed Air and Boilers § 57.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2011-07-01

108

30 CFR 56.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2012 CFR

...requirements for boilers and pressure vessels. 56.13001 Section...NONMETAL MINES Compressed Air and Boilers § 56.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2012-07-01

109

30 CFR 56.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

...requirements for boilers and pressure vessels. 56.13001 Section...NONMETAL MINES Compressed Air and Boilers § 56.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2013-07-01

110

29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Portable air receivers and other unfired pressure vessels. 1915.172... Portable, Unfired Pressure Vessels, Drums and...1915.172 Portable air receivers and other unfired pressure vessels. (a)...

2013-07-01

111

29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Portable air receivers and other unfired pressure vessels. 1915.172... Portable, Unfired Pressure Vessels, Drums and...1915.172 Portable air receivers and other unfired pressure vessels. (a)...

2012-07-01

112

30 CFR 57.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

...requirements for boilers and pressure vessels. 57.13001 Section...NONMETAL MINES Compressed Air and Boilers § 57.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2013-07-01

113

29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.  

...2014-07-01 false Portable air receivers and other unfired pressure vessels. 1915.172... Portable, Unfired Pressure Vessels, Drums and...1915.172 Portable air receivers and other unfired pressure vessels. (a)...

2014-07-01

114

30 CFR 56.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2011 CFR

...requirements for boilers and pressure vessels. 56.13001 Section...NONMETAL MINES Compressed Air and Boilers § 56.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2011-07-01

115

30 CFR 56.13001 - General requirements for boilers and pressure vessels.  

Code of Federal Regulations, 2010 CFR

...requirements for boilers and pressure vessels. 56.13001 Section...NONMETAL MINES Compressed Air and Boilers § 56.13001...requirements for boilers and pressure vessels. All boilers and pressure vessels shall be...

2010-07-01

116

46 CFR 54.01-17 - Pressure vessel for human occupancy (PVHO).  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Pressure vessel for human occupancy (PVHO...SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-17 Pressure vessel for human occupancy...

2011-10-01

117

29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2011 CFR

...Portable air receivers and other unfired pressure vessels. 1915.172 Section 1915...SHIPYARD EMPLOYMENT Portable, Unfired Pressure Vessels, Drums and Containers, Other...Portable air receivers and other unfired pressure vessels. (a) Portable,...

2011-07-01

118

Journal of Pressure Vessel Technology, Vol. 131, 2009, 041401 The Effects of Filler Metal Transformation Temperature on Residual Stresses in a  

E-print Network

with these phase changes can have dramatically different consequences for the development of residual stress of bainite or martensite, the phase change causes a deformation which is an invariant-plane strain consisting of a large shear on the habit plane and a dilatational strain normal to the plane. Each austenite grain can

Cambridge, University of

119

Design of Semi-composite Pressure Vessel using Fuzzy and FEM  

NASA Astrophysics Data System (ADS)

The present study attempts to present a new method to design a semi-composite pressure vessel (known as hoop-wrapped composite cylinder) using fuzzy decision making and finite element method. A metal-composite vessel was designed based on ISO criteria and then the weight of the vessel was optimized for various fibers of carbon, glass and Kevlar in the cylindrical vessel. Failure criteria of von-Mises and Hoffman were respectively employed for the steel liner and the composite reinforcement to characterize the yielding/ buckling of the cylindrical pressure vessel. The fuzzy decision maker was used to estimate the thickness of the steel liner and the number of composite layers. The ratio of stresses on the composite fibers and the working pressure as well as the ratio of stresses on the composite fibers and the burst (failure) pressure were assessed. ANSYS nonlinear finite element solver was used to analyze the residual stress in the steel liner induced due to an auto-frettage process. Result of analysis verified that carbon fibers are the most suitable reinforcement to increase strength of cylinder while the weight stayed appreciably low.

Sabour, Mohammad H.; Foghani, Mohammad F.

2010-04-01

120

Heavy wall pressure vessels for energy systems  

SciTech Connect

Modifications of steels currently accepted in the Code appear to provide improved mechanical properties. These steels may permit the fabrication of larger diameter vessels with thinner section sizes and improved reliability and integrity. Adapting current specifications should expedite Code approval. Finally the challenge of improving welding procedures and adapting processes for field applications will result in higher quality weldments.

Canonico, D.A.

1980-06-17

121

Jam proof closure assembly for lidded pressure vessels  

SciTech Connect

This patent describes a pressure vessel cover adapted for sealing engagement with an outer peripheral lip of an underlying pressure vessel and having a compressible annular gasket overlying the lip, the cover further comprising: a spaced peripheral array of cylindrical bored passageways communicating between outer and inner planar surfaces of the vessel cover; a rigid, comparatively thick-walled, annular sleeve insert; a substantially rigid retainer element configured to seat tightly against the inserted sleeve; bolt threaded to engage an inner surface of the positioned sleeve insert.

Ciolett, O.C.

1992-06-09

122

Low-Cost, Lightweight Pressure Vessel Proof Test  

NASA Astrophysics Data System (ADS)

This experiment seeks to determine the burst strength of the low-cost, lightweight pressure vessel fabricated by the Suborbital Center of Excellence (SCE). Moreover, the test explores the effects of relatively large gage pressures on material strain for ‘pumpkin-shaped' pressure vessels. The SCE team used pressure transducers and analog gauges to measure the gage pressure while a video camera assembly recorded several gores in the shell for strain analysis. The team loaded the vessel in small intervals of pressure until the structure failed. Upon test completion, the pressure readings and video recordings were analyzed to determine the burst strength and material strain in the shell. The analysis yielded a burst pressure of 13.5 psi while the strain analysis reported in the shell. While the results of this proof test are encouraging, the structure's factor of safety must be increased for actual balloon flights. Furthermore, the pressure vessel prototype must be subjected to reliability tests to show the design can sustain gage pressures for the length of a balloon flight.

Chanez, Eric

123

Time-dependent response of filamentary composite spherical pressure vessels  

NASA Technical Reports Server (NTRS)

A filamentary composite spherical pressure vessel is modeled as a pseudoisotropic (or transversely isotropic) composite shell, with the effects of the liner and fill tubes omitted. Equations of elasticity, macromechanical and micromechanical formulations, and laminate properties are derived for the application of an internally pressured spherical composite vessel. Viscoelastic properties for the composite matrix are used to characterize time-dependent behavior. Using the maximum strain theory of failure, burst pressure and critical strain equations are formulated, solved in the Laplace domain with an associated elastic solution, and inverted back into the time domain using the method of collocation. Viscoelastic properties of HBFR-55 resin are experimentally determined and a Kevlar/HBFR-55 system is evaluated with a FORTRAN program. The computed reduction in burst pressure with respect to time indicates that the analysis employed may be used to predict the time-dependent response of a filamentary composite spherical pressure vessel.

Dozier, J. D.

1983-01-01

124

Integrity of PWR pressure vessels during overcooling accidents  

SciTech Connect

The reactor pressure vessel in a pressurized water reactor is normally subjected to temperatures and pressures that preclude propagation of sharp, crack-like defects that might exist in the wall of the vessel. However, there is a class of postulated accidents, referred to as overcooling accidents, that can subject the pressure vessel to severe thermal shock while the pressure is substantial. As a result of such accidents, vessels containing high concentrations of copper and nickel, which enhance radiation embrittlement, may possess a potential for extensive propagation of preexistent inner surface flaws prior to the vessel's normal end of life. A state-of-the-art fracture-mechanics model was developed and has been used for conducting parametric analyses and for calculating several recorded PWR transients. Results of the latter analysis indicate that there may be some vessels that have a potential for failure in a few years if subjected to a Rancho Seco-type transient. However, the calculational model may be excessively conservative, and this possibility is under investigation.

Cheverton, R.D.; Iskander, S.K.; Whitman, G.D.

1982-01-01

125

Transportable, small high-pressure preservation vessel for cells  

NASA Astrophysics Data System (ADS)

We have previously reported that the survival rate of astrocytes increases under high-pressure conditions at 4°C. However, pressure vessels generally have numerous problems for use in cell preservation and transportation: (1) they cannot be readily separated from the pressurizing pump in the pressurized state; (2) they are typically heavy and expensive due the use of materials such as stainless steel; and (3) it is difficult to regulate pressurization rate with hand pumps. Therefore, we developed a transportable high-pressure system suitable for cell preservation under high-pressure conditions. This high-pressure vessel has the following characteristics: (1) it can be easily separated from the pressurizing pump due to the use of a cock-type stop valve; (2) it is small and compact, is made of PEEK and weighs less than 200 g; and (3) pressurization rate is regulated by an electric pump instead of a hand pump. Using this transportable high-pressure vessel for cell preservation, we found that astrocytes can survive for 4 days at 1.6 MPa and 4°C.

Kamimura, N.; Sotome, S.; Nakajima, K.; Yoshimura, Y.; Shimizu, A.

2010-03-01

126

Advanced technology for minimum weight pressure vessel system  

NASA Technical Reports Server (NTRS)

Bosses were made of fiber/resin composite materials to evaluate their potential in lightweight pressure vessels. An approximate 25% weight savings over the standard aluminum boss was achieved without boss failures during burst tests. Polymer liners and metal liners are used in fiber composite pressure vessels for containment of gases. The internal support of these liners required during the filament winding process has previously been provided by dissolvable salt mandrels. An internal pressurization technique has been developed which allows overwinding the liner without other means of support and without collapse. Study was made of several additional concepts including styrene/Saran, styrene/flexible epoxy.

Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

1977-01-01

127

Weld evaluation on spherical pressure vessels using holographic interferometry  

SciTech Connect

Waist welds on spherical experimental pressure vessels have been evaluated under pressure using holographic interferometry. A coincident viewing and illumination optical configuration coupled with a parabolic mirror was used so that the entire weld region could be examined with a single hologram. Positioning the pressure vessel at the focal point of the parabolic mirror provides a relatively undistorted 360 degree view of the waist weld. Double exposure and real time holography were used to obtain displacement information on the weld region. Results are compared with radiographic and ultrasonic inspections.

Boyd, D.M.; Wilcox, W.W.

1980-05-14

128

Nickel hydrogen multicell common pressure vessel battery development update  

NASA Technical Reports Server (NTRS)

The technology background and design qualification of the multicell common pressure vessel nickel hydrogen battery are described. The results of full flight qualification, including random vibration at 19.5 g for two minutes in each axis, electrical characterization in a thermal vacuum chamber, and mass spectroscopy vessel leak detection are reviewed and 12.7 cm qualification and 25.4 cm design adaptation are discussed.

Zagrodnik, Jeffrey P.; Jones, Kenneth R.

1992-01-01

129

Report of the terawatt laser pressure vessel committee  

SciTech Connect

In 1995 the ATF project sent out an RFP for a CO2 Laser System having a TeraWatt output. Eight foreign and US firms responded. The Proposal Evaluation Panel on the second round selected Optoel, a Russian firm based in St. Petersburg, on the basis of the technical criteria and cost. Prior to the award, BNL representatives including the principal scientist, cognizant engineer and a QA representative visited the Optoel facilities to assess the company's capability to do the job. The contract required Optoel to provide a x-ray preionized high pressure amplifier that included: a high pressure cell, x-ray tube, internal optics and a HV pulse forming network for the main discharge and preionizer. The high-pressure cell consists of a stainless steel pressure vessel with various ports and windows that is filled with a gas mixture operating at 10 atmospheres. In accordance with BNL Standard ESH 1.4.1 ''Pressurized Systems For Experimental Use'', the pressure vessel design criteria is required to comply with the ASME Boiler and Pressure Vessel Code In 1996 a Preliminary Design Review was held at BNL. The vendor was requested to furnish drawings so that we could confirm that the design met the above criteria. The vendor furnished drawings did not have all dimensions necessary to completely analyze the cell. Never the less, we performed an analysis on as much of the vessel as we could with the available information. The calculations concluded that there were twelve areas of concern that had to be addressed to assure that the pressure vessel complied with the requirements of the ASME code. This information was forwarded to the vendor with the understanding that they would resolve these concerns as they continued with the vessel design and fabrication. The assembled amplifier pressure vessel was later hydro tested to 220 psi (15 Atm) as well as pneumatically to 181 psi (12.5 Atm) at the fabricator's Russian facility and was witnessed by a BNL engineer. The unit was shipped to the US and installed at the ATF. As part of the commissioning of the device the amplifier pressure vessel was disassembled several times at which time it became apparent that the vendor had not addressed 7 of the 12 issues previously identified. Closer examination of the vessel revealed some additional concerns including quality of workmanship. Although not required by the contract, the vendor furnished radiographs of a number of pressure vessel welds. A review of the Russian X-rays revealed radiographs of both poor and unreadable quality. However, a number of internal weld imperfections could be observed. All welds in question were excavated and then visually and dye penetrant inspected. These additional inspections confirmed that the weld techniques used to make some of these original welds were substandard. The applicable BNL standard, ESH 1.4.1, addresses the problem of pressure vessel non-compliance by having a committee appointed by the Department Chairman review the design and provide engineering solutions to assure equivalent safety. On January 24, 2000 Dr. M. Hart, the NSLS Chairman, appointed this committee with this charge. This report details the engineering investigations, deliberations, solutions and calculations which were developed by members of this committee to determine that with repairs, new components, appropriate NDE, and lowering the design pressure, the vessel can be considered safe to use.

Woodle, M.H.; Beauman, R.; Czajkowski, C.; Dickinson, T.; Lynch, D.; Pogorelsky, I.; Skjaritka, J.

2000-09-25

130

Hydroide Storage Vessel wall stress measurements  

Microsoft Academic Search

Holographic Interferometry and strain gauge measurements were used to determine whether a prototype Hydride Storage Vessel (HSV) swelled while it was loaded in eleven stages with hydrogen. Bed swelling is inferred from deformation of the surface of the HSV. No swelling was detected, even after saturating the hydride material inside the HSV. The large chunky morphology of the titanium is

E. A. Clark; M. J. Pechersky

1997-01-01

131

Using the adaptive SMA composite cylinder concept to reduce radial dilation in composite pressure vessels  

NASA Astrophysics Data System (ADS)

Composite materials are widely used in the design of pressurized gas and fluid vessels for applications ranging from underground gasoline storage tanks to rocket motors for the space shuttle. In the design of a high pressure composite vessel (Pi > 12 Ksi), thick-wall (R/h < 15) vessels are required. For efficient material use in composite material vessels, the radial dilation (expansion or swelling) of the composite vessel can often approach values nearing 2 percent of the diameter. Over long periods of internal pressure loading over elevated temperatures, composite material cylinders may also experience substantial creep. The short term dilation and long term creep are not problematic for applications requiring only the containment of the pressurized fluid. In applications where metallic liners are required, however, substantial dilation and creep causes plastic yielding which leads to reduced fatigue life. To applications such as a hydraulic accumulator, where a piston is employed to fit and seal the fluid in the composite cylinder, the dilation and creep may allow leakage and pressure loss around the piston. A concept called the adaptive composite cylinder is experimentally presented. Shape memory alloy wire in epoxy resin is wrapped around or within polymer matrix composite cylinders to reduce radial dilation of the cylinder. Experimental results are presented that demonstrate the ability of the SMA wire layers to reduce radial dilation. Results from experimental testing of the recovery stress fatigue response of nitinol shape memory alloy wires is also presented.

Paine, Jeffrey S.; Rogers, Craig A.

1995-05-01

132

A new ultrasonographic instrument for measuring vessel wall shear stress.  

PubMed

A new ultrasonographic machine (FRP II) has been developed to measure vessel wall shear stress. A multigate ultrasound probe sends an ultrasound beam simultaneously focused in subsequent points 0.2 mm from each other along the transverse axis of a blood vessel. Blood velocity is measured by cross-correlation technique, which allows a rapid and economical analysis. Thus, the instantaneous (every 5 msec) blood velocity profile is reconstructed for the duration of the entire cardiac cycle. In order to verify the precision and sensitivity of the FRP II in measuring shear stress, 36 measurements were performed on the common carotid artery in 9 hypertensive subjects in different hemodynamic conditions. The FRP II-measured shear stress (the product of the shear rate and blood viscosity) was compared to that calculated by the Womersley's mathematical model (Y = 2K.Vcl/D, where Y = shear rate, Vcl = vessel center line blood velocity, D = vessel diameter). A good correlation (r = 0.77, p < 0.0001) was found between the peak systolic shear stresses measured by FRP II and that calculated by the Womersley's mathematical model, although an underestimation for higher values was observed with the latter method. In conclusion, we propose a new ultrasonographic instrument to measure "in vivo" the vessel wall shear stress. PMID:8086161

Bardelli, M; Carretta, R; Dotti, D; Fabris, B; Fischetti, F; Cominotto, F; Ussi, D; Calci, M; Candido, R

1994-04-01

133

Liquid-Level Monitor for Pressurized Vessels  

NASA Technical Reports Server (NTRS)

Technique for monitoring water levels in pressurized stainless-steel cylinders, based on differences in gamma-ray attenuation coefficients in water and air, developed. Full-scale laboratory prototype system constructed to test technique. Technique usable with liquids other than water, since linear attenuation coefficients for intermediate-energy gamma rays in air considerably lower than in liquids. Also adaptable for continuous monitoring of liquid levels in resevoir systems and in underground storage tanks.

Singh, J. J.; Davis, W. T.; Mall, G. H.

1986-01-01

134

A DISLOCATION-BASED CLEAVAGE INITIATION MODEL FOR PRESSURE VESSEL  

SciTech Connect

Efforts are under way to develop a theoretical, multi-scale model for the prediction of fracture toughness of ferritic steels in the ductile-to-brittle transition temperature (DBTT) region that accounts for temperature, irradiation, strain rate, and material condition (chemistry and heat treatment) effects. This new model is intended to address difficulties associated with existing empirically-derived models of the DBTT region that cannot be extrapolated to conditions for which data are unavailable. Dislocation distribution equations, derived from the theories of Yokobori et al., are incorporated to account for the local stress state prior to and following initiation of a microcrack from a second-phase particle. The new model is the basis for the DISlocation-based FRACture (DISFRAC) computer code being developed at the Oak Ridge National Laboratory (ORNL). The purpose of this code is to permit fracture safety assessments of ferritic structures with only tensile properties required as input. The primary motivation for the code is to assist in the prediction of radiation effects on nuclear reactor pressure vessels, in parallel with the EURATOM PERFORM 60 project.

Cochran, Kristine B [ORNL] [ORNL; Erickson, Marjorie A [ORNL] [ORNL; Williams, Paul T [ORNL] [ORNL; Klasky, Hilda B [ORNL] [ORNL; Bass, Bennett Richard [ORNL] [ORNL

2012-01-01

135

SMART composite high pressure vessels with integrated optical fiber sensors  

NASA Astrophysics Data System (ADS)

In this paper application of integrated Optical Fiber Sensors for strain state monitoring of composite high pressure vessels is presented. The composite tanks find broad application in areas such as: automotive industry, aeronautics, rescue services, etc. In automotive application they are mainly used for gaseous fuels storage (like CNG or compressed Hydrogen). In comparison with standard steel vessels, composite ones have many advantages (i.e. high mechanical strength, significant weight reduction, etc). In the present work a novel technique of vessel manufacturing, according to this construction, was applied. It is called braiding technique, and can be used as an alternative to the winding method. During braiding process, between GFRC layers, two types of optical fiber sensors were installed: point sensors in the form of FBGs as well as interferometric sensors with long measuring arms (SOFO®). Integrated optical fiber sensors create the nervous system of the pressure vessel and are used for its structural health monitoring. OFS register deformation areas and detect construction damages in their early stage (ensure a high safety level for users). Applied sensor system also ensured a possibility of strain state monitoring even during the vessel manufacturing process. However the main application of OFS based monitoring system is to detect defects in the composite structure. An idea of such a SMART vessel with integrated sensor system as well as an algorithm of defect detection was presented.

Blazejewski, Wojciech; Czulak, Andrzej; Gasior, Pawel; Kaleta, Jerzy; Mech, Rafal

2010-04-01

136

Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) Nickel-Hydrogen Battery Performance Under LEO Cycling Conditions  

NASA Technical Reports Server (NTRS)

LEO life cycle testing of Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) nickel-hydrogen cell packs have been sponsored by the NASA Aerospace Flight Battery Program. The cell packs have cycled under both 35% and 60% depth-of- discharge and temperature conditions of -5 C and +lO C. The packs have been on test since as early as 1992 and have generated a substantial database. This report will provide insight into performance trends as a function of the specific cell configuration and manufacturer for eight separate nickel-hydrogen battery cell packs.

Miller, Thomas B.; Lewis, Harlan L.

2004-01-01

137

Assessment of radiation effects relating to reactor pressure vessel cladding  

Microsoft Academic Search

Because the weld overlay cladding on the interior of light-water reactor pressure vessels was applied for corrosion resistance and not for structure, little attention has been given to the potential of mechanical property degradation due to radiation exposure. In light of the concerns recently raised regarding overcooling transients in nuclear power reactors, it has been suggested that any such degradation

Corwin

1984-01-01

138

MATERIAL REQUIREMENTS FOR LONG-LIFE PRESSURE VESSELS  

Microsoft Academic Search

A treatment is given of the various possible modes of failure of a ; pressure vessel intended for long service and of the material properties which ; are of significance in preventing them. The failure modes discussed are: plastic ; deformation and bursting; brittle fracture; fatigue failure; creep deformation ; and creep rupture; and corrosion. The need for additional information

B. F. Langer; W. L. Harding

1963-01-01

139

Placement of trans-sternal wires according to an ellipsoid pressure vessel model of sternal forces.  

PubMed

Dehiscence of median sternotomy wounds remains a clinical problem. Wall forces in thin-walled pressure vessels can be calculated by membrane stress theory. An ellipsoid pressure vessel model of sternal forces is presented together with its application for optimal wire placement in the sternum. Sternal forces were calculated by computational simulation using an ellipsoid chest wall model. Sternal forces were correlated with different sternal thicknesses and radio-density as measured by computerized tomography (CT) scans of the sternum. A comparison of alternative placement of trans-sternal wires located either at the levels of the costal cartilages or the intercostal spaces was made. The ellipsoid pressure vessel model shows that higher levels of stress are operative at increasing chest diameter (P < 0.001). CT scans show that the thickness of the sternal body is on average 3 mm and 30% thicker (P < 0.001) and 53% more radio-dense (P < 0.001) at the costal cartilage levels when compared with adjacent intercostal spaces. This results in a decrease of average sternal stress from 438 kPa at the intercostal space level to 338 kPa at the costal cartilage level (P = 0.003). Biomechanical modelling suggests that placement of trans-sternal wires at the thicker bone and more radio-dense level of the costal cartilages will result in reduced stress. PMID:22186126

Casha, Aaron R; Manché, Alex; Gauci, Marilyn; Camilleri-Podesta, Marie-Therese; Schembri-Wismayer, Pierre; Sant, Zdenka; Gatt, Ruben; Grima, Joseph N

2012-03-01

140

Computational experiments; Proceedings of the ASME\\/JSME Pressure Vessels and Piping Conference, Honolulu, HI, July 23-27, 1989  

Microsoft Academic Search

Papers applying FEM to engineering problems are presented, covering topics such as a numerical approach to software development for thermoforming simulations, flow three-dimensional analysis of pressure responses in an enclosed launching system, comparing flow three-dimensional calculations with very large amplitude slosh data, and the computational analysis of stress concentrations in pressure vessel cascades. Other topics include FEM studies of flow

W. K. Liu; P. Smolinski; R. Ohayon; J. Navickas; J. Gvildys

1989-01-01

141

46 CFR 109.421 - Report of repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Report of repairs to boilers and pressure vessels. 109.421 Section...Notifications § 109.421 Report of repairs to boilers and pressure vessels. Before making...replacement of valves or pressure seals, to boilers or unfired pressure vessels in...

2011-10-01

142

46 CFR 109.421 - Report of repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Report of repairs to boilers and pressure vessels. 109.421 Section...Notifications § 109.421 Report of repairs to boilers and pressure vessels. Before making...replacement of valves or pressure seals, to boilers or unfired pressure vessels in...

2013-10-01

143

46 CFR 109.421 - Report of repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Report of repairs to boilers and pressure vessels. 109.421 Section...Notifications § 109.421 Report of repairs to boilers and pressure vessels. Before making...replacement of valves or pressure seals, to boilers or unfired pressure vessels in...

2010-10-01

144

46 CFR 109.421 - Report of repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Report of repairs to boilers and pressure vessels. 109.421 Section...Notifications § 109.421 Report of repairs to boilers and pressure vessels. Before making...replacement of valves or pressure seals, to boilers or unfired pressure vessels in...

2012-10-01

145

A finite element presentation of an optimum design for composite multilayered cylindrical pressure vessels with creep relaxation  

SciTech Connect

The subject of this paper is the application of the finite element analysis to an optimum design technique for a composite, multilayered cylindrical pressure vessels with creep relaxation. This optimum design technique enables the designer to calculate readily the stresses and displacements in each layer during the fabrication process or during the use of the cylinder. The finite element codes, CAEDS and SAP IV, were employed in this study. The comparisons of the finite element predictions with those obtained from the exact solution have shown reasonably good overall agreement. The decay in the interface pressures and the prestresses in each layer due to creep relaxation, as a function of time are obtained by employing power-function creep law. This study shows that in order to maintain the same level of maximum stress, either a gradually increasing external pressure should be applied or the vessel`s inside pressure should gradually be decreased.

Kolkailah, F.A. [California Polytechnic State Univ., San Luis Obispo, CA (United States)

1993-12-31

146

Using the adaptive SMA composite cylinder concept to reduce radial dilation in composite pressure vessels  

Microsoft Academic Search

Composite materials are widely used in the design of pressurized gas and fluid vessels for applications ranging from underground gasoline storage tanks to rocket motors for the space shuttle. In the design of a high pressure composite vessel (Pi > 12 Ksi), thick-wall (R\\/h < 15) vessels are required. For efficient material use in composite material vessels, the radial dilation

Jeffrey S. Paine; Craig A. Rogers

1995-01-01

147

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs)  

NASA Technical Reports Server (NTRS)

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This report contains the outcome of the assessment and the findings, observations, and NESC recommendations to the Agency and individual NASA Centers.

Prosser, William H.

2014-01-01

148

Lightweight pressure vessels and unitized regenerative fuel cells  

SciTech Connect

Energy storage systems have been designed using lightweight pressure vessels with unitized regenerative fuel cells (URFCs). The vessels provide a means of storing reactant gases required for URFCs; they use lightweight bladder liners that act as inflatable mandrels for composite overwrap and provide a permeation barrier. URFC systems have been designed for zero emission vehicles (ZEVs); they are cost competitive with primary FC powered vehicles that operate on H/air with capacitors or batteries for power peaking and regenerative braking. URFCs are capable of regenerative braking via electrolysis and power peaking using low volume/low pressure accumulated oxygen for supercharging the power stack. URFC ZEVs can be safely and rapidly (<5 min.) refueled using home electrolysis units. Reversible operation of cell membrane catalyst is feasible without significant degradation. Such systems would have a rechargeable specific energy > 400 Wh/kg.

Mitlitsky, F.; Myers, B.; Weisberg, A.H.

1996-09-06

149

Corrosion of steel tendons used in prestressed concrete pressure vessels  

Microsoft Academic Search

The purpose of this investigation was to determine the corrosion behavior of a high strength steel (ASTM A416-74 grade 270), typical of those used as tensioning tendons in prestressed concrete pressure vessels, in several corrosive environments and to demonstrate the protection afforded by coating the steel with either of two commercial petroleum-base greases or Portland Cement grout. In addition, the

J. C. Griess; D. J. Naus

2009-01-01

150

H.B. Robinson-2 pressure vessel benchmark  

SciTech Connect

The H. B. Robinson Unit 2 Pressure Vessel Benchmark (HBR-2 benchmark) is described and analyzed in this report. Analysis of the HBR-2 benchmark can be used as partial fulfillment of the requirements for the qualification of the methodology for calculating neutron fluence in pressure vessels, as required by the U.S. Nuclear Regulatory Commission Regulatory Guide DG-1053, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence. Section 1 of this report describes the HBR-2 benchmark and provides all the dimensions, material compositions, and neutron source data necessary for the analysis. The measured quantities, to be compared with the calculated values, are the specific activities at the end of fuel cycle 9. The characteristic feature of the HBR-2 benchmark is that it provides measurements on both sides of the pressure vessel: in the surveillance capsule attached to the thermal shield and in the reactor cavity. In section 2, the analysis of the HBR-2 benchmark is described. Calculations with the computer code DORT, based on the discrete-ordinates method, were performed with three multigroup libraries based on ENDF/B-VI: BUGLE-93, SAILOR-95 and BUGLE-96. The average ratio of the calculated-to-measured specific activities (C/M) for the six dosimeters in the surveillance capsule was 0.90 {+-} 0.04 for all three libraries. The average C/Ms for the cavity dosimeters (without neptunium dosimeter) were 0.89 {+-} 0.10, 0.91 {+-} 0.10, and 0.90 {+-} 0.09 for the BUGLE-93, SAILOR-95 and BUGLE-96 libraries, respectively. It is expected that the agreement of the calculations with the measurements, similar to the agreement obtained in this research, should typically be observed when the discrete-ordinates method and ENDF/B-VI libraries are used for the HBR-2 benchmark analysis.

Remec, I.; Kam, F.B.K.

1998-02-01

151

Thermally activated deformation of irradiated reactor pressure vessel steel  

NASA Astrophysics Data System (ADS)

Temperature and strain rate change tensile tests were performed on two VVER 1000-type reactor pressure vessel welds with different contents of nickel in unirradiated and irradiated conditions in order to determine the activation parameters of the contribution of the thermally activated deformation. There are no differences of the activation parameters in the unirradiated and the irradiated conditions as well as for the two different materials. This shows that irradiation hardening preferentially results from a friction hardening mechanism by long-range obstacles.

Böhmert, J.; Müller, G.

2002-03-01

152

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

...AND NONMETAL MINES Compressed Air and Boilers § 56.13015 Inspection of compressed-air...National Board Inspection Code, a Manual for Boiler and Pressure Vessel Inspectors, 1979...the publisher, the National Board of Boiler and Pressure Vessel Inspector, 1055...

2014-07-01

153

30 CFR 56.13001 - General requirements for boilers and pressure vessels.  

...2014-07-01 false General requirements for boilers and pressure vessels. 56.13001 Section...METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13001 General requirements for boilers and pressure vessels. All...

2014-07-01

154

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

...AND NONMETAL MINES Compressed Air and Boilers § 57.13015 Inspection of compressed-air...National Board Inspection Code, a Manual for Boiler and Pressure Vessel Inspectors, 1979...the publisher, the National Board of Boiler and Pressure Vessel Inspectors,...

2014-07-01

155

30 CFR 57.13001 - General requirements for boilers and pressure vessels.  

...2014-07-01 false General requirements for boilers and pressure vessels. 57.13001 Section...METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13001 General requirements for boilers and pressure vessels. All...

2014-07-01

156

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2010 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2010-07-01

157

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2013 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2013-07-01

158

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2011 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2011-07-01

159

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2011 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2011-07-01

160

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2012 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2012-07-01

161

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2013 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2013-07-01

162

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2012 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2012-07-01

163

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.  

Code of Federal Regulations, 2010 CFR

... Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section... Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other...

2010-07-01

164

Dual shell reactor vessel: A pressure-balanced system for high pressure and temperature reactions  

Microsoft Academic Search

The main purpose of this work was to demonstrate the Dual Shell Pressure Balanced Vessel (DSPBV) as a safe and economical reactor for the hydrothermal water oxidation of hazardous wastes. Experimental tests proved that the pressure balancing piston and the leak detection concept designed for this project will work. The DSPBV was sized to process 10 gal\\/hr of hazardous waste

R. J. Robertus; A. G. Fassbender; G. S. Deverman

1995-01-01

165

46 CFR 50.05-5 - Existing boilers, pressure vessels or piping systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Existing boilers, pressure vessels or piping systems...Application § 50.05-5 Existing boilers, pressure vessels or piping systems...exists as to the safety of an existing boiler, pressure vessel, or piping...

2012-10-01

166

46 CFR 50.05-5 - Existing boilers, pressure vessels or piping systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Existing boilers, pressure vessels or piping systems...Application § 50.05-5 Existing boilers, pressure vessels or piping systems...exists as to the safety of an existing boiler, pressure vessel, or piping...

2013-10-01

167

46 CFR 50.05-5 - Existing boilers, pressure vessels or piping systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Existing boilers, pressure vessels or piping systems...Application § 50.05-5 Existing boilers, pressure vessels or piping systems...exists as to the safety of an existing boiler, pressure vessel, or piping...

2011-10-01

168

46 CFR 50.05-5 - Existing boilers, pressure vessels or piping systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Existing boilers, pressure vessels or piping systems...Application § 50.05-5 Existing boilers, pressure vessels or piping systems...exists as to the safety of an existing boiler, pressure vessel, or piping...

2010-10-01

169

46 CFR 54.01-17 - Pressure vessel for human occupancy (PVHO).  

Code of Federal Regulations, 2010 CFR

46 ? Shipping ? 2 ? 2010-10-01 ? 2010-10-01 ? false ? Pressure vessel for human occupancy (PVHO). ? 54.01-17 ? Section 54.01-17 ? Shipping ? COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ? MARINE ENGINEERING ? PRESSURE VESSELS ? General Requirements ? § 54.01-17 ? Pressure vessel...

2010-10-01

170

Investigation of postweld heat treatment of quenched and tempered pressure vessel steels  

Microsoft Academic Search

Longitudinal and circumferential welds in transportable pressure vessels are produced by submerged-arc welding using a single vee preparation and multiple weld runs. Quenched and tempered (QT) steels, which are commonly used for transportable pressure vessels, require mandatory postweld heat treatment (PWHT) regardless of the plate thickness. During their life transportable pressure vessels may have up to four PWHT cycles, and

Zoran Sterjovski

2003-01-01

171

46 CFR 38.05-3 - Design and construction of pressure vessel type cargo tanks-TB/ALL.  

Code of Federal Regulations, 2011 CFR

... false Design and construction of pressure vessel type cargo tanks-TB/ALL...05-3 Design and construction of pressure vessel type cargo tanks—TB/ALL. (a) Cargo tanks of pressure vessel configuration...

