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1

Discontinuity stresses in metallic pressure vessels  

NASA Technical Reports Server (NTRS)

The state of the art, criteria, and recommended practices for the theoretical and experimental analyses of discontinuity stresses and their distribution in metallic pressure vessels for space vehicles are outlined. The applicable types of pressure vessels include propellant tanks ranging from main load-carrying integral tank structure to small auxiliary tanks, storage tanks, solid propellant motor cases, high pressure gas bottles, and pressurized cabins. The major sources of discontinuity stresses are discussed, including deviations in geometry, material properties, loads, and temperature. The advantages, limitations, and disadvantages of various theoretical and experimental discontinuity analysis methods are summarized. Guides are presented for evaluating discontinuity stresses so that pressure vessel performance will not fall below acceptable levels.

1971-01-01

2

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

3

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

4

Terahertz NDE of Stressed Composite Overwrapped Pressure Vessels - Initial Testing  

NASA Technical Reports Server (NTRS)

Terahertz radiation nondestructive evaluation was applied to a set of Kevlar composite overwrapped pressure vessel bottles that had undergone a series of thermal and pressure tests to simulate stress rupture effects. The bottles in these nondestructive evaluation tests were bottles that had not ruptured but had survived various times at the elevated load and temperature levels. Some of the bottles showed evidence of minor composite failures. The terahertz radiation did detect visible surface flaws, but did not detect any internal chemical or material degradation of the thin overwraps.

Madaras, Eric I.; Seebo, Jeffrey P.; Anatasi, Robert F.

2009-01-01

5

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

6

RESIDUAL STRESS DISTRIBUTIONS FOR MULTI-PASS WELDS IN PRESSURE VESSEL AND PIPING COMPONENTS  

E-print Network

RESIDUAL STRESS DISTRIBUTIONS FOR MULTI-PASS WELDS IN PRESSURE VESSEL AND PIPING COMPONENTS stresses on multi-pass welds. The simulation involves performing thermo-elasto-plastic analyses using a consistent element activation approach in the mechanical analysis. A compendium of residual stress

Michaleris, Panagiotis

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

Experimental Investigation of the Shuttle Transportation System Composite Overwrapped Pressure Vessels for Stress Rupture Life  

NASA Technical Reports Server (NTRS)

A viewgraph presentation describing stress rupture testing on Composite Overwrapped Pressure Vessels (COPV) is shown. The topics include: 1) Purpose for Testing; 2) NASA WSTF COPV Test Program; 3) NASA WSTF Test Facilities; 4) COPV Impact Study; 5) Fluids Compatibility Testing; 6) Stress Rupture Testing; and 7) COPV Lifting.

Greene, Nathanael; Saulsberry, Regor; Yoder, Tommy; Forsyth, Brad; Carillo, Marlene; Thesken, John

2006-01-01

10

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

11

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

E-print Network

is subjected to high internal pressure till its wall becomes partially plastic. The resulting compressive hoopResidual 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

Vaziri, Ashkan

12

A mathematical model for the stressed state analysis of cylindrical laminated-composite pressure vessels  

NASA Astrophysics Data System (ADS)

An algorithm and a computer program have been developed for calculating the strength of pressure vessels made of laminated composites. Numerical results for pressure vessels of Kevlar 49 laminates are compared with experimental data in the literature.

Bak, Roman; Matyja, Tomasz

13

Pressure vessel integrity 1991  

SciTech Connect

This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on nuclear industry applications. The papers were prepared for technical sessions developed under the sponsorship of the ASME Pressure Vessels and Piping Division Committees for Codes and Standards, Computer Technology, Design and Analysis, and Materials Fabrication. They were presented at the 1991 Pressure Vessels and Piping Division Conference in San Diego, California, June 23-27. The primary objective of the sponsoring organization is to provide a forum for the dissemination and discussion of information on development and application of technology for the structural integrity assessment of pressure vessels and piping. This publication includes contributions from authors from Australia, France, Japan, Sweden, Switzerland, the United Kingdom, and the United States. The papers here are organized in six sections, each with a particular emphasis as indicated in the following section titles: Fracture Technology Status and Application Experience; Crack Initiation, Propagation and Arrest; Ductile Tearing; Constraint, Stress State, and Local-Brittle-Zones Effects; Computational Techniques for Fracture and Corrosion Fatigue; and Codes and Standards for Fatigue, Fracture and Erosion/Corrosion.

Bhandari, S. (Framatome (FR)); Doney, R.O.; McDonald, M.S. (ABB Combustion Engineering Nuclear Power (US)); Jones, D.P.; Wilson, W.K. (Westinghouse Bettis Atomic Power Laboratory (US)); Pennell, W.E. (Oak Ridge National Laboratory (US))

1991-01-01

14

Design prediction for long term stress rupture service of composite pressure vessels  

NASA Technical Reports Server (NTRS)

Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

Robinson, Ernest Y.

1992-01-01

15

Design prediction for long term stress rupture service of composite pressure vessels  

NASA Astrophysics Data System (ADS)

Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

Robinson, Ernest Y.

1992-09-01

16

AN IMPROVED TREATMENT OF RESIDUAL STRESSES IN FLAW ASSESSMENT OF PIPES AND PRESSURE VESSELS FABRICATED FROM FERRITIC STEELS  

E-print Network

FABRICATED FROM FERRITIC STEELS William C. Mohr, Panagiotis Michaleris, and Mark T. Kirk Edison Welding ferritic steels. Information on these residual stresses are drawn from the literature; both measured treatment of residual stresses produced by welding in pipes and pressure vessels fabricated from ferritic

Michaleris, Panagiotis

17

Stress Corrosion Cracking and Fatigue Crack Growth Studies Pertinent to Spacecraft and Booster Pressure Vessels  

NASA Technical Reports Server (NTRS)

This experimental program was divided into two parts. The first part evaluated stress corrosion cracking in 2219-T87 aluminum and 5Al-2.5Sn (ELI) titanium alloy plate and weld metal. Both uniform height double cantilever beam and surface flawed specimens were tested in environments normally encountered during the fabrication and operation of pressure vessels in spacecraft and booster systems. The second part studied compatibility of material-environment combinations suitable for high energy upper stage propulsion systems. Surface flawed specimens having thicknesses representative of minimum gage fuel and oxidizer tanks were tested. Titanium alloys 5Al-2.5Sn (ELI), 6Al-4V annealed, and 6Al-4V STA were tested in both liquid and gaseous methane. Aluminum alloy 2219 in the T87 and T6E46 condition was tested in fluorine, a fluorine-oxygen mixture, and methane. Results were evaluated using modified linear elastic fracture mechanics parameters.

Hall, L. R.; Finger, R. W.

1972-01-01

18

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 Overwrapped 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 uncertainties 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

2007-01-01

19

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

20

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

21

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

22

Sapphire tube pressure vessel  

SciTech Connect

A pressure vessel is provided for observing corrosive fluids at high temperatures and pressures. A transparent Teflon bag contains the corrosive fluid and provides an inert barrier. The Teflon bag is placed within a sapphire tube, which forms a pressure boundary. The tube is received within a pipe including a viewing window. The combination of the Teflon bag, sapphire tube and pipe provides a strong and inert pressure vessel. In an alternative embodiment, tie rods connect together compression fittings at opposite ends of the sapphire tube.

Outwater, J.O.

2000-05-23

23

Pressure vessel bottle mount  

NASA Technical Reports Server (NTRS)

A mounting assembly for mounting a composite pressure vessel to a vehicle includes a saddle having a curved surface extending between two pillars for receiving the vessel. The saddle also has flanged portions which can be bolted to the vehicle. Each of the pillars has hole in which is mounted the shaft portion of an attachment member. A resilient member is disposed between each of the shaft portions and the holes and loaded by a tightening nut. External to the holes, each of the attachment members has a head portion to which a steel band is attached. The steel band circumscribes the vessel and translates the load on the springs into a clamping force on the vessel. As the vessel expands and contracts, the resilient members expand and contract so that the clamping force applied by the band to the vessel remains constant.

Wingett, Paul (Inventor)

2001-01-01

24

Stress corrosion cracking of low-alloy, reactor-pressure-vessel steels in oxygenated, high-temperature water  

Microsoft Academic Search

The stress corrosion cracking (SCC) behaviour of low-alloy, reactor-pressure-vessel (RPV) steels in oxygenated, high-temperature water and its relevance to boiling water reactor (BWR) power operation, in particular its possible effect on both RPV structural integrity and safety, has been a subject of controversial discussions for many years. This paper presents the results of an experimental study on crack growth through

J. Heldt; H. P. Seifert

2001-01-01

25

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

26

Attachment Fitting for Pressure Vessel  

NASA Technical Reports Server (NTRS)

This invention provides sealed access to the interior of a pressure vessel and consists of a tube. a collar, redundant seals, and a port. The port allows the seals to be pressurized and seated before the pressure vessel becomes pressurized.

Smeltzer, Stanley S., III (Inventor); Carrigan, Robert W. (Inventor)

2002-01-01

27

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

28

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

29

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

30

Hybrid Inflatable Pressure Vessel  

NASA Technical Reports Server (NTRS)

Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts. Figure 2 depicts selected aspects of the design of a vessel of this type with a toroidal configuration. The bladder serves as an impermeable layer to keep air within the pressure vessel and, for this purpose, is sealed to the central structural core. The web includes longitudinal and circumferential straps. To help maintain the proper shape upon inflation after storage, longitudinal and circumferential straps are indexed together at several of their intersections. Because the web is not required to provide a pressure seal and the bladder is not required to sustain structural loads, the bladder and the web can be optimized for their respective functions. Thus, the bladder can be sealed directly to the rigid core without having to include the web in the seal substructure, and the web can be designed for strength. The ends of the longitudinal straps are attached to the ends of the rigid structural core by means of clevises. Each clevis pin is surrounded by a roller, around which a longitudinal strap is wrapped to form a lap seam with itself. The roller is of a large diameter chosen to reduce bending of the fibers in the strap. The roller also serves to equalize the load in the portions of the strap on both sides of the clevis pin. The lap seam is formed near the clevis by use of a tapered diamond stitch: This stitch is designed specifically to allow fibers in the stitch and strap to relax under load in such a manner that the load becomes more nearly evenly distributed among all fibers in the stitch region. Thus, the tapered diamond stitch prevents load concentrations that could cause premature failure of the strap and thereby increases the strength of the strap/structural-core joint. The lap seam can be rated at >90 percent of the strength of the strap material.

Raboin, Jasen; Valle, Gerard D.; Edeen, Gregg; DeLaFuente, Horacio M.; Schneider, William C.; Spexarth, Gary R.; Johnson, Christopher J.; Pandya, Shalini

2004-01-01

31

Apollo experience report: Pressure vessels  

NASA Technical Reports Server (NTRS)

The Apollo spacecraft pressure vessels, associated problems and resolutions, and related experience in evaluating potential problem areas are discussed. Information is provided that can be used as a guideline in the establishment of baseline criteria for the design and use of lightweight pressure vessels. One of the first practical applications of the use of fracture-mechanics technology to protect against service failures was made on Apollo pressure vessels. Recommendations are made, based on Apollo experience, that are designed to reduce the incidence of failure in pressure-vessel operation and service.

Ecord, G. M.

1972-01-01

32

Graphite filament wound pressure vessels  

NASA Technical Reports Server (NTRS)

Filament wound NOL rings, 4-inch and 8-inch diameter closed-end vessels involving three epoxy resin systems and three graphite fibers were tested to develop property data and fabrication technology for filament wound graphite/epoxy pressure vessels. Vessels were subjected to single-cycle burst tests at room temperature. Manufacturing parameters were established for tooling, winding, and curing that resulted in the development of a pressure/vessel performance factor (pressure x volume/weight) or more than 900,000 in. for an oblate spheroid specimen.

Feldman, A.; Damico, J. J.

1972-01-01

33

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

34

Stress-intensity factors for internal surface cracks in cylindrical pressure vessels  

NASA Technical Reports Server (NTRS)

The stress intensity factors were calculated by a three dimensional finite element method. The finite element models employed singularity elements along the crack front and linear strain elements elsewhere. The models had about 6500 degrees of freedom. The stress intensity factors were evaluated from a nodal force method. An equation for the stress intensity factors was obtained form the results of the present analysis. The equation applies over a wide range of configuration parameters and was within about 5 percent of the present results. A comparison was made between the present results and other analyses of internal surface cracks in cylinders. The results from a boundary integral equation method were in agreement (+ or - 2 percent) and those from another finite element were in fair agreement (+ or - 8 percent) with the present results.