2011-10-01

172

46 CFR 38.05-3 - Design and construction of pressure vessel type cargo tanks-TB/ALL.  

Code of Federal Regulations, 2010 CFR

... false Design and construction of pressure vessel type cargo tanks-TB/ALL...05-3 Design and construction of pressure vessel type cargo tanks—TB/ALL. (a) Cargo tanks of pressure vessel configuration...

2010-10-01

173

Crack initiation and arrest in a pressurized thermal shock test for a model pressure vessel made of VVER-440 reactor pressure vessel steel  

Microsoft Academic Search

A joint pressure vessel integrity research programme involving three partners is being carried out during 1990–1995. The partners are the Central Research Institute of Structural Materials “Prometey” from Russia, IVO International Ltd (IVO) from Finland, and the Technical Research Centre of Finland (VTT). The main objective of the research programme is to increase the reliability of the VVER-440 reactor pressure

Heikki Keinänen; Heli Talja; Rauno Rintamaa; Kari Törrönen; Ralf Ahlstrand; Pekka Nurkkala; George Karzov; Boris Timofeev; Alexander Blumin

1995-01-01

174

Prevention of non-ductile fracture in 6061-T6 aluminum nuclear pressure vessels  

SciTech Connect

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Committee has approved rules for the use of 6061-T6 and 6061-T651 aluminum for the construction of Class 1 welded nuclear pressure vessels for temperatures not exceeding 149 C (300 F). Nuclear Code Case N-519 allows the use of this aluminum in the construction of low temperature research reactors such as the Advanced Neutron Source. The rules for protection against non-ductile fracture are discussed. The basis for a value of 25.3 MPa {radical}m (23 ksi {radical}in.) for the critical or reference stress intensity factor for use in the fracture analysis is presented. Requirements for consideration of the effects of neutron irradiation on the fracture toughness are discussed.

Yahr, G.T. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.

1995-06-01

175

Evaluation of Data-Logging Transducer to Passively Collect Pressure Vessel p/T History  

NASA Technical Reports Server (NTRS)

Pressure vessels owned and operated by NASA are required to be regularly certified per agency policy. Certification requires an assessment of damage mechanisms and an estimation of vessel remaining life. Since detail service histories are not typically available for most pressure vessels, a conservative estimate of vessel pressure/temperature excursions is typically used in assessing fatigue life. This paper details trial use of a data-logging transducer to passively obtain actual pressure and temperature service histories of pressure vessels. The approach was found to have some potential for cost savings and other benefits in certain cases.

Wnuk, Stephen P.; Le, Son; Loew, Raymond A.

2013-01-01

176

Elevated temperature mechanical properties of a reactor pressure vessel steel  

NASA Astrophysics Data System (ADS)

A testing program is in progress to define the tensile and creep properties of SA533 Grade B Class 1 steel at temperatures from 371 to 538 °C. The overall objective is to provide the data necessary to obtain ASME Code approval for use of this material for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) vessel during short-term temperature excursions above 371 °C. Testing and evaluation involve three heats of base metal, two submerged arc welds, and a shielded metal arc weld. The creep strengths of the base metal heats and the weldments were found to be equivalent; the weld metal itself is slightly stronger. The data obtained indicate that stress to produce 1% strain will likely be the controlling factor in setting the allowable stresses for design.

McCoy, H. E.; Rittenhouse, P. L.

1990-04-01

177

Determination of the yield strength of nuclear reactor pressure vessel steels by means of amplitude-dependent internal friction  

Microsoft Academic Search

Amplitude-dependent internal friction measurements allow the determination of a critical amplitude which corresponds to the onset of plastic behaviour and is related to the yield stress (YS) in torsion. The results compare well with the YS obtained from static tensile tests on three different pressure vessel steels and can be fitted with a two- or three-component model comprising long- and

K. Van Ouytsel; A. Fabry; R. De Batist; R. Schaller

2000-01-01

178

Flat rolled and hot-formed parts of high-strength steels for heavy pressure vessels  

Microsoft Academic Search

From 2nd international congress for pressure vessel and piping ; technology; San Antonio, Texas, USA (1 Oct 1973). See CONF731003-P2. It is ; pointed out that pressure vessel size increased steadily during the last 20 years ; in West Germany. At the same time, the use of high-strength steels permitted ; reductions in wall thickness. Several examples of such vessels

Neuhaus

1973-01-01

179

Making a Metal-Lined Composite-Overwrapped Pressure Vessel  

NASA Technical Reports Server (NTRS)

process has been devised for the fabrication of a pressure vessel that comprises a composite-material (matrix/fiber) shell with a metal liner on its inner surface. The use of the composite material makes it possible for the tank to be strong enough to withstand the anticipated operating pressure and yet weigh less than does an equivalent all-metal tank. The metal liner is used as a barrier against permeation: In the absence of such a barrier, the pressurized gas in the tank could leak by diffusing through the composite-material shell. The figure depicts workpieces at four key stages in the process, which consists of the following steps: 1. A mandrel that defines the size and shape of the pressure vessel is made by either molding or machining a piece of tooling wax. 2. Silver paint is applied to the surface of the mandrel to make it electrically conductive. 3. The ends of the mandrel are fitted with metal bosses. 4. The mandrel is put into a plating bath, wherein the metal liner is electrodeposited. Depending on the applications, the liner metal could be copper, nickel, gold, or an alloy. Typical liner thicknesses range from 1 to 10 mils (0.025 to 0.25 mm). 5. The wax is melted from within, leaving the thin metal liner. 6. A hollow shaft that includes holes and fittings through which the liner can be pressurized is sealed to both ends of the liner. The liner is pressurized to stiffen (and hence stabilize) it for the next step. 7. The pressurized liner is placed in a filament-winding machine, which is then operated to cover the liner with multiple layers of an uncured graphite-fiber/epoxy-matrix or other suitable composite material. 8. The composite-overwrapped liner is cured in an oven. 9. The pressure is relieved and the shaft is removed. The tank is then ready for use. The process as described above accommodates variations: a) The mandrel could be made of a wax that melts at a higher temperature and not removed until the tank is cured in the oven. b) The tank need not be cylindrical or axisymmetric, as long as the filament-winding machine can accommodate the chosen shape. c) Shallow grooves could be formed on the surface of the mandrel to give the liner a bellows-like character for reinforcement and/or to accommodate expansion and contraction.

DeLay, Tom

2005-01-01

180

Improved fireman's compressed air breathing system pressure vessel development program  

NASA Technical Reports Server (NTRS)

Prototype high pressure glass filament-wound, aluminum-lined pressurant vessels suitable for use in a fireman's compressed air breathing system were designed, fabricated, and acceptance tested in order to demonstrate the feasibility of producing such high performance, lightweight units. The 4000 psi tanks have a 60 standard cubic foot (SCF) air capacity, and have a 6.5 inch diamter, 19 inch length, 415 inch volume, weigh 13 pounds when empty, and contain 33 percent more air than the current 45 SCF (2250 psi) steel units. The current steel 60 SCF (3000 psi) tanks weigh approximately twice as much as the prototype when empty, and are 2 inches, or 10 percent shorter. The prototype units also have non-rusting aluminum interiors, which removes the hazard of corrosion, the need for internal coatings, and the possibility of rust particles clogging the breathing system.

King, H. A.; Morris, E. E.

1973-01-01

181

Retinal vessel diameter changes induced by transient high perfusion pressure  

PubMed Central

AIM To investigate the effects of transient high perfusion pressure on the retinal vessel diameter and retinal ganglion cells. METHODS The animals were divided into four groups according to different infusion pressure and infusion time (60 mm Hg-3min, 60 mm Hg-5min, 100 mm Hg-3min, 100 mm Hg-5min). Each group consisted of six rabbits. The left eye was used as the experimental eye and the right as a control. Retinal vascular diameters were evaluated before, during infusion, immediately after infusion, 5min, 10min and 30min after infusion based on the fundus photographs. Blood pressure was monitored during infusion. The eyes were removed after 24h. Damage to retinal ganglion cell (RGC) was analyzed by histology. RESULTS Retina became whiten and papilla optic was pale during perfusion. Measurements showed signi?cant decrease in retinal artery and vein diameter during perfusion in all of the four groups at the proximal of the edge of the optic disc. The changes were significant in the 100 mm Hg-3min group and 100 mm Hg-5min group compared with 60 mm Hg-3min group (P1=0.025, P2=0.000). The diameters in all the groups recovered completely after 30min of reperfusion. The number of RGC showed no signi?cant changes at the IOP in 100 mm Hg with 5min compared with contralateral untreated eye (P>0.05). CONCLUSION Transient fluctuations during infusion lead to temporal changes of retinal vessels, which could affect the retinal blood circulation. The RGCs were not affected by this transient fluctuation. Further studies are necessary to evaluate the effect of pressure during real-time phacoemusification on retinal blood circulation. PMID:25161928

Zhao, Yin-Ying; Chang, Ping-Jun; Yu, Fang; Zhao, Yun-E

2014-01-01

182

Relationship between target organ damage and blood pressure, retinal vessel calibre, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes in patients with hypertension: a case-control study protocol (LOD-Hipertensi?n)  

PubMed Central

Introduction Target organ damage (TOD) is associated with increased cardiovascular risk. The study objectives were to analyse the relationship of TOD to blood pressure, size of retinal arteries and veins, oxidative stress and different polymorphisms in the VAV-2 and VAV-3 genes in participants with hypertension. Methods and analysis A case–control study to analyse the relationship between clinical, biochemical and genetic parameters and presence of cardiac, vascular and renal TOD in 486 patients with hypertension. Participants with TOD will be considered as cases, and those without TOD will be enrolled as controls. This will be a collaborative study conducted by the groups of Primary Care, Cardiovascular and Metabolic and Degenerative Diseases of the Instituto de Investigación Biomédica of Salamanca (IBSAL). Assessment of cardiac, renal and vascular TOD. Measurement of peripheral and central blood pressure, size of eye fundus arteries and veins, and oxidative stress, and polymorphisms in the VAV-2 and VAV-3 genes. Ethics and dissemination The study will be conducted after approval is obtained from the Ethics Committee of Hospital Clínico Universitario of Salamanca. All study participants will sign an informed consent to agree to participate in the study, and another consent to agree on the genetic study, in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow for an understanding of the relationship of the different TODs with blood pressure, retinal artery and vein diameters, oxidative stress and polymorphisms in VAV-2 and VAV-3 genes. Trial registration number Clinical Trials. gov Identifier: NCT02022618. PMID:24699462

Gomez-Marcos, Manuel A; Gonzalez-Sarmiento, Rogelio; Recio-Rodriguez, Jose I; Agudo-Conde, Cristina; Gamella-Pozuelo, Luis; Perretta-Tejedor, Nuria; Martinez-Salgado, Carlos; Garcia-Ortiz, Luis

2014-01-01

183

Review of current practices and requirements for the inspection of prestressed concrete pressure vessels  

SciTech Connect

Code requirements for pre- and in-service inspection of prestressed concrete pressure vessels as utilized in gas-cooled reactors are reviewed and compared with practices and experiences during construction, commissioning, and operation of such reactors. The pre-service inspection relies heavily on embedded instrumentation for measurements of stresses, temperatures, and displacements. The same instrumentation is later used for in-service surveillance, which additionally includes visual examination of exposed surfaces, monitoring of tendon conditions, and measurement of tendon loads. Improvement of present monitoring instrumentation and/or techniques, rather than development of new in-service inspection methods, is recommended.

Reimann, K.J.

1980-12-01

184

Burst prediction by acoustic emission in filament-wound pressure vessels  

NASA Technical Reports Server (NTRS)

Acoustic emission in 51-cm diameter graphite/epoxy pressure vessels was monitored during pressurization (hydrotesting). Several vessels were subjected to impact by a blunt impactor, but only after the vessels had been proofed; that is, pressurized to 80 percent of nominal burst pressure as determined from control (unimpacted) vessels. AE activity was then monitored throughout a series of successively higher pressure cycles ranging from 10 to 60 percent of ultimate. Each cycle included a ramp up to pressure followed by a 4-min hold period and then pressure unload. The event rate was high, and especially modified AE analyzers had to be used to acquire the data. This paper presents the AE event count versus pressure history of these tests and demonstrates the ability of the AE technique to monitor the growth of damage and to estimate the effect on ultimate strength. The number of events that occurred during pressure holds proved to be a reasonable estimator of vessel performance.

Gorman, Michael R.

1990-01-01

185

Stress anisotropy and concentration effects in high pressure measurements. [sodium chloride  

NASA Technical Reports Server (NTRS)

Sodium chloride is used as an internal pressure standard in high pressure research. Possible corrections are discussed which are needed in the calibration of this standard due to the independent effects of stress anisotropy and stress concentration in pressure vessels. The first is due to the lack of a truly hydrostatic state of stress in solid state pressure vessels. The second is due to the difference in the compressibilities between the pressure transmitting substances (sodium chloride) and a stiffer test specimen. These two corrections are then combined and a total correction, as a function of measured pressure, is discussed for two systems presently in use. The predicted value of the combined effect is about 5-10% of the pressure at 30 GPa.

Nelson, D. A., Jr.; Ruoff, A. L.

1974-01-01

186

Probability of fracture for HFIR pressure vessel caused by random crack size or by random toughness  

Microsoft Academic Search

The probability of fracture (or the fracture fragility) for a range of internal pressure-pulses for the HFIR pressure vessel is obtained. The fracture is assumed to be caused by randomly distributed cracks and by fracture toughness of variable magnitudes. The probability curve is applied to estimate the vessel fracture strength against the pressure-pulses of hypothetical accident. Both the crack population

S.-J. Chang

1994-01-01

187

Metallic Pressure Vessels Failures M. Mosnier, B. Daudonnet, J. Renard and G. Mavrothalassitis  

E-print Network

identification of possible explosion scénarios involving metallic vessels. Based on thé review of scientific to store or to transport gas or pressurized liquid (such as LPG or LNG), to dry, or as steam boiler... etc or an internai explosion. For this reason, thé pressure inside thé vessel exceeds thé dynamic pressure limit

Paris-Sud XI, Université de

188

THE USER'S RESPONSIBILITY All Parr reactors and pressure vessels are designed  

E-print Network

THE USER'S RESPONSIBILITY All Parr reactors and pressure vessels are designed and manufactured. Select a reactor or pressure vessel which has the capacity, pressure rating, corrosion resistance equipment and material options with prospective users, but the final responsibility for selecting a reactor

Shull, Kenneth R.

189

Techniques for embedding instrumentation in pressure vessel test articles  

NASA Astrophysics Data System (ADS)

Many interesting structural and thermal events occur in materials that are housed within a surrounding pressure vessel. In order to measure the environment during these events and explore their causes instrumentation must be installed on or in the material. Transducers can be selected that are small enough to be embedded within the test material but these instruments must interface with an external system in order to apply excitation voltages and output the desired data. The methods for installing the instrumentation and creating an interface are complicated when the material is located in a case or housing containing high pressures and hot gases. Installation techniques for overcoming some of these difficulties were developed while testing a series of small-scale solid propellant and hybrid rocket motors at Marshall Space Flight Center. These techniques have potential applications in other test articles where data are acquired from materials that require containment due to the severe environment encountered during the test process. This severe environment could include high pressure, hot gases, or ionized atmospheres. The development of these techniques, problems encountered, and the lessons learned from the ongoing testing process are summarized.

Cornelius, Michael

2006-05-01

190

Continuous Cooling Transformations in Nuclear Pressure Vessel Steels  

NASA Astrophysics Data System (ADS)

A class of low-alloy steels often referred to as SA508 represent key materials for the manufacture of nuclear reactor pressure vessels. The alloys have good properties, but the scatter in properties is of prime interest in safe design. Such scatter can arise from microstructural variations but most studies conclude that large components made from such steels are, following heat treatment, fully bainitic. In the present work, we demonstrate with the help of a variety of experimental techniques that the microstructures of three SA508 Gr.3 alloys are far from homogeneous when considered in the context of the cooling rates encountered in practice. In particular, allotriomorphic ferrite that is expected to lead to a deterioration in toughness, is found in the microstructure for realistic combinations of austenite grain size and the cooling rate combination. Parameters are established to identify the domains in which SA508 Gr.3 steels transform only into the fine bainitic microstructures.

Pous-Romero, Hector; Bhadeshia, Harry K. D. H.

2014-10-01

191

ASTM Standards for Reactor Dosimetry and Pressure Vessel Surveillance  

SciTech Connect

The ASTM standards provide guidance and instruction on how to field and interpret reactor dosimetry. They provide a roadmap towards understanding the current ''state-of-the-art'' in reactor dosimetry, as reflected by the technical community. The consensus basis to the ASTM standards assures the user of an unbiased presentation of technical procedures and interpretations of the measurements. Some insight into the types of standards and the way in which they are organized can assist one in using them in an expeditious manner. Two example are presented to help orient new users to the breadth and interrelationship between the ASTM nuclear metrology standards. One example involves the testing of a new ''widget'' to verify the radiation hardness. The second example involves quantifying the radiation damage at a pressure vessel critical weld location through surveillance dosimetry and calculation.

GRIFFIN, PATRICK J.

1999-09-14

192

Sustained load behavior of graphite/epoxy metal-lined pressure vessels for long-life space applications  

NASA Technical Reports Server (NTRS)

Tests were performed on candidate graphite yarns for the overwraps to be used on the Space Station Freedom's pressure vessels. The objective was to determine the performance and ranking of these overwraps to ensure that sustained loads would not be a problem during their 30-yr life in space. Tests were conducted at high stress levels for short time periods on subscale composite bottles. The average delivered fiber stresses were determined from the measured burst pressures via SCI analysis that accounts for both geometry and the properties of the resin and yarn.

Babel, H. W.; Vickers, B. D.; Thomas, D. A.

1989-01-01

193

Composite Overwrapped Pressure Vessels (COPV): Flight Rationale for the Space Shuttle Program  

NASA Technical Reports Server (NTRS)

Each Orbiter Vehicle (Space Shuttle Program) contains up to 24 Kevlar49/Epoxy Composite Overwrapped Pressure Vessels (COPV) for storage of pressurized gases. In the wake of the Columbia accident and the ensuing Return To Flight (RTF) activities, Orbiter engineers reexamined COPV flight certification. The original COPV design calculations were updated to include recently declassified Kevlar COPV test data from Lawrence Livermore National Laboratory (LLNL) and to incorporate changes in how the Space Shuttle was operated as opposed to orinigially envisioned. 2005 estimates for the probability of a catastrophic failure over the life of the program (from STS-1 through STS-107) were one-in-five. To address this unacceptable risk, the Orbiter Project Office (OPO) initiated a comprehensive investigation to understand and mitigate this risk. First, the team considered and eventually deemed unfeasible procuring and replacing all existing flight COPVs. OPO replaced the two vessels with the highest risk with existing flight spare units. Second, OPO instituted operational improvements in ground procedures to signficiantly reduce risk, without adversely affecting Shuttle capability. Third, OPO developed a comprehensive model to quantify the likelihood of occurrance. A fully-instrumented burst test (recording a lower burst pressure than expected) on a flight-certified vessel provided critical understanding of the behavior of Orbiter COPVs. A more accurate model was based on a newly-compiled comprehensive database of Kevlar data from LLNL and elsewhere. Considering hardware changes, operational improvements and reliability model refinements, the mean reliability was determined to be 0.998 for the remainder of the Shuttle Program (from 2007, for STS- 118 thru STS-135). Since limited hardware resources precluded full model validation through multiple tests, additional model confidence was sought through the first-ever Accelerated Stress Rupture Test (ASRT) of a flown flight article. A Bayesian statistical approach was developed to interpret possible test results. Since the lifetime observed in the ASRT exceeded initial estimates by one to two orders of magnitude, the Space Shuttle Program deemed there was significant conservatism in the model and accepted continued operation with existing flight hardware. Given the variability in tank-to-tank original prooftest response, a non-destructive evaluation (NDE) technique utilizing Raman Spectroscopy was developed to directly measure COPV residual stress state. Preliminary results showed that patterns of low fiber elastic strains over the outside vessel surface, together with measured permanent volume growth during proof, could be directly correlated to increased fiber stress ratios on the inside fibers adjacent to the liner, and thus reduced reliability.

Kezirian, Michael T.; Johnson, Kevin L.; Phoenix, Stuart L.

2011-01-01

194

NEUTRON DAMAGE IN REACTOR PRESSURE-VESSEL STEEL EXAMINED WITH POSITRON ANNIHILATION LIFETIME SPECTROSCOPY  

E-print Network

spectroscopy to study the development of damage and annealing behavior ofneutron-irradiated reactor pressure. 439©1997 Materials Research Society #12;EXPERIMENTAL METHODS ASTM A508 reactor pressure-vessel steel

Motta, Arthur T.

195

Dual shell reactor vessel: A pressure-balanced system for high pressure and temperature reactions  

SciTech Connect

The main purpose of this work was to demonstrate the Dual Shell Pressure Balanced Vessel (DSPBV) as a safe and economical reactor for the hydrothermal water oxidation of hazardous wastes. Experimental tests proved that the pressure balancing piston and the leak detection concept designed for this project will work. The DSPBV was sized to process 10 gal/hr of hazardous waste at up to 399{degree}C (750{degree}F) and 5000 psia (34.5 MPa) with a residence time of 10 min. The first prototype reactor is a certified ASME pressure vessel. It was purchased by Innotek Corporation (licensee) and shipped to Pacific Northwest Laboratory for testing. Supporting equipment and instrumentation were, to a large extent, transported here from Battelle Columbus Division. A special air feed system and liquid pump were purchased to complete the package. The entire integrated demonstration system was assembled at PNL. During the activities conducted for this report, the leak detector design was tested on bench top equipment. Response to low levels of water in oil was considered adequate to ensure safety of the pressure vessel. Shakedown tests with water only were completed to prove the system could operate at 350{degree}C at pressures up to 3300 psia. Two demonstration tests with industrial waste streams were conducted, which showed that the DSPBV could be used for hydrothermal oxidation. In the first test with a metal plating waste, chemical oxygen demand, total organic carbon, and cyanide concentrations were reduced over 90%. In the second test with a munitions waste, the organics were reduced over 90% using H{sub 2}O{sub 2} as the oxidant.

Robertus, R.J.; Fassbender, A.G.; Deverman, G.S.

1995-03-01

196

Numerical Simulation of Impact Damage Induced by Orbital Debris on Shielded Wall of Composite Overwrapped Pressure Vessel  

NASA Astrophysics Data System (ADS)

This paper presents a methodology for numerical simulation of the formation of the front wall damage in composite overwrapped pressure vessels under hypervelocity impact. Both SPH particles and Lagrangian finite elements were employed in combination for numerical simulations. Detailed numerical models implementing two filament winding patterns with different degree of interweaving were developed and used to simulate 2.5 km/s and 5.0 km/s impacts of 5 mm-diameter spherical aluminum-alloy projectile. Obtained results indicate that winding pattern may have a pronounced effect on vessel damage in case of orbital debris impact, influencing propagation of the stress waves in composite material.

Cherniaev, Aleksandr; Telichev, Igor

2014-02-01

197

Device for suspending and supporting a reactor pressure vessel in a nuclear power plant  

Microsoft Academic Search

A device is described for suspending and supporting a reactor pressure ; vessel in a reactor chamber of a nuclear power plant and includes a cover for the ; reactor chamber formed with an opening through which the pressure vessel extends ; into the reactor chamber, the cover being of compartment-shaped steel ; construction, support paws extending from the outer

M. Scholz; F. Wakonig

1973-01-01

198

Advances in crack-arrest technology for reactor pressure vessels  

SciTech Connect

The Heavy-Section Steel Technology (HSST) Program at the Oak Ridge National Laboratory (ORNL) under the sponsorship of the US Nuclear Regulatory Commission is continuing to improve the understanding of conditions that govern the initiation, rapid propagation, arrest, and ductile tearing of cracks in reactor pressure vessel (RPV) steels. This paper describes recent advances in a coordinated effort being conducted under the HSST Program by ORNL and several subcontracting groups to develop the crack-arrest data base and the analytical tools required to construct inelastic dynamic fracture models for RPV steels. Large-scale tests are being carried out to generate crack-arrest toughness data at temperatures approaching and above the onset of Charpy upper-shelf behavior. Small- and intermediate-size specimens subjected to static and dynamic loading are being developed and tested to provide additional fracture data for RPV steels. Viscoplastic effects are being included in dynamic fracture models and computer programs and their utility validated through analyses of data from carefully controlled experiments. Recent studies are described that examine convergence problems associated with energy-based fracture parameters in viscoplastic-dynamic fracture applications. Alternative techniques that have potential for achieving convergent solutions for fracture parameters in the context of viscoplastic-dynamic models are discussed. 46 refs., 15 figs., 3 tabs.

Bass, B.R.; Pugh, C.E.

1988-01-01

199

Coordinated sensing and autonomous repair of pressure vessels and structures  

NASA Astrophysics Data System (ADS)

Self-repairing structural systems can potentially improve performance ranges and lifetimes compared to those of conventional systems without self-healing capability. Self-healing materials have been used in automotive and aeronautical applications for over a century. The bulk of these systems operate by using the damage to directly initiate the repair response without any supervisory coordination. Integrating sensing and supervisory control technologies with self-healing may improve the safety and reliability of critical components and structures. This project used laboratory scale test beds to illustrate the benefit of an integrated sensing, control and self-healing system. A thermal healing polymer embedded with resistive heating wires acted as the sensing-healing material. Sensing duties were performed using an impedance, capacitance, and resistance testing device and a PC acted as the controller. As damage occurs to the polymer it is detected, located, and characterized. Based on the sensor signal, a decision is made as to whether to execute a repair and then to subsequently monitor the repair process to ensure completeness. The second demonstration was a self-sealing pressure vessel with integrated sensing and healing capability. These proof-of-concept prototypes can likely be expanded and improved with alternative sensor options, sensing-healing materials, and system architecture.

Huston, Dryver R.; Hurley, David A.; Gollins, Kenneth; Gervais, Anthony

2010-04-01

200

Programmable calculator stress analysis  

SciTech Connect

Advanced programmable alphanumeric calculators are well suited for closed-form calculation of pressure-vessel stresses. They offer adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs that demonstrate calculator capabilities are presented. Problems treated are stress and strength calculations in thick-walled pressure vessels and the computation of stresses near head/pressure-vessel junctures.

Van Gulick, L.A.

1983-01-01

201

46 CFR 54.01-2 - Adoption of division 1 of section VIII of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2011 CFR

...of section VIII of the ASME Boiler and Pressure Vessel Code. 54.01-2 Section...CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54...of section VIII of the ASME Boiler and Pressure Vessel Code. (a) Pressure...

2011-10-01

202

46 CFR 54.01-2 - Adoption of division 1 of section VIII of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2010 CFR

...of section VIII of the ASME Boiler and Pressure Vessel Code. 54.01-2 Section...CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54...of section VIII of the ASME Boiler and Pressure Vessel Code. (a) Pressure...

2010-10-01

203

Swim Pressure: Stress Generation in Active Matter  

NASA Astrophysics Data System (ADS)

We discover a new contribution to the pressure (or stress) exerted by a suspension of self-propelled bodies. Through their self-motion, all active matter systems generate a unique swim pressure that is entirely athermal in origin. The origin of the swim pressure is based upon the notion that an active body would swim away in space unless confined by boundaries—this confinement pressure is precisely the swim pressure. Here we give the micromechanical basis for the swim stress and use this new perspective to study self-assembly and phase separation in active soft matter. The swim pressure gives rise to a nonequilibrium equation of state for active matter with pressure-volume phase diagrams that resemble a van der Waals loop from equilibrium gas-liquid coexistence. Theoretical predictions are corroborated by Brownian dynamics simulations. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria to catalytic nanobots to molecular motors that activate the cellular cytoskeleton.

Takatori, S. C.; Yan, W.; Brady, J. F.

2014-07-01

204

Applications of energy-release-rate techniques to part-through cracks in experimental pressure vessels  

SciTech Connect

In nonlinear applications of computational fracture mechanics, energy release rate techniques are used increasingly for computing stress intensity parameters of crack configurations. Recently, deLorenzi used the virtual-crack-extension method to derive an analytical expression for the energy release rate that is better suited for three-dimensional calculations than the well-known J-integral. Certain studies of fracture phenomena, such as pressurized-thermal-shock of cracked structures, require that crack tip parameters be determined for combined thermal and mechanical loads. A method is proposed here that modifies the isothermal formulation of deLorenzi to account for thermal strains in cracked bodies. This combined thermo-mechanical formulation of the energy release rate is valid for general fracture, including nonplanar fracture, and applies to thermo-elastic as well as deformation plasticity material models. Two applications of the technique are described here. In the first, semi-elliptical surface cracks in an experimental test vessel are analyzed under elastic-plastic conditions using the finite element method. The second application is a thick-walled test vessel subjected to combined pressure and thermal shock loadings.

Bass, B.R.; Bryan, R.H.; Bryson, J.W.; Merkle, J.G.

1982-01-01

205

Structural Integrity of Gas-Filled Composite Overwrapped Pressure Vessels Subjected to Orbital Debris Impact  

NASA Astrophysics Data System (ADS)

Gas-filled pressure vessels are extensively used in spacecraft onboard systems. During operation on the orbit they exposed to the space debris environment. Due to high energies they contain, pressure vessels have been recognized as the most critical spacecraft components requiring protection from orbital debris impact. Major type of pressurized containers currently used in spacecraft onboard systems is composite overwrapped pressure vessels (COPVs) manufactured by filament winding. In the present work we analyze the structural integrity of vessels of this kind in case of orbital debris impact at velocities ranging from 2 to 10 km/s. Influence of such parameters as projectile energy, shielding standoff, internal pressure and filament winding pattern on COPVs structural integrity has been investigated by means of numerical and physical experiments.

Telichev, Igor; Cherniaev, Aleksandr

206

46 CFR 53.01-3 - Adoption of section IV of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2011 CFR

...Adoption of section IV of the ASME Boiler and Pressure Vessel Code. 53.01-3 Section...Adoption of section IV of the ASME Boiler and Pressure Vessel Code. (a) Heating boilers...with section IV of the ASME Boiler and Pressure Vessel Code (incorporated by...

2011-10-01

207

46 CFR 53.01-3 - Adoption of section IV of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2010 CFR

...Adoption of section IV of the ASME Boiler and Pressure Vessel Code. 53.01-3 Section...Adoption of section IV of the ASME Boiler and Pressure Vessel Code. (a) Heating boilers...with section IV of the ASME Boiler and Pressure Vessel Code (incorporated by...

2010-10-01

208

Thrombospondin1 and CD47 regulate blood pressure and cardiac responses to vasoactive stress  

Microsoft Academic Search

Nitric oxide (NO) locally regulates vascular resistance and blood pressure by modulating blood vessel tone. Thrombospondin-1 signaling via its receptor CD47 locally limits the ability of NO to relax vascular smooth muscle cells and increase regional blood flow in ischemic tissues. To determine whether thrombospondin-1 plays a broader role in central cardiovascular physiology, we examined vasoactive stress responses in mice

Jeff S. Isenberg; Yan Qin; Justin B. Maxhimer; John M. Sipes; Daryl Despres; Jurgen Schnermann; William A. Frazier; David D. Roberts

2009-01-01

209

Joining dissimilar stainless steels for pressure vessel components  

NASA Astrophysics Data System (ADS)

A series of studies was carried out to examine the weldability and properties of dissimilar steel joints between martensitic and austenitic stainless steels - F6NM (OCr13Ni4Mo) and AISI 347, respectively. Such joints are important parts in, e.g. the primary circuit of a pressurized water reactor (PWR). This kind of joint requires both good mechanical properties, corrosion resistance and a stable magnetic permeability besides good weldability. The weldability tests included weld thermal simulation of the martensitic steel for investigating the influence of weld thermal cycles and post-weld heat treatment (PWHT) on the mechanical properties of the heat-affected zone (HAZ); implant testing for examining the tendency for cold cracking of martensitic steel; rigid restraint testing for determining hot crack susceptibility of the multi-pass dissimilar steel joints. The joints were subjected to various mechanical tests including a tensile test, bending test and impact test at various temperatures, as well as slow strain-rate test for examining the stress corrosion cracking tendency in the simulated environment of a primary circuit of a PWR. The results of various tests indicated that the quality of the tube/tube joints is satisfactory for meeting all the design requirements.

Sun, Zheng; Han, Huai-Yue

1994-03-01

210

46 CFR 35.25-5 - Repairs of boilers and unfired pressure vessels and reports of repairs or accidents by chief...  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Repairs of boilers and unfired pressure vessels and reports...Department § 35.25-5 Repairs of boilers and unfired pressure vessels and reports... (a) Before making any repairs to boilers or unfired pressure vessels,...

2012-10-01

211

46 CFR 35.25-5 - Repairs of boilers and unfired pressure vessels and reports of repairs or accidents by chief...  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Repairs of boilers and unfired pressure vessels and reports...Department § 35.25-5 Repairs of boilers and unfired pressure vessels and reports... (a) Before making any repairs to boilers or unfired pressure vessels,...

2013-10-01

212

Nondestructive Methods and Special Test Instrumentation Supporting NASA Composite Overwrapped Pressure Vessel Assessments  

NASA Technical Reports Server (NTRS)

Many aging composite overwrapped pressure vessels (COPVs), being used by the National Aeronautics and Space Administration (NASA) are currently under evaluation to better quantify their reliability and clarify their likelihood of failure due to stress rupture and age-dependent issues. As a result, some test and analysis programs have been successfully accomplished and other related programs are still in progress at the NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) and other NASA centers, with assistance from the commercial sector. To support this effort, a group of Nondestructive Evaluation (NDE) experts was assembled to provide NDE competence for pretest evaluation of test articles and for application of NDE technology to real-time testing. Techniques were required to provide assurance that the test article had adequate structural integrity and manufacturing consistency to be considered acceptable for testing and these techniques were successfully applied. Destructive testing is also being accomplished to better understand the physical and chemical property changes associated with progression toward "stress rupture" (SR) failure, and it is being associated with NDE response, so it can potentially be used to help with life prediction. Destructive work also includes the evaluation of residual stresses during dissection of the overwrap, laboratory evaluation of specimens extracted from the overwrap to evaluate physical property changes, and quantitative microscopy to inform the theoretical micromechanics.

Saulsberry, Regor; Greene, Nathanael; Cameron, Ken; Madaras, Eric; Grimes-Ledesma, Lorie; Thesken, John; Phoenix, Leigh; Murthy, Pappu; Revilock, Duane

2007-01-01

213

Pressure vessels fabricated with high-strength wire and electroformed nickel  

NASA Technical Reports Server (NTRS)

Metal pressure vessels of various shapes having high strength-to-weight ratios are fabricated by using known techniques of filament winding and electroforming. This eliminates nonuniform wall thickness and unequal wall strength which resulted from welding formed vessel segments together.

Roth, B.

1966-01-01

214

Filament-reinforced metal composite pressure vessel evaluation and performance demonstration  

NASA Technical Reports Server (NTRS)

Two different Kevlar-49 filament-reinforced metal sphere designs were developed, and six vessels of each type were fabricated and subjected to fatigue cycling, sustained loading, and hydrostatic burst. The 61 cm (24 inch) diameter Kevlar-49/cryoformed 301 stainless steel pressure vessels demonstrated the required pressure cycle capability, burst factor of safety, and a maximum pressure times volume divided by weight (pV/W) performance of 210 J/g (834 000 in-lb/lbm) at burst; this represented a 25 to 30% weight saving over the lightest weight comparable, 6A1-4V Ti, homogeneous pressure vessel. Both the Kevlar/stainless steel design and the 97 cm (38 inch) diameter Kevlar-49/2219-T62 aluminum sphere design demonstrated nonfragmentation and controlled failure mode features when pressure cycled to failure at operating pressure. When failure occurred during pressure cycling, the mode was localized leakage and not catastrophic. Kevlar/stainless steel vessels utilized a unique conical boss design, and Kevlar/aluminum vessels incorporated a tie-rod to carry port loads; both styles of polar fittings performed as designed during operational testing of the vessels.

Landes, R. E.

1976-01-01

215

Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement  

SciTech Connect

The objective of this project is to develop a technique for real-time monitoring of neutron dose and of the onset and progression of embrittlement in operating nuclear pressure vessels. The technique relies on the measurement of magnetic properties of steel and other magnetic materials which are extremely sensitive to radiation-induced properties changes. The approach being developed here is innovative and unique. It promises to be readily applicable to all existing and planned reactor structures. The significance of this program is that it addresses a major concern in the operation of existing nuclear pressure vessels. The development of microscopic defect clusters during irradiation in the nuclear pressure vessel beltline region leads to an increase in material yield strength and a concomitant decrease in ductility, or ability to absorb energy in fracture (i.e. fracture toughness). This decrease in fracture toughness is alarming since it may impair the ability of the pressure vessel to resist fracture during unusual loading situations.

Stubbins, J.F.; Ougouag, A.M.; Williams, J.G.

1992-07-01

216

Hydrogen degradation and microstructural effects of the near-threshold fatigue resistance of pressure vessel steels  

E-print Network

Safety of pressure vessels for applications such as coal conversion reactors requires understanding of the mechanism of environmentally-induced crack propagation and the mechanism by which process-induced microstructures ...

Fuquen-Molano, Rosendo

1982-01-01

217

Substantiation of Thermodynamic Criteria of Explosion Safety in Process of Severe Accidents in Pressure Vessel Reactors  

E-print Network

The paper represents original development of thermodynamic criteria of occurrence conditions of steam-gas explosions in the process of severe accidents. The received results can be used for modelling of processes of severe accidents in pressure vessel reactors.

Skalozubov, V I; Jarovoj, S S; Kochnyeva, V Yu

2012-01-01

218

Substantiation of Thermodynamic Criteria of Explosion Safety in Process of Severe Accidents in Pressure Vessel Reactors  

E-print Network

The paper represents original development of thermodynamic criteria of occurrence conditions of steam-gas explosions in the process of severe accidents. The received results can be used for modelling of processes of severe accidents in pressure vessel reactors.

V. I. Skalozubov; V. N. Vashchenko; S. S. Jarovoj; V. Yu. Kochnyeva

2012-03-27

219

98. ARAIII. ML1 reactor pressure vessel is lowered into reactor ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. ARA-III. ML-1 reactor pressure vessel is lowered into reactor pit by hoist. July 13, 1963. Ineel photo no. 63-4049. Photographer: Lowin. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

220

Finite elements in the analysis of pressure vessels and piping, an addendum (1996–1998)  

Microsoft Academic Search

The article gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures\\/components and piping from the theoretical as well as practical points of view. This bibliography is an addendum to the Finite elements in the analysis of pressure vessels and piping-a bibliography (1976–1996) published in the Int. J. Press. Ves. Piping 1996;69:279–339.

J. Mackerle

1999-01-01

221

Pressure Vessel with Impact and Fire Resistant Coating and Method of Making Same  

NASA Technical Reports Server (NTRS)

An impact and fire resistant coating laminate is provided which serves as an outer protective coating for a pressure vessel such as a composite overwrapped vessel with a metal lining. The laminate comprises a plurality of fibers (e.g., jute twine or other, stronger fibers) which are wound around the pressure vessel and an epoxy matrix resin for the fibers. The epoxy matrix resin including a plurality of microspheres containing a temperature responsive phase change material which changes phase in response to exposure thereof to a predetermined temperature increase so as to afford increased insulation and hear absorption.

DeLay, Thomas K. (Inventor)

2005-01-01

222

Analysis of gamma ray displacement damage in Light Water Reactor pressure vessels  

SciTech Connect

In addition to fast neutrons, the copious energetic gamma rays, present in a reactor environment, induce displacement damage in the reactor pressure vessel. The contribution of gamma ray damage to embrittlement is most pronounced in reactors with large water gaps separating the core from the reactor pressure vessel. Water moderates the energies of fast neutrons much more effectively than it attenuates the high energy gamma flux, and thus enhances the high energy gamma flux, incident on the vessel relative to the fast neutron flux. In this paper, an analysis of computer transport calculations is presented which quantifies the relative contribution of gamma ray damage in various pressure vessels. The results indicate that gamma ray damage must be included for accurate predictions of radiation-induced embrittlement.

Alexander, D.E.; Rehn, L.E.

1995-05-01

223

Brief account of the effect of overcooling accidents on the integrity of PWR pressure vessels  

SciTech Connect

The occurrence in recent years of several (PWR) accident initiating events that could lead to severe thermal shock to the reactor pressure vessel, and the growing awareness that copper and nickel in the vessel material significantly enhance radiation damage in the vessel, have resulted in a reevaluation of pressure-vessel integrity during postulated overcooling accidents. Analyses indicate that the accidents of concern are those involving both thermal shock and pressure loadings, and that an accident similar to that at Rancho Seco in 1978 could, under some circumstances and at a time late in the normal life of the vessel, result in propagation of preexistent flaws in the vessel wall to the extent that they might completely penetrate the wall. More severe accidents have been postulated that would result in even shorter permissible lifetimes. However, the state-of-the-art fracture-mechanics analysis may contain excessive conservatism, and this possibility is being investigated. Furthermore, there are several remedial measures, such as fuel shuffling, to reduce the damage rate, and vessel annealing, to restore favorable material properties, that may be practical and used if necessary. 5 figures.

Cheverton, R.D.

1982-01-01

224

OVERVIEW OF PRESSURE VESSEL DESIGN CRITERIA FOR INTERNAL DETONATION (BLAST) LOADING  

SciTech Connect

Spherical and cylindrical pressure vessels are often used to completely contain the effects of high explosions. These vessels generally fall into two categories. The first includes vessels designed for multiple use ([1]-[6]). Applications of such multiple-use vessels include testing of explosive components and bomb disposal. Because of the multiple-use requirement, response of the vessel is restricted to the elastic range. The second category consists of vessels designed for one-time use only ([7]-[9]). Vessels in this category are typically used to contain accidental explosions and are designed to efficiently utilize the significant plastic energy absorption capacity of ductile materials. Because these vessels may undergo large permanent plastic deformations, they may not be reusable. Ideally one would design a Containment Vessel according to some National or International Consensus Standard, such as the ASME Boiler and Pressure Vessel Code. Unfortunately, however, a number of issues preclude direct use of the ASME Code in its present form to the design of Containment Vessels. These issues are described in Section 2, along with a request for guidance from the PVRC as to a suitable path forward for developing appropriate ASME B&PV design guidance for Containment Vessels. Next, a discussion of the nature of impulsive loading as a result of an internal detonation of the high explosive within a Containment Vessel is described in Section 3. Ductile failure criteria utilized for LANL Containment Vessels are described in Section 4. Finally, brittle fracture criteria currently utilized by LANL are presented in Section 5. This memo is concluded with a brief summary of results and an appeal to PVRC to recommend and develop an appropriate path forward (Section 6). This path forward could be of a short-term specialized nature (e.g., Code Case) for specific guidance regarding design of the LANL Containment Vessels; a long-term development of a general design approach applicable to all Containment Vessels, including those at LANL; or a combination of the two. This memo supplements information provided in the viewgraphs of the Presentation by E.A. Rodriguez to be given to the PVRC at the May Meeting. The Presentation is entitled, ''Design Criteria for Internal Detonation (Blast) Loading''.

T. A. DUFFEY; E. A. RODRIGUEZ

2001-05-01

225

Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR (pressurized-water-reactor) plants  

SciTech Connect

Recent pressure-vessel surveillance data from the High Flux Isotope Reactor (HFIR) indicate an embrittlement fluence-rate effect that is applicable to the evaluation of the integrity of light-water reactor (LWR) pressure vessel supports. A preliminary evaluation using the HFIR data indicated increases in the nil ductility transition temperature at 32 effective full-power years (EFPY) of 100 to 130/degree/C for pressurized-water-reactor (PWR) vessel supports located in the cavity at midheight of the core. This result indicated a potential problem with regard to life expectancy. However, an accurate assessment required a detailed, specific-plant, fracture-mechanics analysis. After a survey and cursory evaluation of all LWR plants, two PWR plants that appeared to have a potential problem were selected. Results of the analyses indicate minimum critical flaw sizes small enough to be of concern before 32 EFPY. 24 refs., 16 figs., 7 tabs.

Cheverton, R.D.; Pennell, W.E.; Robinson, G.C.; Nanstad, R.K.

1988-01-01

226

Prediction of failure behavior of a welded pressure vessel containing flaws during a hydrogen-charged burst test  

SciTech Connect

An industry-government collaborative program was carried out with an aim to promoting the acceptance of fracture mechanics-based fitness-for-service assessment methodology for a service-damaged pressure vessel. A collaborative round robin exercise was carried out to predict the fracture behavior of a vessel containing hydrogen damage, fabrication-related lack-of-fusion defects, an artificially induced fatigue crack, and a localized thinned area. The fracture assessment procedures used include the US ASME Material Property Council`s PREFIS Program based on the British Standard (BS) Published Document (PD) 6493, ASME Section XI and The Central Electricity Generating Board (CEGB) R6 approach, The Welding Institute (TWI) CRACKWISE program (based on BS PD6493 Level 2 approach), a variant of the R6 approach, J-tearing instability approaches, various J-estimation schemes, LEFM approach, and simplified stress analysis. Assessments were compared with the results obtained from a hydrogen-charged burst test of the vessel. Predictions, based on the J-tearing approach, compared well with the actual burst test results. Actual burst pressure was about five times the operating pressure.

Bhuyan, G.S. [Powertech Labs Inc., Surrey, British Columbia (Canada); Sperling, E.J. [BP-Amoco, Calgary, Alberta (Canada); Shen, G. [CANMET, Ottawa, Ontario (Canada). Metals Technology Labs.; Yin, H. [Mobil Technology Co., Dallas, TX (United States); Rana, M.D. [Praxair, Inc., Tonawanda, NY (United States)

1999-08-01

227

Prediction of failure behavior of a welded pressure vessel containing flaws during a hydrogen-charged burst test  

SciTech Connect

An industry-government collaborative program was carried out with an aim to promoting the acceptance of fracture mechanics based fitness-for-service assessment methodology for a service-damaged pressure vessel. A collaborative round robin exercise was carried out to predict the fracture behavior of a vessel containing hydrogen damage, fabrication related lack-of-fusion defects, an artificially induced fatigue crack and a localized thinned area. The fracture assessment procedures used include the US ASME Material Property Council`s PREFIS Program based on the British Standard (BS) Published Document (PD) 6493, ASME Section XI and The Central Electricity Generating Board (CEGB) R6 approach; The welding Institute (TWI) CRACKWISE program (based on BS PD6493 Level 2 approach), a variant of the R6 approach, J-tearing instability approaches, various J-estimation schemes, LEFM approach and simplified stress analysis. Assessments were compared with the results obtained from a hydrogen charged burst test of the vessel. Predictions, based on the J-tearing approach, compared well with the actual burst test results. Actual burst pressure was about five times the operating pressure.

Bhuyan, G.S. [Powertech Labs. Inc., Surrey, British Columbia (Canada); Sperling, E.J. [Amoco Corp., Naperville, IL (United States); Shen, G. [CANMET, Ottawa, Ontario (Canada). Metals Technology Labs.; Yin, H. [Mobil Research and Development Corp., Farmers Branch, TX (United States); Rana, M.D. [Praxair, Inc., Tonawanda, NY (United States)

1996-12-01

228

Creep failure of a reactor pressure vessel lower head under severe accident conditions  

Microsoft Academic Search

A severe accident in a nuclear power plant could result in the relocation of large quantities of molten core material onto the lower head of he reactor pressure vessel (RPV). In the absence of inherent cooling mechanisms, failure of the RPV ultimately becomes possible under the combined effects of system pressure and the thermal heat-up of the lower head. Sandia

M. M. Pilch; J. S. Ludwigsen; T. Y. Chu; Y. R. Rashid

1998-01-01

229

Safety against brittle fracture of the reactor pressure vessel in the nuclear power plant Obrigheim  

Microsoft Academic Search

Obrigheim, the first pressurized light water reactor built in Germany, operates with a nominal power of 357 MW. Since the beginning of electricity production in 1968 the nuclear power plant Obrigheim (KWO) has proved to be a reliable and safe operation with a high availability, in terms of time, of 81.4% over 29 years. The reactor pressure vessel could be

R Bartsch; M Wenk

2000-01-01

230

Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels  

SciTech Connect

It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The former condition was chosen with the intent of using the welds in either the 'as welded' condition or after a simple low-temperature aging treatment. Since preliminary stress-analyses showed that stresses in and near the welds would probably exceed the yield-strength of both 'as welded' and welded and aged weld-joints, a post-weld solution-treatment, quenching, and aging treatment was also examined. Once a suitable set of welding and post-weld heat-treatment parameters was established, the project divided into two parts. The first part concentrated on developing the necessary process information to be able to make defect-free friction-stir welds in 3.8 cm. thick Al alloy 2219 in the form of circumferential welds that would join two hemispherical forgings with a 102 cm. inside diameter. This necessitated going to a bobbin-tool welding-technique to simplify the tooling needed to react the large forces generated in friction-stir welding. The bobbin-tool technique was demonstrated on both flat-plates and plates that were bent to the curvature of the actual vessel. An additional issue was termination of the weld, i.e. closing out the hole left at the end of the weld by withdrawal of the friction-stir welding tool. This was accomplished by friction-plug welding a slightly-oversized Al alloy 2219 plug into the termination-hole, followed by machining the plug flush with both the inside and outside surfaces of the vessel. The second part of the project involved demonstrating that the welds were fit for the intended service. This involved determining the room-temperature tensile and elastic-plastic fracture-toughness properties of the bobbin-tool friction-stir welds after a post-weld solution-treatment, quenching, and aging heat-treatment. These mechanical properties were used to conduct fracture-mechanics analyses to determine critical flaw sizes. Phased-array and conventional ultrasonic non-destructive examination was used to demonstrate that no flaws that match or exceed the calculated critical flaw-sizes exist in or near the friction-stir welds.

Dalder, E C; Pastrnak, J W; Engel, J; Forrest, R S; Kokko, E; Ternan, K M; Waldron, D

2007-06-06

231

Evaluation of hydrogen pressure vessels using slow strain rate testing and fracture mechanics analysis  

SciTech Connect

A total of 108 seamless, forged pressure vessels, fabricated from ASTM A372 type IV (UNS K14508) and type V low alloy steel, are currently in 4,200 psi (29 MPa) gaseous hydrogen (GH{sub 2}) service at the Kennedy Space Center`s (KSC) Space Shuttle Launch Complex 39 (LC-39). The vessels were originally used in 6,000 psi (41 MPa) GH{sub 2} service during the Apollo program. NASA recently received a letter of warning from the manufacturer of the vessels stating that the subject vessels should be now be removed from GH{sub 2} service due to the fact that the ultimate tensile strength (UTS) of many of the vessels exceeds the maximum limit of 126 ksi (869 MPa) now imposed on A372 steel intended for GH{sub 2} service, and therefore are susceptible to hydrogen environment embrittlement. Due to the expense associated with vessel replacement, it was decided to determine by testing and analysis whether or not the vessels needed to be removed from GH{sub 2} service. Slow strain rate testing was performed under hydrogen charging conditions to determine the value of the threshold fracture toughness for sustained loading crack growth in GH{sub 2}, (K{sub H}) for the vessel material, this value was then used in a fracture mechanics safe-life analysis (a 20-year service life was modeled) that indicated the vessels are safe for continued use.

Murray, S.H. [National Aeronautics and Space Administration, Kennedy Space Center, FL (United States). Materials Science Div.; Desai, V.H. [Univ. of Central Florida, Orlando, FL (United States)

1998-12-31

232

A novel high pressure, high temperature vessel used to conduct long-term stability measurements of silicon MEMS pressure transducers  

NASA Astrophysics Data System (ADS)

The need to quantify and to improve long-term stability of pressure transducers is a persistent requirement from the aerospace sector. Specifically, the incorporation of real-time pressure monitoring in aircraft landing gear, as exemplified in Tire Pressure Monitoring Systems (TPMS), has placed greater demand on the pressure transducer for improved performance and increased reliability which is manifested in low lifecycle cost and minimal maintenance downtime through fuel savings and increased life of the tire. Piezoresistive (PR) silicon MEMS pressure transducers are the primary choice as a transduction method for this measurement owing to their ability to be designed for the harsh environment seen in aircraft landing gear. However, these pressure transducers are only as valuable as the long-term stability they possess to ensure reliable, real-time monitoring over tens of years. The "heart" of the pressure transducer is the silicon MEMS element, and it is at this basic level where the long-term stability is established and needs to be quantified. A novel High Pressure, High Temperature (HPHT) vessel has been designed and constructed to facilitate this critical measurement of the silicon MEMS element directly through a process of mechanically "floating" the silicon MEMS element while being subjected to the extreme environments of pressure and temperature, simultaneously. Furthermore, the HPHT vessel is scalable to permit up to fifty specimens to be tested at one time to provide a statistically significant data population on which to draw reasonable conclusions on long-term stability. With the knowledge gained on the silicon MEMS element, higher level assembly to the pressure transducer envelope package can also be quantified as to the build-effects contribution to long-term stability in the same HPHT vessel due to its accommodating size. Accordingly, a HPHT vessel offering multiple levels of configurability and robustness in data measurement is presented, along with 10 year long-term stability results.

Wisniewiski, David

2014-03-01

233

The effect of spacing and location of bolt holes of steel flanges for pressure vessels and piping  

E-print Network

the data obtaine4 were used in 4eveloping an analysis oi the stresses in hubbed flanges having a large oircular fillet at the Junction of hub and ring. When the rules for flanges in the A. S. M. E. and the A. P. I. -A. S. M. E. Unfired Pressure Vessel... assumptions which gave rise to 4'ifficulties. The method of handling hubs of non-uniform thickness, such as tapered hubs and large oircular fillets, proved unsatisfaotory. It was oonsidered that the formulas did not give proper credit for reinforcement...

Hall, Harris Harlan

2012-06-07

234

Variabilities detected by acoustic emission from filament-wound Aramid fiber/epoxy composite pressure vessels  

NASA Technical Reports Server (NTRS)

Two hundred and fifty Aramid fiber/epoxy pressure vessels were filament-wound over spherical aluminum mandrels under controlled conditions typical for advanced filament-winding. A random set of 30 vessels was proof-tested to 74% of the expected burst pressure; acoustic emission data were obtained during the proof test. A specially designed fixture was used to permit in situ calibration of the acoustic emission system for each vessel by the fracture of a 4-mm length of pencil lead (0.3 mm in diameter) which was in contact with the vessel. Acoustic emission signatures obtained during testing showed larger than expected variabilities in the mechanical damage done during the proof tests. To date, identification of the cause of these variabilities has not been determined.

Hamstad, M. A.

1978-01-01

235

Optical fiber sensors in health monitoring of composite high-pressure vessels for hydrogen  

NASA Astrophysics Data System (ADS)

In the present work we present the results of our latest research into an implementation of optical fiber sensors for flaw tolerance test application on high pressure composite hydrogen vessels. For monitoring influence of flaws on composite parameters, as point measurement heads permanently installed on tank's surface, fiber Bragg gratings (FBG) were used. The aim of our experiments was to examine structural behavior of the composite hydrogen vessels and test appropriate topologies of sensors to detect the damages.

G?sior, Pawe?; Kaleta, Jerzy; Sankowska, Anna

2007-06-01

236

Effect of gravitation stress and hypokinesia on blood vessels of the testicle  

NASA Technical Reports Server (NTRS)

Rabbits were exposed to single maximum endurable stresses of cranio-caudal direction, hypokinesia for periods of one to eight weeks, and hypokinesia followed by gravitation stresses. The stresses caused dilatation of vessels, greater sinuosity, and occasional ruptures of the walls and extravasation. The greater part of the capillaries were dilated; the greatest part constricted. In hypokinesia there was an increasing atrophy of the testes. Significant results are reported.

Palazhchenko, E. F.

1979-01-01

237

Pressure vessel with improved impact resistance and method of making the same  

NASA Technical Reports Server (NTRS)

A composite overwrapped pressure vessel is provided which includes a composite overwrapping material including fibers disposed in a resin matrix. At least first and second kinds of fibers are used. These fibers typically have characteristics of high strength and high toughness to provide impact resistance with increased pressure handling capability and low weight. The fibers are applied to form a pressure vessel using wrapping or winding techniques with winding angles varied for specific performance characteristics. The fibers of different kinds are dispersed in a single layer of winding or wound in distinct separate layers. Layers of fabric comprised of such fibers are interspersed between windings for added strength or impact resistance. The weight percentages of the high toughness and high strength materials are varied to provide specified impact resistance characteristics. The resin matrix is formed with prepregnated fibers or through wet winding. The vessels are formed with or without liners.

DeLay, Thomas K. (Inventor); Patterson, James E. (Inventor); Olson, Michael A. (Inventor)

2010-01-01

238

Reactor pressure vessel structural integrity research in the US Nuclear Regulatory Commission HSST and HSSI Programs  

SciTech Connect

This report discusses development on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels containing flaws. Fracture mechanics tests on reactor pressure vessel steel have shown that local brittle zones do not significantly degrade the material fracture toughness, constraint relaxation at the crack tip of shallow surface flaws results in increased fracture toughness, and biaxial loading reduces but does not eliminate the shallow-flaw fracture toughness elevation. Experimental irradiation investigations have shown that the irradiation-induced shift in Charpy V-notch versus temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement and the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties.

Pennell, W.E.; Corwin, W.R.

1994-02-01

239

Simple method for forming thin-wall pressure vessels  

NASA Technical Reports Server (NTRS)

Application of internal hydrostatic pressure to seam-welded circular cylindrical tanks having corner-welded, flat, circular ends forms large thin-walled high quality tanks. Form limits expansion of cylindrical portion of final tank while hemispherical ends develop freely; no external form or restraint is required to fabricate spherical tanks.

Erickson, A. L.; Guist, L. R.

1972-01-01

240

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs) . Volume 2; Appendices  

NASA Technical Reports Server (NTRS)

In coordination with the Office of Safety and Mission Assurance and the respective Center Pressure System Managers (PSMs), the NASA Engineering and Safety Center (NESC) was requested to formulate a consensus draft proposal for the development of additional testing and analysis methods to establish the technical validity, and any limitation thereof, for the continued safe operation of facility non-code layered pressure vessels. The PSMs from each NASA Center were asked to participate as part of the assessment team by providing, collecting, and reviewing data regarding current operations of these vessels. This document contains the appendices to the main report.

Prosser, William H.

2014-01-01

241

Ten year environmental test of glass fiber/epoxy pressure vessels  

NASA Technical Reports Server (NTRS)

By the beginning of the 1970's composite pressure vessels had received a significant amount of development effort, and applications were beginning to be investigated. One of the first applications grew out of NASA Johnson Space Center efforts to develop a superior emergency breathing system for firemen. While the new breathing system provided improved wearer comfort and an improved mask and regulator, the primary feature was low weight which was achieved by using a glass fiber reinforced aluminum pressure vessel. Part of the development effort was to evaluate the long term performance of the pressure vessel and as a consequence, some 30 bottles for a test program were procured. These bottles were then provided to NASA Lewis Research Center where they were maintained in an outdoor environment in a pressurized condition for a period of up to 10 yr. During this period, bottles were periodically subjected to cyclic and burst testing. There was no protective coating applied to the fiberglass/epoxy composite, and significant loss in strength did occur as a result of the environment. Similar bottles stored indoors showed little, if any, degradation. This report contains a description of the pressure vessels, a discussion of the test program, data for each bottle, and appropriate plots, comparisons, and conclusions.

Faddoul, J. R.

1985-01-01

242

Subcritical crack growth of selected aerospace pressure vessel materials  

NASA Technical Reports Server (NTRS)

This experimental program was undertaken to determine the effects of combined cyclic/sustained loads, stress level, and crack shape on the fatigue crack growth rate behavior of cracks subjected to plane strain conditions. Material/environment combinations tested included: 2219-T87 aluminum plate in gaseous helium, room air, and 3.5% NaCl solution at room temperature, liquid nitrogen, and liquid hydrogen; 5Al-2.5 Sn (ELI) titanium plate in liquid nitrogen and liquid hydrogen and 6AL-4V (ELI) STA titanium plate in gaseous helium and methanol at room temperature. Most testing was accomplished using surface flawed specimens instrumented with a clip gage to continuously monitor crack opening displacements at the specimen surface. Tapered double cantilever beam specimens were also tested. Static fracture and ten hour sustained load tests were conducted to determine fracture toughness and apparent threshold stress intensity values. Cyclic tests were performed using sinusoidal loading profiles at 333 MHz (20 cpm) and trapezoidal loading profiles at both 8.3 MHz (0.5 cpm) and 3.3 MHz (0.2 cpm). Data were evaluated using modified linear elastic fracture mechanics parameters.

Hall, L. R.; Bixler, W. D.

1972-01-01

243

Failure Analysis of Weld Cracking in a Thick-Walled 2.25Cr-1Mo Steel Pressure Vessel  

NASA Astrophysics Data System (ADS)

A crack in thick-walled 2.25Cr-1Mo steel pressure vessel girth weld was found during manufacturing. To investigate the cause of failure, optical microscopy, scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, and microhardness tester were used in this study. According to test results, the fracture is classified as reheat cracking with multiple origins. The cracking occurred during surfacing or final post-weld heat treatment process. Coarse-grains in the weld and bulk-carbides precipitated along grain boundaries induced by multiple heating are main causes of the fracture from material aspect, while high level of the hoop stress component and excess localized deformation in stress relief procedure are mechanical aspect causes of the cracking. The fracture surfaces present major intergranular feature with a small fraction of transgranular morphologies. Large numbers of M3C and M23C6 carbides particles were found on the fracture surface, these carbides mainly precipitated on prior austenite-grain boundaries, columnar-grain boundaries, and sub-grain boundaries. Additionally, several proposals were also offered to reduce weld cracking of 2.25Cr-1Mo steel pressure vessels.

Lei, Xiaowei; Niu, Jing; Zhang, Jianxun; Fu, Anqing; Feng, Yaorong

2014-04-01

244

Fast neutron fluence of yonggwang nuclear unit 1 reactor pressure vessel  

SciTech Connect

The Code of Federal Regulations, Title 10, Part 50, Appendix H, requires that the neutron dosimetry be present to monitor the reactor vessel throughout plant life. The Ex-Vessel Neutron Dosimetry System has been installed for Yonggwang Nuclear Unit 1 after complete withdrawal of all six in-vessel surveillance capsules. This system has been installed in the reactor cavity annulus in order to measure the fast neutron spectrum coming out through the reactor pressure vessel. Cycle specific neutron transport calculations were performed to obtain the energy dependent neutron flux throughout the reactor geometry including dosimetry positions. Comparisons between calculations and measurements were performed for the reaction rates of each dosimetry sensors and results show good agreements. (authors)

Yoo, C.; Km, B.; Chang, K.; Leeand, S. [Korea Atomic Energy Research Inst., 150 Dukjin-dong, Yuseung-gu, Daejeon 305-353 (Korea, Republic of); Park, J. [Chungnam National Univ., 220 Gung-dong, Yuseung-gu, Daejeon 305-764 (Korea, Republic of)

2006-07-01

245

Reactor Pressure Vessel Temperature Analysis for Prismatic and Pebble-Bed VHTR Designs  

SciTech Connect

Analyses were performed to determine maximum temperatures in the reactor pressure vessel for two potential Very-High Temperature Reactor (VHTR) designs during normal operation and during a depressurized conduction cooldown accident. The purpose of the analyses was to aid in the determination of appropriate reactor vessel materials for the VHTR. The designs evaluated utilized both prismatic and pebble-bed cores that generated 600 MW of thermal power. Calculations were performed for fluid outlet temperatures of 900 and 950 °C, corresponding to the expected range for the VHTR. The analyses were performed using the RELAP5-3D and PEBBED-THERMIX computer codes. Results of the calculations were compared with preliminary temperature limits derived from the ASME pressure vessel code.

H. D. Gougar; C. B. Davis

2006-04-01

246

The LEPRICON code system: Consolidation of transport analytical and unfolding procedures in LWR pressure vessel dosimetry  

SciTech Connect

The LEPRICON (for {und L}east-Squares {und E}lectric {und P}ower {und R}esearch {und I}nstitute {und Con}solidation program) code system has been developed over the past 10 yr to provide a complete analysis of light water reactor (LWR) pressure vessel dosimetry. The system incorporates nine modules. All but one of the modules treat various aspects of neutron transport from the core through the reactor internals to dosimetry locations in the downcomer and/or reactor cavity regions and to critical fluence locations in the pressure vessel. The LEPRICON adjustment module, on the other hand, performs a state-of-the-art least-squares analysis of the results from the transport modules, a procedure often referred to as spectral unfolding or the combining of integral and differential data. In terms of development, the adjustment module alone required {approximately}70% of the total effort, for reasons that soon will become apparent. The results from the LEPRICON system thus represent prior and adjusted fluences in each of 38 groups from 0.1 to 20 MeV, along with their corresponding standard deviations, at critical locations in the pressure vessel. The complete LEPRICON methodology provides a comprehensive and accurate analysis of LWR dosimetry and, as a result, has been recommended as serving the needs of the US Nuclear Regulatory Commission for extended pressure vessel lifetime monitoring.

Maerker, R.E. (Oak Ridge National Lab., TN (USA))

1988-01-01

247

Design by analysis versus design by formula of high strength steel pressure vessels: a comparative study  

Microsoft Academic Search

A comparative study for design by analysis and design by formula of a cylinder to nozzle intersection has been made using different finite element techniques. The cylinder to nozzle intersection investigated is part of a typical vertical pressure vessel with a skirt support. For the study the commonly used ductile P355 steel alloy and the high strength steel alloy P500

A. Th. Diamantoudis; Th. Kermanidis

2005-01-01

248

Quantification of the toughness distribution in a heavy section submerged arc multilayer reactor pressure vessel weldment  

Microsoft Academic Search

In a working procedure qualification test weld representing a heavy section circumferential reactor pressure vessel (RPV) weld tested in 1968, lower toughness values were observed in the top layer region compared to those found in the filler region. Gleeble simulation, extensive microscopic evaluation, diligent Charpy V-notch testing and modelling of the bead sequence and distribution of alloying elements was applied

H Cerjak; G Nagel; R Prader

1999-01-01

249

Certification Testing and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen Storage  

E-print Network

pressure vessels. Introduction Hydrogen-fueled vehicles present features that make them serious candidates as alternatives to today's petroleum-powered vehicles. Hydrogen vehicles can use the advanced technology it provides a 640-km (400-mile) range in a 34 km/liter (80 mpg) hybrid vehicle or fuel cell vehicle. Storing

250

REACTOR PRESSURE VESSEL ISSUES FOR THE LIGHT-WATER REACTOR SUSTAINABILITY PROGRAM  

Microsoft Academic Search

The Light Water Reactor Sustainability Program Plan is a collaborative program between the U.S. Department of Energy and the private sector directed at extending the life of the present generation of nuclear power plants to enable operation to at least 80 years. The reactor pressure vessel (RPV) is one of the primary components requiring significant research to enable such long-term

Randy K Nanstad; George Robert Odette

2010-01-01

251

Catalase activity measured with a micro oxygen electrode in a pressurized reaction vessel. [Mice, rats  

Microsoft Academic Search

The assembly and the use of a simple airtight pressurized reaction vessel are described for the measurement of catalase activity with a micro oxygen electrode in an optically heterogenous medium. The oxygen concentration is expressed as the ratio of observed current to the current in an air-saturated solution. Thus, an individual standard can be obtained for each measurement and the

Halbach

1977-01-01

252

Finite elements in the analysis of pressure vessels and piping—a bibliography (1976–1996)  

Microsoft Academic Search

The paper gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures\\/components and piping from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore the aim of this review is to give

Jaroslav Mackerle

1996-01-01

253

A Modification of the Inner and Outer Core for Reactor Pressure Vessel Lifetime Extension  

Microsoft Academic Search

The feasibility of nuclear power plant lifetime extension was examined by reducing the fast neutron fluence at the reactor pressure vessel (RPV) and relieving irradiation embrittlement of materials, and thus ensuring enough structural integrity beyond the design lifetime. Two fluence reduction options, peripheral assembly replacement and additional shield installation in the outer core structures, were applied to the Kori Unit-1

Bo Kyun Seo; Jong Kyung Kim; Chang Ho Shin; Tae Je Kwon

2001-01-01

254

Mechanisms of microbubble-vessel interactions and induced stresses: A numerical study  

PubMed Central

Oscillating microbubbles within microvessels could induce stresses that lead to bioeffects or vascular damage. Previous work has attributed vascular damage to the vessel expansion or bubble jet. However, ultra-high speed images of recent studies suggest that it could happen due to the vascular invagination. Numerical simulations of confined bubbles could provide insight into understanding the mechanism behind bubble–vessel interactions. In this study, a finite element model of a coupled bubble/fluid/vessel system was developed and validated with experimental data. Also, for a more realistic study viscoelastic properties of microvessels were assessed and incorporated into this comprehensive numerical model. The wall shear stress (WSS) and circumferential stress (CS), metrics of vascular damage, were calculated from these simulations. Resultant amplitudes of oscillation were within 15% of those measured in experiments (four cases). Among the experimental cases, it was numerically found that maximum WSS values were between 1.1–18.3?kPa during bubble expansion and 1.5–74?kPa during bubble collapse. CS was between 0.43–2.2?MPa during expansion and 0.44–6?MPa while invaginated. This finding confirmed that vascular damage could occur during vascular invaginations. Predicted thresholds in which these stresses are higher during vessel invagination were calculated from simulations. PMID:23967921

Hosseinkhah, N.; Chen, H.; Matula, T. J.; Burns, P. N.; Hynynen, K.