Newman, J. C., Jr.; Raju, I. S.

1979-01-01

35

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

36

46 CFR 119.330 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessels. 119.330 Section 119.330 Shipping...INSTALLATION Auxiliary Machinery § 119.330 Pressure vessels. All unfired pressure vessels must be installed to the satisfaction...

2010-10-01

37

46 CFR 182.330 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessels. 182.330 Section 182.330 Shipping...INSTALLATION Auxiliary Machinery § 182.330 Pressure vessels. All unfired pressure vessels must be installed to the...

2010-10-01

38

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

39

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

40

Hydrogen Pressure Vessel Testing Program  

Microsoft Academic Search

The Hydrogen Pressure Vessel Testing Program has been designed to meet two objectives, including: 1) providing visual and quantitative information to OEM's, regulatory agencies, and the public, regarding the consequences of on-board high pressure hydrogen as a fuel source and 2) through a collaborative effort with experts in the field, use the data generated from this project to provide a

Ben C. Odegard Jr; George J. Thomas

41

Pressure vessel having continuous sidewall  

NASA Technical Reports Server (NTRS)

A spacecraft pressure vessel has a tub member. A sidewall member is coupled to the tub member so that a bottom section of the sidewall member extends from an attachment intersection with the tub member and away from the tub member. The bottom section of the sidewall member receives and transfers a load through the sidewall member.

Simon, Xavier D. (Inventor); Barackman, Victor J. (Inventor)

2011-01-01

42

Ultrasonic pressure measurement in pressure vessels  

NASA Astrophysics Data System (ADS)

Based on the reflected longitudinal wave, a new non-intrusive method for pressure measurement is proposed. The acoustoelastic theory and the thin-shell theory are introduced to develop the pressure measurement model in cylindrical pressure vessels. And a pressure measurement system is constructed to evaluate the effectiveness of the proposed method. The pressure measurement is implemented by measuring the travel-time change between two received ultrasonic sensors. The experimental results verify the feasibility and effectiveness of this new non-intrusive method. Compared with the non-intrusive pressure measurement method based on the critically refracted longitudinal wave (LCR wave), the proposed non-intrusive pressure measurement method has the advantages of higher sensitivity and higher signal-to-noise ratio.

Bi, Yao; Zhou, Hongliang; Huang, Zhiyao; Zhou, Hanhua; Yang, Xianglong

2014-12-01

43

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

44

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

45

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

46

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

47

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

48

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. 6 figures.

Sawabe, J.K.

1994-01-11

49

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

50

STUDIES OF THE FATIGUE STRENGTH OF PRESSURE VESSELS. (1) CYCLIC PRESSURE TESTS OF LARGE SIZE PRESSURE VESSELS. (2) EFFECTS OF NOTCHES AND WELD DEFECTS ON PRESSURE VESSEL FATIGUE STRENGHT  

Microsoft Academic Search

The plastic fatigue strength of 36-in. ID pressure vessels is ; investigated. The pressure vessels are fabricated from A-201, A-302, and T-1 ; steels and have a wall thickness of 2 in. Variables investigated are material ; properties, design details, fabrication methods, and inspection techniques. The ; fatigue strength of weld-repaired fatigue cracks is evaluated. Stress ; concentration factors determined

A. G. Pickett; J. D. Michie

1963-01-01

51

Steel pressure vessels for hydrostatic pressures to 50 kilobars.  

PubMed

Cylindrical steel pressure vessels are described that can be used for hydrostatic pressures up to 50 kilobars. Monoblock vessels of 350 maraging steel can be used to 40 kilobars and compound vessels with an inner vessel of 350 maraging steel and an outer vessel of 300 maraging steel to 50 kilobars. Neither requires the cylinder to be end loaded, and so they are much easier to use than the more usual compound vessels with a tungsten carbide inner and steel outer vessel. PMID:18699223

Lavergne, A; Whalley, E

1978-07-01

52

Wrapped Wire Detects Rupture Of Pressure Vessel  

NASA Technical Reports Server (NTRS)

Simple, inexpensive technique helps protect against damage caused by continuing operation of equipment after rupture or burnout of pressure vessel. Wire wrapped over area on outside of vessel where breakthrough most likely. If wall breaks or burns, so does wire. Current passing through wire ceases, triggering cutoff mechanism stopping flow in vessel to prevent further damage. Applied in other situations in which pipes or vessels fail due to overpressure, overheating, or corrosion.

Hunt, James B.

1990-01-01

53

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

54

Lightweight bladder lined pressure vessels  

DOEpatents

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 spherical or near tori spherical 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 sealed 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. 19 figs.

Mitlitsky, F.; Myers, B.; Magnotta, F.

1998-08-25

55

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

56

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

57

Failure analysis of a fiberglass-reinforced plastic pressure vessel  

SciTech Connect

A fiberglass-reinforced plastic (FRP) pressure vessel containing sulfuric acid failed catastrophically in service. Preliminary investigations ruled out failure due to sabotage and chemical or mechanical overpressure. Subsequent examination of the fiber fracture surfaces and measurements of mirror radii indicated that fiber failure had occurred at stresses significantly below the fibers` expected strength. Further examination by scanning electron microscopy and energy dispersive spectroscopy indicated that the glass fibers had been exposed to sulfuric acid, a reagent that corrodes this type of glass and degrades its strength. Finite element analysis indicated stresses in an exposed region of the vessel that exceeded the strengths of the FRP during normal vessel operation. Numerous cracks were detected in this region using a vicinal optical illumination technique. We concluded that vessel failure was caused by progressive degradation and rupture of fibers starting at the outer surface of the FRP and extending inwards and laterally, until a crack of critical size was produced.

Glass, S.J.; Beauchamp, E.K.; Carr, M.; Guess, T.R.; Monroe, S.L.; Moore, R.J.; Slavin, A.; Sorenson, N.R.

1995-09-01

58

Summary of Activities for Health Monitoring of Composite Overwrapped Pressure Vessels Updated January 2014  

NASA Technical Reports Server (NTRS)

This three year project (FY12-14) will design and demonstrate the ability of new Magnetic Stress Gages for the measurement of stresses on the inner diameter of a Composite Overwrapped Pressure Vessel overwrap.

Skow, Miles G.

2014-01-01

59

Vehicular storage of hydrogen in insulated pressure vessels  

Microsoft Academic Search

This paper describes an alternative technology for storing hydrogen fuel onboard vehicles. Insulated pressure vessels are cryogenic capable vessels that can accept cryogenic liquid hydrogen, cryogenic compressed gas or compressed hydrogen gas at ambient temperature. Insulated pressure vessels offer advantages over conventional storage approaches. Insulated pressure vessels are more compact and require less carbon fiber than compressed hydrogen vessels. They

Salvador M. Aceves; Gene D. Berry; Joel Martinez-Frias; Francisco Espinosa-Loza

2006-01-01

60

Beryllium pressure vessels for creep tests in magnetic fusion energy  

SciTech Connect

Beryllium has interesting applications in magnetic fusion experimental machines and future power-producing fusion reactors. Chief among the properties of beryllium that make these applications possible is its ability to act as a neutron multiplier, thereby increasing the tritium breeding ability of energy conversion blankets. Another property, the behavior of beryllium in a 14-MeV neutron environment, has not been fully investigated, nor has the creep behavior of beryllium been studied in an energetic neutron flux at thermodynamically interesting temperatures. This small beryllium pressure vessel could be charged with gas to test pressures around 3, 000 psi to produce stress in the metal of 15,000 to 20,000 psi. Such stress levels are typical of those that might be reached in fusion blanket applications of beryllium. After contacting R. Powell at HEDL about including some of the pressure vessels in future test programs, we sent one sample pressure vessel with a pressurizing tube attached (Fig. 1) for burst tests so the quality of the diffusion bond joints could be evaluated. The gas used was helium. Unfortunately, budget restrictions did not permit us to proceed in the creep test program. The purpose of this engineering note is to document the lessons learned to date, including photographs of the test pressure vessel that show the tooling necessary to satisfactorily produce the diffusion bonds. This document can serve as a starting point for those engineers who resume this task when funds become available.

Neef, W.S.

1990-07-20

61

Low-Stress Sealing of Pressure Transducers  

NASA Technical Reports Server (NTRS)

Compliant washer seals high pressures without excessive compressive stress on transducer. Conformal washer serves as effective seal for transducer passing through walls of pressure vessel. Washer makes it unnecessary to tighten mounting nut to high torque, which could damage transducer or adversely affect accuracy. Washer also used to seal mountings for temperature sensors and other devices.

Kroy, R. E.

1985-01-01

62

Liquid Nitrogen Subcooler Pressure Vessel Engineering Note  

SciTech Connect

The normal operating pressure of this dewar is expected to be less than 15 psig. This vessel is open to atmospheric pressure thru a non-isolatable vent line. The backpressure in the vent line was calculated to be less than 1.5 psig at maximum anticipated flow rates.

Rucinski, R.; /Fermilab

1997-04-24

63

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

64

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

65

Stresses on pulmonary blood vessels  

Microsoft Academic Search

PRIOR TO 1960, there was a great deal of discussion in the literature over the differences between positive and negative inflation of the lungs, with particular emphasis on the pulmo- nary vasculature. The vasculature of the lung is unique among organs, since it is constantly subjected to rhythmic and some- times extreme stretching. How it has adapted to these stresses

Wayne Mitzner

2004-01-01

66

Cavity closure arrangement for high pressure vessels  

DOEpatents

A closure arrangement for a pressure vessel such as the pressure vessel of a high temperature gas-cooled reactor wherein a liner is disposed within a cavity penetration in the reactor vessel and defines an access opening therein. A closure is adapted for sealing relation with an annular mounting flange formed on the penetration liner and has a plurality of radially movable locking blocks thereon having outer serrations adapted for releasable interlocking engagement with serrations formed internally of the upper end of the penetration liner so as to effect high strength closure hold-down. In one embodiment, ramping surfaces are formed on the locking block serrations to bias the closure into sealed relation with the mounting flange when the locking blocks are actuated to locking positions.

Amtmann, Hans H. (San Diego, CA)

1981-01-01

67

Material Issues in Space Shuttle Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPV) store gases used in four subsystems for NASA's Space Shuttle Fleet. While there are 24 COPV on each Orbiter ranging in size from 19-40", stress rupture failure of a pressurized Orbiter COPV on the ground or in flight is a catastrophic hazard and would likely lead to significant damage/loss of vehicle and/or life and is categorized as a Crit 1 failure. These vessels were manufactured during the late 1970's and into the early 1980's using Titanium liners, Kevlar 49 fiber, epoxy matrix resin, and polyurethane coating. The COPVs are pressurized periodically to 3-5ksi and therefore experience significant strain in the composite overwrap. Similar composite vessels were developed in a variety of DOE Programs (primarily at Lawrence Livermore National Laboratories or LLNL), as well as for NASA Space Shuttle Fleet Leader COPV program. The NASA Engineering Safety Center (NESC) formed an Independent Technical Assessment (ITA) team whose primary focus was to investigate whether or not enough composite life remained in the Shuttle COPV in order to provide a strategic rationale for continued COPV use aboard the Space Shuttle Fleet with the existing 25-year-old vessels. Several material science issues were examined and will be discussed in this presentation including morphological changes to Kevlar 49 fiber under stress, manufacturing changes in Kevlar 49 and their effect on morphology and tensile strength, epoxy resin strain, composite creep, degradation of polyurethane coatings, and Titanium yield characteristics.

Sutter, James K.; Jensen, Brian J.; Gates, Thomas S.; Morgan, Roger J.; Thesken, John C.; Phoenix, S. Leigh

2006-01-01

68

Advanced toroidal facility vaccuum vessel stress analyses  

SciTech Connect

The complex geometry of the Advance Toroidal Facility (ATF) vacuum vessel required special analysis techniques in investigating the structural behavior of the design. The response of a large-scale finite element model was found for transportation and operational loading. Several computer codes and systems, including the National Magnetic Fusion Energy Computer Center Cray machines, were implemented in accomplishing these analyses. The work combined complex methods that taxed the limits of both the codes and the computer systems involved. Using MSC/NASTRAN cyclic-symmetry solutions permitted using only 1/12 of the vessel geometry to mathematically analyze the entire vessel. This allowed the greater detail and accuracy demanded by the complex geometry of the vessel. Critical buckling-pressure analyses were performed with the same model. The development, results, and problems encountered in performing these analyses are described. 5 refs., 3 figs.