2013-01-01

255

Development of a production prototype pressure vessel imaging system. Final report  

SciTech Connect

Advances in fracture mechanics techniques used to perform structural analyses of weld zones in nuclear reactor pressure vessels have generated an increasing need for more accurate data than can be provided by current in-service inspection (ISI) pulse-echo ultrasonic (UT) methods. Research efforts have been successful and have produced proof-of-principle prototypes that significantly advanced the development of improved inspection technology and formed the basis for RP606-8, Development of a Production Prototype Pressure Vessel Imaging System (PVIS), which is the final phase preceding full commercialization. The production prototype was designed as an add-on tool for existing Pressurized Water Reactor (PWR) ISI and, in addition to conventional UT inspection data, it provides plan and section views, three-dimensional (3-D) isometric displays, and holographic imaging.

Neeley, V.I.

1983-10-01

256

Dosimetry analyses of the Ringhals 3 and 4 reactor pressure vessels  

SciTech Connect

A comprehensive series of neutron dosimetry measurements consisting of surveillance capsules, reactor pressure vessel cladding samples, and ex-vessel neutron dosimetry has been analyzed and compared to the results of three-dimensional, cycle-specific neutron transport calculations for the Ringhals Unit 3 and Unit 4 reactors in Sweden. The comparisons show excellent agreement between calculations and measurements. The measurements also demonstrate that it is possible to perform retrospective dosimetry measurements using the {sup 93}Nb (n,n') {sup 93m}Nb reaction on samples of 18-8 austenitic stainless steel with only trace amounts of elemental niobium. (authors)

Kulesza, J.A.; Fero, A.H. [Westinghouse Electric Company, Cranberry Township, PA 16066 (United States); Rouden, J.; Green, E.L. [Vattenfall/Ringhals AB, 432 85 Vaeroebacka (Sweden)

2011-07-01

257

Next Generation Nuclear Plant Reactor Pressure Vessel Materials Research and Development Plan (PLN-2803)  

SciTech Connect

The U.S. Department of Energy has selected the High Temperature Gas-cooled Reactor design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900°C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic, or pebble-bed reactor and use low-enriched uranium, Tri-Isotopic-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development Program is responsible for performing research and development on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. Studies of potential Reactor Pressure Vessel (RPV) steels have been carried out as part of the pre-conceptual design studies. These design studies generally focus on American Society of Mechanical Engineers (ASME) Code status of the steels, temperature limits, and allowable stresses. Three realistic candidate materials have been identified by this process: conventional light water reactor RPV steels A508/533, 2¼Cr-1Mo in the annealed condition, and modified 9Cr 1Mo ferritic martenistic steel. Based on superior strength and higher temperature limits, the modified 9Cr-1Mo steel has been identified by the majority of design engineers as the preferred choice for the RPV. All of the vendors have concluded, however, that with adequate engineered cooling of the vessel, the A508/533 steels are also acceptable.

J. K. Wright; R. N. Wright

2008-04-01

258

Atom probe characterization of the microstructure of nuclear pressure vessel surveillance materials after neutron irradiation and after annealing treatments  

NASA Astrophysics Data System (ADS)

Microstructural changes due to neutron irradiation of weld and forging materials were characterized using the atom probe field ion microscope (APFIM). Neutron-induced clusters containing Cu, P, Ni, Mn and Si were detected in the high copper weld (0.24 at.% Cu) after irradiation to fluences of 6.6 × 10 22 and 3.47 × 10 23 n m -2; only phosphorus atmospheres were observed in the low copper forging material (0.02 at.% Cu) irradiated to an intermediate fluence of 1.5 × 10 23 n m -2. These results are in agreement with previous studies and with their respective measured transition temperature shifts. In addition, APFIM experiments were carried out on the high fluence weld material after two post-irradiation annealing treatments. The first annealing treatment of 168 h at 454°C is similar to the proposed condition for in situ pressure vessel annealing and the second, 29 h at 610°C, is similar to the final stress relief heat treatment employed in vessel fabrication. Annealing at 454°C led to coarsening of the copper-enriched precipitates and a 92% recovery of the radiation-induced transition temperature shift. Essentially complete rehomogenization of the solutes was obtained in the simulated stress relief treatment at 610°C.

Pareige, P.; Stoller, R. E.; Russell, K. F.; Miller, M. K.

1997-10-01

259

Predictive reactor pressure vessel steel irradiation embrittlement models: Issues and opportunities  

NASA Astrophysics Data System (ADS)

Nuclear plant life extension to 80 years will require accurate predictions of neutron irradiation-induced increases in the ductile-brittle transition temperature (?T) of reactor pressure vessel steels at high fluence conditions that are far outside the existing database. Remarkable progress in mechanistic understanding of irradiation embrittlement has led to physically motivated ?T correlation models that provide excellent statistical fits to the existing surveillance database. However, an important challenge is developing advanced embrittlement models for low flux-high fluence conditions pertinent to extended life. These new models must also provide better treatment of key variables and variable combinations and account for possible delayed formation of “late blooming phases” in low copper steels. Other issues include uncertainties in the compositions of actual vessel steels, methods to predict ?T attenuation away from the reactor core, verification of the master curve method to directly measure the fracture toughness with small specimens and predicting ?T for vessel annealing remediation and re-irradiation cycles.

Odette, G. R.; Nanstad, R. K.

2009-07-01

260

Under Pressure: Sensing Stress of Computer Users Javier Hernandez1  

E-print Network

completely aware about feeling stressed, your body was experiencing a chain of physiological changes: pupilUnder Pressure: Sensing Stress of Computer Users Javier Hernandez1 Pablo Paredes2 Asta Roseway3 when computer users are stressed can help reduce their frustration and prevent a large variety

261

Multifractal characterization of blood pressure dynamics: stress-induced phenomena  

Microsoft Academic Search

We investigate the scaling features of blood pressure dynamics in healthy rats by means of the wavelet transform modulus maxima method. We discuss how stress affects the phenomenon of multifractality in the cardiovascular dynamics. Typical reactions to stress are considered, and distinctions in the stress-induced effects for male and female rats are reported. 2004 Elsevier Ltd. All rights reserved.

A. N. Pavlov; A. R. Ziganshin; O. A. Klimova

2005-01-01

262

A Multiscale Modeling Approach to Analyze Filament-Wound Composite Pressure Vessels  

SciTech Connect

A multiscale modeling approach to analyze filament-wound composite pressure vessels is developed in this article. The approach, which extends the Nguyen et al. model [J. Comp. Mater. 43 (2009) 217] developed for discontinuous fiber composites to continuous fiber ones, spans three modeling scales. The microscale considers the unidirectional elastic fibers embedded in an elastic-plastic matrix obeying the Ramberg-Osgood relation and J2 deformation theory of plasticity. The mesoscale behavior representing the composite lamina is obtained through an incremental Mori-Tanaka type model and the Eshelby equivalent inclusion method [Proc. Roy. Soc. Lond. A241 (1957) 376]. The implementation of the micro-meso constitutive relations in the ABAQUS® finite element package (via user subroutines) allows the analysis of a filament-wound composite pressure vessel (macroscale) to be performed. Failure of the composite lamina is predicted by a criterion that accounts for the strengths of the fibers and of the matrix as well as of their interface. The developed approach is demonstrated in the analysis of a filament-wound pressure vessel to study the effect of the lamina thickness on the burst pressure. The predictions are favorably compared to the numerical and experimental results by Lifshitz and Dayan [Comp. Struct. 32 (1995) 313].

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-07-22

263

Pore-pressure gradients, stresses, and induced earthquakes  

Microsoft Academic Search

In the theory of poroelasticity, spatial gradients in pore-pressure enter the equilibrium equations in the same way as distributed body forces. Pore-pressure gradients are thus associated with poroelastic stresses in the same way that temperature gradients associated with thermoelastic stresses. The author has suggested that pore-pressure gradients caused by pumping are responsible for earthquakes near some oil and gas fields.

Segall

1992-01-01

264

Uniform Transmural Strain in Pre-Stressed Arteries Occurs at Physiological Pressure  

PubMed Central

Residual deformation (strain) exists in arterial vessels, and has been previously proposed to induce homogeneous transmural strain distribution. In this work, we present analytical formulations that predict the existence of a finite internal (homeostatic) pressure for which the transmural deformation is homogenous, and the corresponding stress field. We provide evidence on the physical existence of homeostatic pressure when the artery is modeled as an incompressible tube with orthotropic constitutive strain-energy function. Based on experimental data of rabbit carotid arteries and porcine coronary arteries, the model predicts a homeostatic mean pressure of ~90 mmHg and 70–120 mmHg, respectively. The predictions are well within the physiological pressure range. Some consequences of this strain homogeneity in the physiological pressure range are explored under the proposed assumptions. PMID:22763133

Destrade, Michel; Liu, Yi; Murphy, Jeremiah G.; Kassab, Ghassan S.

2012-01-01

265

An Improved Method for Postulating Fabrication Flaws in Reactor Pressure Vessels for Structural Integrity Evaluation  

SciTech Connect

This paper presents an improved model for postulating fabrication flaws in reactor pressure vessels (RPVs) and for the treatment of measured flaw data by probabilistic fracture mechanics (PFM) codes that are used for structural integrity evaluations. The model used to develop the current pressurized thermal shock (PTS) regulations conservatively postulated that all fabrication flaws were inner-surface breaking flaws. To reduce conservatisms and uncertainties in flaw-related inputs, the United States Nuclear Regulatory Commission (USNRC) has supported research at Pacific Northwest National Laboratory (PNNL) that has resulted in data on fabrication flaws from non-destructive and destructive examinations of actual RPV material. Statistical distributions have been developed to characterize the number and sizes of flaws in the various material regions of a vessel. The regions include the main seam welds, repair welds, base metal of plates and forgings, and the cladding that is applied to the inner surface of the vessel. Flaws are also characterized as being located within the interior of these regions or along the weld fusion lines that join the regions. Flaws are taken that occur at random locations relative to the embrittled inner region of the vessel. The probabilistic fracture mechanics model associates each of the simulated flaw types with the fracture properties of the region being addressed. (authors)

Simonen, F.A. [Pacific Northwest National Laboratory, P.O. Box 999 Richland, WA 99352 (United States); Dickson, T.L. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)

2002-07-01

266

Fabrication Flaw Density and Distribution in the Repairs of Reactor Pressure Vessels  

SciTech Connect

The Pacific Northwest National Laboratory (PNNL) is developing a generalized flaw size and density distribution for the population of U.S. reactor pressure vessels (RPVs). The purpose of the generalized flaw distribution is to predict vessel specific flaw rates for use in probabilistic fracture mechanics calculations that estimate vessel failure probability. Considerable progress has been made on the construction of an engineering data base of fabrication flaws in U.S. nuclear RPVs. The fabrication processes and product forms used to construct U.S. RPVs are represented in the data base. A validation methodology has been developed for characterizing the flaws for size, shape, orientation, and composition. The relevance of construction records has been established for describing fabrication processes and product forms. The fabrication flaws were detected in material removed from cancelled nuclear power plants using high sensitivity nondestructive ultrasonic testing, and validated by other nondestructive evaluation (NDE) techniques, and complemented by destructive testing. This paper describes research that has generated data on welding flaws, which indicated that the largest flaws occur in weld repairs. Recent research results confirm that repair flaws are complex in composition and may include cracks on the repair ends. Section III of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code for nuclear power plant components requires radiographic examinations (RT) of welds and requires repairs for RT indications that exceed code acceptable sizes. PNNL has previously obtained the complete construction records for two RPVs. Analysis of these records show a significant change in repair frequency.

Schuster, George J.; Doctor, Steven R.; Simonen, Fredric A.

2006-02-15

267

The LEPRICON code system: Consolidation of transport analytical and unfolding procedures in LWR pressure vessel dosimetry  

Microsoft Academic Search

The LEPRICON (for {und L}east-Squares {und E}lectric {und P}ower {und R}esearch {und I}nstitute {und Con}solidation program) code system has been developed over the past 10 yr to provide a complete analysis of light water reactor (LWR) pressure vessel dosimetry. The system incorporates nine modules. All but one of the modules treat various aspects of neutron transport from the core through

Maerker

1988-01-01

268

Investigation of black spots and other blemishes inside small stainless steel pressure vessels  

SciTech Connect

Black spots and other blemishes were found on the inside surface of small stainless steel pressure vessels by borescope inspection. Most of the black spots originated from pyrolysis of lint contaminating the interior surface of these parts prior to welding. The lint originated from cotton gloves used to handle parts and from cotton gauze used to clean the parts. Pyrolysis of other hydrocarbons can also create black spots. 34 figs.

Heiple, C.R.; Doyle, J.H.; Burgardt, P.

1990-08-14

269

Results of examinations of pressure vessel samples and instrument nozzles from the TMI2 lower head  

Microsoft Academic Search

15 prism-shaped steel samples were removed from the lower head of the damaged Three Mile Island Unit 2 (TMI-2) nuclear reactor pressure vessel to assess the effects of approximately 19 tonne of molten core debris that had relocated there during the 1979 loss-of-coolant accident. Metallographic examinations of the samples revealed that inside-surface temperatures of 800–1100°C were attained during the accident,

G. E. Korth; D. R. Diercks; L. A. Neimark

1997-01-01

270

Pressure vessel sliding support unit and system using the sliding support unit  

DOEpatents

Provided is a sliding support and a system using the sliding support unit. The sliding support unit may include a fulcrum capture configured to attach to a support flange, a fulcrum support configured to attach to the fulcrum capture, and a baseplate block configured to support the fulcrum support. The system using the sliding support unit may include a pressure vessel, a pedestal bracket, and a plurality of sliding support units.

Breach, Michael R.; Keck, David J.; Deaver, Gerald A.

2013-01-15

271

Improvements to the Pool Critical Assembly Pressure Vessel Benchmark with 3-D Parallel SN PENTRAN  

NASA Astrophysics Data System (ADS)

The internationally circulated Pool Critical Assembly (PCA) Pressure Vessel Benchmark was analyzed using the PENTRAN Parallel SN code system for the geometry, material, and source specifications as described in the PCA Benchmark documentation. Improvements to the benchmark are proposed here through the application of more representative flux and volume weighted homogenized cross sections for the PCA reactor core, which were obtained from a rigorous heterogeneous modeling of all fuel assembly types in the core. A new source term definition is also proposed based on calculated relative power in each core fuel assembly with a spectrum based on the Uranium-235 fission spectra. This research focused on utilizing the BUGLE-96 cross section library and accompanying reaction rates, while also examining PENTRAN's adaptive differencing implemented on a coarse mesh basis, as well as fixed use of Directional Theta-Weighted (DTW) SN differencing scheme in order to compare the calculated PENTRAN results to measured data. The results show good comparison with the measured benchmark data, which suggests PENTRAN is a viable, reliable code system for calculation of light water reactor neutron shielding and pressure vessel dosimetry calculations. Furthermore, the improvements to the benchmark methodology resulting from this work provide a 6 percent increase in accuracy of the calculation (based on the average of all calculation points), when compared with experimentally measured results at the same spatial locations in the PCA pressure vessel simulator.

Edgar, Christopher A.; Sjoden, Glenn E.; Yi, Ce

2014-06-01

272

Burst pressure prediction in fiberglass/epoxy pressure vessels using acoustic emission and neural networks  

SciTech Connect

A burst pressure prediction model was generated from the acoustic emission (AE) amplitude distribution data taken during hydroproof testing for a set of eleven ASTM standard 5.75 inch diameter filament wound, fiberglass/epoxy bottles. The bottles were tested at three different temperatures - 32{degrees}F, 70{degrees}F, and 110{degrees}F - which were input as categorical variables, allowing the prediction of burst pressures in all three sets of bottles using a single backpropagation neural network. Two of the bottles contained simulated manufacturing defects which lowered their burst pressures. Architecturally, the neural network consisted of 42 input neurons (one categorical variable for temperature plus forty-one amplitude frequencies), a 15 neuron hidden layer for mapping, and a single output neuron for the predicted burst pressure. Seven of the eleven bottles were used to train the network. The AE amplitude distribution data taken up to 25% of the expected burst pressure were used as network inputs, and the actual burst pressures were used as target values for the supervised training phase. The trained network was not able to predict burst pressures accurately on the two defective bottles with such a small test group; they were therefore not considered. The network then used six of the nine bottles for training and blind predicted on the remaining three bottles. The network was then able to predict burst pressures with a worst case error within the desired goal of {+-} 5%.

Fisher, M.E.; Hill, E.V.K. [Embry-Riddle Aeronautical Univ., Daytona Beach, FL (United States)

1994-12-31

273

Circadian Blood Pressure Patterns and Life Stress  

Microsoft Academic Search

Background: Scarce data are available on the influence of psychological aspects on 24-hour ambulatory blood pressure patterns either in normotensive or hypertensive subjects. This study was designed to evaluate the relationship between psychological profile and changes in daytime\\/nighttime blood pressure rhythm. Methods:Nocturnal dipping was defined as the night\\/day ratio of ambulatory mean systolic and\\/or diastolic blood pressure ?0.87. Three-hundred and

Francesco Fallo; Luisa Barzon; Franco Rabbia; Cecilia Navarrini; Andrea Conterno; Franco Veglio; Manuela Cazzaro; Giovanni A. Fava; Nicoletta Sonino

2002-01-01

274

Fabrication Flaw Density and Distribution In Repairs to Reactor Pressure Vessel and Piping Welds  

SciTech Connect

The Pacific Northwest National Laboratory is developing a generalized fabrication flaw distribution for the population of nuclear reactor pressure vessels and for piping welds in U.S. operating reactors. The purpose of the generalized flaw distribution is to predict component-specific flaw densities. The estimates of fabrication flaws are intended for use in fracture mechanics structural integrity assessments. Structural integrity assessments, such as estimating the frequency of loss-of-coolant accidents, are performed by computer codes that require, as input, accurate estimates of flaw densities. Welds from four different reactor pressure vessels and a collection of archived pipes have been studied to develop empirical estimates of fabrication flaw densities. This report describes the fabrication flaw distribution and characterization in the repair weld metal of vessels and piping. This work indicates that large flaws occur in these repairs. These results show that repair flaws are complex in composition and sometimes include cracks on the ends of the repair cavities. Parametric analysis using an exponential fit is performed on the data. The relevance of construction records is established for describing fabrication processes and product forms. An analysis of these records shows there was a significant change in repair frequency over the years when these components were fabricated. A description of repair flaw morphology is provided with a discussion of fracture mechanics significance. Fabrication flaws in repairs are characterized using optimized-access, high-sensitivity nondestructive ultrasonic testing. Flaw characterizations are then validated by other nondestructive evaluation techniques and complemented by destructive testing.

GJ Schuster, FA Simonen, SR Doctor

2008-04-01

275

Monitoring Composite Material Pressure Vessels with a Fiber-Optic/Microelectronic Sensor System  

NASA Technical Reports Server (NTRS)

We discuss the concept of an integrated, fiber-optic/microelectronic distributed sensor system that can monitor composite material pressure vessels for Air Force space systems to provide assessments of the overall health and integrity of the vessel throughout its entire operating history from birth to end of life. The fiber optic component would include either a semiconductor light emitting diode or diode laser and a multiplexed fiber optic sensing network incorporating Bragg grating sensors capable of detecting internal temperature and strain. The microelectronic components include a power source, a pulsed laser driver, time domain data acquisition hardware, a microprocessor, a data storage device, and a communication interface. The sensing system would be incorporated within the composite during its manufacture. The microelectronic data acquisition and logging system would record the environmental conditions to which the vessel has been subjected to during its storage and transit, e.g., the history of thermal excursions, pressure loading data, the occurrence of mechanical impacts, the presence of changing internal strain due to aging, delamination, material decomposition, etc. Data would be maintained din non-volatile memory for subsequent readout through a microcomputer interface.

Klimcak, C.; Jaduszliwer, B.

1995-01-01

276

Balancing food and predator pressure induces chronic stress in songbirds  

Microsoft Academic Search

The never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. The 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these insepar- able effects on physiology will produce inseparable effects on demography because of the

Michael Clinchy; Liana Zanette; Rudy Boonstra; John C. Wingfield; James N. M. Smith

2004-01-01

277

Blood Pressure Variability and Stress Management Training for Essential Hypertension  

ERIC Educational Resources Information Center

The purpose of this study was to determine whether stress management training reduces blood pressure (BP) variability in hypertensive patients. Previous literature suggests that cardiovascular risk is not only a function of BP levels, but also of BP variability, and this partially depends on changes induced by the stress of everyday life. The…

Garcia-Vera, Maria Paz; Sanz, Jesus; Labrador, Francisco J.

2004-01-01

278

D-Zero Central Calorimeter Technical Appendix to Cryogenic Pressure Vessels  

SciTech Connect

DO (D Zero) is a large Liquid Argon (LAr) HEP Calorimeter designed to function in the laboratories P-Pbar collider at the DO section of the Tevatron accelerator. It contains 5,000 gls. of LAr in the CC cryostat, and 3,000 gls. in each of two, a north and south, EC cryostats. These low pressure vessels are filled with detector modules built of stainless steel, copper and depleted uranium. The LAr functions as the ionization medium, and the spatial and temporal of the collection of the charge of the electrons produced signals the passsage of charged particles. The collection of these charges in 4 pi is related to the energy of the particles, and their measurement is called calorimetry. The contained LAr (T=90K) is isolated from the ambient temperatures in specially designed, vacuum and superinsulated, vessels (cryostats) provided with liquid nitrogen, heat of vaporization, cooling.

Mulholland, G.T.; Rucinski, R.A.; /Fermilab

1990-11-19

279

Finite elements in the analysis of pressure vessels and piping, an addendum: a bibliography (1998–2001)  

Microsoft Academic Search

The paper gives a bibliographical review of finite element methods (FEMs) applied for the analysis of pressure vessel structures\\/components and piping from the theoretical as well as practical points of view. This bibliography is an addendum to the Finite elements in the analysis of pressure vessels and piping—a bibliography (1976–1996) published [Int J Press Vess Piping 69 (1996) 279] and

Jaroslav Mackerle

2002-01-01

280

Finite elements in the analysis of pressure vessels and piping, an addendum: A bibliography (2001–2004)  

Microsoft Academic Search

The paper gives a bibliographical review of finite element methods(FEMs) applied for the analysis of pressure vessel structures\\/components and piping from the theoretical as well as practical points of view. This bibliography is a new addendum to the Finite elements in the analysis of pressure vessels and piping—a bibliography [1–3]. The listings at the end of the paper contain 856

Jaroslav Mackerle

2005-01-01

281

Damage Control Plan for International Space Station Recharge Tank Assembly Composite Overwrapped Pressure Vessel  

NASA Technical Reports Server (NTRS)

As NASA has retired the Space Shuttle Program, a new method of transporting compressed gaseous nitrogen and oxygen needed to be created for delivery of these crucial life support resources to the International Space Station (ISS). One of the methods selected by NASA includes the use of highly pressurized, unprotected Recharge Tank Assemblies (RTAs) utilizing Composite Overwrapped Pressure Vessels (COPVs). A COPV consists of a thin liner wrapped with a fiber composite and resin or epoxy. It is typically lighter weight than an all metal pressure vessel of similar volume and therefore provides a higher-efficiency means for gas storage. However COPVs are known to be susceptible to damage resulting from handling, tool drop impacts, or impacts from other objects. As a result, a comprehensive Damage Control Plan has been established to mitigate damage to the RTA COPV throughout its life cycle. The DCP is intended to evaluate and mitigate defined threats during manufacturing, shipping and handling, test, assembly level integration, shipment while pressurized, launch vehicle integration and mission operations by defining credible threats and methods for preventing potential damage while still maintaining the primary goal of resupplying ISS gas resources. A comprehensive threat assessment is performed to identify all threats posed to the COPV during the different phases of its lifecycle. The threat assessment is then used as the basis for creating a series of general inspection, surveillance and reporting requirements which apply across all phases of the COPV's life, targeted requirements only applicable to specific work phases and a series of training courses for both ground personnel and crew aboard the ISS. A particularly important area of emphasis deals with creating DCP requirements for a highly pressurized, large and unprotected RTA COPV for use during Inter Vehicular Activities (IVA) operations in the micro gravity environment while supplying pressurized gas to the ISS for crew life support.

Cook, Anthony J.

2011-01-01

282

The criteria of fracture in the case of the leak of pressure vessels  

SciTech Connect

In order to forecast the break of the high pressure vessels and the network of pipes in a nuclear reactor, according to the concept of leak before break of pressure vessels, it is necessary to analyze the conditions of project, production, and mounting quality as well as of exploitation. It is also necessary to evaluate the process of break by the help of the fracture criteria. In the Ignalina Nuclear Power Plant of, in Lithuania, the most important objects of investigation are: the highest pressure pipes, made of Japanese steel 19MN5 and having an anticorrosive austenitic: coal inside, the pipes of distribution, which arc made of 08X1810T steel. The steel of the network of pipes has a quality of plasticity: therefore the only criteria of fragile is impossible to apply to. The process of break would be best described by the universal criteria of elastic - plastic fracture. For this purpose the author offers the criterion of the double parameter.

Habil; Ziliukas, A.

1997-04-01

283

Construction and design of elliptical transitions in vessels and apparatus working under internal pressure  

Microsoft Academic Search

The elliptical transition under consideration consists of two coaxial cylindrical shells (large and small casings), connected by an elliptical shell (elliptical bottom), and loaded by an internal pressure. The calculating scheme of the joint is given in Fig. 1. The scheme shows the positive directions of the radial displacements, the angles of rotation of the cross sections, the radial stresses,

1977-01-01

284

Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels  

Microsoft Academic Search

It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The

E C Dalder; J W Pastrnak; J Engel; R S Forrest; E Kokko; K M Ternan; D Waldron

2007-01-01

285

BWR In-Core Monitor Housing Replacement Under Dry Condition of Reactor Pressure Vessel  

SciTech Connect

A new method of In-Core Monitor Housing replacement has been successfully applied to Tokai Unit 2 (BWR with 1100 MWe) in April of 2001. It was designed to replace a housing under dry condition of reactor pressure vessel (RPV): this enabled the elimination of water filled-up and drained processes during the replacement procedure resulting in the reduction of implementation schedule. To realize the dry condition, the radiation shields were placed in the RPV and the hollow guide pipe (GP) was adopted to transfer the apparatuses from the top to the bottom work area. (authors)

Tatsuo Ishida; Shoji Yamamoto; Fujitoshi Eguchi [Japan Atomic Power Company (Japan); Motomasa Fuse; Kouichi Kurosawa; Sadato Shimizu; Minoru Masuda [Hitachi Ltd. (Japan); Shinya Fujii; Junji Tanaka [General Electric International Inc. (Japan); Jacobson, Bryce A. [General Electric Company (United States)

2002-07-01

286

The effect of compression on individual pressure vessel nickel/hydrogen components  

NASA Technical Reports Server (NTRS)

Compression tests were performed on representative Individual Pressure Vessel (IPV) Nickel/Hydrogen cell components in an effort to better understand the effects of force on component compression and the interactions of components under compression. It appears that the separator is the most easily compressed of all of the stack components. It will typically partially compress before any of the other components begin to compress. The compression characteristics of the cell components in assembly differed considerably from what would be predicted based on individual compression characteristics. Component interactions played a significant role in the stack response to compression. The results of the compression tests were factored into the design and selection of Belleville washers added to the cell stack to accommodate nickel electrode expansion while keeping the pressure on the stack within a reasonable range of the original preset.

Manzo, Michelle A.; Perez-Davis, Marla E.

1988-01-01

287

The development of radiation embrittlement models for US power reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

A new approach of utilizing information fusion technique is developed to predict the radiation embrittlement of reactor pressure vessel steels. The Charpy transition temperature shift data contained in the Power Reactor Embrittlement Database is used in this study. Six parameters-Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature - are used in the embrittlement prediction models. The results indicate that this new embrittlement predictor achieved reductions of about 49.5% and 52% in the uncertainties for plate and weld data, respectively, for pressurized water reactor and boiling water reactor data, compared with the Nuclear Regulatory Commission Regulatory Guide 1.99, Rev. 2. The implications of dose-rate effect and irradiation temperature effects for the development of radiation embrittlement models are also discussed.

Wang, J. A.; Rao, N. S. V.; Konduri, S.

2007-05-01

288

Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels  

SciTech Connect

In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic K{sub Jc} values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for K{sub Jc} data. By converting PCVN data to IT compact specimen equivalent K{sub Jc} data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic K{sub Jc} database and the ASME lower bound K{sub Ic} curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of K{sub Jc} with respect to K{sub Ic} in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for K{sub Jc} data from PCVN specimens. 13 refs., 8 figs., 1 tab.

Sokolov, M.A.; Wallin, K.; McCabe, D.E.

1996-12-31

289

Helium leak testing of a radioactive contaminated vessel under high pressure in a contaminated environment  

SciTech Connect

At ANL-W, with the shutdown of EBR-II, R&D has evolved from advanced reactor design to the safe handling, processing, packaging, and transporting spent nuclear fuel and nuclear waste. New methods of processing spent fuel rods and transforming contaminated material into acceptable waste forms are now in development. Storage of nuclear waste is a high interest item. ANL-W is participating in research of safe storage of nuclear waste, with the WIPP (Waste Isolation Pilot Plant) site in New Mexico the repository. The vessel under test simulates gas generated by contaminated materials stored underground at the WIPP site. The test vessel is 90% filled with a mixture of contaminated material and salt brine (from WIPP site) and pressurized with N2-1% He at 2500 psia. Test acceptance criteria is leakage < 10{sup -7} cc/seconds at 2500 psia. The bell jar method is used to determine leakage rate using a mass spectrometer leak detector (MSLD). The efficient MSLD and an Al bell jar replaced a costly, time consuming pressure decay test setup. Misinterpretation of test criterion data caused lengthy delays, resulting in the development of a unique procedure. Reevaluation of the initial intent of the test criteria resulted in leak tolerances being corrected and test efficiency improved.

Winter, M.E.

1996-10-01

290

Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement  

NASA Astrophysics Data System (ADS)

This program developed a nondestructive technique for gauging the progress of embrittlement of nuclear pressure vessel steels (PVS) by means of monitoring radiation-induced changes in magnetic properties. The technique was developed by running a series of experiments in reactor on typical nuclear pressure vessel steels and weldment material. Following irradiation, changes in magnetic properties were measured and correlated with irradiation dose and with mechanical properties changes, where possible. The changes in magnetic properties were unique to the irradiation environment, and were much larger than those produce by thermal aging in the absence of irradiation. Special techniques for magnetic properties change measurement were developed and complimented by more standard magnetic properties measurement techniques including SQUID measurements. The results of the experiments revealed that magnetic properties were very sensitive to irradiation. Changes in microstructurally-related magnetic properties of as much as 40% were noted after irradiation exposure of as little as 10(exp 17) n/sq cm (E greater than 0.1 MeV). The magnetic properties changes plateaued out after doses of around as 10(exp 18) n/cm(sup 2) (E greater than 0.1 MeV). It is unclear whether further changes would be noted at higher doses which would also be useful for tracking the embrittlement phenomenon. This is recommended for further study. The work supported here resulted in several publications in the open scientific literature.

Ougouag, A. M.; Stubbins, J. F.; Williams, J. F.; Shong, Wei-Ja

1995-04-01

291

Radiation damage characterization in reactor pressure vessel steels with nonlinear ultrasound  

NASA Astrophysics Data System (ADS)

Nuclear generation currently accounts for roughly 20% of the US baseload power generation. Yet, many US nuclear plants are entering their first period of life extension and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. This means that critical components, such as the reactor pressure vessel (RPV), will be exposed to higher levels of radiation than they were originally intended to withstand. Radiation damage in reactor pressure vessel steels causes microstructural changes such as vacancy clusters, precipitates, dislocations, and interstitial loops that leave the material in an embrittled state. The development of a nondestructive evaluation technique to characterize the effect of radiation exposure on the properties of the RPV would allow estimation of the remaining integrity of the RPV with time. Recent research has shown that nonlinear ultrasound is sensitive to radiation damage. The physical effect monitored by nonlinear ultrasonic techniques is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave, arising from the interaction of the ultrasonic wave with microstructural features such as dislocations, precipitates, and their combinations. Current findings relating the measured acoustic nonlinearity parameter to increasing levels of neutron fluence for different representative RPV materials are presented.

Matlack, K. H.; Kim, J.-Y.; Wall, J. J.; Qu, J.; Jacobs, L. J.

2014-02-01

292

Studying the stressed state and operating characteristics of high-pressure deaerators' metal and assessment of their longevity  

NASA Astrophysics Data System (ADS)

Damage to high-pressure deaerators’ metal and possible causes thereof are analyzed. The results of calculations and experimental studies of the stressed state of a deaerator vessel in the zones of maximum loading are presented. The results of studying the operating characteristics of carbon steels (Grades St3sp and St3kp) and welded seams made of these steels in different states are given as well. Examples are given of calculations of deaerator vessel longevity under conditions of low-cyclic fatigue at the stage of corrosion-fatigue crack development.

Grin', E. A.; Zelenskii, A. V.