Hammonds, C.J.; Mayhall, J.A.

1987-01-01

69

Cracking progress and mechanism of 16MNR pressure vessel material  

SciTech Connect

A new testing device has been developed to test the antifatigue abilities of several pressure vessel materials. Crack initiation and propagation through grain boundaries can be seen clearly by the optical microscope and computer multi-media system at the microscopic level. It has been determined that the shear stress plays subtle effects to the first stage of crack initiation. The effects of small defects to fatigue lives are also discussed.

Pan, J.Z.; Sun, X.M. [East China Univ. of Science and Technology, Shanghai (China); Jin, L. [Shanghai Inst. of Chemical Technology (China)

1996-12-01

70

Isotropic thin-walled pressure vessel experiment  

NASA Technical Reports Server (NTRS)

The objectives are: (1) to investigate the stress and strain distributions on the surface of a thin walled cylinder subject to internal pressure and/or axial load; and (2) to relate stress and strain distributions to material properties and cylinder geometry. The experiment, supplies, and procedure are presented.

Denton, Nancy L.; Hillsman, Vernon S.

1992-01-01

71

Guide for certifying pressure vessels and systems  

NASA Technical Reports Server (NTRS)

This guide is intended to provide methodology and describe the intent of the Pressure Vessel and System (PV/S) Certification program. It is not meant to be a mandated document, but is intended to transmit a basic understanding of the PV/S program, and include examples. After the reader has familiarized himself with this publication, he should have a basic understanding of how to go about developing a PV/S certification program.

Lundy, Floyd; Krusa, Paul W.

1992-01-01

72

Evaluation of insulated pressure vessels for cryogenic hydrogen storage  

Microsoft Academic Search

This paper presents an analytical and experimental evaluation of the applicability of insulated pressure vessels for hydrogen-fueled light-duty vehicles. Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH?) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for

S M Aceves; O Garcia-Villazana; J Martinez-Frias

1999-01-01

73

Pressure vessel burst test program - Progress paper No. 4  

NASA Astrophysics Data System (ADS)

A status report is presented for a program studying the characteristics of the blast waves and fragmentation caused by ruptured gas-filled pressure vessels. Experimental data trends have been derived from 14 burst pressure vessels. Attention is given to energy release in bursting, blast wave and fragmentation behavior, height of burst effects, fragment velocity vs vessel pressure, and comparative blast effects for spherical/composite vs cylindrical/steel pressure vessels.

Cain, Maurice R.; Sharp, Douglas E.

1993-06-01

74

Reliability Considerations for Composite Overwrapped Pressure Vessels on Spacecraft  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPVs) are used to store gases under high pressure onboard spacecraft. These are used for a variety of purposes such as propelling liquid fuel etc, Kevlar, glass, Carbon and other more recent fibers have all been in use to overwrap the vessels. COPVs usually have a thin metallic liner with the primary purpose of containing the gases and prevent any leakage. The liner is overwrapped with filament wound composite such as Kevlar, Carbon or Glass fiber. Although the liner is required to perform in the leak before break mode making the failure a relatively benign mode, the overwrap can fail catastrophically under sustained load due to stress rupture. It is this failure mode that is of major concern as the stored energy of such vessels is often great enough ta cause loss of crew and vehicle. The present paper addresses some of the reliability concerns associated specifically with Kevlar Composite Overwrapped Pressure Vessels. The primary focus of the paper is on how reliability of COPV's are established for the purpose of deciding in general their flight worthiness and continued use. Analytical models based on existing design data will be presented showing how to achieve the required reliability metric to the end of a specific period of performance. Uncertainties in the design parameters and how they affect reliability and confidence intervals will be addressed as well. Some trade studies showing how reliability changes with time during a program period will be presented.

Murthy, Pappu L. N.; Gyekenyesi, John P.; Grimes-Ledesma, Lorie; Phoenix, S. L.

2007-01-01

75

46 CFR 176.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Pressure vessels and boilers. 176.812 Section 176.812 Shipping...Inspections § 176.812 Pressure vessels and boilers. (a) Pressure vessels must be...inspection and testing requirements for boilers are contained in § 61.05 in...

2010-10-01

76

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

77

46 CFR 50.30-15 - Class II pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15...Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to shop...

2010-10-01

78

46 CFR 176.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Pressure vessels and boilers. 176.812 Section 176.812 Shipping...Inspections § 176.812 Pressure vessels and boilers. (a) Pressure vessels must be...inspection and testing requirements for boilers are contained in § 61.05 in...

2014-10-01

79

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

80

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

81

46 CFR 176.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Pressure vessels and boilers. 176.812 Section 176.812 Shipping...Inspections § 176.812 Pressure vessels and boilers. (a) Pressure vessels must be...inspection and testing requirements for boilers are contained in § 61.05 in...

2013-10-01

82

46 CFR 176.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Pressure vessels and boilers. 176.812 Section 176.812 Shipping...Inspections § 176.812 Pressure vessels and boilers. (a) Pressure vessels must be...inspection and testing requirements for boilers are contained in § 61.05 in...

2011-10-01

83

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

84

46 CFR 176.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Pressure vessels and boilers. 176.812 Section 176.812 Shipping...Inspections § 176.812 Pressure vessels and boilers. (a) Pressure vessels must be...inspection and testing requirements for boilers are contained in § 61.05 in...

2012-10-01

85

46 CFR 115.812 - Pressure vessels and boilers.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 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...

2014-10-01

86

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

87

Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Acoustic emission data were collected during the hydroburst testing of eleven 15 inch diameter filament wound composite overwrapped pressure vessels. A neural network burst pressure prediction was generated from the resulting AE amplitude data. The bottles shared commonality of graphite fiber, epoxy resin, and cure time. Individual bottles varied by cure mode (rotisserie versus static oven curing), types of inflicted damage, temperature of the pressurant, and pressurization scheme. Three categorical variables were selected to represent undamaged bottles, impact damaged bottles, and bottles with lacerated hoop fibers. This categorization along with the removal of the AE data from the disbonding noise between the aluminum liner and the composite overwrap allowed the prediction of burst pressures in all three sets of bottles using a single backpropagation neural network. Here the worst case error was 3.38 percent.

Hill, Eric v. K.; Dion, Seth-Andrew T.; Karl, Justin O.; Spivey, Nicholas S.; Walker, James L., II

2007-01-01

88

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

89

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

90

Plating Repair Of Nickel-Alloy Pressure Vessels  

NASA Technical Reports Server (NTRS)

Procedure for localized electrodeposition of nickel enables repair of small damaged nickel-based pressure vessels. Electrodeposition restores weakened areas of vessel wall to at least their former strength.

Ricklefs, Steve K.; Chagnon, Kevin M.

1989-01-01

91

Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests  

NASA Technical Reports Server (NTRS)

Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.

Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.

2007-01-01

92

Asymmetric Bulkheads for Cylindrical Pressure Vessels  

NASA Technical Reports Server (NTRS)

Asymmetric bulkheads are proposed for the ends of vertically oriented cylindrical pressure vessels. These bulkheads, which would feature both convex and concave contours, would offer advantages over purely convex, purely concave, and flat bulkheads (see figure). Intended originally to be applied to large tanks that hold propellant liquids for launching spacecraft, the asymmetric-bulkhead concept may also be attractive for terrestrial pressure vessels for which there are requirements to maximize volumetric and mass efficiencies. A description of the relative advantages and disadvantages of prior symmetric bulkhead configurations is prerequisite to understanding the advantages of the proposed asymmetric configuration: In order to obtain adequate strength, flat bulkheads must be made thicker, relative to concave and convex bulkheads; the difference in thickness is such that, other things being equal, pressure vessels with flat bulkheads must be made heavier than ones with concave or convex bulkheads. Convex bulkhead designs increase overall tank lengths, thereby necessitating additional supporting structure for keeping tanks vertical. Concave bulkhead configurations increase tank lengths and detract from volumetric efficiency, even though they do not necessitate additional supporting structure. The shape of a bulkhead affects the proportion of residual fluid in a tank that is, the portion of fluid that unavoidably remains in the tank during outflow and hence cannot be used. In this regard, a flat bulkhead is disadvantageous in two respects: (1) It lacks a single low point for optimum placement of an outlet and (2) a vortex that forms at the outlet during outflow prevents a relatively large amount of fluid from leaving the tank. A concave bulkhead also lacks a single low point for optimum placement of an outlet. Like purely concave and purely convex bulkhead configurations, the proposed asymmetric bulkhead configurations would be more mass-efficient than is the flat bulkhead configuration. In comparison with both purely convex and purely concave configurations, the proposed asymmetric configurations would offer greater volumetric efficiency. Relative to a purely convex bulkhead configuration, the corresponding asymmetric configuration would result in a shorter tank, thus demanding less supporting structure. An asymmetric configuration provides a low point for optimum location of a drain, and the convex shape at the drain location minimizes the amount of residual fluid.

Ford, Donald B.

2007-01-01

93

Environmental Testing of Glass-Fiber/Epoxy Pressure Vessels  

NASA Technical Reports Server (NTRS)

Pair of reports discusses long-term environmental tests of glassfiber/epoxy composite pressure vessels. Strength diminishes during long exposure to environment. Since such data necessary for accurate design of long-life structures such as pressure vessels, NASA Lewis Research Center built outdoor test stand in 1973. Test stand maintains system under constant pressure loading without frequent intervention of personnel.

Faddoul, J. R.

1987-01-01

94

Auger spectroscopy of Magnox pressure vessel steels  

SciTech Connect

Magnox Electric maintains a significant microstructural program in support of its safety case for operation of its stations with steel pressure vessels. An important part of this program is the characterization of grain boundary chemistry using Auger spectroscopy. Mechanical testing and subsequent examination of surveillance material has shown that some Charpy specimens display a proportion of intergranular fracture and Auger work has linked this to the presence of phosphorus on the grain boundaries. A feature of particular interest in the study of the boundaries is the co-segregation of carbon. The measurement of the true levels of phosphorus and carbon segregation is complicated by the presence of carbon contamination. This paper describes the simple approach used to overcome this problem.

Fisher, S.; Knowles, G.; Lee, B. [Magnox Electric plc, Berkeley (United Kingdom)

1999-10-01

95

Radiation effects on reactor pressure vessel supports  

SciTech Connect

The purpose of this report is to present the findings from the work done in accordance with the Task Action Plan developed to resolve the Nuclear Regulatory Commission (NRC) Generic Safety Issue No. 15, (GSI-15). GSI-15 was established to evaluate the potential for low-temperature, low-flux-level neutron irradiation to embrittle reactor pressure vessel (RPV) supports to the point of compromising plant safety. An evaluation of surveillance samples from the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) had suggested that some materials used for RPV supports in pressurized-water reactors could exhibit higher than expected embrittlement rates. However, further tests designed to evaluate the applicability of the HFIR data to reactor RPV supports under operating conditions led to the conclusion that RPV supports could be evaluated using traditional method. It was found that the unique HFIR radiation environment allowed the gamma radiation to contribute significantly to the embrittlement. The shielding provided by the thick steel RPV shell ensures that degradation of RPV supports from gamma irradiation is improbable or minimal. The findings reported herein were used, in part, as the basis for technical resolution of the issue.

Johnson, R.E. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering Technology; Lipinski, R.E. [Idaho National Engineering Lab., Rockville, MD (United States)

1996-05-01

96

Autogenous pressurization of cryogenic vessels using submerged vapor injection  

Microsoft Academic Search

Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet, a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency with pressurant gas requirements

Robert J. Stochl; Neil T. van Dresar; Raymond F. Lacovic

1991-01-01

97

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

E-print Network

Transformation Temperature on Residual Stresses in a High Strength Steel Weld J. A. Francis School of Materials replaced with compressive stresses if the transformation temperature is lowered sufficiently. The results in the system as a whole [1-4]. The conventional way of coping with the prospect of high weld residual stresses

Cambridge, University of

98

Low Temperature and High Pressure Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage  

Microsoft Academic Search

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LHâ) or ambient-temperature compressed hydrogen (CHâ). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available

S. M. Aceves; J. Martinez-Frias; O. Garcia-Villazana

2000-01-01

99

Hypervelocity impact testing of pressure vessels to simulate spacecraft failure  

Microsoft Academic Search

A series of hypervelocity impact tests are conducted against thin-walled aluminum pressure vessels to investigate failure mechanisms. The vessels, 0.05 and 0.08 inches thick, are constructed to replicate the material properties of the International Space Station (ISS). The vessels are pressurized to simulate the conditions experienced by the habitable modules of the ISS. A test matrix incorporating shielded thin plates,

Gregory D. Olsen; Angela M. Nolen

2001-01-01

100

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

101

Predicting Structural Behavior of Filament Wound Composite Pressure Vessel Using Three Dimensional Shell Analysis  

NASA Astrophysics Data System (ADS)

Fiber reinforced polymer composite materials with their higher specific strength, moduli and tailorability characteristics will result in reduction of weight of the structure. The composite pressure vessels with integrated end domes develop hoop stresses that are twice longitudinal stresses and when isotropic materials like metals are used for development of the hardware and the material is not fully utilized in the longitudinal/meridional direction resulting in over weight components. The determination of a proper winding angles and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In the present study a methodology is developed to understand structural characteristics of filament wound pressure vessels with integrated end domes. Progressive ply wise failure analysis of composite pressure vessel with geodesic end domes is carried out to determine matrix crack failure, burst pressure values at various positions of the shell. A three dimensional finite element analysis is computed to predict the deformations and stresses in the composite pressure vessel. The proposed method could save the time to design filament wound structures, to check whether the ply design is safe for the given input conditions and also can be adapted to non-geodesic structures. The results can be utilized to understand structural characteristics of filament wound pressure vessels with integrated end domes. This approach can be adopted for various applications like solid rocket motor casings, automobile fuel storage tanks and chemical storage tanks. Based on the predictions a composite pressure vessel is designed and developed. Hydraulic test is performed on the composite pressure vessel till the burst pressure.

Madhavi, M.; Venkat, R.

2014-01-01

102

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

103

High-performance fiber/epoxy composite pressure vessels  

NASA Technical Reports Server (NTRS)

Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

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

1978-01-01

104

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

105

Common/Dependent-Pressure-Vessel Nickel-Hydrogen Batteries  

NASA Technical Reports Server (NTRS)

The term "common/dependent pressure vessel" (C/DPV) denotes a proposed alternative configuration for a nickelhydrogen battery. The C/DPV configuration is so named because it is a hybrid of two prior configurations called "common pressure vessel" (CPV) and "dependent pressure vessel" (DPV). The C/DPV configuration has been proposed as a basis for designing highly reliable, long-life Ni/H2-batteries and cells for anticipated special applications in which it is expected that small charge capacities will suffice and sizes and weights must be minimized.

Timmerman, Paul J.

2003-01-01

106

Recent progress in understanding reactor pressure vessel steel embrittlement  

NASA Astrophysics Data System (ADS)

This paper reviews the current understanding of the basic mechanisms of irradiation embrittlement in reactor pressure vessel steels. Radiation enhanced diffusiona at operating temperatures around 290°C leads to the formation of various ultrafine scale hardening phases, including copper rich and copper catalysed manganese-nickel rich precipitates. Other nanofeatures that do not require copper, so-called matrix defects, include alloy phosphides and carbonitrides as well as defect cluster-solute complexes. Matrix defects that are thermally unstable (anneal) under irradiation play a very important role in mediating flux and temperature effects. The balance of features depends on the composition of the steel and the irradiation conditions. Copper enriched phases, which are the dominant embrittling feature in alloys containing significant trace quantities of this element, are fairly well understood. In contrast, the detailed identity and etiology of the matrix defects and manganese-nickel rich phases that may form in very low copper steels has not yet been established. Embrittlement of typical (Mn-Mo-Ni) pressure vessel steels, manifested as shifts in Charpy V-notch transition temperature, can generally be related to yield stress increases. Yield stress increases from copper rich precipitates are consistent with predictions using defect-obstacle interaction theory coupled with a new model for superposition of the hardening from both pre- and post-irradiation sources of strength. Details of the strengthening contributions from the other irradiation features are not as well established, but appear to be reasonably consistent with theory. These concepts have led to the development of thermodynamic-kinetic-micromechanical models that are broadly consistent with experiment, and rationalize the highly synergistic effects of important irradiation (e.g., temperature, flux, fluence) and metallurgical (e.g., copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and hardening recovery during post-irradiation annealing. Open questions can be addressed with a hierarchy of new theoretical and experimental tools, which range from atomistic modeling to tomographic methods of observing the sequence-of-events leading to fracture. Advanced microstructural evolution, microstructure-property and micromechanical models, validated and calibrated by well designed experiments, will greatly enhance our ability to predict pressure vessel embrittlement and to resolve out-standing technical issues.

Odette, G. R.; Lucas, G. E.

107

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

108

ASME code ductile failure criteria for impulsively loaded pressure vessels  

SciTech Connect

Ductile failure criteria suitable for application to impulsively loaded high pressure vessels that are designed to the rules of the ASME Code Section VI11 Division 3 are described and justified. The criteria are based upon prevention of load instability and the associated global failure mechanisms, and on protection against progressive distortion for multiple-use vessels. The criteria are demonstrated by the design and analysis of vessels that contain high explosive charges.

Nickell, Robert E.; Duffey, T. A. (Thomas A.); Rodriguez, E. A. (Edward A.)

2003-01-01

109

46 CFR 167.25-1 - Boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Boilers, pressure vessels, piping and appurtenances... Marine Engineering § 167.25-1 Boilers, pressure vessels, piping and appurtenances...with one of the following standards for boilers, pressure vessels, piping and...

2010-10-01

110

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

Code of Federal Regulations, 2010 CFR

... 2010-10-01 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...

2010-10-01

111

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

112

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 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...

2010-10-01

113

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

114

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

Code of Federal Regulations, 2010 CFR

...compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56...receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels shall be inspected by...

2010-07-01

115

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

Code of Federal Regulations, 2010 CFR

...compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57...receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels shall be inspected by...

2010-07-01

116

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 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...

2011-10-01

117

46 CFR 167.25-1 - Boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Boilers, pressure vessels, piping and appurtenances... Marine Engineering § 167.25-1 Boilers, pressure vessels, piping and appurtenances...with one of the following standards for boilers, pressure vessels, piping and...

2014-10-01

118

46 CFR 167.25-1 - Boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Boilers, pressure vessels, piping and appurtenances... Marine Engineering § 167.25-1 Boilers, pressure vessels, piping and appurtenances...with one of the following standards for boilers, pressure vessels, piping and...

2011-10-01

119

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

120

46 CFR 167.25-1 - Boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Boilers, pressure vessels, piping and appurtenances... Marine Engineering § 167.25-1 Boilers, pressure vessels, piping and appurtenances...with one of the following standards for boilers, pressure vessels, piping and...

2012-10-01

121

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

122

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

Code of Federal Regulations, 2014 CFR

... 2014-10-01 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,...

2014-10-01

123

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

124

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

Code of Federal Regulations, 2014 CFR

... 2014-10-01 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...

2014-10-01

125

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

Code of Federal Regulations, 2014 CFR

...2014-10-01 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...

2014-10-01

126

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

127

46 CFR 167.25-1 - Boilers, pressure vessels, piping and appurtenances.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Boilers, pressure vessels, piping and appurtenances... Marine Engineering § 167.25-1 Boilers, pressure vessels, piping and appurtenances...with one of the following standards for boilers, pressure vessels, piping and...

2013-10-01

128

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

129

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 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...

2012-10-01

130

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

Code of Federal Regulations, 2014 CFR

... 2014-10-01 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...

2014-10-01

131

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

132

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

133

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

134

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

135

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

136

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels...Policy Letter 04-12, ``Alternative Pressure Relief Valve Settings on Vessels Carrying...Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section VIII...

2012-09-27

137

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

Code of Federal Regulations, 2010 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,...

2010-07-01

138

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

139

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessel for human occupancy (PVHO...SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-17 Pressure vessel for human occupancy...

2010-10-01

140

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pressure vessel for human occupancy (PVHO...SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-17 Pressure vessel for human occupancy...

2013-10-01

141

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

Code of Federal Regulations, 2014 CFR

...compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57...compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels shall be inspected by...

2014-07-01

142

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

Code of Federal Regulations, 2012 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,...

2012-07-01

143

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

144

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

Code of Federal Regulations, 2014 CFR

...compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56...compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels shall be inspected by...

2014-07-01

145

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

Code of Federal Regulations, 2013 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,...

2013-07-01

146

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Pressure vessel for human occupancy (PVHO...SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-17 Pressure vessel for human occupancy...

2012-10-01

147

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

Code of Federal Regulations, 2014 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,...

2014-07-01

148

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

149

SMART composite high pressure vessels with integrated optical fiber sensors  

Microsoft Academic Search

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

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

2010-01-01

150

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

151

46 CFR 58.60-3 - Pressure vessel.  

Code of Federal Regulations, 2011 CFR

...HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Industrial Systems and Components on Mobile Offshore...pressure vessel that is a component in an industrial system under this subpart must...

2011-10-01

152

46 CFR 58.60-3 - Pressure vessel.  

Code of Federal Regulations, 2012 CFR

...HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Industrial Systems and Components on Mobile Offshore...pressure vessel that is a component in an industrial system under this subpart must...

2012-10-01

153

46 CFR 58.60-3 - Pressure vessel.  

Code of Federal Regulations, 2013 CFR

...HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Industrial Systems and Components on Mobile Offshore...pressure vessel that is a component in an industrial system under this subpart must...

2013-10-01

154

46 CFR 58.60-3 - Pressure vessel.  

Code of Federal Regulations, 2010 CFR

...HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Industrial Systems and Components on Mobile Offshore...pressure vessel that is a component in an industrial system under this subpart must...

2010-10-01

155

Brittle fracture of nuclear pressure vessel steels—I. Local criterion for cleavage fracture  

Microsoft Academic Search

Brittle fracture of nuclear pressure vessel steels has been investigated on the basis of physical and mechanical modelling for processes of nucleation, start and propagation of cleavage microcracks in the material substructure, as changed by plastic deformation. It is shown that depending on stress triaxiality, temperature and material properties the brittle fracture in macrovolume may be controlled either by cleavage

B. Z. Margolin; V. A. Shvetsova; G. P. Karzov

1997-01-01

156

Brittle fracture of nuclear pressure vessel steels—II. Prediction of fracture toughness  

Microsoft Academic Search

A model for the prediction of fracture toughness for nuclear pressure vessel steels has been worked out on the basis of brittle and ductile fracture criteria formulated by the authors in an earlier paper. An analysis was performed of the stress-strain state near the crack tip in the finite strain statement. The model proposed allows one to obtain an adequate

B. Z. Margolin; G. P. Karzov; V. A. Shvetsova

1997-01-01

157

Progressive Fracture and Damage Tolerance of Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

Structural performance (integrity, durability and damage tolerance) of fiber reinforced composite pressure vessels, designed for pressured shelters for planetary exploration, is investigated via computational simulation. An integrated computer code is utilized for the simulation of damage initiation, growth, and propagation under pressure. Aramid fibers are considered in a rubbery polymer matrix for the composite system. Effects of fiber orientation and fabrication defect/accidental damages are investigated with regard to the safety and durability of the shelter. Results show the viability of fiber reinforced pressure vessels as damage tolerant shelters for planetary colonization.

Chamis, Christos C.; Gotsis, Pascal K.; Minnetyan, Levon

1997-01-01

158

Dimensional analysis of blood vessels in the pressure myograph  

NASA Astrophysics Data System (ADS)

The accuracy of conventional and emerging methods for the dimensional analysis of optically imaged arterial vessels, isolated in a pressure myograph, is investigated. The pressure myograph is a device used to study the structure and function of isolated sections of small resistance arteries, as a function of chemical, mechanical and electrical stimuli. The arterial wall and lumen dimensions are particularly important indicators of anatomy and pathology. The conventional method of dimensional analysis uses edge detection, however the accuracy of this approach is questionable when the vessel is in a contracted state since contrast deteriorates or is lost between lumen and vessel wall. The conventional and emerging methods are examined experimentally with vessel phantoms, to provide known characteristics. A novel algorithm, based on a measurement of the vessel extinction coefficient, is also examined theoretically and experimentally. A discussion centers on the possibility for realistic lumen size measurement when edge detection can not be applied and when the accuracy of edge detection is questionable.