2009-02-01

293

Mix Model of FE Method and IPSO Algorithm for Dome Shape Optimization of Articulated Pressure Vessels Considering the Effect of Non-geodesic Trajectories  

NASA Astrophysics Data System (ADS)

The main essential topic for the design of articulated pressure vessels is related to the determination of the optimal meridian profile. This article, aimed to present the new model for optimum design of dome contours for filament wound articulated pressure vessels based on non-geodesic trajectories. The current model is a mix of finite element analysis and inertia weight particle swarm optimization algorithm. Geometrical limitations, stability-ensuring winding conditions and the Tsai-Wu failure criterion have been used as optimization constraints. Classical lamination theory and non-geodesic trajectories are used to analyse the field stress equations and increase the structural performance. The geometry of dome contours is defined by the B-spline curves with twenty-one points. The results, when compared to the previously published results, indicate the efficiency of the presented model in achieving superior performance of dome shape for articulated pressure vessels. Also, it is shown that the design based on non-geodesic trajectories using this model gains better response than the design by geodesics type.

Paknahad, A.; Nourani, R.

2014-04-01

294

Principal stress pore pressure prediction: utilizing drilling measurements to predict pore pressure  

E-print Network

the stresses at the bottom of the borehole. From the stress state and knowledge of Mohr’s Envelope, the pore pressure is predicted. To verify the method, a test procedure was developed. The test procedure enabled systematic collection and processing...

Richardson, Kyle Wade

2009-05-15

295

Fluid pressure and effective stress in sandbox models  

NASA Astrophysics Data System (ADS)

We have done a series of simple tests on sandpacks, involving upward flow of compressed air through the pores and its effect on the yield strength. The ultimate objective is to model deformation coupled with fluid flow in sedimentary basins. For all tests, we used a single batch of Fontainebleau sand, sieved to a grain size between 0.200 and 0.315 mm, poured into a cylindrical container and then fluidized. The density of this sand was 1.585 g/cm 3, irrespective of sand thickness. The lithostatic pressure was proportional to the thickness of the sandpack. A yield envelope was obtained by shearing the sandpack horizontally. Compressed air entered the base of the sandpack and flowed upwards through the pore spaces. For 69 measurements on air flow without shearing, a plot of discharge velocity versus gradient of fluid pressure is close to a straight line, verifying Darcy's law and yielding an intrinsic permeability of about 1.7 darcy for the sand. For 72 tests on simultaneous shearing and fluid flow, the estimated effective stress (lithostatic stress minus estimated pore fluid pressure) ranged from 0 to 1600 Pa and the pore fluid ratio (between air pressure and lithostatic pressure) from 0.0 to 1.0. A plot of shear stress versus effective stress at failure is almost linear, verifying Terzaghi's principle of effective stress. The best-fit slope (coefficient of internal friction) is about 0.55 and the intercept on the shear stress axis (cohesion) is less than 85 Pa. The tests show that it is feasible to use compressed air within sandpacks, as a means of modelling deformation coupled with fluid flow. The next step will be to build sandbox models of layered sequences and to investigate detachments caused by abnormal fluid pressures.

Cobbold, P. R.; Castro, L.

1999-01-01

296

[Structural-functional characteristics of cervical vessels in hypertensive patients under changed atmospheric pressure].  

PubMed

The ultrasonic location technique was used to measure intima-media thickness (IMT), as well as internal systolic diameter of and linear blood velocity in the cervical arteries in people with initial hypertension. Correlation analysis elicited a temporal contingency between these parameters and daily average values of atmospheric pressure. Thus, common carotid artery IMT tended to increase on high-pressure days. Besides, diameters of the common and internal carotid arteries, and vertebral artery were narrowed and, consequently, linear blood velocity in these vessels increased. This relationship is more evident in men than women and in elderly subjects than young. These results are suggestive of a vasoconstrictive action of high atmospheric pressure on these arteries. The relationship is not universal, as it is nonlinear for diameter of the internal carotid artery and inverse for the external one. This implies different sensitivity of arteries to the factor under study and possible blood redistribution in the arterial basin depending on external pressure. The relationship was observed equally on the day of investigation and previous days, which points to its temporal stability. PMID:25163339

Mel'nikov, V N; Poliakov, V Ia; Krivoshchekov, S G; Baranov, V I; Rechkina, S Iu

2014-01-01

297

Stress-Induced Blood Pressure Reactivity and Silent Cerebrovascular Disease  

Microsoft Academic Search

Background and Purpose—Exaggerated blood pressure (BP) responses to mental stress, an index of autonomic dysregulation, have been related to enhanced risk for stroke. This study examined cross-sectional relations of stress-induced BP reactivity to silent cerebrovascular disease assessed by magnetic resonance imaging (MRI) in healthy older adults. Methods—Sixty-seven nondemented, community-dwelling older adults (ages 55 to 81; 75% male) free of major

Shari R. Waldstein; Eliot L. Siegel; David Lefkowitz; Karl J. Maier; Jessica R. Pelletier Brown; Abraham M. Obuchowski; Leslie I. Katzel

2010-01-01

298

Relationship between self-perceived stress and blood pressure  

Microsoft Academic Search

Objective: The importance of stress in the pathogenesis of essential hypertension is controversial. In this study we wanted to evaluate the relation between self-perceived stress and the blood pressure (BP) in a asymptomatic healthy population.Subjects and methods: A total of 1666 guests (mean ± s.d. age 50 ± 16 years) attending the air show AIR94 in Buochs, Switzerland volunteered to

PM Suter; R Maire; D Holtz; W Vetter

1997-01-01

299

Caffeine, extended stress, and blood pressure in borderline hypertensive men  

Microsoft Academic Search

Caffeine increases blood pressure (BP), and its pressor effects are larger in borderline hypertensive (BH) men than in controls.\\u000a This article extends findings of larger caffeine effects on BP at rest and to brief mental stress in BH to a new analysis\\u000a of caffeine and prolonged mental stress in BH. In a double-blind, crossover study, 24 male BH (140\\/90 mmHg

William R. Lovallo; Mustafa al’Absi; Gwen A. Pincomb; Richard B. Passey; Bong Hee Sung; Michael F. Wilson

2000-01-01

300

Characterization of Quench-Extracted High Pressure Stressed Microorganisms  

NASA Astrophysics Data System (ADS)

In-situ high pressure microbiology work by Sharma et al (2002) presented a unique approach with diamond anvil cells to the study of microbes under environmental stress. This study focused on high pressure exposure as the stress component and provided a technique to directly monitor microbial activity. However, it lacked the much desired biochemical and biophysical information that could reflect the state of surviving microorganisms with insights into the process of adaptation at extreme. More recent work (Sharma et al 2011) expands on the previous study by including synergistic effect of high temperature with increased pressures along variable time scale. With the cell extraction and subsequent cell growth demonstrated, Sharma et al. (2011) show that more than pressure, temperature remains the environmental variable that defines the limits of life's survival. In this study we have refined the extraction process from the diamond anvil cell such that the stressed microorganisms can be routinely available for in-depth physiological study using conventional and state-of-the-art high resolution imaging tools. Here we present some recent in-depth FESEM, AFM and optical spectroscopy data to study the effect of stress on Escherichia coli. Contrary to earlier studies where various cell membrane ruptures were reported after moderate pressure exposure, we find that most cells remain viable and except for some occasional anomalous morphology, the surviving cells were similar to the unstressed state. Preliminary results suggest that the stress response in Escherichia coli exposed to short term extreme pressures (ranging from 1 -24 hrs) seems rapidly reversible. Biophysical entities such as the cell membrane, therefore, remain intact in the whole organism (and colony of microorganisms) at significantly higher pressure conditions than 300 MPa as reported in previous biophysics literature.

Sharma, P.; Sharma, A.

2011-12-01

301

Balancing food and predator pressure induces chronic stress in songbirds.  

PubMed Central

The never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. The 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these inseparable effects on physiology will produce inseparable effects on demography because of the resulting adverse health effects. This hypothesis was originally proposed to explain synergistic (inseparable) food and predator effects on demography in snowshoe hares (Lepus americanus). We conducted a 2 x 2, manipulative food addition plus natural predator reduction experiment on song sparrows (Melospiza melodia) that was, to our knowledge, the first to demonstrate comparable synergistic effects in a bird: added food and lower predator pressure in combination produced an increase in annual reproductive success almost double that expected from an additive model. Here we report the predicted simultaneous food and predator effects on measures of chronic stress in the context of the same experiment: birds at unfed, high predator pressure (HPP) sites had the highest stress levels; those at either unfed or HPP sites showed intermediate levels; and fed birds at low predator pressure sites had the lowest stress levels. PMID:15590598

Clinchy, Michael; Zanette, Liana; Boonstra, Rudy; Wingfield, John C.; Smith, James N. M.

2004-01-01

302

Balancing food and predator pressure induces chronic stress in songbirds.  

PubMed

The never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. The 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these inseparable effects on physiology will produce inseparable effects on demography because of the resulting adverse health effects. This hypothesis was originally proposed to explain synergistic (inseparable) food and predator effects on demography in snowshoe hares (Lepus americanus). We conducted a 2 x 2, manipulative food addition plus natural predator reduction experiment on song sparrows (Melospiza melodia) that was, to our knowledge, the first to demonstrate comparable synergistic effects in a bird: added food and lower predator pressure in combination produced an increase in annual reproductive success almost double that expected from an additive model. Here we report the predicted simultaneous food and predator effects on measures of chronic stress in the context of the same experiment: birds at unfed, high predator pressure (HPP) sites had the highest stress levels; those at either unfed or HPP sites showed intermediate levels; and fed birds at low predator pressure sites had the lowest stress levels. PMID:15590598

Clinchy, Michael; Zanette, Liana; Boonstra, Rudy; Wingfield, John C; Smith, James N M

2004-12-01

303

Evidence for neutron irradiation-induced metallic precipitates in model alloys and pressure-vessel weld steel  

E-print Network

-vessel weld steel Stephen E. Cumblidge a , Arthur T. Motta a,*, Gary L. Catchen a , Gerhard Brauer b , Juurgen-irradiated model alloys (1 · 1023 n/m2 , E > 0:5 MeV) and 73W-weld steel (to 1.8 · 1023 n/m2 , E > 1 Me the pressure-vessel weld steel) showed evidence for both irradiation-induced metallic precipitation

Motta, Arthur T.

304

Advanced Dependent Pressure Vessel (DPV) nickel-hydrogen spacecraft cell and battery design  

NASA Technical Reports Server (NTRS)

The dependent pressure vessel (DPV) nickel-hydrogen (NiH2) battery is being developed as a potential spacecraft battery design for both military and commercial satellites. Individual pressure vessel (IPV) NiH2 batteries are currently flying on more than 70 Earth orbital satellites and have accumulated more than 140,000,000 cell-hours in actual spacecraft operation. The limitations of standard NiH2 IPV flight battery technology are primarily related to the internal cell design and the battery packaging issues associated with grouping multiple cylindrical cells. The DPV cell design offers higher specific energy and reduced cost, while retaining the established IPV NiH2 technology flight heritage and database. The advanced cell design offers a more efficient mechanical, electrical and thermal cell configuration and a reduced parts count. The internal electrode stack is a prismatic flat-plate arrangement. The flat individual cell pressure vessel provides a maximum direct thermal path for removing heat from the electrode stack. The cell geometry also minimizes multiple-cell battery packaging constraints by using an established end-plateltie-rod battery design. A major design advantage is that the battery support structure is efficiently required to restrain only the force applied to a portion of the end cell. As the cells are stacked in series to achieve the desired system voltage, this increment of the total battery weight becomes small. The geometry of the DPV cell promotes compact, minimum volume packaging and places all cell terminals along the length of the battery. The resulting ability to minimize intercell wiring offers additional design simplicity and significant weight savings. The DPV battery design offers significant cost and weight savings advantages while providing minimal design risks. Cell and battery level design issues will be addressed including mechanical, electrical and thermal design aspects. A design performance analysis will be presented at both the cell and battery level. The DPV is capable of delivering up to 76 Watt-hours per kilogram (Wh/kg) at the cell level and 70 Wh/kg at the full battery level. This represents a 40 percent increase in specific energy at the cell level and a 60 percent increase in specific energy at the battery level compared to current IPV NiH2 technology.

Coates, Dwaine; Wright, Doug; Repplinger, Ron

1995-01-01

305

Survey of welding processes for field fabrication of 2 1/4 Cr-1 Mo steel pressure vessels. [128 references  

SciTech Connect

Any evaluation of fabrication methods for massive pressure vessels must consider several welding processes with potential for heavy-section applications. These include submerged-arc and shielded metal-arc, narrow-joint modifications of inert-gas metal-arc and inert-gas tungsten-arc processes, electroslag, and electron beam. The advantage and disadvantages of each are discussed. Electroslag welding can be dropped from consideration for joining of 2 1/4 Cr-1 Mo steel because welds made with this method do not provide the required mechanical properties in the welded and stress relieved condition. The extension of electron-beam welding to sections as thick as 4 or 8 inches (100 or 200 mm) is too recent a development to permit full evaluation. The manual shielded metal-arc and submerged-arc welding processes have both been employed, often together, for field fabrication of large vessels. They have the historical advantage of successful application but present other disadvantages that make them otherwise less attractive. The manual shielded metal-arc process can be used for all-position welding. It is however, a slow and expensive technique for joining heavy sections, requires large amounts of skilled labor that is in critically short supply, and introduces a high incidence of weld repairs. Automatic submerged-arc welding has been employed in many critical applications and for welding in the flat position is free of most of the criticism that can be leveled at the shielded metal-arc process. Specialized techniques have been developed for horizontal and vertical position welding but, used in this manner, the applications are limited and the cost advantage of the process is lost.

Grotke, G.E.

1980-04-01

306

Manufacturing Cost Analysis of Novel Steel/Concrete Composite Vessel for Stationary Storage of High-Pressure Hydrogen  

SciTech Connect

A novel, low-cost, high-pressure, steel/concrete composite vessel (SCCV) technology for stationary storage of compressed gaseous hydrogen (CGH2) is currently under development at Oak Ridge National Laboratory (ORNL) sponsored by DOE s Fuel Cell Technologies (FCT) Program. The SCCV technology uses commodity materials including structural steels and concretes for achieving cost, durability and safety requirements. In particular, the hydrogen embrittlement of high-strength low-alloy steels, a major safety and durability issue for current industry-standard pressure vessel technology, is mitigated through the use of a unique layered steel shell structure. This report presents the cost analysis results of the novel SCCV technology. A high-fidelity cost analysis tool is developed, based on a detailed, bottom-up approach which takes into account the material and labor costs involved in each of the vessel manufacturing steps. A thorough cost study is performed to understand the SCCV cost as a function of the key vessel design parameters, including hydrogen pressure, vessel dimensions, and load-carrying ratio. The major conclusions include: The SCCV technology can meet the technical/cost targets set forth by DOE s FCT Program for FY2015 and FY2020 for all three pressure levels (i.e., 160, 430 and 860 bar) relevant to the hydrogen production and delivery infrastructure. Further vessel cost reduction can benefit from the development of advanced vessel fabrication technologies such as the highly automated friction stir welding (FSW). The ORNL-patented multi-layer, multi-pass FSW can not only reduce the amount of labor needed for assembling and welding the layered steel vessel, but also make it possible to use even higher strength steels for further cost reductions and improvement of vessel structural integrity. It is noted the cost analysis results demonstrate the significant cost advantage attainable by the SCCV technology for different pressure levels when compared to the industry-standard pressure vessel technology. The real-world performance data of SCCV under actual operating conditions is imperative for this new technology to be adopted by the hydrogen industry for stationary storage of CGH2. Therefore, the key technology development effort in FY13 and subsequent years will be focused on the fabrication and testing of SCCV mock-ups. The static loading and fatigue data will be generated in rigorous testing of these mock-ups. Successful tests are crucial to enabling the near-term impact of the developed storage technology on the CGH2 storage market, a critical component of the hydrogen production and delivery infrastructure. In particular, the SCCV has high potential for widespread deployment in hydrogen fueling stations.

Feng, Zhili [ORNL; Zhang, Wei [ORNL; Wang, Jy-An John [ORNL; Ren, Fei [ORNL

2012-09-01

307

Corrosion monitoring on a large steel pressure vessel by thin-layer activation  

SciTech Connect

Thin-layer activation (TLA) is a technique in which a surface is irradiated by a nuclear accelerator and thereby labeled with an accurate depth profile of low-level radioactivity. By monitoring this activity it is possible to calculate how much of that surface has been removed by corrosion. As the radioactivity is marked by the emission of penetrating gamma rays, it is possible to monitor this corrosion remotely through several centimeters of steel. This technique has been used to monitor erosion-corrosion occurring on the inner carbon steel wall of a continuous Kraft pulp digester at a paper mill. Representative coupons of the same steel as the digester wall were irradiated and fixed to the walls in the liquor extraction zone during a maintenance shutdown. The loss of metal over the six months was measured by external monitoring of gamma radiation through the vessel wall, and converted to a corrosion rate. Subsequent weight-loss measurements and comparison with ultrasonic thickness measurements established that the corrosion rate measured gave accurate results over a much shorter time scale. TLA thus enables current, rather than historical corrosion rates to be measured in a large steel pressure vessel.

Wallace, G. (Inst. of Nuclear Sciences, Dept. of Scientific and Industrial Research, P.O. Box 31312, Lower Hutt (NZ)); Boulton, L.H. (Auckland Industrial Development Div., Dept. of Scientific and Industrial Research, P.O. Box 2225, Auckland (NZ)); Hodder, D. (NZFP Pulp and Paper Ltd., Private Bag, Tokoroa (NZ))

1989-12-01

308

Magma chambers: Formation, local stresses, excess pressures, and compartments  

NASA Astrophysics Data System (ADS)

An existing magma chamber is normally a necessary condition for the generation of a large volcanic edifice. Most magma chambers form through repeated magma injections, commonly sills, and gradually expand and change their shapes. Highly irregular magma-chamber shapes are thermo-mechanically unstable; common long-term equilibrium shapes are comparatively smooth and approximate those of ellipsoids of revolution. Some chambers, particularly small and sill-like, may be totally molten. Most chambers, however, are only partially molten, the main part of the chamber being crystal mush, a porous material. During an eruption, magma is drawn from the crystal mush towards a molten zone beneath the lower end of the feeder dyke. Magma transport to the feeder dyke, however, depends on the chamber's internal structure; in particular on whether the chamber contains pressure compartments that are, to a degree, isolated from other compartments. It is only during large drops in the hydraulic potential beneath the feeder dyke that other compartments become likely to supply magma to the erupting compartment, thereby contributing to its excess pressure (the pressure needed to rupture a magma chamber) and the duration of the eruption. Simple analytical models suggest that during a typical eruption, the excess-pressure in the chamber decreases exponentially. This result applies to a magma chamber that (a) is homogeneous and totally fluid (contains no compartments), (b) is not subject to significant replenishment (inflow of new magma into the chamber) during the eruption, and (c) contains magma where exsolution of gas has no significant effect on the excess pressure. For a chamber consisting of pressure compartments, the exponential excess-pressure decline applies primarily to a single erupting compartment. When more than one compartment contributes magma to the eruption, the excess pressure may decline much more slowly and irregularly. Excess pressure is normally similar to the in-situ tensile strength of the host rock, 0.5-9 MPa. These in-situ strength estimates are based on hydraulic fracture measurements in drill-holes worldwide down to crustal depths of about 9 km. These measurements do not support some recent magma-chamber stress models that predict (a) extra gravity-related wall-parallel stresses at the boundaries of magma chambers and (b) magma-chamber excess pressures prior to rupture of as much as hundreds of mega-pascals, particularly at great depths. General stress models of magma chambers are of two main types: analytical and numerical. Earlier analytical models were based on a nucleus-of-strain source (a 'point pressure source') for the magma chamber, and have been very useful for rough estimates of magma-chamber depths from surface deformation during unrest periods. More recent models assume the magma chamber to be axisymmetric ellipsoids or, in two-dimensions, ellipses of various shapes. Nearly all these models use the excess pressure in the chamber as the only loading (since lithostatic stress effects are then automatically taken into account), assume the chamber to be totally molten, and predict similar local stress fields. The predicted stress fields are generally in agreement with the world-wide stress measurements in drill-holes and, in particular, with the in-situ tensile-strength estimates. Recent numerical models consider magma-chambers of various (ideal) shapes and sizes in relation to their depths below the Earth's surface. They also take into account crustal heterogeneities and anisotropies; in particular the effects of the effects of a nearby free surface and horizontal and inclined (dipping) mechanical layering. The results show that the free surface may have strong effects on the local stresses if the chamber is comparatively close to the surface. The mechanical layering, however, may have even stronger effects. For realistic layering, and other heterogeneities, the numerical models predict complex local stresses around magma chambers, with implications for dyke paths, dyke arrest, and ring-fault formation.

Gudmundsson, Agust

2012-09-01

309

Boric acid corrosion of light water reactor pressure vessel head materials.  

SciTech Connect

This work presents experimental data on electrochemical potential and corrosion rates for the materials found in the reactor pressure vessel head and control rod drive mechanism (CRDM) nozzles in boric acid solutions of varying concentrations at temperatures of 95-316 C. Tests were conducted in (a) high-temperature, high-pressure aqueous solutions with a range of boric acid concentrations, (b) high-temperature (150-316 C)H-B-Osolutions at ambient pressure, in wet and dry conditions, and (c) low-temperature (95 C) saturated, aqueous, boric acid solutions. These correspond to the following situations: (a) low leakage through the nozzle and nozzle/head annulus plugged, (b) low leakage through the nozzle and nozzle/head annulus open, and (c) significant cooling due to high leakage and nozzle/head annulus open. The results showed significant corrosion only for the low-alloy steel and no corrosion for Alloy 600 or 308 stainless steel cladding. Also, corrosion rates were significant in saturated boric acid solutions, and no material loss was observed in H-B-O solution in the absence of moisture. The results are compared with the existing corrosion/wastage data in the literature.

Park, J.-H.; Chopra, O. K.; Natesan, K.; Shack, W. J.; Cullen, Jr.; W. H.; Energy Technology; USNRC

2005-01-01

310

Study, Examinations, and Stress: Blood Pressure Assessments in College Students  

ERIC Educational Resources Information Center

The issue of stress associated with higher education and its impact on markers of student health is explored in three experiments looking at blood pressure levels in college students. All participants were full-time undergraduate students of psychology. In Experiment 1, academic fear of failure, assessed using psychometric testing, was found to be…

Hughes, Brian M.

2005-01-01

311

Reactor pressure vessel integrity research at the Oak Ridge National Laboratory  

SciTech Connect

Maintaining the integrity of the reactor pressure vessel (RPV) in a light-water-cooled nuclear power plant is crucial in preventing and controlling severe accidents that have the potential for major contamination release. The RPV is the only key safety-related component of the plant for which a duplicate or redundant backup system does not exist. It is therefore imperative to understand and be able to predict the integrity inherent in the RPV. For this reason, the U.S. Nuclear Regulatory Commission has established the related research programs at ORNL described herein to provide for the development and confirmation of the methods used for: (1) establishing the irradiation exposure conditions within the RPV in the Embrittlement Data Base and Dosimetry Evaluation Program, (2) assessing the effects of irradiation on the RPV materials in the Heavy-Section Steel Irradiation Program, and (3) developing overall structural and fracture analyses of RPVs in the Heavy-Section Steel Technology Program.

Corwin, W.R.; Pennell, W.E.; Pace, J.V.

1995-12-31

312

Control of the ORR-PSF pressure-vessel surveillance irradiation experiment temperature  

SciTech Connect

Control of the Oak Ridge Research Reactor Pool Side Facility (ORR-PSF) pressure vessel surveillance irradiation experiment temperature is implemented by digital computer control of electrical heaters under fixed cooling conditions. Cooling is accomplished with continuous flows of water in pipes between specimen sets and of helium-neon gas in the specimen set housings. Control laws are obtained from solutions of the discrete-time Riccati equation and are implemented with direct digital control of solid state relays in the electrical heater circuit. Power dissipated by the heaters is determined by variac settings and the percent of time that the solid state relays allow power to be supplied to the heaters. Control demands are updated every forty seconds.

Miller, L.F.

1982-01-01

313

Assemblies and methods for mitigating effects of reactor pressure vessel expansion  

DOEpatents

Support assemblies for allowing RPV radial expansion while simultaneously limiting horizontal, vertical, and azimuthal movement of the RPV within a nuclear reactor are described. In one embodiment, the support assembly includes a support block and a guide block. The support block includes a first portion and a second portion, and the first portion is rigidly coupled to the RPV adjacent the first portion. The guide block is rigidly coupled to a reactor pressure vessel support structure and includes a channel sized to receive the second portion of the support block. The second portion of the support block is positioned in the guide block channel to movably couple the guide block to the support block.

Challberg, Roy C. (Livermore, CA); Gou, Perng-Fei (Saratoga, CA); Chu, Cherk Lam (San Jose, CA); Oliver, Robert P. (Topsham, ME)

1999-01-01

314

Kinetics of irradiation-induced Cu precipitation in nuclear reactor pressure vessel steels  

SciTech Connect

The followup of the embrittlement of nuclear power reactor pressure vessels (RPVs) is of critical importance for the safety assessment in the nuclear industry. The prediction of their future degradation is based on the extrapolation of the past testing of surveillance materials irradiated in the power reactor and in material testing reactors with accelerated dose rates. Using positron annihilation spectroscopy, however, we here reveal a kinetics of irradiation-induced precipitation, i.e., very low dose rate can significantly enhance Cu nanoprecipitation. The mechanism results in the embrittlement in practical RPVs, occurring at a much earlier stage than that found from accelerated tests, suggesting that accelerated tests are not enough for prediction of the embrittlement from Cu nanoprecipitation.

Nagai, Y.; Toyama, T.; Nishiyama, Y.; Suzuki, M.; Tang, Z.; Hasegawa, M. [Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2005-12-26

315

Notch position in the HAZ specimen of reactor pressure vessel steel  

NASA Astrophysics Data System (ADS)

Variations in the notch toughness in the heat-affected zone (HAZ) were investigated by positioning the Charpy V-notches along the line normal to the weld fusion line of a SA 508 Cl.3 reactor pressure vessel (RPV) steel. In the notch position for common surveillance HAZ specimens, rather higher toughness values were acquired. The minimum properties were noted in the region of 4-5 mm apart from the fusion boundary, where the values of toughness and strength were both poorer than those of the other regions of the HAZ and the base metal. The causes for these variations were discussed with reference to the microstructures from the actual and the simulated welding processes.

Kim, J. H.; Yoon, E. P.

1998-12-01

316

Microstructural characterization of irradiation-induced Cu-enriched clusters in reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

The effect of irradiation on microstructure of four irradiated reactor pressure vessel steels (a low copper A533B-1 plate, a low copper A508-3 forging, a high copper Linde 80 flux weld and a high copper Linde 1092 flux weld) was determined by using complementary microstructural techniques such as optical position-sensitive atom probe (OPoSAP), field emission gun scanning transmission electron microscopy (FEGSTEM) and small angle neutron scattering (SANS). In the low copper steels, irradiation resulted in small shifts in transition temperature and small changes in hardness increments. The microstructural analyzes showed that this response was dominated by matrix damage. In contrast, both copper-enriched clusters and matrix damage formed in the high copper welds. This information was then used as input to the Russell-Brown model to predict the change in hardness resulting from copper-enriched clusters. The calculated hardness increments were found to be consistent with the experimental data.

Carter, R. G.; Soneda, N.; Dohi, K.; Hyde, J. M.; English, C. A.; Server, W. L.

2001-10-01

317

Kinetics of irradiation-induced Cu precipitation in nuclear reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

The followup of the embrittlement of nuclear power reactor pressure vessels (RPVs) is of critical importance for the safety assessment in the nuclear industry. The prediction of their future degradation is based on the extrapolation of the past testing of surveillance materials irradiated in the power reactor and in material testing reactors with accelerated dose rates. Using positron annihilation spectroscopy, however, we here reveal a kinetics of irradiation-induced precipitation, i.e., very low dose rate can significantly enhance Cu nanoprecipitation. The mechanism results in the embrittlement in practical RPVs, occurring at a much earlier stage than that found from accelerated tests, suggesting that accelerated tests are not enough for prediction of the embrittlement from Cu nanoprecipitation.

Nagai, Y.; Toyama, T.; Nishiyama, Y.; Suzuki, M.; Tang, Z.; Hasegawa, M.

2005-12-01

318

Carbon Resistor Pressure Gauge Calibration at Low Stresses  

NASA Astrophysics Data System (ADS)

The 470 Ohm carbon resistor gauge has been used in the stress range up to 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. Gauge drawbacks are the long time response to pressure equilibration and gauge resistance hysteresis. In the regime below 0.4 GPa, gauge calibration has been extrapolated. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results are discussed and compared to a calibration curve fit to previously published calibration data.

Cunningham, Bruce; Vandersall, Kevin S.; Niles, Angela M.; Greenwood, Daniel W.; Garcia, Frank; Forbes, Jerry W.; Wilson, William H.

2002-07-01

319

Stress intensity factors for an underclad nozzle corner crack subjected to pressure and thermal loading  

SciTech Connect

The opening mode linear elastic stress intensity factor, K{sub I}, was computed, via 3-D elastic finite element techniques, for an embedded elliptical crack located just beneath the cladding at the nozzle corner in a pressure vessel. Pressure loading and several thermal transient loading conditions were analyzed. The underclad crack was explicitly modeled and K{sub I} was computed explicitly, from the energy release rate, J. The variation of the maximum principal stress along the minor axis of the elliptical crack was determined for a companion set of thermal/structural analyses that were performed in the absence of the crack. These stress distributions were linearized into equivalent membrane and bending stress components that were used to compute K{sub I} from the Shah and Kobayashi solutions for near-surface embedded elliptical cracks. The explicitly computed K{sub I} values were found to be in very good agreement with the K{sub I} values computed from the flat plate'' solutions of Reference 1, for all the loading cases analyzed. An additional comparison was made between the energy release rate results and the results obtained by fitting the 1/{radical}r stress singularity to the crack tip stress field at the Gaussian integration points nearest to the crack front. The observed excellent agreement between the two independent explicit'' computational methods served to verify each of the methods and also demonstrated the adequacy of the refinement of the finite element mesh. These observations support the use of the Shah and Kobayashi flat plate K{sub I} solutions for analyzing underclad cracks at the nozzle corner. 7 refs., 11 figs.

Wilkening, W.W.

1991-06-01

320

In-Situ Nondestructive Evaluation of Kevlar(Registered Trademark)and Carbon Fiber Reinforced Composite Micromechanics for Improved Composite Overwrapped Pressure Vessel Health Monitoring  

NASA Technical Reports Server (NTRS)

NASA has been faced with recertification and life extension issues for epoxy-impregnated Kevlar 49 (K/Ep) and carbon (C/Ep) composite overwrapped pressure vessels (COPVs) used in various systems on the Space Shuttle and International Space Station, respectively. Each COPV has varying criticality, damage and repair histories, time at pressure, and pressure cycles. COPVs are of particular concern due to the insidious and catastrophic burst-before-leak failure mode caused by stress rupture (SR) of the composite overwrap. SR life has been defined [1] as the minimum time during which the composite maintains structural integrity considering the combined effects of stress level(s), time at stress level(s), and associated environment. SR has none of the features of predictability associated with metal pressure vessels, such as crack geometry, growth rate and size, or other features that lend themselves to nondestructive evaluation (NDE). In essence, the variability or surprise factor associated with SR cannot be eliminated. C/Ep COPVs are also susceptible to impact damage that can lead to reduced burst pressure even when the amount of damage to the COPV is below the visual detection threshold [2], thus necessitating implementation of a mechanical damage control plan [1]. Last, COPVs can also fail prematurely due to material or design noncompliance. In each case (SR, impact or noncompliance), out-of-family behavior is expected leading to a higher probability of failure at a given stress, hence, greater uncertainty in performance. For these reasons, NASA has been actively engaged in research to develop NDE methods that can be used during post-manufacture qualification, in-service inspection, and in-situ structural health monitoring. Acoustic emission (AE) is one of the more promising NDE techniques for detecting and monitoring, in real-time, the strain energy release and corresponding stress-wave propagation produced by actively growing flaws and defects in composite materials [3,4,5,6,7,8]. To gain further insight into the mechanisms responsible for composite rupture, broadband modal acoustic emission analysis was used. Also, since AE data reduction proved to be very time consuming, specialized data reduction software was written to automate the process.

Waller, Jess; Saulsberry, Regor

2012-01-01

321

Advanced Models of LWR Pressure Vessel Embrittlement for Low Flux-HighFluence Conditions  

SciTech Connect

Neutron embrittlement of reactor pressure vessels (RPVs) is an unresolved issue for light water reactor life extension, especially since transition temperature shifts (TTS) must be predicted for high 80-year fluence levels up to approximately 1,020 n/cm{sup 2}, far beyond the current surveillance database. Unfortunately, TTS may accelerate at high fluence, and may be further amplified by the formation of late blooming phases that result in severe embrittlement even in low-copper (Cu) steels. Embrittlement by this mechanism is a potentially significant degradation phenomenon that is not predicted by current regulatory models. This project will focus on accurately predicting transition temperature shifts at high fluence using advanced physically based, empirically validated and calibrated models. A major challenge is to develop models that can adjust test reactor data to account for flux effects. Since transition temperature shifts depend on synergistic combinations of many variables, flux-effects cannot be treated in isolation. The best current models systematically and significantly under-predict transition temperature at high fluence, although predominantly for irradiations at much higher flux than actual RPV service. This project will integrate surveillance, test reactor and mechanism data with advanced models to address a number of outstanding RPV embrittlement issues. The effort will include developing new databases and preliminary models of flux effects for irradiation conditions ranging from very low (e.g., boiling water reactor) to high (e.g., accelerated test reactor). The team will also develop a database and physical models to help predict the conditions for the formation of Mn-Ni-Si late blooming phases and to guide future efforts to fully resolve this issue. Researchers will carry out other tasks on a best-effort basis, including prediction of transition temperature shift attenuation through the vessel wall, remediation of embrittlement by annealing, and fracture toughness master curve issues.