Crabtree, Vincent P.; Smith, Peter R.

1999-01-01

159

Autogenous pressurization of cryogenic vessels using submerged vapor injection  

NASA Astrophysics Data System (ADS)

Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet, a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency with pressurant gas requirements approximately five times greater than ideal amounts. Consequently, submerged vapor injection should be avoided as a low-gravity autogenous pressurization method whenever possible. The work presented herein validates that pressurant requirements are accurately predicted by a homogeneous thermodynamic model when the submerged injection technique is employed.

Stochl, Robert J.; van Dresar, Neil T.; Lacovic, Raymond F.

160

Autogenous pressurization of cryogenic vessels using submerged vapor injection  

NASA Technical Reports Server (NTRS)

Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet, a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency with pressurant gas requirements approximately five times greater than ideal amounts. Consequently, submerged vapor injection should be avoided as a low-gravity autogenous pressurization method whenever possible. The work presented herein validates that pressurant requirements are accurately predicted by a homogeneous thermodynamic model when the submerged injection technique is employed.

Stochl, Robert J.; Van Dresar, Neil T.; Lacovic, Raymond F.

1991-01-01

161

Autogenous pressurization of cryogenic vessels using submerged vapor injection  

NASA Technical Reports Server (NTRS)

Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet; a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency, with pressurant gas requirements approximately five times greater than ideal amounts. Consequently, submerged vapor injection should be avoided as a low-gravity autogenous pressurization method whenever possible. The work presented herein validates that pressurent requirements are accurately predicted by a homogeneous thermodynamic model when the submerged injection technique is employed.

Stochl, Robert J.; Vandresar, Neil T.; Lacovic, Raymond F.

1991-01-01

162

AN IBM 7090 FORTRAN PROGRAM FOR ASME UNFIRED PRESSURE VESSEL DESIGN AND PRELIMINARY COST ESTIMATION  

Microsoft Academic Search

An IBM 7090 FORTRAN program was written for the preliminary design and ; cost estimation of unfired pressure vessels with or without a jacket. Both ; vessel and jacket designs conform to the 1959 ASME Boiler and Pressure Vessel ; Code, Section VIII, Unfired Pressure Vessels. Vessels and jackets from 5 in. ; pipe through 84 in. o.d. and 1\\/4

C. E. Prince; R. P. Milford

1962-01-01

163

Summary of Activities for Health Monitoring of Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

This three-year project (FY12-14) will design and demonstrate the ability of new Magnetic Stress Gages for the measurement of stresses on the inner diameter of a Composite Overwrapped Pressure Vessel overwrap. The sensors are being tested at White Sands Testing Facility (WSTF) where the results will be correlated with a known nondestructive technique acoustic emission. The gages will be produced utilizing Meandering Winding Magnetometer (MWM) and/or MWM array eddy current technology. The ultimate goal is to utilize this technology for the health monitoring of Composite Overwrapped Pressure Vessels for all future flight programs. The first full-scale pressurization test was performed at WSTF in June 2012. The goals of this test were to determine adaptations of the magnetic stress gauge instrumentation that would be necessary to allow multiple sensors to monitor the vessel's condition simultaneously and to determine how the sensor response changes with sensor selection and orientation. The second full scale pressurization test was performed at WSTF in August 2012. The goals of this test were to monitor the vessel's condition with multiple sensors simultaneously, to determine the viability of the multiplexing units (MUX) for the application, and to determine if the sensor responses in different orientations are repeatable. For both sets of tests the vessel was pressured up to 6,000 psi to simulate maximum operating pressure. Acoustic events were observed during the first pressurization cycle. This suggested that the extended storage period prior to use of this bottle led to a relaxation of the residual stresses imparted during auto-frettage. The pressurization tests successfully demonstrated the use of multiplexers with multiple MWM arrays to monitor a vessel. It was discovered that depending upon the sensor orientation, the frequencies, and the sense element, the MWM arrays can provide a variety of complementary information about the composite overwrapped pressure vessel load conditions. For example, low frequency measurements can be used to monitor the overwrap thickness and changes associated with pressure level. High frequency data is dominated by the properties of the overwrap, including the fiber orientations and lay-up of the layers.

Russell, Rick; Skow, Miles

2013-01-01

164

Validation and Verification of Composite Pressure Vessel Design  

NASA Technical Reports Server (NTRS)

Ten composite pressure vessels were instrumented with fiber Bragg grating sensors and pressure tested Through burst. This paper and presentation will discuss the testing methodology, the test results, compare the testing results to the analytical model, and also compare the fiber Bragg grating sensor data with data obtained against that obtained from foil strain gages.

Kreger, Stephen T.; Ortyl, Nicholas; Grant, Joseph; Taylor, F. Tad

2006-01-01

165

Neutron fluence management to optimize pressure vessel lifetime  

SciTech Connect

Pressure vessel steel embrittlement management is need to predict the tearing resistance at end of life, but also to update these predictions taking into account the evolution of the principal parameters, such as fuel management, thermohydraulics of the primary coolant circuit, and lifetime extension capability. French 900-MW units are characterized by a high neutron fluence on the inner face of the pressure vessel at the predicted end of life. Electricite de France`s (EDF) purpose is to establish the appropriate knowledge and software to predict the pressure vessel embrittlement during operation. This work is in progress in two ways. First, appropriate existing software is being used to calculate the consequences in terms of neutron flux, on the inner face of the pressure vessel, of various operating conditions and fuel patterns, and to be able to select the best of these. Second, specific software is being developed to calculate the maximum neutron flux on the inner face of the pressure vessel, according to the contribution of the major fuel elements so the authors can appreciate the fluence level of each refueling pattern and choose the one that is less severe. These results have shown that a benefit of about 30% can be obtained by optimized patterns with high discharge burn-up. Neutron fluence management can be successfully integrated in the core refueling calculation procedure, but further progress is necessary for complete validation and background to optimize the steel surveillance program.

Lefebvre, J.C.; Rieg, C. [Electricite de France, Villeurbanne (France); Leroy, P. [EDF-DPT/DCN, Paris (France); Schaeffer, H. [EDF-DER/PhR, Clamart (France); Nimal, J.C. [Commissariat a l`Energie Atomique, Gif-sur-Yvette (France). Centre d`Etudes Nucleaires de Saclay; Lloret, R. [CEA-DRN/DRE-SES, Grenoble (France). Centre d`Etudes Nucleaires de Grenoble

1993-12-01

166

Transient Response of FGM Pressure Vessels  

NASA Astrophysics Data System (ADS)

The present study aims to investigate the transient behavior of thick-walled cylinders under dynamic internal pressure. Analytical solutions are possible only for simple time-dependent pressure functions. The solution procedure presented is general in the sense that the pressure applied may be an arbitrary continuous function of time, impulsive or given in a discrete form. The material considered is isotropic and heterogeneous with properties varying in the radial direction termed as Functionally Graded Material (FGM). Laplace transform method is used and the inversion into the time domain is performed using the modified Durbin's method. Verification of the numerical procedure is performed by comparing the results with those of an analytical solution available in the literature for a simple exponentially-varying pressure. The inhomogeneity constant in the material property model is shown to have a significant effect on the transient response.

Pekel, Hakan; Keles, Ibrahim; Temel, Beytullah; Tutuncu, Naki

167

Summary of Activities for Health Monitoring of Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

This new start project (FY12-14) will design and demonstrate the ability of nondestructive evaluation sensors for the measurement of stresses on the inner diameter of a Composite Overwrapped Pressure Vessel overwrap. Results will be correlated with other nondestructive evaluation technologies such as Acoustic Emission. The project will build upon a proof of concept study performed at KSC which demonstrated the ability of Magnetic Stress Gages to measure stresses at internal overwraps and upon current acoustic emission research being performed at WSTF; The gages will be produced utilizing Maundering Winding Magnetometer and/or Maundering Winding Magnetometer-array eddy current technology. The proof-of-concept study demonstrated a correlation between the sensor response and pressure or strain. The study also demonstrated the ability of Maundering Winding Magnetometer technology to monitor the stresses in a Composite Overwrapped Pressure Vessel at different orientations and depths. The ultimate goal is to utilize this technology for the health monitoring of Composite Overwrapped Pressure Vessels for all future flight programs.

Russell, Rick

2012-01-01

168

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

169

Study on the development of composite CNG pressure vessels  

NASA Astrophysics Data System (ADS)

The development of composite CNG (compressed natural gas) pressure vessels with HDPE (high density polyethylene) liner and metal end nozzles was studied. The CNG environmental tests carried out for HDPE, resins and reinforcing fibres showed no significant damages. The metal end nozzles and the dome contour of the liner were designed, respectively. The stacking sequence was analysed and applied in filament winding of the pressure vessels. They showed satisfactory results when subjected to burst tests. The fibre volume fractions, Vf, were obtained by image analyser and the average Vfs were 54.09% and 53.49% in hoop and helical regions, respectively.

Kim, B. S.; Kim, B. H.; Kim, J. B.; Joe, C. R.

170

Cleavage Fracture Modeling of Pressure Vessels Under Transient Thermo-Mechanical Loading  

SciTech Connect

Abstract The next generation of fracture assessment procedures for nuclear reactor pressure vessels (RPVs) will combine nonlinear analyses of crack-front response with stochastic treatments of crack size, shape, orientation, location, material properties and thermal-pressure transients. The projected computational demands needed to support stochastic approaches with detailed 3-D, nonlinear stress analyses of vessels containing defects appear well beyond current and near-term capabilities. In the interim, 2-D models be-come appealing to approximate certain classes of critical flaws in RPVs, and have computational demands within reach for stochastic frameworks. The present work focuses on the capability of 2-D models to provide values for the Weibull stress fracture parameter with accuracy comparable to those from very detailed 3-D models. Weibull stress approaches provide one route to connect nonlinear vessel response with fracture toughness values measured using small laboratory specimens. The embedded axial flaw located in the RPV wall near the cladding-vessel interface emerges from current linear-elastic, stochastic investigations as a critical contributor to the conditional probability of initiation. Three different types of 2-D models reflecting this configuration are subjected to a thermal-pressure transient characteristic of a critical pressurized thermal shock event. The plane-strain, 2-D models include: the modified boundary layer (MBL) model, the middle tension (M(T)) model, and the 2-D RPV model. The 2-D MBL model provides a high quality estimate for the Weibull stress but only in crack-front regions with a positive T-stress. For crack-front locations with low constraint (T-stress < 0), the M(T) specimen provides very accurate Weibull stress values but only for pressure load acting alone on the RPV. For RPVs under a combined thermal-pressure transient, Weibull stresses computed from the 2-D RPV model demonstrate close agreement with those computed from the corresponding crack-front locations in the 3-D RPV model having large negative T-stresses. Applications of this family of 2-D models provide Weibull stress values in excellent agreement with very detailed 3-D models while retaining practical levels of computational effort.

Qian, Xudong [National University of Singapore; Dodds, Robert [University of Illinois; Yin, Shengjun [ORNL; Bass, Bennett Richard [ORNL

2008-01-01

171

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

172

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2011 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2011-10-01

173

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2014 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2014-10-01

174

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2012 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2012-10-01

175

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2013 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2013-10-01

176

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

177

Multilayer Pressure Vessel Materials Testing and Analysis. Phase 1  

NASA Technical Reports Server (NTRS)

To provide NASA a comprehensive suite of materials strength, fracture toughness and crack growth rate test results for use in remaining life calculations for aging multilayer pressure vessels, Southwest Research Institute (R) (SwRI) was contracted in two phases to obtain relevant material property data from a representative vessel. This report describes Phase 1 of this effort which includes a preliminary material property assessment as well as a fractographic, fracture mechanics and fatigue crack growth analyses of an induced flaw in the outer shell of a representative multilayer vessel that was subjected to cyclic pressure test. SwRI performed this Phase 1 effort under contract to the Digital Wave Corporation in support of their contract to Jacobs ATOM for the NASA Ames Research Center.

Cardinal, Joseph W.; Popelar, Carl F.; Page, Richard A.

2014-01-01

178

Creep of A508/533 Pressure Vessel Steel  

SciTech Connect

ABSTRACT Evaluation of potential Reactor Pressure Vessel (RPV) steels has been carried out as part of the pre-conceptual Very High Temperature Reactor (VHTR) design studies. These design studies have generally focused on American Society of Mechanical Engineers (ASME) Code status of the steels, temperature limits, and allowable stresses. Initially, three candidate materials were identified by this process: conventional light water reactor (LWR) RPV steels A508 and A533, 2¼Cr-1Mo in the annealed condition, and Grade 91 steel. The low strength of 2¼Cr-1Mo at elevated temperature has eliminated this steel from serious consideration as the VHTR RPV candidate material. Discussions with the very few vendors that can potentially produce large forgings for nuclear pressure vessels indicate a strong preference for conventional LWR steels. This preference is based in part on extensive experience with forging these steels for nuclear components. It is also based on the inability to cast large ingots of the Grade 91 steel due to segregation during ingot solidification, thus restricting the possible mass of forging components and increasing the amount of welding required for completion of the RPV. Grade 91 steel is also prone to weld cracking and must be post-weld heat treated to ensure adequate high-temperature strength. There are also questions about the ability to produce, and very importantly, verify the through thickness properties of thick sections of Grade 91 material. The availability of large components, ease of fabrication, and nuclear service experience with the A508 and A533 steels strongly favor their use in the RPV for the VHTR. Lowering the gas outlet temperature for the VHTR to 750°C from 950 to 1000°C, proposed in early concept studies, further strengthens the justification for this material selection. This steel is allowed in the ASME Boiler and Pressure Vessel Code for nuclear service up to 371°C (700°F); certain excursions above that temperature are allowed by Code Case N-499-2 (now incorporated as an appendix to Section III Division 5 of the Code). This Code Case was developed with a rather sparse data set and focused primarily on rolled plate material (A533 specification). Confirmatory tests of creep behavior of both A508 and A533 are described here that are designed to extend the database in order to build higher confidence in ensuring the structural integrity of the VHTR RPV during off-normal conditions. A number of creep-rupture tests were carried out at temperatures above the 371°C (700°F) Code limit; longer term tests designed to evaluate minimum creep behavior are ongoing. A limited amount of rupture testing was also carried out on welded material. All of the rupture data from the current experiments is compared to historical values from the testing carried out to develop Code Case N-499-2. It is shown that the A508/533 basemetal tested here fits well with the rupture behavior reported from the historical testing. The presence of weldments significantly reduces the time to rupture. The primary purpose of this report is to summarize and record the experimental results in a single document.

Richard Wright

2014-08-01

179

Design Guide for glass fiber reinforced metal pressure vessel  

NASA Technical Reports Server (NTRS)

Design Guide has been prepared for pressure vessel engineers concerned with specific glass fiber reinforced metal tank design or general tank tradeoff study. Design philosophy, general equations, and curves are provided for safelife design of tanks operating under anticipated space shuttle service conditions.

Landes, R. E.

1973-01-01

180

A life under pressure: circumferential stress in the microvascular wall.  

PubMed

Microvessels live 'a life under pressure' in several ways. In a literal sense, vessels of the microcirculation are exposed to high levels of stress caused primarily by the intravascular pressure head. In a figurative sense, the individual vessel and the microvascular network as a whole must continuously strive to meet the changing demands of the surrounding tissue. The 'principle of optimal operation' as formulated by Y. C. Fung states that living tissues adapts structurally through remodelling and growth until a level of tensile and compressive stresses is reached at which tissue performance is optimal. This behaviour is characteristic for the microvascular wall. It is highly plastic by nature and meets sustained changes by structural adaptation so as to maintain functional optimality. Owing to the orientation of the vascular smooth muscle cell in the media, in particular, the circumferential stress component has a huge impact on the state of the vascular wall. It is involved as a unifying factor on vastly different timescales in processes as diverse as acute regulation of vessel diameter, structural vessel remodelling and growth or atrophy of the vascular wall. The aim of this MiniReview was to outline in brief this integrative role of circumferential wall stress in the microcirculation. PMID:21917118

Jacobsen, Jens C B; Holstein-Rathlou, Niels-Henrik

2012-01-01

181

Coevolution of solid stress and interstitial fluid pressure in tumors during progression: implications for vascular collapse.  

PubMed

The stress harbored by the solid phase of tumors is known as solid stress. Solid stress can be either applied externally by the surrounding normal tissue or induced by the tumor itself due to its growth. Fluid pressure is the isotropic stress exerted by the fluid phase. We recently showed that growth-induced solid stress is on the order of 1.3 to 13.0 kPa (10-100 mmHg)--high enough to cause compression of fragile blood vessels, resulting in poor perfusion and hypoxia. However, the evolution of growth-induced stress with tumor progression and its effect on cancer cell proliferation in vivo is not understood. To this end, we developed a mathematical model for tumor growth that takes into account all three types of stresses: growth-induced stress, externally applied stress, and fluid pressure. First, we conducted in vivo experiments and found that growth-induced stress is related to tumor volume through a biexponential relationship. Then, we incorporated this information into our mathematical model and showed that due to the evolution of growth-induced stress, total solid stress levels are higher in the tumor interior and lower in the periphery. Elevated compressive solid stress in the interior of the tumor is sufficient to cause the collapse of blood vessels and results in a lower growth rate of cancer cells compared with the periphery, independently from that caused by the lack of nutrients due to vessel collapse. Furthermore, solid stress in the periphery of the tumor causes blood vessels in the surrounding normal tissue to deform to elliptical shapes. We present histologic sections of human cancers that show such vessel deformations. Finally, we found that fluid pressure increases with tumor growth due to increased vascular permeability and lymphatic impairment, and is governed by the microvascular pressure. Crucially, fluid pressure does not cause vessel compression of tumor vessels. PMID:23633490

Stylianopoulos, Triantafyllos; Martin, John D; Snuderl, Matija; Mpekris, Fotios; Jain, Saloni R; Jain, Rakesh K

2013-07-01

182

Fabrication of toroidal composite pressure vessels. Final report  

SciTech Connect

A method for fabricating composite pressure vessels having toroidal geometry was evaluated. Eight units were fabricated using fibrous graphite material wrapped over a thin-walled aluminum liner. The material was wrapped using a machine designed for wrapping, the graphite material was impregnated with an epoxy resin that was subsequently thermally cured. The units were fabricated using various winding patterns. They were hydrostatically tested to determine their performance. The method of fabrication was demonstrated. However, the improvement in performance to weight ratio over that obtainable by an all metal vessel probably does not justify the extra cost of fabrication.

Dodge, W.G.; Escalona, A.

1996-11-24

183

Improved Attachment in a Hybrid Inflatable Pressure Vessel  

NASA Technical Reports Server (NTRS)

The vessel is a hybrid that comprises an inflatable shell attached to a rigid structure. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a restraint layer that comprises a web of straps made from high-strength polymeric fabrics. The present improvements are intended to overcome deficiencies in those aspects of the original design that pertain to attachment of the inflatable shell to the rigid structure. In a typical intended application, such attachment(s) would be made at one or more window or hatch frames to incorporate the windows or hatches as integral parts of the overall vessel.

Johnson, Christopher J.; Patterson, Ross; Spexarth, Gary R.

2010-01-01

184

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

185

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

186

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

Code of Federal Regulations, 2014 CFR

...2014-10-01 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...

2014-10-01

187

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

188

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 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...

2010-07-01

189

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 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...

2010-07-01

190

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 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...

2011-07-01

191

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 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...

2012-07-01

192

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

Code of Federal Regulations, 2014 CFR

...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

193

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 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...

2013-07-01

194

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 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...

2013-07-01

195

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 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...

2012-07-01

196

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 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...

2011-07-01

197

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

Code of Federal Regulations, 2014 CFR

...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

198

Lessons Learned From Developing Reactor Pressure Vessel Steel Embrittlement Database  

SciTech Connect

Materials behaviors caused by neutron irradiation under fission and/or fusion environments can be little understood without practical examination. Easily accessible material information system with large material database using effective computers is necessary for design of nuclear materials and analyses or simulations of the phenomena. The developed Embrittlement Data Base (EDB) at ORNL is this comprehensive collection of data. EDB database contains power reactor pressure vessel surveillance data, the material test reactor data, foreign reactor data (through bilateral agreements authorized by NRC), and the fracture toughness data. The lessons learned from building EDB program and the associated database management activity regarding Material Database Design Methodology, Architecture and the Embedded QA Protocol are described in this report. The development of IAEA International Database on Reactor Pressure Vessel Materials (IDRPVM) and the comparison of EDB database and IAEA IDRPVM database are provided in the report. The recommended database QA protocol and database infrastructure are also stated in the report.

Wang, Jy-An John [ORNL

2010-08-01

199

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

200

An Acoustic Emission and Acousto-Ultrasonic Analysis of Impact Damaged Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

The research presented herein summarizes the development of acoustic emission (AE) and acousto-ultrasonic (AU) techniques for the nondestructive evaluation of filament wound composite pressure vessels. Vessels fabricated from both graphite and kevlar fibers with an epoxy matrix were examined prior to hydroburst using AU and during hydroburst using AE. A dead weight drop apparatus featuring both blunt and sharp impactor tips was utilized to produce a single known energy 'damage' level in each of the vessels so that the degree to which the effects of impact damage could be measured. The damage levels ranged from barely visible to obvious fiber breakage and delamination. Independent neural network burst pressure prediction models were developed from a sample of each fiber/resin material system. Here, the cumulative AE amplitude distribution data collected from low level proof test (25% of the expected burst for undamaged vessels) were used to measure the effects of the impact on the residual burst pressure of the vessels. The results of the AE/neural network model for the inert propellant filled graphite/epoxy vessels 'IM7/3501-6, IM7/977-2 and IM7/8553-45' demonstrated that burst pressures can be predicted from low level AE proof test data, yielding an average error of 5.0%. The trained network for the IM7/977-2 class vessels was also able to predict the expected burst pressure of taller vessels (three times longer hoop region length) constructed of the same material and using the same manufacturing technique, with an average error of 4.9%. To a lesser extent, the burst pressure prediction models could also measure the effects of impact damage to the kevlar/epoxy 'Kevlar 49/ DPL862' vessels. Here though, due to the higher attenuation of the material, an insufficient amount of AE amplitude information was collected to generate robust network models. Although, the worst case trial errors were less than 6%, when additional blind predictions were attempted, errors as high as 50% were produced. An acousto-ultrasonic robotic evaluation system (AURES) was developed for mapping the effects of damage on filament wound pressure vessels prior to hydroproof testing. The AURES injects a single broadband ultrasonic pulse into each vessel at preprogrammed positions and records the effects of the interaction of that pulse on the material volume with a broadband receiver. A stress wave factor in the form of the energy associated with the 750 to 1000 kHz and 1000 to 1250 kHz frequency bands were used to map the potential failure sites for each vessel. The energy map associated with the graphite/epoxy vessels was found to decrease in the region of the impact damage. The kevlar vessels showed the opposite trend, with the energy values increasing around the damage/failure sites.

Walker, James L.; Workman, Gary L.; Workman, Gary L.

1996-01-01

201

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

202

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

203

Fast Neutron Fluence Calculation of BWR Pressure Vessel Internals  

SciTech Connect

In recent years, cracks were found in some boiling water reactor (BWR) pressure vessel internals. This study is to help identify locations of possible failures due to the irradiation of fast neutrons at the BWR plant in Taiwan. This study shows that with proper geometric modeling, a nodal version of the three-dimensional discrete ordinates code TORT can be used to obtain quite accurate results in BWR fast neutron fluence calculations in reasonable computing time.