Odette, G. Robert; Yamamoto, Takuya

2013-06-17

322

Technology update: Nickel-hydrogen Common Pressure Vessel (CPV) 2.5V twin stack cell designs  

NASA Technical Reports Server (NTRS)

Information is given in viewgraph form on the nickel hydrogen common pressure vessel (CPV) 2.5V twin stack cell designs. Information given includes an energy analysis, a CPV design comparison, a summary of CPV characterization testing, a comparison of discharge voltage among designs, and life test performance summaries.

Harvey, Tim; Miller, Lee

1992-01-01

323

Thermal Analysis to Calculate the Vessel Temperature and Stress in Alcator C-Mod Due to the Divertor Upgrade  

SciTech Connect

Alcator C-Mod is planning an upgrade to its outer divertor. The upgrade is intended to correct the existing outer divertor alignment with the plasma, and to operate at elevated temperatures. Higher temperature operation will allow study of edge physics behavior at reactor relevant temperatures. The outer divertor and tiles will be capable of operating at 600oC. Longer pulse length, together with the plasma and RF heat of 9MW, and the inclusion of heater elements within the outer divertor produces radiative energy which makes the sustained operation much more difficult than before. An ANSYS model based on ref. 1 was built for the global thermal analysis of C-Mod. It models the radiative surfaces inside the vessel and between the components, and also includes plasma energy deposition. Different geometries have been simulated and compared. Results show that steady state operation with the divertor at 600oC is possible with no damage to major vessel internal components. The differential temperature between inner divertor structure, or "girdle" and inner vessel wall is ~70oC. This differential temperature is limited by the capacity of the studs that hold the inner divertor backing plates to the vessel wall. At a 70oC temperature differential the stress on the studs is within allowable limits. The thermal model was then used for a stress pass to quantify vessel shell stresses where thermal gradients are significant.

Han Zhang, Peter H. Titus, Robert Ellis, Soren Harrison and Rui Vieira

2012-08-29

324

Health Monitoring of Composite Overwrapped Pressure Vessels (COPVs) Using Meandering Winding Magnetometer ((MWM(Registered Trademark)) Eddy Current Sensors  

NASA Technical Reports Server (NTRS)

There are 3 mechanisms that affect the life of a COPV are: a) The age life of the overwrap; b) Cyclic fatigue of the metallic liner; c) Stress Rupture life. The first two mechanisms are understood through test and analysis. A COPV Stress Rupture is a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. Currently there is no simple, deterministic method of determining the stress rupture life of a COPV, nor a screening technique to determine if a particular COPV is close to the time of a stress rupture failure. Conclusions: Demonstrated a correlation between MWM response and pressure or strain. Demonstrated the ability to monitor stress in COPV at different orientations and depths. FA41 provides best correlation with bottle pressure or stress.

Russell, Rick; Grundy, David; Jablonski, David; Martin, Christopher; Washabaugh, Andrew; Goldfine, Neil

2011-01-01

325

Effects of 50/degree/C surveillance and test reactor irradiations on ferritic pressure vessel steel embrittlement  

SciTech Connect

The results of surveillance tests on the High-Flux Isotope Reactor (HFIR) pressure vessel at the Oak Ridge National Laboratory revealed that a greater than expected embrittlement had taken place after about 17.5 effective full-power years of operation and an operational assessment program was undertaken to fully evaluate the vessel condition and recommend conditions under which operation could be resumed. A research program was undertaken that included irradiating specimens in the Oak Ridge Research Reactor. Specimens of the A212 grade B vessel shell material were included, along with specimens from a nozzle qualification weld and a submerged-arc weld fabricated at ORNL to reproduce the vessel seam weld. The results of the surveillance program and the materials research program performed in support of the evaluation of the HFIR pressure vessel are presented and show the welds to be more radiation resistant than the A212B. Results of irradiated tensile and annealing experiments are described as well as a discussion of mechanisms which may be responsible for enhanced hardening at low damage rates. 20 refs., 22 figs., 5 tabs.

Nanstad, R.K.; Iskander, S.K.; Rowcliffe, A.F.; Corwin, W.R.; Odette, G.R.

1988-01-01

326

Dual-pump CARS of Air in a Heated Pressure Vessel up to 55 Bar and 1300 K  

NASA Technical Reports Server (NTRS)

Dual-pump Coherent anti-Stokes Raman scattering (CARS) measurements have been performed in a heated pressure vessel at NASA Langley Research Center. Each measurement, consisting of 500 single shot spectra, was recorded at a fixed location in dry air at various pressures and temperatures, in a range of 0.03-55×10(exp 5) Pa and 300-1373 K, where the temperature was varied using an electric heater. The maximum output power of the electric heater limited the combinations of pressures and temperatures that could be obtained. Charts of CARS signal versus temperature (at constant pressure) and signal versus pressure (at constant temperature) are presented and fit with an empirical model to validate the range of capability of the dual-pump CARS technique; averaged spectra at different conditions of pressure and temperature are also shown.

Cantu, Luca; Gallo, Emanuela; Cutler, Andrew D.; Danehy, Paul M.

2014-01-01

327

Crack arrest behavior of reactor pressure vessel steels at high temperatures  

SciTech Connect

The Heavy-Section Steel Technology Program at the Oak Ridge National Laboratory under the sponsorship of the US Nuclear Regulatory Commission is conducting experimental and analytical studies to improve the understanding of conditions that govern the initiation, rapid propagation, arrest and ductile tearing of cracks in reactor pressure vessel (RPV) steels. In support of this objective, large-scale wide-plate experiments are performed to generate crack-arrest toughness data for RPV steels at temperatures approaching and above the onset of Charpy upper-shelf behavior. Analytical studies are addressing the role of dynamics and nonlinear rate-dependent (i.e., viscoplastic) effects in the interpretation of crack run-arrest events in these ductile materials. A summary of the wide-plate tests performed to date is presented, including details of test procedures, test data, and results of analyses performed to date. The importance of incorporating viscoplastic effects into dynamic analysis of crack run-arrest events in these strain-rate sensitive steels is examined through applications of selected proposed viscoplastic constitutive equations and fracture parameters to the interpretation of data from the wide-plate tests. The crack-arrest data are compared with those from small ASTM-type specimens and other large structural tests.

Pugh, C.E.; Naus, D.J.; Bass, B.R.

1988-01-01

328

On the thermal stability of late blooming phases in reactor pressure vessel steels: An atomistic study  

NASA Astrophysics Data System (ADS)

Radiation-induced embrittlement of bainitic steels is the lifetime limiting factor of reactor pressure vessels in existing nuclear light water reactors. The primary mechanism of embrittlement is the obstruction of dislocation motion produced by nanometric defect structures that develop in the bulk of the material due to irradiation. In view of improving the predictive capability of existing models it is necessary to understand better the mechanisms leading to the formation of these defects, amongst which the so-called "late blooming phases". In this work we study the stability of the latter by means of density functional theory (DFT) calculations and Monte Carlo simulations based on a here developed quaternary FeCuNiMn interatomic potential. The potential is based on extensive DFT and experimental data. The reference DFT data on solute-solute interaction reveal that, while Mn-Ni pairs and triplets are unstable, larger clusters are kept together by attractive binding energy. The NiMnCu synergy is found to increase the temperature range of stability of solute atom precipitates in Fe significantly as compared to binary FeNi and FeMn alloys. This allows for thermodynamically stable phases close to reactor temperature, the range of stability being, however, very sensitive to composition.

Bonny, G.; Terentyev, D.; Bakaev, A.; Zhurkin, E. E.; Hou, M.; Van Neck, D.; Malerba, L.

2013-11-01

329

International Atomic Energy Agency (IAEA) Coordinated Research Projects on Structural Integrity of Reactor Pressure Vessels  

SciTech Connect

The International Atomic Energy Agency (IAEA) has conducted a series of Coordinated Research Projects (CRPs) that have focused on irradiated reactor pressure vessel (RPV) steel fracture toughness properties and approaches for assuring structural integrity of RPVs throughout operating life. A series of nine CRPs have been sponsored by the IAEA, starting in the early 1970s, focused on neutron radiation effects on RPV steels. The purpose of the CRPs was to develop comparisons and correlations to test the uniformity of irradiated results through coordinated international research studies and data sharing. Consideration of dose rate effects, effects of alloying (nickel, manganese, silicon, etc.) and residual elements (eg., copper and phosphorus), and drop in upper shelf toughness are also important for assessing neutron embrittlement effects. The ultimate use of embrittlement understanding is assuring structural integrity of the RPV under current and future operation and accident conditions. Material fracture toughness is the key ingredient needed for this assessment, and many of the CRPs have focused on measurement and application of irradiated fracture toughness. This paper presents an overview of the progress made since the inception of the CRPs in the early 1970s. The chronology and importance of each CRP have been reviewed and put into context for continued and long-term safe operation of RPVs.

Server, W. L. [ATI Consulting, Pinehurst, NC; Nanstad, Randy K [ORNL

2009-01-01

330

Irradiation Induced Defect Characterization in Reactor Pressure Vessel Steel by Small Angle Neutron Scattering  

NASA Astrophysics Data System (ADS)

The degradation of the mechanical properties of the RPV (Reactor Pressure Vessel) steel during an irradiation in a nuclear power plant is closely related to the irradiation induced defects. The size of these defects is known to be a few nanometer, and the small angle neutron scattering technique is regarded as the best non destructive technique to characterize the nano sized inhomogeneities in bulk samples. The investigated the RPV steel has been used in YeongKwang nuclear power plant at Korea and the Cu content of the RPV steel is 0.06 wt%. The RPV steel was irradiated in the HANARO reactor at KAERI. The small angle neutron scattering experiments were performed by the SANS instrument in the HANARO reactor. The nano sized irradiation induced defects were quantitatively analyzed by SANS and the type of the irradiation induced defects was discussed in detail. The relation between irradiation induced defects and the yield strength was investigated. The characteristics of irradiation induced defects in low Cu containing RPV steel were discussed.

Han, Yougn-Soo; Shin, Eun-Joo; Lee, Chang-Hee; Park, Duck-Gun

331

The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement  

SciTech Connect

The results of recent molecular dynamics simulations of displacement cascades in iron indicate that small interstitial clusters may have a very low activation energy for migration, and that their migration is 1-dimensional, rather than 3-dimensional. The mobility of these clusters can have a significant impact on the predictions of radiation damage models, particularly at the relatively low temperatures typical of commercial, light water reactor pressure vessels (RPV) and other out-of-core components. A previously-developed kinetic model used to investigate RPV embrittlement has been modified to permit an evaluation of the mobile interstitial clusters. Sink strengths appropriate to both 1- and 3-dimensional motion of the clusters were evaluated. High cluster mobility leads to a reduction in the amount of predicted embrittlement due to interstitial clusters since they are lost to sinks rather than building up in the microstructure. The sensitivity of the predictions to displacement rate also increases. The magnitude of this effect is somewhat reduced if the migration is 1-dimensional since the corresponding sink strengths are lower than those for 3-dimensional diffusion. The cluster mobility can also affect the evolution of copper-rich precipitates in the model since the radiation-enhanced diffusion coefficient increases due to the lower interstitial cluster sink strength. The overall impact of the modifications to the model is discussed in terms of the major irradiation variables and material parameter uncertainties.

Stoller, R.E.

1998-05-01

332

A Modification of the Inner and Outer Core for Reactor Pressure Vessel Lifetime Extension  

SciTech Connect

The feasibility of nuclear power plant lifetime extension was examined by reducing the fast neutron fluence at the reactor pressure vessel (RPV) and relieving irradiation embrittlement of materials, and thus ensuring enough structural integrity beyond the design lifetime. Two fluence reduction options, peripheral assembly replacement and additional shield installation in the outer core structures, were applied to the Kori Unit-1 reactor, and the fluence reduction effect was carefully analyzed. For an accurate estimate of the neutron fluence at the RPV and a reasonable description of the modified peripheral assemblies, a full-scope explicit modeling of a Monte Carlo simulation was employed in all calculations throughout this study. The Kori Unit-1 cycle-16 core was modeled on a three-dimensional representation by using the MCNP4B code, and the fluence distribution was estimated at the inner wall beltline around the circumferential weld of the RPV. On the basis of fracture toughness requirements of the RPV, the two modified cases were predicted to have an additional life of 7 to 10 effective full-power years. Throughout the core nuclear characteristics analyses, it was confirmed that the critical peaking factors for safe reactor operation were satisfied with the design limits.

Seo, Bo Kyun [Hanyang University (Korea, Republic of); Kim, Jong Kyung [Hanyang University (Korea, Republic of); Shin, Chang Ho [Hanyang University (Korea, Republic of); Kwon, Tae Je [Nuclear Fuel Company (Korea, Republic of)

2001-03-15

333

Blood Pressure and Heart Rate Responses to Anticipated High-stress Dental Treatment  

Microsoft Academic Search

Twenty-four healthy adults participated in a study to determine the effects of anticipated high-stress dental treatment on blood pressure and heart rate. Blood pressure, heart rate, and state anxiety were assessed prior to four consecutive dental appointments. Appointments 1, 2, and 4 were of relatively low stress and appointment 3 was of relatively high stress. Blood pressure was unaffected while

Frank M. Beck; Joël M. Weaver

1981-01-01

334

Hydrogen induced plastic damage in pressure vessel steel of 2.25Cr?1Mo  

Microsoft Academic Search

2.25Cr-1Mo steel is generally employed as a hydrogenation reaction vessel material used at elevated temperature and in a hydrogen containing environment. During service of the reaction vessel, a large number of hydrogen atoms would enter its wall. When the reaction vessel is shutdown and the temperature reduces to about ambient temperature, the hydrogen atoms remaining in the wall would induce

Y. J. Song

1995-01-01

335

Proteoglycans and Vascular Residual Stress: Exposing a Hidden Mechanism for Regulating Blood Vessel Bio mechanics  

Microsoft Academic Search

Biomechanics plays a fundamental role in understanding how blood vessels function in the body, and how they adapt in response to abnormal loading conditions that accompany many devastating cardiovascular diseases. In particular, blood vessels contain so-called \\

Vikrum Thimmappa; Evren U. Azeloglu; Gerard A. Ateshian; Kevin D. Costa

336

D0 Silicon Upgrade: Gas Helium Storage Tank Pressure Vessel Engineering Note  

SciTech Connect

This is to certify that Beaird Industries, Inc. has done a white metal blast per SSPC-SP5 as required per specifications on the vessel internal. Following the blast, a black light inspection was performed by Beaird Quality Control personnel to assure that all debris, grease, etc. was removed and interior was clean prior to closing vessel for helium test.

Rucinski, Russ; /Fermilab

1996-11-11

337

On the character of nanoscale features in reactor pressure vessel steels under neutron irradiation  

NASA Astrophysics Data System (ADS)

Nanostructural features that form in reactor pressure vessel steels under neutron irradiation at around 290°C are responsible for significant hardening and embrittlement. It is well established that the nanostructural features can be separated into well formed precipitates and matrix features comprised of point defect clusters complexed with solutes, which may also include regions of solute enrichment that are not well formed precipitates. However, a more detailed atomicscale understanding of these features is needed to better interpret experimental measurements and provide a physical basis for predictive embrittlement models. The overall objective of this work is to provide atomic-level insight into the character of the nanostructural features and the physical processes involved in their formation. One focus of this work has been on modeling cascade aging; defined as the evolution of self-interstitial and vacancy defects spanning from their spatially correlated birth in displacement cascades over picoseconds to times on the order of >10 5 seconds, when defect populations have built up to steady-state values and no longer have a geometric correlation. During cascade aging, the self-interstitial and vacancy fluxes are responsible for radiation enhanced diffusion, resulting in wellformed precipitates, and are a direct source of matrix defect features. Many-bodied molecular-statics energy relaxation methods have been used to investigate the structure and energetics of self-interstitial and vacancy clusters. The characterization reveals that self-interstitial clusters form as highly kinked, prismatic, perfect proto dislocation loops and vacancy clusters form as faceted three-dimensional clusters. Molecular dynamics simulations of self-interstitial cluster migration reveal that they undergo easy one-dimensional glide, probably due to the presence and easy motion of intrinsic kinks. Our study of the structural characteristics and mobility of the self-interstitial clusters leads to the conclusion of limited vacancy-interstitial recombination during cascade aging. Kinetic Lattice Monte Carlo (KLMC) simulations have been used to provide insight into the coupled vacancy and solute clustering during cascade aging. The simulations reveal that cascade vacancy-solute clustering may play a role in the formation of dilute atmospheres of solute enrichment and serve to enhance the formation of manganese-nickel rich precipitates at low copper levels. KLMC simulations have also been used to study copper diffusion and precipitation in dilute Fe-Cu alloys and reveal that highly correlated copper cluster migration mechanisms occur in these steels. The primary result is that larger clusters, with 5-30 vacancies, form in cascades with thermal lifetimes up to 7.1x105s . The nanostructural features have been experimentally characterized using small angle neutron scattering (SANS). This work describes the comprehensive single variable experimental studies which characterize the evolution of copper and/or manganese nickel rich precipitates (CRP and/or MNP) as a function of key embrittlement variables. Post-irradiation annealing is a method of ameliorating irradiation embrittlement in these steels, and a set of SANS experiments have been performed which characterize the precipitate evolution during post-irradiation annealing (PIA) at 400 and 450°C . The character of matrix defect features cannot be obtained from SANS experiments alone, but have been studied in irradiated low copper steels which do not contain well-formed precipitates. In summary, this work has provided a semi-quantitative analysis of cascade aging in reactor pressure vessel steels under neutron irradiation, with an emphasis on the character of the nano-scale features.

Wirth, Brian David

338

Design, Analysis, Manufacture, and Test of Shallow Water Pressure Vessels Using E-Glass\\/Epoxy Woven Composite Material for a SemiAutonomous Underwater Vehicle  

Microsoft Academic Search

Six E-glass\\/Epoxy shallow water composite pressure vessels with effective length of 45.72 cm and inner diameter of 33.02 cm were designed, analyzed, manufactured, and tested for an external hydrostatic design pressure of 1.14 MPa that corresponds to a depth of 91m in ocean. Composite pressure vessels were designed as composite cylinders fabricated by roll-wrapping and enclosed by two flat plug-supported

R. K. H. Ng; Ali Yousefpour; M. Uyema; Mehrdad N Ghasemi Nejhad

2002-01-01

339

On the thermal rupture of 1.9 m 3 propane pressure vessels with defects in their thermal protection system  

Microsoft Academic Search

This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100min in

A. M. Birk; D. Poirier; C. Davison

2006-01-01

340

LWR Pressure Vessel Surveillance Dosimetry Improvement Program for NRC (Nuclear Regulatory Commission) Materials Engineering Branch: 1985 summary annual report  

Microsoft Academic Search

The objective of this program is to make measurements in neutron fields (''Benchmark'' and reactor ''Test Surveillance Regions'') for the subsequent validation\\/calibration of available state-of-the-art physics-dosimetry-metallurgy, damage correlation, and associated reactor analysis procedures and data. These procedures and data are in turn used for predicting the integrated effects of neutron exposure to Light Water Reactor (LWR) Pressure Vessel (PV) and

McElroy

1988-01-01

341

Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept  

NASA Technical Reports Server (NTRS)

A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

Taylor, M. F.; Whitmarsh, C. L., Jr.; Sirocky, P. J., Jr.; Iwanczyke, L. C.

1973-01-01

342

Residual stress effects in containment analysis.  

SciTech Connect

The manufacturing of steel containment vessels starts with the forming of flat plates into curved plates. A steel containment structure is made by welding individual plates together to form the sections that make up the complex shaped vessels. The metal forming and welding process leaves residual stresses in the vessel walls. Generally, the effect of metal forming residual stresses can be reduced or virtually eliminated by thermally stress relieving the vessel. In large containment vessels this may not be practical and thus, the residual stresses due to manufacturing may become important. The residual stresses could possibly affect the response of the vessel to internal pressurization. When the level of residual stresses is significant it will affect the vessel's response, for instance the yielding pressure and possibly the failure pressure. This paper will address the effect of metal forming residual stresses on the response of a generic pressure vessel to internal pressurization. A scoping analysis investigated the effect of residual forming stresses on the response of an internally pressurized vessel. A simple model was developed to gain understanding of the mechanics of the problem. Residual stresses due to the welding process were not considered in this investigation.

Pfeiffer, P. A.

1998-04-24

343

Influence of long-term thermal aging on the microstructural evolution of nuclear reactor pressure vessel materials: An atom probe study  

SciTech Connect

Atom probe field ion microscopy (APFIM) investigations of the microstructure of unaged (as-fabricated) and long-term thermally aged ({approximately} 100,000 h at 280 C) surveillance materials from commercial reactor pressure vessel steels were performed. This combination of materials and conditions permitted the investigation of potential thermal-aging effects. This microstructural study focused on the quantification of the compositions of the matrix and carbides. The APFIM results indicate that there was no significant microstructural evolution after a long-term thermal exposure in weld, plate, or forging materials. The matrix depletion of copper that was observed in weld materials was consistent with the copper concentration in the matrix after the stress-relief heat treatment. The compositions of cementite carbides aged for 100,000 h were compared with the Thermocalc{trademark} prediction. The APFIM comparisons of materials under these conditions are consistent with the measured change in mechanical properties such as the Charpy transition temperature.

Pareige, P.; Russell, K.F.; Stoller, R.E.; Miller, M.K. [Oak Ridge National Lab., TN (United States)

1998-03-01

344

Temperature Field and Thermal Stress Analysis of the HT7U Vacuum Vessel  

Microsoft Academic Search

The HT-7U vacuum vessel is an all-metal-welded double-wall interconnected with toroidal and poloidal stiffening ribs. The channels formed between the ribs and walls are filled with boride water as a nuclear shielding. On the vessel surface facing the plasma are installed cable-based Ohmic heaters. Prior to plasma operation the vessel is to be baked out and discharge cleaned at about

Yun-tao Song; Da-mao Yao; Song-tao Wu; Pei-de Weng

2000-01-01

345

46 CFR 154.650 - Cargo tank and process pressure vessel welding.  

Code of Federal Regulations, 2011 CFR

...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Construction...full penetration tee welds. (2) Each nozzle weld must be of the full penetration...measures, weld procedure qualification, design details, materials,...

2011-10-01

346

46 CFR 154.650 - Cargo tank and process pressure vessel welding.  

Code of Federal Regulations, 2012 CFR

...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Construction...full penetration tee welds. (2) Each nozzle weld must be of the full penetration...measures, weld procedure qualification, design details, materials,...

2012-10-01

347

46 CFR 154.650 - Cargo tank and process pressure vessel welding.  

Code of Federal Regulations, 2010 CFR

...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Construction...full penetration tee welds. (2) Each nozzle weld must be of the full penetration...measures, weld procedure qualification, design details, materials,...

2010-10-01

348

46 CFR 154.650 - Cargo tank and process pressure vessel welding.  

Code of Federal Regulations, 2013 CFR

...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Construction...full penetration tee welds. (2) Each nozzle weld must be of the full penetration...measures, weld procedure qualification, design details, materials,...

2013-10-01

349

46 CFR 196.30-1 - Repairs to boilers and pressure vessels.  

Code of Federal Regulations, 2010 CFR

...Section 196.30-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Reports of Accidents, Repairs, and Unsafe Equipment § 196.30-1 Repairs to boilers and...

2010-10-01

350

Evolution of shear stress, protein expression, and vessel area in an animal model of arterial dilatation in hemodialysis grafts  

PubMed Central

Purpose To evaluate the wall shear stress, protein expression of matrix metalloproteinases-2 (MMP-2), -9 (MMP-9), and the inhibitors (tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), and -2 (TIMP-2)), and vessel area over time in a porcine model for hemodialysis polytetrafluoroethylene (PTFE) grafts. Materials and methods In 21 pigs, subtotal renal infarction was performed and 28 days later, a PTFE graft was placed to connect the carotid artery to the ipsilateral jugular vein. Phase contrast MR was used to measure blood flow and vessel area at 1, 3, 7, and 14 days after graft placement. Wall shear stress was estimated from Poiseuille’s law. Animals were sacrificed at day 3 (N=7), day 7 (N=7), and day 14 (N=7) and expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined at the grafted and control arteries. Results The mean wall shear stress of the grafted artery was higher than the control artery at all time points (P<0.05). It peaked by day 3 and decreased by days 7–14 as the vessel area nearly doubled. By days 7–14, there was a significant increase in active MMP-2 followed by a significant increase in pro and active MMP-9 by day 14 (P<0.05, grafted artery versus control). TIMP-1 expression peaked by day 7 and then decreased while TIMP-2 expression was decreased at days 7–14. Conclusions The wall shear stress of the grafted artery peaks by day 3 with increased MMP-2 activity by days 7–14 followed by pro and active MMP-9 by day 14 and the vessel area nearly doubled. PMID:20123196

Misra, Sanjay; Fu, Alex A.; Misra, Khamal D.; Glockner, James F.; Mukhopadyay, Debabrata

2010-01-01

351

Preliminary materials selection issues for the next generation nuclear plant reactor pressure vessel.  

SciTech Connect

In the coming decades, the United States and the entire world will need energy supplies to meet the growing demands due to population increase and increase in consumption due to global industrialization. One of the reactor system concepts, the Very High Temperature Reactor (VHTR), with helium as the coolant, has been identified as uniquely suited for producing hydrogen without consumption of fossil fuels or the emission of greenhouse gases [Generation IV 2002]. The U.S. Department of Energy (DOE) has selected this system for the Next Generation Nuclear Plant (NGNP) Project, to demonstrate emissions-free nuclear-assisted electricity and hydrogen production within the next 15 years. The NGNP reference concepts are helium-cooled, graphite-moderated, thermal neutron spectrum reactors with a design goal outlet helium temperature of {approx}1000 C [MacDonald et al. 2004]. The reactor core could be either a prismatic graphite block type core or a pebble bed core. The use of molten salt coolant, especially for the transfer of heat to hydrogen production, is also being considered. The NGNP is expected to produce both electricity and hydrogen. The process heat for hydrogen production will be transferred to the hydrogen plant through an intermediate heat exchanger (IHX). The basic technology for the NGNP has been established in the former high temperature gas reactor (HTGR) and demonstration plants (DRAGON, Peach Bottom, AVR, Fort St. Vrain, and THTR). In addition, the technologies for the NGNP are being advanced in the Gas Turbine-Modular Helium Reactor (GT-MHR) project, and the South African state utility ESKOM-sponsored project to develop the Pebble Bed Modular Reactor (PBMR). Furthermore, the Japanese HTTR and Chinese HTR-10 test reactors are demonstrating the feasibility of some of the planned components and materials. The proposed high operating temperatures in the VHTR place significant constraints on the choice of material selected for the reactor pressure vessel for both the PBMR and prismatic design. The main focus of this report is the RPV for both design concepts with emphasis on material selection.

Natesan, K.; Majumdar, S.; Shankar, P. S.; Shah, V. N.; Nuclear Engineering Division

2007-03-21

352

Tachycardic vs. pharmacologic stress myocardial perfusion imaging: differential implications in multi-vessel ischemia  

PubMed Central

Background In patients unable to exercise, potential methods of induction of reversible myocardial ischemia include physiological heart rate acceleration via pacing or dobutamine infusion and asymmetric coronary vasodilatation using dipyridamole. Although their bases for induction of ischemia are widely disparate, no direct comparison of these techniques has previously been reported. Methods We performed a randomised, paired comparison of dipyridamole and pacing myocardial perfusion imaging (MPI) in 28 patients in whom exercise stress imaging was precluded, comparing the detection, localisation and quantitation of ischemia. Results Reversible myocardial ischemia was detected in 21 patients, concordantly in 13 (p = 0.042). There was a high degree of concordance (p < 0.0001) regarding locations of sites of ischemia. While there was a good correlation (r = 0.74, p < 0.0001) between size of total ischemic zones with dipyridamole and pacing, the magnitude of ischemia tended to be greater with dipyridamole (mean percentage of left ventricular myocardium ± SD, 9.4 ± 11.0% vs. 7.0 ± 9.0%, p = 0.091). Furthermore, this difference resulted from accentuation of the primary ischemic zone with dipyridamole in patients with multi-vessel ischemia (mean ± SD, 28.1 ± 21.1% vs. 18.7 ± 16.1%, p = 0.046). Conclusions Despite major differences in mechanism(s) of induction of ischemia, dipyridamole and pacing produce similar results regarding detection, localisation and severity of ischemia. However, dipyridamole accentuates ischemia in primary (vs. secondary) ischemic zones, consistent with known induction of coronary “steal". This should be taken into account in interpretation of scan results. PMID:22254212

Nguyen, Thanh H; Horowitz, John D; Unger, Steven A

2012-01-01

353

Subjective Stress and Coping Resources Interact To Predict Blood Pressure Reactivity in Black College Students.  

ERIC Educational Resources Information Center

Examined the effects of subjective stress and coping resources on blood pressure reactivity among black college students. The interactive effects of subjective stress and coping resources predicted diastolic blood pressure reactivity. Higher levels of problem-focused coping related to more marked diastolic blood pressure changes under conditions…

Clark, Rodney

2003-01-01

354

Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement. Technical progress report for year 2, October 1, 1991--September 30, 1992  

SciTech Connect

The objective of this project is to develop a technique for real-time monitoring of neutron dose and of the onset and progression of embrittlement in operating nuclear pressure vessels. The technique relies on the measurement of magnetic properties of steel and other magnetic materials which are extremely sensitive to radiation-induced properties changes. The approach being developed here is innovative and unique. It promises to be readily applicable to all existing and planned reactor structures. The significance of this program is that it addresses a major concern in the operation of existing nuclear pressure vessels. The development of microscopic defect clusters during irradiation in the nuclear pressure vessel beltline region leads to an increase in material yield strength and a concomitant decrease in ductility, or ability to absorb energy in fracture (i.e. fracture toughness). This decrease in fracture toughness is alarming since it may impair the ability of the pressure vessel to resist fracture during unusual loading situations.

Stubbins, J.F.; Ougouag, A.M.; Williams, J.G.

1992-07-01

355

Development of a New Flame Speed Vessel to Measure the Effect of Steam Dilution on Laminar Flame Speeds of Syngas Fuel Blends at Elevated Pressures and Temperatures  

E-print Network

content (0 ? 15% by volume), temperature (323 ? 423 K), and pressure (1 ? 10 atm) on syngas mixtures by measuring the laminar flame speed in a newly developed constant-volume, heated experimental facility. This heated vessel also broadens the experimental...

Krejci, Michael

2012-07-16

356

Analytical modeling of the effect of crack depth, specimen size, and biaxial stress on the fracture toughness of reactor vessel steels  

SciTech Connect

Fracture, toughness values for A533-B reactor pressure vessel (RPV) steel obtained from test programs at Oak Ridge National Laboratory (ORNL) and University of Kansas (KU) are interpreted using the J-A{sub 2} analytical model. The analytical model is based on the critical stress concept and takes into consideration the constraint effect using the second parameter A{sub 2} in addition to the generally accepted first parameter J which represents the loading level. It is demonstrated that with the constraint level included in the model effects of crack depth (shallow vs deep), specimen size (small vs. large), and loading type (uniaxial vs biaxial) on the fracture toughness from the test programs can be interpreted and predicted.

Chao, Yuh-Jin [Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering; Lam, Poh-Sang [Westinghouse Savannah River Co., Aiken, SC (United States)

1995-02-01

357

77 FR 59408 - Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying...  

Federal Register 2010, 2011, 2012, 2013

...Guard regulations regarding the allowable stress factors for type B and type C independent...first promulgated regulations on allowable stress factors on May 3, 1979. CG-ENG Policy...techniques, the IMO standards for allowable stress factors provide a level of safety...

2012-09-27

358

Composite Overwrapped Pressure Vessels: Database Extension Task 3.0 and Impact Damage Effects Control Task 8.0  

NASA Technical Reports Server (NTRS)

This document represents efforts accomplished at the NASA Johnson Space Center White Sands Test Facility (WSTF) in support of the Enhanced Technology for Composite Overwrapped Pressure Vessels (COPV) Program, a joint research and technology effort among the U.S. Air Force, NASA, and the Aerospace Corporation. WSTF performed testing for several facets of the program. Testing that contributed to the Task 3.0 COPV database extension objective included baseline structural strength, failure mode and safe-life, impact damage tolerance, sustained load/impact effect, and materials compatibility. WSTF was also responsible for establishing impact protection and control requirements under Task 8.0 of the program. This included developing a methodology for establishing an impact control plan. Seven test reports detail the work done at WSTF. As such, this document contributes to the database of information regarding COPV behavior that will ensure performance benefits and safety are maintained throughout vessel service life.

Beeson, Harold D.; Davis, Dennis D.; Ross, William L., Sr.; Tapphorn, Ralph M.

2002-01-01

359

Kinetic of solute clustering in neutron irradiated ferritic model alloys and a French pressure vessel steel investigated by atom probe tomography  

Microsoft Academic Search

The embrittlement of reactor pressure vessel steels under neutron irradiation is partly due to the formation of solute clusters. To gain more insight into their formation mechanisms, ferritic model alloys (low copper Fe–0.08at.% Cu, Fe–0.09 Cu–1.1 Mn–0.7 Ni (at.%), and a copper free Fe–1.1 Mn–0.7 Ni (at.%)) and a French 16MND5 reactor pressure vessel steel, were irradiated in a test

E. Meslin; B. Radiguet; P. Pareige; A. Barbu

2010-01-01

360

A safety evaluation for overlay disbonding of high-temperature and pressure vessels  

SciTech Connect

Hydrogen induced disbonding test (autoclave test) of stainless weld-overlaid 2-1/4Cr-1Mo and 2-1/4Cr-1Mo-1/4V steel, and the calculations of residual hydrogen contents at the fusion boundary in the specimens and actual vessels, were performed. The effects of microstructure of weld overlay near the fusion boundary and postweld heat treatment on disbonding resistance were clarified, and critical hydrogen content values in weld overlay to prevent disbonding were obtained. A simple evaluation method for disbonding in actual vessels using Tempering Parameter was established.

Horita, Ryuichi; Nakajima; Hiroyuki [Hitachi Zosen Corporation, Osaka (Japan). Technical Research Institute; Tanaka, Kazunori; Murakami, Shunzo [Hitachi Zosen Corporation, Kumamoto (Japan). Ariake Works; Fujii, Tadaomi [Nichizo Tech Incorporation, Osaka (Japan). Technology Headquarters

1995-11-01

361

Static and dynamic fatigue behavior of glass filament-wound pressure vessels at ambient and cryogenic temperatures.  