Yen-Wan Hsueh Liu; Y. H. Teng; J. J. Hu

2000-06-04

204

ANALYSIS AND EXPERIMENTAL TESTING OF INSULATED PRESSURE VESSELS FOR AUTOMOTIVE HYDROGEN STORAGE  

Microsoft Academic Search

This paper presents an analytical and experimental evaluation of the applicability of insulated pressure vessels for hydrogen-fueled light-duty vehicles. Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH 2) or ambient- temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy

S. M. Aceves; J. Martinez-Frias

1999-01-01

205

Microwave determination of the volume of a pressure vessel  

NASA Astrophysics Data System (ADS)

Using microwave techniques that are scalable to very large volumes, we measured the interior volume of a 0.3?m3, commercially manufactured pressure vessel with a relative uncertainty of 0.06%, as confirmed by independent, more-accurate gas-expansion measurements. This pressure vessel (or a much larger one of a similar design) could be used as either a calibrated volume standard or as a gas source and/or a gas collector for the calibration of gas-flow meters. In addition, we determined the expansion of the vessel with temperature (?V/?T)p/V = (35.3? ± ?1.9) × 10?6?K?1, and we estimated the pressure expansion (?V/?p)T/V = 0.9? × ?10?3?MPa?1. The volume measurement did not require careful thermostatting; its uncertainty was dominated by imperfect modeling of the volume’s shape. (The estimated uncertainties are one standard uncertainty with coverage factor k = 1 corresponding to 68% confidence level.)

Moldover, M. R.; Schmidt, J. W.; Gillis, K. A.; Mehl, J. B.; Wright, J. D.

2015-01-01

206

Composite Pressure Vessel Variability in Geometry and Filament Winding Model  

NASA Technical Reports Server (NTRS)

Composite pressure vessels (CPVs) are used in a variety of applications ranging from carbon dioxide canisters for paintball guns to life support and pressurant storage on the International Space Station. With widespread use, it is important to be able to evaluate the effect of variability on structural performance. Data analysis was completed on CPVs to determine the amount of variation that occurs among the same type of CPV, and a filament winding routine was developed to facilitate study of the effect of manufacturing variation on structural response.

Green, Steven J.; Greene, Nathanael J.

2012-01-01

207

Insulated Pressure Vessels for Vehicular Hydrogen Storage: Analysis and Performance Evaluation  

Microsoft Academic Search

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH) or ambient-temperature compressed hydrogen (CH). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available

S M Aceves; J Martinez-Frias; O Garcia-Villazana; F Espinosa-Loza

2001-01-01

208

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

209

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

210

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

211

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

212

Distributed Sensing of Composite Over-wrapped Pressure Vessel Using Fiber-Bragg Gratings at Ambient and Cryogenic Temperatures  

NASA Technical Reports Server (NTRS)

Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in laminate structure. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 2800 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Grant, Joseph

2004-01-01

213

Distributed sensing of Composite Over-wrapped Pressure Vessel using Fiber-Bragg Gratings at Ambient and Cryogenic Temperatures  

NASA Technical Reports Server (NTRS)

Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in laminate structure. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 2800 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Grant, Joseph

2005-01-01

214

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

Code of Federal Regulations, 2012 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...

2012-10-01

215

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

216

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

217

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

Code of Federal Regulations, 2014 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...

2014-10-01

218

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

Code of Federal Regulations, 2013 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...

2013-10-01

219

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

220

Condition health monitoring of composite wound pressure vessels using fiber Bragg gratings  

NASA Astrophysics Data System (ADS)

Structure health monitoring refers to a real time and in situ monitoring system. It can diagnose the condition status of composite structure in time and effectively estimate the safety, increasing the reliability, extending the service life, at the same time, reducing the maintenance cost. In this paper, the sensing technology based on FBG sensors is employed to monitor the health of composite wound pressure vessel in service. Strain monitoring of the vessel in fatigue tests is carried out with the surface mounted FBG sensors. The experiment result shows that FBG sensors have several excellent performances: it has anti-fatigue capability to accurately measure the cycle strain; it is linear with the inner pressure and can be used as pressure sensor; the wavelength is diverged in the high stress gradient field, so the FBG can be used to measure the non-homogeneous strain field. Based on the fatigue damage mechanism of composite laminates and stiffness degradation model, the variation regularity of cycle strain of composite pressure vessel is studied and the residual stiffness during damage is obtained.

Zhang, Xiaojing; Zhang, Boming; Wu, Zhanjun

2007-07-01

221

PRESSURIZATION OF CONTAINMENT VESSELS FROM PLUTONIUM OXIDE CONTENTS  

SciTech Connect

Transportation and storage of plutonium oxide is typically done using a convenience container to hold the oxide powder which is then placed inside a containment vessel. Intermediate containers which act as uncredited confinement barriers may also be used. The containment vessel is subject to an internal pressure due to several sources including; (1) plutonium oxide provides a heat source which raises the temperature of the gas space, (2) helium generation due to alpha decay of the plutonium, (3) hydrogen generation due to radiolysis of the water which has been adsorbed onto the plutonium oxide, and (4) degradation of plastic bags which may be used to bag out the convenience can from a glove box. The contributions of these sources are evaluated in a reasonably conservative manner.

Hensel, S.

2012-03-27

222

Testing of Full Scale Flight Qualified Kevlar Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Many decades ago NASA identified a need for low-mass pressure vessels for carrying various fluids aboard rockets, spacecraft, and satellites. A pressure vessel design known as the composite overwrapped pressure vessel (COPV) was identified to provide a weight savings over traditional single-material pressure vessels typically made of metal and this technology has been in use for space flight applications since the 1970's. A typical vessel design consisted of a thin liner material, typically a metal, overwrapped with a continuous fiber yarn impregnated with epoxy. Most designs were such that the overwrapped fiber would carry a majority of load at normal operating pressures. The weight advantage for a COPV versus a traditional singlematerial pressure vessel contributed to widespread use of COPVs by NASA, the military, and industry. This technology is currently used for personal breathing supply storage, fuel storage for auto and mass transport vehicles and for various space flight and aircraft applications. The NASA Engineering and Safety Center (NESC) was recently asked to review the operation of Kevlar 2 and carbon COPVs to ensure they are safely operated on NASA space flight vehicles. A request was made to evaluate the life remaining on the Kevlar COPVs used on the Space Shuttle for helium and nitrogen storage. This paper provides a review of Kevlar COPV testing relevant to the NESC assessment. Also discussed are some key findings, observations, and recommendations that may be applicable to the COPV user community. Questions raised during the investigations have revealed the need for testing to better understand the stress rupture life and age life of COPVs. The focus of this paper is to describe burst testing of Kevlar COPVs that has been completed as a part of an the effort to evaluate the effects of ageing and shelf life on full scale COPVs. The test articles evaluated in this discussion had a diameter of 22 inches for S/N 014 and 40 inches for S/N 011. The time between manufacture and burst was 28 and 22 years. Visual inspection, shearography, heat soak thermography and borescope inspection were performed on vessel S/N 011 and all but shearography was performed on S/N 014 before they were tested and details of this work can be found in a companion paper titled, "Nondestructive Methods and Special Test Instrumentation Supporting NASA Composite Overwrapped Pressure Vessel Assessments." The vessels were instrumented so that measurements could be made to aid in the understanding of vessel response. Measurements made on the test articles included girth, boss displacement, internal volume, multiple point strain, full field strain, eddy current, acoustic emission (AE) pressure and temperature. The test article before and during burst is shown with the pattern used for digital image correlation full field strain measurement blurring as the vessel fails.

Greene, Nathanael; Saulsberry, Regor; Yoder, Tommy; Forsyth, Brad; Thesken, John; Phoenix, Leigh

2007-01-01

223

Dynamic loads from reactor pressure vessel core melt-through under high primary systems pressure  

SciTech Connect

Estimates are presented of the thermal-hydraulic load acting on a pressurized water reactor pressure vessel and its support girder after lower head failure at high pressure (227 MPa). The estimates are based on one-dimensional calculations performed with the RELAP5/MOD3 transient analysis thermal-hydraulics code. The information obtained provides a force-function input for structural dynamic calculations of an increased containment. On the assumption of a global circumferential rupture of the vessel lower head, the computations show a load peak of 340 MN and a continuing load of 160 MN acting on the vessel support ring. The analysis is related to the containment concept of Eibl, Kessler, and Hennies, which is aimed at developing passive mechanisms that can safely confine core-melt consequences.

Jacobs, G. [Forschungszentrum Karlsruhe (Germany)

1995-09-01

224

Design and analysis of piping, pressure vessels, and components  

SciTech Connect

This book contains 26 selections. Some of the titles are: Pipe rupture hardware minimization in pressurized water reactor systems; Development of shell and tube LNG vaporizers using titanium heat transfer tubes; Design improvements of an in-line process gas desuperheater in high temperature service; and Modes of failure-primary and secondary stresses.

Short, W.E.; Dermenjian, A.A.; McGrattan, R.J.; Bhandari, S.K.

1987-01-01

225

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

226

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-Hipertensión)  

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-Rodríguez, José I; Agudo-Conde, Cristina; Gamella-Pozuelo, Luis; Perretta-Tejedor, Nuria; Martínez-Salgado, Carlos; García-Ortiz, Luis

2014-01-01

227

Prediction of Composite Pressure Vessel Failure Location using Fiber Bragg Grating Sensors  

NASA Technical Reports Server (NTRS)

Ten composite pressure vessels were instrumented with fiber Bragg grating sensors in order to assess the strain levels of the vessel under various loading conditions. This paper and presentation will discuss the testing methodology, the test results, compare the testing results to the analytical model, and present a possible methodology for predicting the failure location and strain level of composite pressure vessels.

Kreger, Steven T.; Taylor, F. Tad; Ortyl, Nicholas E.; Grant, Joseph

2006-01-01

228

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

229

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

Microsoft Academic Search

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests

S M Aceves; J Martinez-Frias; F Espinosa-Loza

2002-01-01

230

Performance Evaluation Tests of Insulated Pressure Vessels for Vehicular Hydrogen Storage  

Microsoft Academic Search

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests

S M Aceves; J Martinez-Frias; F Espinoza-Loza

2002-01-01

231

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

232

Thin-metal lined PRD 49-III composite vessels. [evaluation of pressure vessels for burst strength and fatigue performance  

NASA Technical Reports Server (NTRS)

Filament wound pressure vessels of various configurations were evaluated for burst strength and fatigue performance. The dimensions and characteristics of the vessels are described. The types of tests conducted are explained. It was determined that all vessels leaked in a relatively few cycles (20 to 60 cycles) with failure occurring in all cases in the metallic liner. The thin liner would de-bond from the composite and buckling took place during depressurization. No composite failures or indications of impeding composite failures were obtained in the metal-lined vessels.

Hoggatt, J. T.

1974-01-01

233

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

SciTech Connect

We are working on developing an alternative technology for storage of hydrogen or natural gas on light-duty vehicles. This technology has been titled insulated pressure vessels. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept either liquid fuel or ambient-temperature compressed fuel. Insulated pressure vessels offer the advantages of cryogenic liquid fuel tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for fuel liquefaction and reduced evaporative losses). The work described in this paper is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen or LNG. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining insulated pressure vessel certification.

Aceves, S M; Martinez-Frias, J; Espinosa-Loza, F; Schaffer, R; Clapper, W

2002-05-22

234

Pressure measurements of nonplanar stress waves  

Microsoft Academic Search

Measuring the pressure of non-planar stress waves using thin piezo-resistive gages requires correcting for induced strain parallel to the sensing elements. A technique has been developed that permits such measurements, making use of a dual element gage. One element, Manganin, is sensitive to stress both parallel and perpendicular to the sensing element; the other element, Constantan, is primarily sensitive to

G. H. Carlson; J. A. Charest

1981-01-01

235

Nondestructive Pressure Measurement in Vessels Using Rayleigh Waves and LCR Waves  

Microsoft Academic Search

In order to avoid the potential safety problems caused by applying traditional pressure measurement methods in vessels, a nondestructive pressure measurement method is presented. This method utilizes ultrasonic Rayleigh waves and critically refracted longitudinal waves (LCr waves). Considering the effect of pressure and temperature of the vessel on both the wave speed and the propagation distance of ultrasonic, a modified

Zhangwei Ling; Hongjian ZhangandHongliang Zhou; Hongliang Zhou

2008-01-01

236

Evaluation of embedded FBGs in composite overwrapped pressure vessels for strain based structural health monitoring  

NASA Astrophysics Data System (ADS)

The increased use of composite overwrapped pressure vessels (COPVs) in space and commercial applications, and the explosive nature of pressure vessel ruptures, make it crucial to develop techniques for early condition based damage detection. The need for a robust health monitoring system for COPVs is a high priority since the mechanisms of stress rupture are not fully understood. Embedded Fiber Bragg Grating (FBG) sensors have been proposed as a potential solution that may be utilized to anticipate and potentially avoid catastrophic failures. The small size and light weight of optical fibers enable manufactures to integrate FBGs directly into composite structures for the purpose of structural health monitoring. A challenging aspect of embedding FBGs within composite structures is the risk of potentially impinging the optical fiber while the structure is under load, thus distorting the optical information to be transferred. As the COPV is pressurized, an embedded optical sensor is compressed between the expansion of the inner bottle, and the outer overwrap layer of composite. In this study, FBGs are installed on the outer surface of a COPV bottle as well as embedded underneath a composite overwrap layer for comparison of strain measurements. Experimental data is collected from optical fibers containing multiple FBGs during incremental pressurization cycles, ranging from 0 to 10,000 psi. The graphical representations of high density strain maps provide a more efficient process of monitoring structural integrity. Preliminary results capture the complex distribution of strain, while furthering the understanding of the failure mechanisms of COPVs.