NASA Technical Reports Server (NTRS)

Investigation of the pressure load carrying capacity and fatigue strength of filament-wound glass-reinforced plastic pressure vessels subjected to static and cyclic loading at ambient and cryogenic (liquid nitrogen) temperature environments. The results indicate that the static fatigue problem is not critical at cryogenic temperatures. Under static loading at liquid nitrogen temperature, a reinforced plastic cylinder sustained pressurization for 88 days without failure at about 90% of the single cycle burst strength. At ambient temperature, the static life at 90% of the burst strength was about 7 min. Under cyclic loading in liquid nitrogen, no failure resulted after 1509 cycles at 55% of the single cycle burst strength. Under the same cyclic loading at ambient temperature, the test results would predict failure in the reinforced plastic. The results of similar tests upon adhesively bonded polyimide aluminum-foil lined cylinders are also reviewed.-

Hanson, M. P.

1972-01-01

362

TECHNICAL BASIS AND APPLICATION OF NEW RULES ON FRACTURE CONTROL OF HIGH PRESSURE HYDROGEN VESSEL IN ASME SECTION VIII, DIVISION 3 CODE  

SciTech Connect

As a part of an ongoing activity to develop ASME Code rules for the hydrogen infrastructure, the ASME Boiler and Pressure Vessel Code Committee approved new fracture control rules for Section VIII, Division 3 vessels in 2006. These rules have been incorporated into new Article KD-10 in Division 3. The new rules require determining fatigue crack growth rate and fracture resistance properties of materials in high pressure hydrogen gas. Test methods have been specified to measure these fracture properties, which are required to be used in establishing the vessel fatigue life. An example has been given to demonstrate the application of these new rules.

Rawls, G

2007-04-30

363

Test results on direct containment heating by high-pressure melt ejection into the Surtsey vessel: The TDS test series  

SciTech Connect

The Technology Development and Scoping (TDS) test series was conducted to test and develop instrumentation and procedures for performing steam-driven, high-pressure melt ejection (HPME) experiments at the Surtsey Test Facility to investigate direct containment heating (DCH). Seven experiments, designated TDS-1 through TDS-7, were performed in this test series. These experiments were conducted using similar initial conditions; the primary variable was the initial pressure in the Surtsey vessel. All experiments in this test series were performed with a steam driving gas pressure of {approx_equal} 4 MPa, 80 kg of lumina/iron/chromium thermite melt simulant, an initial hole diameter of 4.8 cm (which ablated to a final hole diameter of {approx_equal} 6 cm), and a 1/10th linear scale model of the Surry reactor cavity. The Surtsey vessel was purged with argon (<0.25 mol% O{sub 2}) to limit the recombination of hydrogen and oxygen, and gas grab samples were taken to measure the amount of hydrogen produced.

Allen, M.D.; Blanchat, T.K.; Pilch, M.M. [Sandia National Lab., Albuquerque, NM (United States). Severe Accident Phenomenology

1994-08-01

364

Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Teactor Pressure Vessels  

SciTech Connect

A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: • Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions. • Perform creep tests and characterize the mechanisms of creep fracture process. • Quantify how the microstructure degradation controls the creep strength of welded steel specimens. • Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds. • Develop a microstructure-based creep fracture model to estimate RPVs service life . • Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates. • Simulate damage evolution in creep specimens by FE analyses. • Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage. • Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength. • Develop a fracture model for the structural integrity of RPVs subjected to creep loads. • Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

Potirniche, Gabriel; Barlow, Fred D.; Charit, Indrajit; Rink, Karl

2013-11-26

365

Alternate design charts for fixed tubesheet design procedure included in ASME Boiler and Pressure Vessel Code, Section 8, Division 1  

SciTech Connect

Design formulas and calculation procedure for the design of fixed tubesheets of shell and tube heat exchangers are included in Appendix AA--Nonmandatory of ASME Boiler and Pressure Vessel code, Section 8, Division 1. To minimize the number of calculations, charts are provided as part of the design procedure. This article provides alternate charts for certain parameters and the original version of the charts are extended for larger values of tubesheet design parameter. Numerical values are given in tabular form for certain functions used in plotting the design charts. This will help to do design calculations without referring to the charts.

Kuppan, T. [Ministry of Railways, Lucknow (India)

1995-05-01

366

Noninvasive identification of left main and triple vessel coronary artery disease: improved accuracy using quantitative analysis of regional myocardial stress distribution and washout of thallium-201  

SciTech Connect

The capabilities of visual and quantitative analysis of stress redistribution thallium-201 scintigrams, exercise electrocardiography and exercise blood pressure response were compared for correct identification of extensive coronary disease, defined as left main or triple vessel coronary artery disease, or both (50% or more luminal diameter coronary narrowing), in 105 consecutive patients with suspected coronary artery disease. Extensive disease was present in 56 patients and the remaining 49 had either less extensive coronary artery disease (n = 34) or normal coronary arteriograms (n = 15). Although exercise blood pressure response, exercise electrocardiography and visual thallium-201 analysis were highly specific (98, 88 and 96%, respectively), they were insensitive for identification of patients with extensive disease (14, 45 and 16%, respectively). Quantitative thallium-201 analysis significantly improved the sensitivity of visual thallium-201 analysis for identification of patients with extensive disease (from 16 to 63%, p less than 0.001) without a significant loss of specificity (96 versus 86%, p = NS). Eighteen (64%) of the 28 patients who were misclassified by visual analysis as having less extensive disease were correctly classified as having extensive disease by virtue of quantitative analysis of regional myocardial thallium-201 washout. When the results of quantitative thallium-201 analysis were combined with those of blood pressure and electrocardiographic response to exercise, the sensitivity and specificity for identification of patients with extensive disease was 86 and 76%, respectively, and the highest overall accuracy (0.82) was obtained.

Maddahi, J.; Abdulla, A.; Garcia, E.V.; Swan, H.J.; Berman, D.S.

1986-01-01

367

Modeling the Ductile Brittle Fracture Transition in Reactor Pressure Vessel Steels using a Cohesive Zone Model based approach  

SciTech Connect

Fracture properties of Reactor Pressure Vessel (RPV) steels show large variations with changes in temperature and irradiation levels. Brittle behavior is observed at lower temperatures and/or higher irradiation levels whereas ductile mode of failure is predominant at higher temperatures and/or lower irradiation levels. In addition to such temperature and radiation dependent fracture behavior, significant scatter in fracture toughness has also been observed. As a consequence of such variability in fracture behavior, accurate estimates of fracture properties of RPV steels are of utmost importance for safe and reliable operation of reactor pressure vessels. A cohesive zone based approach is being pursued in the present study where an attempt is made to obtain a unified law capturing both stable crack growth (ductile fracture) and unstable failure (cleavage fracture). The parameters of the constitutive model are dependent on both temperature and failure probability. The effect of irradiation has not been considered in the present study. The use of such a cohesive zone based approach would allow the modeling of explicit crack growth at both stable and unstable regimes of fracture. Also it would provide the possibility to incorporate more physical lower length scale models to predict DBT. Such a multi-scale approach would significantly improve the predictive capabilities of the model, which is still largely empirical.

Pritam Chakraborty; S. Bulent Biner

2013-10-01

368

46 CFR 54.30-10 - Method of performing mechanical stress relief.  

Code of Federal Regulations, 2010 CFR

...false Method of performing mechanical stress relief. 54.30-10 Section 54...ENGINEERING PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical...

2010-10-01

369

46 CFR 54.30-10 - Method of performing mechanical stress relief.  

Code of Federal Regulations, 2013 CFR

...false Method of performing mechanical stress relief. 54.30-10 Section 54...ENGINEERING PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical...

2013-10-01

370

46 CFR 54.30-10 - Method of performing mechanical stress relief.  

Code of Federal Regulations, 2011 CFR

...false Method of performing mechanical stress relief. 54.30-10 Section 54...ENGINEERING PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical...

2011-10-01

371

46 CFR 54.30-10 - Method of performing mechanical stress relief.  

Code of Federal Regulations, 2012 CFR

...false Method of performing mechanical stress relief. 54.30-10 Section 54...ENGINEERING PRESSURE VESSELS Mechanical Stress Relief § 54.30-10 Method of performing mechanical stress relief. (a) The mechanical...

2012-10-01

372

Hydraulic fracture reopening pressure and the estimation of maximum horizontal stress  

Microsoft Academic Search

In hydrofracture stress measurements, the magnitude of the maximum horizontal stress, SH, is commonly estimated from the borehole pressure required to reopen an induced axial crack. Examination of the processes which govern the borehole pressure history recorded during the reopening cycle of such tests indicates two sources of error in the estimates of SH derived using the conventional method proposed

T. Ito; K. Evans; K. Kawai; K. Hayashi

1999-01-01

373

Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve  

NASA Astrophysics Data System (ADS)

We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

2013-12-01

374

PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning  

PubMed Central

We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance. PMID:22505638

Sriram, Krishna; Tsai, Amy G.; Cabrales, Pedro; Meng, Fantao; Acharya, Seetharama A.; Tartakovsky, Daniel M.

2012-01-01

375

Potential high fluence response of pressure vessel internals constructed from austenitic stainless steels  

SciTech Connect

Many of the in-core components in pressurized water reactors are constructed of austenitic stainless steels. The potential behavior of these components can be predicted using data on similar steels irradiated at much higher displacement rates in liquid-metal reactors or water-cooled mixed-spectrum reactors. Consideration of the differences between the pressurized water environment and that of the other reactors leads to the conclusion that significant amounts of void swelling, irradiation creep, and embrittlement will occur in some components, and that the level of damage per atomic displacement may be larger in the pressurized water environment.

Garner, F.A.; Greenwood, L.R. [Pacific Northwest Lab., Richland, WA (United States); Harrod, D.L. [Westinghouse Electric Corp., Pensacola, FL (United States)

1993-08-01

376

Personal mastery predicts pain, stress, fatigue, and blood pressure in adults with rheumatoid arthritis  

Microsoft Academic Search

Among individuals with rheumatoid arthritis (RA), stress-associated disease flare can severely impact well-being. Psychological factors such as personal mastery may buffer an individual from the negative effects of those flares. We tested the hypothesis that a high sense of personal mastery would prospectively predict stress reactivity. Measures of pain, perceived stress, fatigue, and mean arterial pressure (MAP) were collected before,

Jarred Younger; Patrick Finan; Alex Zautra; Mary Davis; John Reich

2008-01-01

377

Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including design changes to miniaturize and make the sensors durable in the vacuum of space

Russell, Richard; Wincheski, Russell; Jablonski, David; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

2011-01-01

378

Identifying the Inertial Cavitation Pressure Threshold and Skull Effects in a Vessel Phantom Using Focused Ultrasound and Microbubbles  

NASA Astrophysics Data System (ADS)

Using Focused Ultrasound (FUS) and microbubbles to open the blood-brain barrier (BBB) has been shown promising for brain drug delivery. However, the exact mechanism behind the opening remains unknown. Here, the effects of the murine skull on the threshold of inertial cavitation were investigated. In order to investigate the pressure threshold for inertial cavitation of preformed microbubbles during sonication, passive cavitation detection in conjunction with B-mode imaging was used. A cylindrical vessel with a 610-?m diameter inside a polyacrylamide gel was generated within a polyacrylamide gel to simulate large blood vessels. Definity® (Lantheus Medical Imaging, MA, USA) microbubbles with a 1.1-3.3 ?m in diameter at 2.5×107 bubbles/mL were injected into the channel before sonication (frequency: 1.525 MHz; pulse length: 100 cycles; PRF: 10 Hz; sonication duration: 2 s) through an excised mouse skull. A cylindrically focused hydrophone, confocal with the FUS transducer, acted as a passive cavitation detector (PCD) to identify the threshold. A 7.5 MHz linear array with the field-of-view perpendicular to the axial length of the FUS beam was also used to image the occurrence of bubble fragmentation. The broadband spectral response acquired at the passive cavitation detector (PCD) and the B-mode images identified the occurrence and location of the inertial cavitation, respectively. Findings indicated that the peak-rarefactional pressure threshold was approximately equal to 0.45 MPa at the presence or the absence of the skull. However, the skull induced 10-50% lower inertial cavitation dose. Mouse skulls did not affect the pressure threshold of inertial cavitation but resulted in a lower inertial cavitation dose. The broadband response could be captured through the murine skull, so the same PCD setup can be used in future in vivo applications.

Tung, Yao-Sheng; Choi, James J.; Konofagou, Elisa E.

2010-03-01

379

Heat-stress-induced changes in central venous pressure do not explain interindividual differences in orthostatic tolerance during heat stress  

PubMed Central

The extent to which heat stress compromises blood pressure control is variable among individuals, with some individuals becoming very intolerant to a hypotensive challenge, such as lower body negative pressure (LBNP) while heat stressed, while others are relatively tolerant. Heat stress itself reduces indexes of ventricular filling pressure, including central venous pressure, which may be reflective of reductions in tolerance in this thermal condition. This study tested the hypothesis that the magnitude of the reduction in central venous pressure in response to heat stress alone is related to the subsequent decrement in LBNP tolerance. In 19 subjects, central hypovolemia was imposed via LBNP to presyncope in both normothermic and heat-stress conditions. Tolerance to LBNP was quantified using a cumulative stress index (CSI), and the difference between normothermic CSI and heat-stress CSI was calculated for each individual. The eight individuals with the greatest CSI difference between normothermic and heat-stress tolerances (LargeDif), and the eight individuals with the smallest CSI difference (SmallDif), were grouped together. By design, the difference in CSI between thermal conditions was greater in the LargeDif group (969 vs. 382 mmHg × min; P < 0.001). Despite this profound difference in the effect of heat stress in decreasing LBNP tolerance between groups, coupled with no difference in the rise in core body temperatures to the heat stress (LargeDif, 1.4 ± 0.1°C vs. SmallDif, 1.4 ± 0.1°C; interaction P = 0.89), the reduction in central venous pressure during heat stress alone was similar between groups (LargeDif: 5.7 ± 1.9 mmHg vs. SmallDif: 5.2 ± 2.0 mmHg; interaction P = 0.85). Contrary to the proposed hypothesis, differences in blood pressure control during LBNP are not related to differences in the magnitude of the heat-stress-induced reductions in central venous pressure. PMID:21415173

Brothers, R. Matthew; Keller, David M.; Wingo, Jonathan E.; Ganio, Matthew S.

2011-01-01

380

Next Generation Nuclear Plant Reactor Pressure Vessel Materials Research and Development Plan (PLN-2803)  

SciTech Connect

The U.S. Department of Energy (DOE) has selected the High-Temperature Gas-cooled Reactor (HTGR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production, with an outlet gas temperature in the range of 750°C, and a design service life of 60 years. The reactor design will be a graphite-moderated, helium-cooled, prismatic, or pebble bed reactor and use low-enriched uranium, Tri-Isotopic (TRISO)-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. This technology development plan details the additional research and development (R&D) required to design and license the NGNP RPV, assuming that A 508/A 533 is the material of construction. The majority of additional information that is required is related to long-term aging behavior at NGNP vessel temperatures, which are somewhat above those commonly encountered in the existing database from LWR experience. Additional data are also required for the anticipated NGNP environment. An assessment of required R&D for a Grade 91 vessel has been retained from the first revision of the R&D plan in Appendix B in somewhat less detail. Considerably more development is required for this steel compared to A 508/A 533 including additional irradiation testing for expected NGNP operating temperatures, high-temperature mechanical properties, and extensive studies of long-term microstructural stability.

J. K. Wright; R. N. Wright

2010-07-01

381

Thrombospondin-1 and CD47 regulate blood pressure and cardiac responses to vasoactive stress  

E-print Network

pressure. CD47-de cient mice have normal central pulse pressure but elevated resting peripheral bloodThrombospondin-1 and CD47 regulate blood pressure and cardiac responses to vasoactive stress Jeff S in revised form 17 December 2008 Accepted 5 January 2009 Keywords: Thrombospondin-1 CD47 Nitric oxide Blood

Frazier, William A.

382

The DOS 1 neutron dosimetry experiment at the HB-4-A key 7 surveillance site on the HFIR pressure vessel  

SciTech Connect

A comprehensive neutron dosimetry experiment was made at one of the prime surveillance sites at the High Flux Isotope Reactor (HFIR) pressure vessel to aid radiation embrittlement studies of the vessel and to benchmark neutron transport calculations. The thermal neutron flux at the key 7, position 5 site was found, from measurements of radioactivation of four cobalt wires and four silver wires, to be 2.4 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}. The thermal flux derived from two helium accumulation monitors was 2.3 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}{sup {minus}1}. The thermal flux estimated by neutron transport calculations was 3.7 {times} 10{sup 12} n{center_dot}m{sup {minus}2}s{sup {minus}1}. The fast flux, >1 MeV, determined from two nickel activation wires, was 1.5 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}, in keeping with values obtained earlier from stainless steel surveillance monitors and with a computed value of 1.2 {times} 10{sup 13} n{center_dot}m{sup {minus}2}{center_dot}{sup {minus}1}. The fast fluxes given by two reaction-product-type monitors, neptunium-237 and beryllium, were 2.6 {times} 10{sup 13} n{center_dot}m{sup {minus}2}{center_dot}s {sup {minus}1} and 2.2 {times} 10{sup 13} n{center_dot}m{sup {minus}2}s{sup {minus}1}, respectively. Follow-up experiments indicate that these latter high values of fast flux are reproducible but are false; they are due to the creation of greater levels of reaction products by photonuclear events induced by an exceptionally high ratio of gamma flux to fast neutron flux at the vessel.

Farrell, K.; Kam, F.B.; Baldwin, C.A. [and others

1994-01-01

383

In-service Inspection Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density and Size Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements  

SciTech Connect

Pressurized thermal shock (PTS) events are system transients in a pressurized water reactor (PWR) in which there is a rapid operating temperature cool-down that results in cold vessel temperatures with or without repressurization of the vessel. The rapid cooling of the inside surface of the reactor pressure vessel (RPV) causes thermal stresses that can combine with stresses caused by high pressure. The aggregate effect of these stresses is an increase in the potential for fracture if a pre-existing flaw is present in a material susceptible to brittle failure. The ferritic, low alloy steel of the reactor vessel beltline adjacent to the core, where neutron radiation gradually embrittles the material over the lifetime of the plant, can be susceptible to brittle fracture. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), “Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events,” adopted on July 23, 1985, establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. The U.S. Nuclear Regulatory Commission (NRC) completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed a rule, §50.61a, published on January 4, 2010, entitled “Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events” (75 FR 13). Use of the new rule by licensees is optional. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants. These analyses are intended to determine if the actual flaw density and size distribution in the licensee’s reactor vessel beltline welds are bounded by the flaw density and size distribution values used in the PTS technical basis. Under a contract with the NRC, Pacific Northwest National Laboratory (PNNL) has been working on a program to assess the ability of current inservice inspection (ISI)-ultrasonic testing (UT) techniques, as qualified through ASME Code, Appendix VIII, Supplements 4 and 6, to detect small fabrication or inservice-induced flaws located in RPV welds and adjacent base materials. As part of this effort, the investigators have pursued an evaluation, based on the available information, of the capability of UT to provide flaw density/distribution inputs for making RPV weld assessments in accordance with §50.61a. This paper presents the results of an evaluation of data from the 1993 Browns Ferry Nuclear Plant, Unit 3, Spirit of Appendix VIII reactor vessel examination, a comparison of the flaw density/distribution from this data with the distribution in §50.61a, possible reasons for differences, and plans and recommendations for further work in this area.

Sullivan, Edmund J.; Anderson, Michael T.; Norris, Wallace

2012-09-17

384

Safety Evaluation Report: Development of Improved Composite Pressure Vessels for Hydrogen Storage, Lincoln Composites, Lincoln, NE, May 25, 2010  

SciTech Connect

Lincoln Composites operates a facility for designing, testing, and manufacturing composite pressure vessels. Lincoln Composites also has a U.S. Department of Energy (DOE)-funded project to develop composite tanks for high-pressure hydrogen storage. The initial stage of this project involves testing the permeation of high-pressure hydrogen through polymer liners. The company recently moved and is constructing a dedicated research/testing laboratory at their new location. In the meantime, permeation tests are being performed in a corner of a large manufacturing facility. The safety review team visited the Lincoln Composites site on May 25, 2010. The project team presented an overview of the company and project and took the safety review team on a tour of the facility. The safety review team saw the entire process of winding a carbon fiber/resin tank on a liner, installing the boss and valves, and curing and painting the tank. The review team also saw the new laboratory that is being built for the DOE project and the temporary arrangement for the hydrogen permeation tests.

Fort, III, William C.; Kallman, Richard A.; Maes, Miguel; Skolnik, Edward G.; Weiner, Steven C.

2010-12-22

385

Cardiovascular recovery from stress predicts longitudinal changes in blood pressure  

Microsoft Academic Search

Cardiovascular reactivity and recovery were examined as predictors of blood pressure changes over 3 years. Blood pressure and heart rate readings were obtained from 73 men and women aged 18–20 years during cold pressor, mental arithmetic, tourniquet ischemia, cycle exercise and step exercise tasks. Regression analyses indicated that after adjustment for initial blood pressure, initial age, initial body-mass index, sex,

Jesse C. Stewart; Christopher R. France

2001-01-01

386

Microstructural changes of a thermally aged stainless steel submerged arc weld overlay cladding of nuclear reactor pressure vessels  

NASA Astrophysics Data System (ADS)

The effect of thermal aging on microstructural changes in stainless steel submerged arc weld-overlay cladding of reactor pressure vessels was investigated using atom probe tomography (APT). In as-received materials subjected to post-welding heat treatments (PWHTs), with a subsequent furnace cooling, a slight fluctuation of the Cr concentration was observed due to spinodal decomposition in the ?-ferrite phase but not in the austenitic phase. Thermal aging at 400 °C for 10,000 h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn = 16:7:6 in the ?-ferrite phase. The degree of the spinodal decomposition in the submerged arc weld sample was similar to that in the electroslag weld one reported previously. We also observed a carbide on the ?-austenite and ?-ferrite interface. There were no Cr depleted zones around the carbide.

Takeuchi, T.; Kameda, J.; Nagai, Y.; Toyama, T.; Matsukawa, Y.; Nishiyama, Y.; Onizawa, K.

2012-06-01

387

Automatic Magnetic Particle Inspection System for the Bracket Welds of Atucha i Nuclear Power Plant Pressure Vessel  

NASA Astrophysics Data System (ADS)

The present work refers to the welding inspection of the brackets of Atucha I Nuclear Power Plant's Pressure Vessel (RPV) using the wet fluorescent magnetic particles technique (MT). Due to limited access and high radiation levels in the inspection area, it was necessary to automate the testing and use non conventional magnetization techniques. This paper describes the design and implementation of an automated inspection device and the tests carried out on the mock-up to set up the system. Also, magnetization techniques used are described, explaining in detail the non conventional technique of magnetization by current plates and the use of magnetic field concentrators to increase the field values in the area of interest. Finally, the device mounted on the RPV, used to inspect the bracket's weld, and the results achieved from the inspection are shown.

Katchadjian, P.; Desimone, C.; Garcia, A.; Antonaccio, C.; Schroeter, F.; Mastroleonardo, P.

2011-06-01

388

Effect of neutron irradiation on the microstructure of the stainless steel electroslag weld overlay cladding of nuclear reactor pressure vessels  

NASA Astrophysics Data System (ADS)

Microstructural changes in the stainless steel weld overlay cladding of reactor pressure vessels subjected to neutron irradiation with a fluence of 7.2 × 1023 n m-2 (E > 1 MeV) and a flux of 1.1 × 1017 n m-2 s-1 at 290 °C were investigated by atom probe tomography. The results showed a difference in the microstructural changes that result from neutron irradiation and thermal aging. Neutron irradiation resulted in the slight progression of Cr spinodal decomposition and an increase in the fluctuation of the Si, Ni, and Mn concentrations in the ferrite phases, with formation of ??-like clusters in the austenite phases. On the other hand, thermal aging resulted in the considerable progression of the Cr spinodal decomposition, formation of G-phases, and a decrease in the Si and an increase in the Ni and Mn concentration fluctuations at the matrix in the ferrite phases, without the microstructural changes in the austenite phases.

Takeuchi, T.; Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Nagai, Y.; Nishiyama, Y.; Katsuyama, J.; Onizawa, K.; Suzuki, M.

2013-11-01

389

Proof testing of an explosion containment vessel  

SciTech Connect

A steel containment vessel was fabricated and proof tested for use by the Los Alamos National Laboratory at their M-9 facility. The HY-100 steel vessel was designed to provide total containment for high explosives tests up to 22 lb (10 kg) of TNT equivalent. The vessel was fabricated from an 11.5-ft diameter cylindrical shell, 1.5 in thick, and 2:1 elliptical ends, 2 in thick. Prior to delivery and acceptance, three types of tests were required for proof testing the vessel: a hydrostatic pressure test, air leak tests, and two full design charge explosion tests. The hydrostatic pressure test provided an initial static check on the capacity of the vessel and functioning of the strain instrumentation. The pneumatic air leak tests were performed before, in between, and after the explosion tests. After three smaller preliminary charge tests, the full design charge weight explosion tests demonstrated that no yielding occurred in the vessel at its rated capacity. The blast pressures generated by the explosions and the dynamic response of the vessel were measured and recorded with 33 strain channels, 4 blast pressure channels, 2 gas pressure channels, and 3 displacement channels. This paper presents an overview of the test program, a short summary of the methodology used to predict the design blast loads, a brief description of the transducer locations and measurement systems, some of the hydrostatic test strain and stress results, examples of the explosion pressure and dynamic strain data, and some comparisons of the measured data with the design loads and stresses on the vessel.

Esparza, E.D. [Esparza (Edward D.), San Antonio, TX (United States); Stacy, H.; Wackerle, J. [Los Alamos National Lab., NM (United States)

1996-10-01

390

Osmium Metal Studied under High Pressure and Nonhydrostatic Stress  

SciTech Connect

Interest in osmium as an ultra-incompressible material and as an analog for the behavior of iron at high pressure has inspired recent studies of its mechanical properties. We have measured elastic and plastic deformation of Os metal at high pressures using in situ high pressure x-ray diffraction in the radial geometry. We show that Os has the highest yield strength observed for any pure metal, supporting up to 10 GPa at a pressure of 26 GPa. Furthermore, our data indicate changes in the nonhydrostatic apparent c/a ratio and clear lattice preferred orientation effects at pressures above 15 GPa.

Weinberger,M.; Tolbert, S.; Kavner, A.

2008-01-01

391

Synchronized Stress-strain Measurements in Dynamic Loading at High Pressure using D-DIA  

SciTech Connect

A new data collection protocol for forced oscillation experiments using a multianvil high pressure device is reported. We derive the stress of the sample at high pressure and temperature from synchrotron x-ray diffraction that is synchronized with sample strain measurements from x-ray radiographs. This method yields stress directly from the sample rather than a stress proxy. Furthermore, the diffraction pattern yields useful information concerning time evolution of structurally related phenomena. Here we illustrate some of these possibilities with high pressure experimental data.

L Li; D Weidner

2011-12-31

392

Evaluation of sildenafil pressurized metered dose inhalers as a vasodilator in umbilical blood vessels of chicken egg embryos.  

PubMed

Sildenafil citrate is a selective phosphodiesterase-5 inhibitor used for the treatment for erectile dysfunction and pulmonary hypertension. The delivery of sildenafil directly to the lung could have several advantages over conventional treatments for pulmonary hypertension because of the local delivery, a more rapid onset of response, and reduced side effects. The major problem of sildenafil citrate is its limited solubility in water. Sildenafil citrate was complexed with cyclodextrins (CDs) to enhance its water solubility prior to development as an inhaled preparation. Four sildenafil citrate inhaled formulations were prepared with the aid of HP-?-CD (#1), ?-CD (#2) and ?-CD (#3) and their effects were compared with the formulations without CDs (#4). The sildenafil citrate pressurized metered dose inhalers (pMDI) used ethanol as a solvent, PEG400 as a stabilizing agent, sorbitan monooleate as a surfactant and HFA-134a as a propellant. All formulations consisted of sildenafil citrate equivalent to a sildenafil content of 20?g/puff. These products were evaluated according to a standard guideline of inhalation products. Vasodilation testing was performed to investigate the efficacy of sildenafil pMDIs in relieving a vasoconstricted umbilical blood vessel of the chicken egg embryo. The sildenafil contents of the pMDI formulations #1-#3 were within the acceptance criteria (80-120%). The emitted doses (ED) were 102.3±11.5%, the fine particle fractions (FPF) were 60.5±5.6% and the mass median aerodynamic diameters (MMAD) were 2.3±0.3?m. The vasodilatory activity of those formulations reduced umbilical blood pressure by 67.1-73.7% after treatment by intravenous injection whereas only a 50.1-58.0% reduced blood pressure was obtained after direct spraying of the sildenafil pMDI containing CDs. With sildenafil formulations of a pMDI without CD the blood pressure was reduced by only 39.0% (P-value<0.05). The available sildenafil in the blood vessels of chicken egg embryos after spraying sildenafil-CDs pMDIs was within the range of 751-825ng/mL which was much higher than that of a sildenafil only pMDI. PMID:24036276

Sawatdee, Somchai; Hiranphan, Phetai; Laphanayos, Kampanart; Srichana, Teerapol

2014-01-01

393

Characterizaton of the Vessel Geometry, Flow Mechanics and Wall Shear Stress in the Great Arteries of Wildtype Prenatal Mouse  

PubMed Central

Introduction Abnormal fluid mechanical environment in the pre-natal cardiovascular system is hypothesized to play a significant role in causing structural heart malformations. It is thus important to improve our understanding of the prenatal cardiovascular fluid mechanical environment at multiple developmental time-points and vascular morphologies. We present such a study on fetal great arteries on the wildtype mouse from embryonic day 14.5 (E14.5) to near-term (E18.5). Methods Ultrasound bio-microscopy (UBM) was used to measure blood velocity of the great arteries. Subsequently, specimens were cryo-embedded and sectioned using episcopic fluorescent image capture (EFIC) to obtain high-resolution 2D serial image stacks, which were used for 3D reconstructions and quantitative measurement of great artery and aortic arch dimensions. EFIC and UBM data were input into subject-specific computational fluid dynamics (CFD) for modeling hemodynamics. Results In normal mouse fetuses between E14.5–18.5, ultrasound imaging showed gradual but statistically significant increase in blood velocity in the aorta, pulmonary trunk (with the ductus arteriosus), and descending aorta. Measurement by EFIC imaging displayed a similar increase in cross sectional area of these vessels. However, CFD modeling showed great artery average wall shear stress and wall shear rate remain relatively constant with age and with vessel size, indicating that hemodynamic shear had a relative constancy over gestational period considered here. Conclusion Our EFIC-UBM-CFD method allowed reasonably detailed characterization of fetal mouse vascular geometry and fluid mechanics. Our results suggest that a homeostatic mechanism for restoring vascular wall shear magnitudes may exist during normal embryonic development. We speculate that this mechanism regulates the growth of the great vessels. PMID:24475188

Yap, Choon Hwai; Liu, Xiaoqin; Pekkan, Kerem

2014-01-01

394

Development of a nuclear technique for monitoring water levels in pressurized vessels  

SciTech Connect

A new technique for monitoring water levels in pressurized stainless steel cylinders was developed. It is based on differences in attenuation coefficients of water and air for Cs137 (662 keV) gamma rays. Experimentally observed gamma ray counting rates with and without water in model reservoir cylinder were compared with corresponding calculated values for two different gamma ray detection theshold energies. Calculated values include the effects of multiple scattering and attendant gamma ray energy reductions. The agreement between the measured and calculated values is reasonably good. Computer programs for calculating angular and spectral distributions of scattered radition in various media are included.

Singh, J.J.; Davis, W.T.

1983-09-01

395

NESC Review of the 8-Foot High Temperature Tunnel (HTT) Oxygen Storage Pressure Vessel Inspection Requirements  

NASA Technical Reports Server (NTRS)

The 8-Foot HTT (refer to Figure 4.0-1) is used to conduct tests of air-breathing hypersonic propulsion systems at Mach numbers 4, 5, and 7. Methane, Air, and LOX are mixed and burned in a combustor to produce test gas stream containing 21 percent by volume oxygen. The NESC was requested by the NASA LaRC Executive Safety Council to review the rationale for a proposed change to the recertification requirements, specifically the internal inspection requirements, of the 8-Foot HTT LOX Run Tank and LOX Storage Tank. The Run Tank is an 8,000 gallon cryogenic tank used to provide LOX to the tunnel during operations, and is pressured during the tunnel run to 2,250 pounds per square inch gage (psig). The Storage Tank is a 25,000 gallon cryogenic tank used to store LOX at slightly above atmospheric pressure as a external shell, with space between the shells maintained under vacuum conditions.

Gilbert, Michael; Raju, Ivatury; Piascik, Robert; Cameron, Kenneth; Kirsch, Michael; Hoffman, Eric; Murthy, Pappu; Hopson, George; Greulich, Owen; Frazier, Wayne

2009-01-01

396

Deformation studies from in situ SEM experiments of a reactor pressure vessel steel at room and low temperatures  

NASA Astrophysics Data System (ADS)

This paper presents the strain fields acquired at micro-structural scale for a pressure vessel steel, used in the French pressurized water reactors (PWR) and designated as 16MND5 or ASTM A508cl3. The experimental observations rely on specific specimen preparation, prior crystallographic orientation characterization by means of electron backscatter diffraction (EBSD), surface patterning using lithography and chemical etching. The specimens are loaded using a miniaturized tensile stage fitted within a scanning electron microscope (SEM) chamber, and images acquired of a small area are used to measure displacement and strain fields using a Digital Image Correlation (DIC) technique. In addition, a specific setup allowed to cool down to -100 °C the specimen during the whole tensile test and the image acquisition. The experimental apparatus and the kinematic field measurements are introduced in two first sections of the paper. Then the results will be presented for two experiments, one conducted at room temperature and the other at -100 °C, including a comparison of strain localization features and a preliminary comparison of plasticity mechanisms.

Latourte, F.; Salez, T.; Guery, A.; Rupin, N.; Mahé, M.

2014-11-01

397

Time Varying Stress in Ligaments of Perforated Plates with Reference to Prestressed Concrete Reactor Vessels  

Microsoft Academic Search

The work described herein relates to the prediction of stresses in materials which exhibit time varying strains with particular reference to the ligaments of perforated circular concrete slabs, subjected to long-term radial prestress and uniform elevated temperature. The perforations are reinforced with steel liners and arranged in a square central lattice symmetrical about two orthogonal axes.Special reference is made to

G. D. STEFANOU

1978-01-01

398

A New High-Pressure, High-Shear Stress Viscometer and Results for Lubricants  

Microsoft Academic Search

A new high-pressure, high-shear stress viscometer has been developed with a pressure capability of 300 MPa and shear stress of 26 MPa for shear which is essentially isothermal in the context of the Theological characterization of shear-thinning lubricants. Four liquid lubricants have been investigated. Newtonian and rate-independent behavior were observed, and it appears that molecular weight may have a role

Scott Bair; Ward O. Winer

1993-01-01

399

The effect of initial flaw configuration on leak critical pressure vessel design  

NASA Technical Reports Server (NTRS)

The effect of initial flaw shape and depth on the cycles required to produce a pressure leak condition in parent and welded 2219-T87 aluminum was examined for thicknesses from 0.04 to 0.3 inch. Initial flaw aspect ratios of 0.5, 0.3, and 0.15 were examined for tests conducted at a frequency of 4 Hz at room temperature and at 300 F. A computer program developed by Forman was used to predict the cycles to leak curve as a function of initial crack aspect ratio, material thickness, and specimen type and the results compared with the experimental data. Sources of error in the crack propagation analysis and the interface with NDI capabilities are discussed.

Pettit, D. E.; Hoeppner, D. W.

1975-01-01

400

RESIDUAL STRESS DISTRIBUTIONS FOR MULTI-PASS WELDS IN PRESSURE VESSEL AND PIPING COMPONENTS  

E-print Network

. Additional analyses are performed to evaluate seam welds and the effects of end restraint and hydrotest. 1 of the latent heat of fusion. Furthermore, the mechanical models lump multiple weld passes into one, resulting in a fundamentally different weld being modelled than the one of interest. More recent computational approaches

Michaleris, Panagiotis

401

Heavy-Section Steel Irradiation Program on irradiation effects in light-water reactor pressure vessel materials  

SciTech Connect

The safety of commercial light-water nuclear plants is highly dependent on the structural integrity of the reactor pressure vessel (RPV). In the absence of radiation damage to the RPV, fracture of the vessel is difficult to postulate. Exposure to high energy neutrons can result in embrittlement of radiation-sensitive RPV materials. The Heavy-Section Steel Irradiation (HSSI) Program at Oak Ridge National Laboratory, sponsored by the US Nuclear Regulatory Commission (USNRC), is assessing the effects of neutron irradiation on RPV material behavior, especially fracture toughness. The results of these and other studies are used by the USNRC in the evaluation of RPV integrity and regulation of overall nuclear plant safety. In assessing the effects of irradiation, prototypic RPV materials are characterized in the unirradiated condition and exposed to radiation under varying conditions. Mechanical property tests are conducted to provide data which can be used in the development of guidelines for structural integrity evaluations, while metallurgical examinations and mechanistic modeling are performed to improve understanding of the mechanisms responsible for embrittlement. The results of these investigations, in conjunction with results from commercial reactor surveillance programs, are used to develop a methodology for the prediction of radiation effects on RPV materials. This irradiation-induced degradation of the materials can be mitigated by thermal annealing, i.e., heating the RPV to a temperature above that of normal operation. Thus, thermal annealing and evaluation of reirradiation behavior are major tasks of the HSSI Program. This paper describes the HSSI Program activities by summarizing some past and recent results, as well as current and planned studies. 30 refs., 8 figs., 1 tab.

Nanstad, R.K.; Corwin, W.R.; Alexander, D.J.; Haggag, F.M.; Iskander, S.K.; McCabe, D.E.; Sokolov, M.A.; Stoller, R.E. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1995-07-01

402

The LEPRICON (Least-Squares Electric Power Research Institute Consolidation) code system: Consolidation of transport analytical and unfolding procedures in LWR (Light Water Reactor) pressure vessel dosimetry  

Microsoft Academic Search

The LEPRICON (for Least-Square Electric Power Research Institute Consolidation program) code system has been developed over the past ten years to provide a complete analysis of Light Water Reactor (LWR) pressure vessel dosimetry. The system incorporated nine modules. All but one of the modules treat various aspects of neutron transport from the core through the reactor internals to dosimetry locations

Maerker

1988-01-01

403

Use of Zircaloy 4 material for the pressure vessels of hot and cold neutron sources and beam tubes for research reactors  

Microsoft Academic Search

The material Zircaloy 4 can be used for the pressure retaining walls for the cold and hot neutron sources and beam tubes. For the research reactor FRM-II of the Technical University Munich, Germany, the material Zircaloy 4 were chosen for the vessels of the cold and hot neutron source and for the beam tube No. 6.The sheets and forgings of

Erwin Gutsmiedl; Anton Scheuer

2002-01-01

404

Impaired Stress-Induced Pressure Natriuresis Is Related to Left Ventricle Structure in Blacks  

Microsoft Academic Search

The mechanisms through which stress may contribute to the racial difference in the prevalence of essential hypertension and associated target organ damage remain unclear. This study examined differences in stress-induced pressure natriuresis in 69 black and 52 white normotensives age 14 to 27 years, all with a positive family history of hypertension. Urine samples for sodium excretion were collected before

Gregory A. Harshfield; Frank A. Treiber; Harry Davis; Gaston K. Kapuku

2010-01-01

405

How Permeability Depends on Stress and Pore Pressure in Coalbeds: A New Model  

E-print Network

How Permeability Depends on Stress and Pore Pressure in Coalbeds: A New Model Ian Palmer, SPE presents a new theoretical model for calculating pore volume (PV) compressibility and permeability in coals stress/permeability function is then compared with the new theory. Introduction During drawdown

406

Tectonic stress and pressure fields in and out of elliptical inclusions  

NASA Astrophysics Data System (ADS)

Shear zones and competent layers and boudins represent viscosity heterogeneities in the rock mass. Differences in viscosity impel differences in strain rates between such heterogeneities and their surroundings. Under mechanical equilibrium, normal and shear forces must be equal across any interface. The Kolosov-Muskhelishvili equations solve this equilibrium for viscous inclusions in a viscous medium. Mohr-circle diagrams further illustrate the state-of-stress of viscous heterogeneities. Systematic investigation of the stress equilibrium at such interfaces shows that the mean stress, equivalent to pressure, is not continuous across viscosity boundaries. The results predict that pressure and stress perturbations depend strongly on the orientation of the long axis of the elliptical heterogeneity with respect to the far-field stresses. A viscosity ratio of 10 between the inclusion and the surrounding material is sufficient to produce pressure discontinuities virtually equal to the magnitude of the strength of the strongest rock under the considered physical conditions. Comparison of the analytical solutions with thermo-mechanical models confirms pressure incongruity and suggests that dynamic parameters such as pressure and temperature vary spatially and temporally within deforming, two-viscosity rock systems. As a corollary, the dependence of metamorphic phase equilibria on thermodynamic pressure and temperature implies that shear zones, taken as weak inclusions, and boudins taken as hard inclusions may not record lithostatic pressure during deformation.

Moulas, Evangelos; Burg, Jean-Pierre; Podladchikov, Yuri

2014-05-01

407

Stress analysis and failure of an internally pressurized composite-jacketed steel cylinder  

NASA Technical Reports Server (NTRS)

This paper presents a nonlinear stress analysis of a thick-walled compound tube subjected to internal pressure. The compound tube is constructed of a steel liner and a graphite-bismaleimide outer shell. Analytical expressions for the stresses, strains, and displacements are derived for all loading ranges up to failure. Numerical results for the stresses and the maximum value that the compound tube can contain without failure are presented.

Chen, Peter C. T.

1992-01-01

408

Soil stresses under a tractor tire at various loads and inflation pressures  

Microsoft Academic Search

Soil stresses were measured under a 18.4R38 R-1 radial-ply tractor tire, operated at two levels each of dynamic load and inflation pressure. Stress state transducers were placed at two depths beneath the centerline of the path of the tractor tire in two different compaction profiles in each of two soils. Peak soil stresses and soil bulk density increased with increases

A. C. Bailey; R. L. Raper; E. C. Burt; C. E. Johnson

1996-01-01

409

Modelling of rapid pressure-strain in Reynolds stress closures — Difficulties associated with rotational mean flows  

Microsoft Academic Search

Intercomponent energy transfer within the context of Reynolds stress closures is studied. Attention is focussed on the rapid limit of homogeneous flow situations where this energy transfer is caused solely by the rapid pressure strain rate. We present and analyze the performance of the recently proposed rapid pressure strain rate model of Johansson & Hallbäck (J Fluid Mech. 1994) in

Arne V. Johansson; Magnus Hallbäck; Erik Lindborg

1994-01-01

410

SHORT COMMUNICATION Stress in the wild: Chronic predator pressure and acute restraint affect  

E-print Network

SHORT COMMUNICATION Stress in the wild: Chronic predator pressure and acute restraint affect plasma circulating steroid levels at baseline and after acute restraint in the breeding and nonbreeding seasons levels than males in high predator pressure (HPP) environments. Also, acute restraint decreased DHEA

Zanette, Liana

411

Stress, Heredity and Black-White Blood Pressure Differences. Progress Report.  

ERIC Educational Resources Information Center

The facts that black Americans at all ages have higher blood pressure levels and higher mortality rates from hypertension than whites provided the impetus for this study. In their efforts to discover whether the level of blood pressure within and between black and white groups is related more to stress or to genetic factors, the researchers…

Harburg, Ernest; And Others

412

Relationship of Early Life Stress and Psychological Functioning to Blood Pressure in the CARDIA Study  

E-print Network

Relationship of Early Life Stress and Psychological Functioning to Blood Pressure in the CARDIA explain these links and relate the model to blood pressure change over a 10-year period in the Coronary of childhood family environment, parental education, health behavior, and adult negative emotionality. Main

Lehman, Barbara J.

413

A high-throughput platform for low-volume high-temperature/pressure sealed vessel solvent extractions.  

PubMed

A high-throughput platform for performing parallel solvent extractions in sealed HPLC/GC vials inside a microwave reactor is described. The system consist of a strongly microwave-absorbing silicon carbide plate with 20 cylindrical wells of appropriate dimensions to be fitted with standard HPLC/GC autosampler vials serving as extraction vessels. Due to the possibility of heating up to four heating platforms simultaneously (80 vials), efficient parallel analytical-scale solvent extractions can be performed using volumes of 0.5-1.5 mL at a maximum temperature/pressure limit of 200°C/20 bar. Since the extraction and subsequent analysis by either gas chromatography or liquid chromatography coupled with mass detection (GC-MS or LC-MS) is performed directly from the autosampler vial, errors caused by sample transfer can be minimized. The platform was evaluated for the extraction and quantification of caffeine from commercial coffee powders assessing different solvent types, extraction temperatures and times. For example, 141±11 ?g caffeine (5 mg coffee powder) were extracted during a single extraction cycle using methanol as extraction solvent, whereas only 90±11 were obtained performing the extraction in methylene chloride, applying the same reaction conditions (90°C, 10 min). In multiple extraction experiments a total of ~150 ?g caffeine was extracted from 5 mg commercial coffee powder. In addition to the quantitative caffeine determination, a comparative qualitative analysis of the liquid phase coffee extracts and the headspace volatiles was performed, placing special emphasis on headspace analysis using solid-phase microextraction (SPME) techniques. The miniaturized parallel extraction technique introduced herein allows solvent extractions to be performed at significantly expanded temperature/pressure limits and shortened extraction times, using standard HPLC autosampler vials as reaction vessels. Remarkable differences regarding peak pattern and main peaks were observed when low-temperature extraction (60°C) and high-temperature extraction (160°C) are compared prior to headspace-SPME-GC-MS performed in the same HPLC/GC vials. PMID:22027122

Damm, Markus; Kappe, C Oliver

2011-11-30

414

Oxidative stress response of Kluyveromyces marxianus to hydrogen peroxide, paraquat and pressure  

Microsoft Academic Search

. The aim of this work was to study the oxidative stress response of Kluyveromyces marxianus to hydrogen peroxide (50 mM), paraquat (1 mM), an increase in air pressure (120 kPa, 600 kPa) and pure oxygen pressure (120-600 kPa) in a pressurized bioreactor. The effect of these oxidants on metabolism and on the induction of antioxidant enzymes was investigated. The

R. Pinheiro; I. Belo; M. Mota

2002-01-01

415

Effect of ethanol of heart rate and blood pressure in nonstressed and stressed rats  

SciTech Connect

The effect of ethanol on the cardiovascular system (ECG, heart rate, blood pressure) was studied in anesthetized, nonstressed or stressed rats. In anesthetized rats, ethanol showed no effect on heart rate or ECG. In nonstressed rats, ethanol sedated the animals but increased heart rate significantly. This ethanol induced tachycardia seemed the result of a direct stimulation of the sympathetic nerves to the heart. Blood pressure was not significantly affected by ethanol in these nonstressed rats. In stressed rats, marked behavioral excitation and significant increases in heart rate and blood pressure were noted. Ethanol pretreatment calmed the animals considerably during restraint. Ethanol did reduce slightly the stress-induced tachycardia but markedly reduced or antagonized stress-induced blood pressure increases. No major changes in the ECG were noted during these studies with the exception of a few individual animals which showed pathologic ECG responses to ethanol. These data show that ethanol affects cardiovascular functions differently in anesthetized, non stressed or stressed rats, and that ethanol can significantly reduce or antagonize stress-induced behavioral excitation, tachycardia and hypertension. 32 references, 4 tables.

Sparrow, M.G.; Roggendorf, H.; Vogel, W.H.

1987-06-29

416

Regulation of Cell Cycle and Stress Responses to Hydrostatic Pressure in Fission Yeast  

PubMed Central

We have investigated the cellular responses to hydrostatic pressure by using the fission yeast Schizosaccharomyces pombe as a model system. Exposure to sublethal levels of hydrostatic pressure resulted in G2 cell cycle delay. This delay resulted from Cdc2 tyrosine-15 (Y-15) phosphorylation, and it was abrogated by simultaneous disruption of the Cdc2 kinase regulators Cdc25 and Wee1. However, cell cycle delay was independent of the DNA damage, cytokinesis, and cell size checkpoints, suggesting a novel mechanism of Cdc2-Y15 phosphorylation in response to hydrostatic pressure. Spc1/Sty1 mitogen-activated protein (MAP) kinase, a conserved member of the eukaryotic stress-activated p38, mitogen-activated protein (MAP) kinase family, was rapidly activated after pressure stress, and it was required for cell cycle recovery under these conditions, in part through promoting polo kinase (Plo1) phosphorylation on serine 402. Moreover, the Spc1 MAP kinase pathway played a key role in maintaining cell viability under hydrostatic pressure stress through the bZip transcription factor, Atf1. Further analysis revealed that prestressing cells with heat increased barotolerance, suggesting adaptational cross-talk between these stress responses. These findings provide new insight into eukaryotic homeostasis after exposure to pressure stress. PMID:17699598

George, Vinoj T.; Brooks, Gavin

2007-01-01

417

Determining the maximum consolidation stress of sedimentary rocks using the porosity-effective confining pressure curves  

NASA Astrophysics Data System (ADS)

Stress history plays an important role on the mechanical behaviors of rocks. Therefore, how to determine the stress history subjected on rocks is crucial. Adopting the same concept for determining the maximum consolidation stress of soils from a consolidation curve, we utilized the curves of porosity versus effective confining pressure to estimate the maximum consolidation stress of sedimentary rocks. Core samples from the scientific Taiwan Chelungpu fault Drilling Project (TCDP), Hole-A, were used. The maximum buried depths of these samples were determined from the estimated maximum consolidation stress and rock density. Consequently, the proposed method can be validated using the maximum buried depth of the tested rocks from geologic profiles. The results show that the proposed method can efficiently estimate the maximum consolidation stress of the sedimentary rocks. Accordingly, the influence of stress history, such as tectonic uplifting and erosion, on the mechanical behaviors of sedimentary rocks can be evaluated.

Dong, J.-J.; Wu, W.-J.

2009-04-01

418

Study of Stress and Strain Rates in a Rotating Cylinder Subjected to Internal and External Pressure  

NASA Astrophysics Data System (ADS)

The creep behavior of a thick walled hollow circular cylinder, made of aluminum silicon carbide particulate composite material has been investigated in the present study and creep behavior in this case is assumed to follow Sherby's constitutive model. The stress and strain rate distributions of cylinder rotating about its own axis, have been obtained using von Mises and Tresca yield criteria. The effect of pressure on the stresses and strain rates in the cylinder has been investigated and it is observed that with the increase of the internal pressure in the cylinder the strain rate increases. The introduction of external pressure along with the internal pressure causes the strain rates to decrease. It is also observed that the values of effective stress and strain rate obtained using Tresca criterion are higher than those obtained using Mises criterion. Thus it is suggested to use Tresca criterion for the analysis while designing the cylinder.

Chamoli, Neeraj; Rattan, Minto; Singh, Satya Bir

2012-06-01

419

Large-scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility  

SciTech Connect

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the ``flooded cavity``, is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array can deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications.

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.; Slezak, S.E.; Simpson, R.B.

1994-04-01

420

Effects of thermal aging on microstructure and hardness of stainless steel weld-overlay claddings of nuclear reactor pressure vessels  

NASA Astrophysics Data System (ADS)

The effects of thermal aging of stainless steel weld-overlay claddings of nuclear reactor pressure vessels on the microstructure and hardness of the claddings were investigated using atom probe tomography and nanoindentation testing. The claddings were aged at 400 °C for periods of 100-10,000 h. The fluctuation in Cr concentration in the ?-ferrite phase, which was caused by spinodal decomposition, progressed rapidly after aging for 100 h, and gradually for aging durations greater than 1000 h. On the other hand, NiSiMn clusters, initially formed after aging for less than 1000 h, had the highest number density after aging for 2000 h, and coarsened after aging for 10,000 h. The hardness of the ?-ferrite phase also increased rapidly for short period of aging, and saturated after aging for longer than 1000 h. This trend was similar to the observed Cr fluctuation concentration, but different from the trend seen in the formation of the NiSiMn clusters. These results strongly suggest that the primary factor responsible for the hardening of the ?-ferrite phase owing to thermal aging is Cr spinodal decomposition.

Takeuchi, T.; Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y.; Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K.; Suzuki, M.

2014-09-01

421

Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program  

SciTech Connect

The Department of Energy s (DOE) Light Water Reactor Sustainability (LWRS) Program is a five year effort which works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operations of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging Non-Destructive Evaluation (NDE) methods which support these objectives. DOE funded Research and Development (R&D) on emerging NDE techniques to support commercial nuclear reactor sustainability is expected to begin next year. This summer, the MAaD Pathway invited subject matter experts to participate in a series of workshops which developed the basis for the research plan of these DOE R&D NDE activities. This document presents the results of one of these workshops which are the DOE LWRS NDE R&D Roadmap for Reactor Pressure Vessels (RPV). These workshops made a substantial effort to coordinate the DOE NDE R&D with that already underway or planned by the Electric Power Research Institute (EPRI) and the Nuclear Regulatory Commission (NRC) through their representation at these workshops.

Smith, Cyrus M [ORNL; Nanstad, Randy K [ORNL; Clayton, Dwight A [ORNL; Matlack, Katie [Georgia Institute of Technology; Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL); Light, Glenn [Southwest Research Institute, San Antonio

2012-09-01

422

Effects of neutron irradiation on microstructures and hardness of stainless steel weld-overlay cladding of nuclear reactor pressure vessels  

NASA Astrophysics Data System (ADS)

The microstructures and the hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to neutron irradiation at a dose of 7.2 × 1019 n cm-2 (E > 1 MeV) and a flux of 1.1 × 1013 n cm-2 s-1 at 290 °C were investigated by atom probe tomography and by a nanoindentation technique. To isolate the effects of the neutron irradiation, we compared the results of the measurements of the neutron-irradiated samples with those from a sample aged at 300 °C for a duration equivalent to that of the irradiation. The Cr concentration fluctuation was enhanced in the ?-ferrite phase of the irradiated sample. In addition, enhancement of the concentration fluctuation of Si, which was not observed in the aged sample, was observed. The hardening in the ?-ferrite phase occurred due to both irradiation and aging; however, the hardening of the irradiated sample was more than that expected from the Cr concentration fluctuation, which suggested that the Si concentration fluctuation and irradiation-induced defects were possible origins of the additional hardening.

Takeuchi, T.; Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y.; Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K.

2014-06-01

423

Cyclically-Induced Pore Pressure at High Confining Stress  

Microsoft Academic Search

Experiments were conducted by the ERDC Centrifuge Research Team to investigate effective confining stress effects on liquefaction potential of fine, clean, Nevada sand, under the boundary and loading conditions of a centrifuge model. For this test series, twenty-six level ground models with either a dense layer over a loose layer or homogeneous profile were tested in an equivalent-shear-beam box. Some

Michael K. Sharp; R. Scott Steedman

424

Effect of thermal pressurization on dynamic rupture propagation under depth-dependent stress  

NASA Astrophysics Data System (ADS)

Fluid and pore pressure evolution can affect dynamic propagation of earthquake ruptures owing to thermal pressurization (e.g., Mase and Smith, 1985). We investigate dynamic rupture propagation with thermal pressurization on a fault subjected to depth-dependent stress, on the basis of 3-D numerical simulations for spontaneous dynamic ruptures. We put a vertical strike-slip rectangular fault in a semi-infinite, homogenous, and elastic medium. The length and width of the fault are 8 and 3 km, respectively. We assume a depth-dependent stress estimated by Yamashita et al. (2004). The numerical algorithm is based on the finite-difference method by Kase and Kuge (2001). A rupture is initiated by increasing shear stress in a small patch at the bottom of the fault, and then proceeds spontaneously, governed by a slip-weakening law with the Coulomb failure criteria. Coefficients of friction and Dc are homogeneous on the fault. On a fault with thermal pressurization, we allow effective normal stress to vary with pore pressure change due to frictional heating by the formulation of Bizzarri and Cocco (2006). When thermal pressurization does not work, tractions drop in the same way everywhere and rupture velocity is subshear except near the free surface. Due to thermal pressurization, dynamic friction on the fault decreases and is heterogeneous not only vertically but horizontally, slip increases, and rupture velocity along the strike direction becomes supershear. As a result, plural peaks of final slip appear, as observed in the case of undrained dip-slip fault by Urata et al. (2008). We found in this study that the early stage of rupture growth under the depth-dependent stress is affected by the location of an initial crack. When a rupture is initiated at the center of the fault without thermal pressurization, the rupture cannot propagate and terminates. Thermal pressurization can help such a powerless rupture to keep propagating.

Urata, Y.; Kuge, K.; Kase, Y.

2009-12-01

425

Heat stress attenuates the increase in arterial blood pressure during the cold pressor test  

PubMed Central

The mechanisms by which heat stress impairs the control of blood pressure leading to compromised orthostatic tolerance are not thoroughly understood. A possible mechanism may be an attenuated blood pressure response to a given increase in sympathetic activity. This study tested the hypothesis that whole body heating attenuates the blood pressure response to a non-baroreflex-mediated sympathoexcitatory stimulus. Ten healthy subjects were instrumented for the measurement of integrated muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP), heart rate, sweat rate, and forearm skin blood flow. Subjects were exposed to a cold pressor test (CPT) by immersing a hand in an ice water slurry for 3 min while otherwise normothermic and while heat stressed (i.e., increase core temperature ?0.7°C via water-perfused suit). Mean responses from the final minute of the CPT were evaluated. In both thermal conditions CPT induced significant increases in MSNA and MAP without altering heart rate. Although the increase in MSNA to the CPT was similar between thermal conditions (normothermia: ?14.0 ± 2.6; heat stress: ?19.1 ± 2.6 bursts/min; P = 0.09), the accompanying increase in MAP was attenuated when subjects were heat stressed (normothermia: ?25.6 ± 2.3, heat stress: ?13.4 ± 3.0 mmHg; P < 0.001). The results demonstrate that heat stress can attenuate the pressor response to a sympathoexcitatory stimulus. PMID:20798269

Cui, Jian; Shibasaki, Manabu; Low, David A.; Keller, David M.; Davis, Scott L.

2010-01-01

426

Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress coupling analysis  

Microsoft Academic Search

Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result

Qing-hong DONG; Wang-hua SUI; Xiao-cui ZHANG; Zeng-min MAO

2009-01-01

427

Culture Volume and Vessel Affect Long-Term Survival, Mutation Frequency, and Oxidative Stress of Escherichia coli  

PubMed Central

Bacteria such as Escherichia coli are frequently studied during exponential- and stationary-phase growth. However, many strains can survive in long-term stationary phase (LTSP), without the addition of nutrients, from days to several years. During LTSP, cells experience a variety of stressors, including reactive oxidative species, nutrient depletion, and metabolic toxin buildup, that lead to physiological responses and changes in genetic stability. In this study, we monitored survival during LTSP, as well as reporters of genetic and physiological change, to determine how the physical environment affects E. coli during long-term batch culture. We demonstrate differences in yield during LTSP in cells incubated in LB medium in test tubes versus Erlenmeyer flasks, as well as growth in different volumes of medium. We determined that these differences are only partially due to differences in oxygen levels by incubating the cells in different volumes of media under anaerobic conditions. Since we hypothesized that differences in long-term survival are the result of changes in physiological outputs during the late log and early stationary phases, we monitored alkalization, mutation frequency, oxidative stress response, and glycation. Although initial cell yields are essentially equivalent under each condition tested, physiological responses vary greatly in response to culture environment. Incubation in lower-volume cultures leads to higher oxyR expression but lower mutation frequency and glycation levels, whereas incubation in high-volume cultures has the opposite effect. We show here that even under commonly used experimental conditions that are frequently treated as equivalent, the stresses experienced by cells can differ greatly, suggesting that culture vessel and incubation conditions should be carefully considered in the planning or analysis of experiments. PMID:24375138

Kram, Karin E.

2014-01-01

428

The Invalidity of the Laplace Law for Biological Vessels and of Estimating Elastic Modulus from Total Stress vs. Strain: a New Practical Method  

E-print Network

The quantification of the stiffness of tubular biological structures is often obtained, both in vivo and in vitro, as the slope of total transmural hoop stress plotted against hoop strain. Total hoop stress is typically estimated using the "Laplace law." We show that this procedure is fundamentally flawed for two reasons: Firstly, the Laplace law predicts total stress incorrectly for biological vessels. Furthermore, because muscle and other biological tissue are closely volume-preserving, quantifications of elastic modulus require the removal of the contribution to total stress from incompressibility. We show that this hydrostatic contribution to total stress has a strong material-dependent nonlinear response to deformation that is difficult to predict or measure. To address this difficulty, we propose a new practical method to estimate a mechanically viable modulus of elasticity that can be applied both in vivo and in vitro using the same measurements as current methods, with care taken to record the referen...

Costanzo, Francesco

2013-01-01

429

The effect of non-metallic inclusions on the fracture toughness master curve in high copper reactor pressure vessel welds  

NASA Astrophysics Data System (ADS)

The fracture toughness of two high copper reactor pressure vessel welds having low upper shelf energy was evaluated in accordance with the master curve method of ASTM E1921. The resultant data were correlated to the metallurgical factors involved in the brittle fracture initiation to provide a metallurgical-based understanding of the master curve. The tests were performed using pre-cracked Charpy V-notched specimens and the master curve was made with an average of T0 values determined at different temperatures. In all specimens, the cleavage fracture initiated at non-metallic inclusion ranging from 0.7 to 3.5 ?m in diameter showing a scatter with the specimens and testing temperatures. Temperature dependency of the triggering particle size was not found. The fracture toughness ( KJC) was inversely proportional to the square root of the triggering inclusion diameter ( di) at respective temperatures. From this relationship, we determined median KJC values which correspond to the average value of triggering inclusion diameter of all tested specimens and defined them as a modified median KJC ( K'JC(med) ). The obtained K'JC(med) values showed quite smaller deviation from the master curve at different temperatures than the experimental median KJC values. This suggests that the master curve is on the premise of a constant dimension of key microstructural factor in a material regardless of the testing temperature. But the inclusion size at trigger point played an important role in the absolute position of the master curve with temperature and the consequent T0 value.

Oh, Yong-Jun; Lee, Bong-Sang; Hong, Jun-Hwa

2002-03-01

430

Weldability and toughness evaluation of pressure vessel quality steel using the shielded metal arc welding (SMAW) process  

NASA Astrophysics Data System (ADS)

The present study was carried out to assess the weldability properties of ASTM A 537 Cl. 1 pressure-vessel quality steel using the shielded metal arc welding (SMAW) process. Implant and elastic restraint cracking (ERC) tests were conducted under different welding conditions to determine the cold cracking susceptibility of the steel. The static fatigue limit values determined for the implant test indicate adequate resistance to cold cracking even with unbaked electrodes. The ERC test, however, established the necessity to rebake the electrodes before use. Lamellar tearing tests carried out using full-thickness plates under three welding conditions showed no incidence of lamellar tearing upon visual examination, ultrasonic inspection, and four-section macroexamination. Lamellar tearing tests were repeated using machined plates, such that the central segregated band located at the midthickness of the plate corresponded to the heat-affected zone (HAZ) of the weld. Only in one (no rebake, heat input: 14.2 kj cm-1, weld restraint load: 42 kg mm-2) of the eight samples tested was lamellar tearing observed. This was probably accentuated due to the combined effects of the presence of localized pockets of a hard phase (bainite) and a high hydrogen level (unbaked electrodes) in the weld joint. Optimal welding conditions were formulated based on the above tests. The weld joint was subjected to extensive tests and found to exhibit excellent strength (tensile strength: 56.8 kg mm-2, or 557 MPa), and low temperature impact toughness (7.4 and 4.5 kg-m at-20 °C for weld metal, WM, and HAZ) properties. Crack tip opening displacement tests carried out for the WM and HAZ resulted in ?m values 0.36 and 0.27 mm, respectively, which indicates adequate resistance to brittle fracture.

Datta, R.; Mukerjee, D.; Mishra, S.

1998-12-01

431

Progress in evaluation and improvement in nondestructive examination reliability for inservice inspection of Light Water Reactors (LWRs) and characterize fabrication flaws in reactor pressure vessels  

SciTech Connect

This paper is a review of the work conducted under two programs. One (NDE Reliability Program) is a multi-year program addressing the reliability of nondestructive evaluation (NDE) for the inservice inspection (ISI) of light water reactor components. This program examines the reliability of current NDE, the effectiveness of evolving technologies, and provides assessments and recommendations to ensure that the NDE is applied at the right time, in the right place with sufficient effectiveness that defects of importance to structural integrity will be reliably detected and accurately characterized. The second program (Characterizing Fabrication Flaws in Reactor Pressure Vessels) is assembling a data base to quantify the distribution of fabrication flaws that exist in US nuclear reactor pressure vessels with respect to density, size, type, and location. These programs will be discussed as two separate sections in this report. 4 refs., 7 figs.

Doctor, S.R.; Bowey, R.E.; Good, M.S.; Friley, J.R.; Kurtz, R.J.; Simonen, F.A.; Taylor, T.T.; Heasler, P.G.; Andersen, E.S.; Diaz, A.A.; Greenwood, M.S.; Hockey, R.L.; Schuster, G.J.; Spanner, J.C.; Vo, T.V.

1991-10-01

432

Cyclic Crack Growth Testing of an A.O. Smith Multilayer Pressure Vessel with Modal Acoustic Emission Monitoring and Data Assessment  

NASA Technical Reports Server (NTRS)

Digital Wave Corp. (DWC) was retained by Jacobs ATOM at NASA Ames Research Center to perform cyclic pressure crack growth sensitivity testing on a multilayer pressure vessel instrumented with DWC's Modal Acoustic Emission (MAE) system, with captured wave analysis to be performed using DWCs WaveExplorerTM software, which has been used at Ames since 2001. The objectives were to document the ability to detect and characterize a known growing crack in such a vessel using only MAE, to establish the sensitivity of the equipment vs. crack size and / or relevance in a realistic field environment, and to obtain fracture toughness materials properties in follow up testing to enable accurate crack growth analysis. This report contains the results of the testing.

Ziola, Steven M.

2014-01-01

433

Modelling of rapid pressure-strain in Reynolds-stress closures  

Microsoft Academic Search

The most general form for the rapid pressure-strain rate, within the context of classical Reynolds-stress transport (RST) closures for homogeneous flows, is derived, and truncated forms are obtained with the aid of rapid distortion theory. By a classical RST-closure we here denote a model with transport equations for the Reynolds stress tensor and the total dissipation rate. It is demonstrated

Arne V. Johansson; Magnus Hallback

1994-01-01

434

Caffeine and Behavioral Stress Effects on Blood Pressure in Borderline Hypertensive Caucasian Men  

Microsoft Academic Search

Caffeine in dietary amounts raises blood pressure (BP), and its use increases during work stress; however, caffeine combined with behavioral stress has not been tested in borderline hypertensive (BH) men. Accordingly, this study tested a psychomotor stressor plus caffeine (3.3 mg\\/kg, equivalent to 2–3 cups of coffee) using a double-blind, crossover design in 24 BH men (140\\/90 mmHg ? BP

William R. Lovallo; Mustafa al'Absi; Gwen A. Pincomb; Susan A. Everson; Bong Hee Sung; Richard B. Passey; Michael F. Wilson

1996-01-01

435

Relationships among socioeconomic status, stress induced changes in cortisol, and blood pressure in african american males  

Microsoft Academic Search

The inverse relation between socioeconomic status (SES) and cardiovascular disease (CVD) risk has been posited to be partially\\u000a due to exaggerated cardiovascular reactivity (CVR) to stress. Stress elicits hypothalamic-pituitary-adrenal axis activation\\u000a (e.g., increased cortisol secretion), which may contribute to subsequent blood pressure (BP) elevation. Univariate associations\\u000a among SES, cortisol secretion, and aggregated change scores to stressors (i.e., video game and

Gaston K. Kapuku; Frank A. Treiber; Harry C. Davis

2002-01-01

436

Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat-stressed humans  

NASA Technical Reports Server (NTRS)

To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat-stressed humans, blood pressure was el