Pena, Francisco; Strutner, Scott M.; Richards, W. Lance; Piazza, Anthony; Parker, Allen R.

2014-03-01

237

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

Microsoft Academic Search

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available

S. M. Aceves; J. Martinez-Frias; O Garcia-Villazana; F Espinosa-Loza

2001-01-01

238

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

239

Analysis of fracture surfaces of reactor pressure-vessel steels  

SciTech Connect

The fracture surfaces of three A533-B pressure-vessel steels have been analyzed using Auger analysis scanning electron microscopy and x-ray microanalysis. The steels included both weld and plate materials with differing radiation sensitivity. The unirradiated specimens were fractured under different conditions to give both ductile and brittle failure modes. The research showed that the copper and carbon concentrations were higher at the fracture surfaces. Very fine precipitates of molybdenum, phosphorus, and sulfur were observed on ductile fracture surfaces of all materials. However, the amount and type of precipitates varied among materials. Auger analysis and x-ray microanalysis provided consistent results and allowed detection of most of the impurity or alloying elements which have been related to radiation sensitivity of A533-B steels.

deHodgins, O.C. (Univ. of Virginia, Charlottesville); Shriver, B.L.

1982-01-01

240

Effect of aging on properties of pressure vessel steels  

SciTech Connect

Manganese-molybdenum-nickel steels are used in nuclear pressure vessels operating at temperatures up to 350/sup 0/C. The effects of thermal ageing in the temperature range 300-550/sup 0/C for durations up to 2 x 10/sup 4/ h have been studied in conventionally quenched and tempered and simulated heat-affected-zone (HAZ) microstructural conditions. Quantitative fractography and Auger spectroscopy have been used to relate changes in mechanical properties with changes in fracture mode and grain boundary chemistry. Aging increases the ductile-brittle transition temperature by an amount dependent on material, prior heat treatment, aging temperature and time. Embrittlement is associated with segregation of phosphorus to grain boundaries and is modelled using McLean's approach to equilibrium segregation.

Druce, S.G.; Gage, G.; Jordan, G.

1986-04-01

241

Macrosegregation and Microstructural Evolution in a Pressure-Vessel Steel  

NASA Astrophysics Data System (ADS)

This work assesses the consequences of macrosegregation on microstructural evolution during solid-state transformations in a continuously cooled pressure-vessel steel (SA508 Grade 3). Stark spatial variations in microstructure are observed following a simulated quench from the austenitization temperature, which are found to deliver significant variations in hardness. Partial-transformation experiments are used to show the development of microstructure in segregated material. Evidence is presented which indicates the bulk microstructure is not one of upper bainite, as it has been described in the past, but one comprised of Widmanstätten ferrite and pockets of lower bainite. Segregation is observed on three different length scales, and the origins of each type are proposed. Suggestions are put forward for how the segregation might be minimized, and its detrimental effects suppressed by heat treatments.

Pickering, E. J.; Bhadeshia, H. K. D. H.

2014-06-01

242

The behavior of shallow flaws in reactor pressure vessels  

SciTech Connect

Both analytical and experimental studies have shown that the effect of crack length, a, on the elastic-plastic toughness of structural steels is significant. The objective of this report is to recommend those research investigations that are necessary to understand the phenomenon of shallow behavior as it affects fracture toughness so that the results can be used properly in the structural margin assessment of reactor pressure vessels (RPVs) with flaws. Preliminary test results of A 533 B steel show an elevated crack-tip-opening displacement (CTOD) toughness similar to that observed for structural steels tested at the University of Kansas. Thus, the inherent resistance to fracture initiation of A 533 B steel with shallow flaws appears to be higher than that used in the current American Society of Mechanical Engineers (ASME) design curves based on testing fracture mechanics specimens with deep flaws. If this higher toughness of laboratory specimens with shallow flaws can be transferred to a higher resistance to failure in RPV design or analysis, then the actual margin of safety in nuclear vessels with shallow flaws would be greater than is currently assumed on the basis of deep-flaw test results. This elevation in toughness and greater resistance to fracture would be a very desirable situation, particularly for the pressurized-thermal shock (PTS) analysis in which shallow flaws are assumed to exist. Before any advantage can be taken of this possible increase in initiation toughness, numerous factors must be analyzed to ensure the transferability of the data. This report reviews those factors and makes recommendations of studies that are needed to assess the transferability of shallow-flaw toughness test results to the structural margin assessment of RPV with shallow flaws. 14 refs., 8 figs.

Rolfe, S.T. (Kansas Univ., Lawrence, KS (United States))

1991-11-01

243

Stress concentration factors for circular, reinforced penetrations in pressurized cylindrical shells. Ph.D. Thesis - Virginia Univ.  

NASA Technical Reports Server (NTRS)

The effect on stresses in a cylindrical shell with a circular penetration subject to internal pressure was investigated in thin, shallow linearly, elastic cylindrical shells. Results provide numerical predictions of peak stress concentration factors around nonreinforced and reinforced penetrations in pressurized cylindrical shells. Analytical results were correlated with published formulas, as well as theoretical and experimental results. An accuracy study was made of the finite element program for each of the configurations considered important in pressure vessel technology. A formula is developed to predict the peak stress concentration factor for analysis and/or design in conjunction with the ASME Boiler and Pressure Vessel Code.

Ramsey, J. W., Jr.

1975-01-01

244

D-Zero Central Calorimeter Pressure Vessel and Vacuum Vessel Safety Notes  

SciTech Connect

The relief valve and relief piping capacity was calculated to be 908 sefm air. This exceeds all relieving conditions. The vessel also has a rupture disc with a 2640 scfm air stamped capacity. In order to significantly decrease the amount of time required to fill the cryostats, it is desired to raise the setpoint of the 'operating' relief valve on the argon storage dewar to 20 psig from its existing 16 psig setting. This additional pressure increases the flow to the cryostats and will overwhelm the relief capacity if the temperature of the modules within these vessels is warm enough. Using some conservative assumptions and simple calculations within this note, the maximum average temperature that the modules within each cryostat can be at prior to filling from the storage dewar with liquid argon is at least 290 K. The average temperature of the module mass for any of the three cryostats can be as high as 290 K prior to filling that particular cryostat. This should not be confused with the average temperature of a single type or location which is useful in protecting the modules-not necessarily the vessel itself. A few modules of each type and at different elevations should be used in an average which would account for the different weights of each module. Note that at 290 K, the actual flow of argon through the relief valve and the rupture disk was under the maximum theoretical flows for each relief device. This means that the bulk temperature could actually have been raised to flow argon through the reliefs at their maximum capacity. Therefore, the temperature of 290 K is a conservative value for the calculated flow rate of 12.3 gpm. Safeguards in addition to and used in conjunction with operating procedures shall be implemented in such a way so that the above temperature limitation is not exceeded and such that it is exclusive of the programmable logic controller (PLC). One suggestion is using a toggle switch for each cryostat mounted in the PLC I/O box which would maintain control of the signals to open the cold fill valves of each cryostat. With the safeguards in place while carefully monitoring the temperatures during a cooldown cycle in each cryostat, the set pressure in the argon storage dewar can safely be increased to 20 psig.

Rucinski, R.; Luther, R.; /Fermilab

1990-10-25

245

Is pressure stressful? The impact of pressure on the stress response and category learning.  

PubMed

We examined the basic question of whether pressure is stressful. We proposed that when examining the role of stress or pressure in cognitive performance, it is important to consider the type of pressure, the stress response, and the aspect of cognition assessed. In Experiment 1, outcome pressure was not experienced as stressful but did lead to impaired performance on a rule-based (RB) category-learning task, but not on a more procedural information-integration (II) task. In Experiment 2, the addition of monitoring pressure resulted in a modest stress response to combined pressure and impairment on both tasks. Across experiments, higher stress appraisals were associated with decreased performance on the RB, but not on the II, task. In turn, higher stress reactivity (i.e., heart rate) was associated with enhanced performance on the II, but not on the RB, task. This work represents an initial step toward integrating the stress cognition and pressure cognition literatures and suggests that integrating these fields may require consideration of the type of pressure, the stress response, and the cognitive system mediating performance. PMID:24129964

McCoy, Shannon K; Hutchinson, Steven; Hawthorne, Lauren; Cosley, Brandon J; Ell, Shawn W

2014-06-01

246

Chronic High Pressure-Induced Arterial Oxidative Stress  

PubMed Central

Regardless of the underlying pathological mechanisms oxidative stress seems to be present in all forms of hypertension. Thus, we tested the hypothesis that chronic presence of high pressure itself elicits increased arterial O2.? production. Hypertension was induced in rats by abdominal aortic banding (Ab). Rats with Ab had elevated pressure in vessels proximal and normal pressure in vessels distal to the coarctation, yet both vascular beds were exposed to the same circulating factors. Compared to normotensive hind limb arteries (HLAs) hypertensive forelimb arteries (FLAs) exhibited 1) impaired dilations to acetylcholine and the nitric oxide donor S-nitroso-N-acetyl-d,l-penicillamine that were restored by administration of superoxide dismutase; 2) an increased production of O2.? (measured by lucigenin chemiluminescence and ethidium bromide fluorescence) that was inhibited or reduced by superoxide dismutase, the NAD(P)H oxidase inhibitors diphenyleneiodonium and apocynin, or the protein kinase C (PKC) inhibitors chelerythrine and staurosporine or by the angiotensin-converting enzyme (ACE) inhibitor captopril; and 3) increased ACE activity. In organ culture, exposure of isolated arteries of normotensive rats to high pressure (160 mmHg, for 24 hours) significantly increased O2.? production compared to that in arteries exposed to 80 mmHg. High pressure-induced O2.? generation was reduced by inhibitors of ACE and PKC. Incubation of cultured arteries with angiotensin II elicited significantly increased O2.? generation that was inhibited by chelerythrine. Thus, we propose that chronic presence of high pressure itself can elicit arterial oxidative stress, primarily by activating directly a PKC-dependent NAD(P)H oxidase pathway, but also, in part, via activation of the local renin-angiotensin system. PMID:15215177

Ungvari, Zoltan; Csiszar, Anna; Kaminski, Pawel M.; Wolin, Michael S.; Koller, Akos

2004-01-01

247

Shippingport reactor pressure vessel safety analysis report for packaging  

SciTech Connect

The Shippingport Atomic Power Station in Shippingport, Pennsylvania, was constructed in the mid-1950s to demonstrate pressurized water reactor (PWR) technology and to generate electric power. The station was operated for >25 yr by Duquesne Light Company, under contract to the Office of the Deputy Assistant Secretary for Naval Reactors in the U.S. Department of Energy (DOE). In later years, experimentation was performed at the facility regarding light water breeder reactor (LWBR) technology. A total of three separate reactor cores were operated at the facility (two PWR and one LWBR). The Shippingport reactor reached the end of its design life and was turned over for decommissioning in 1984. Prior to the start of decommissioning, all fuel was removed and shipped off site. The integral reactor pressure vessel/neutron shield tank (RPV/NST) was then filled with a lightweight concrete material. The filled RPV/NST was removed as a unit and transported to the DOE Hanford reservation in Richland, Washington, for interment.

Ferrell, P.C. [Westinghouse Hanford Co., Richland, WA (United States)

1996-12-31

248

Pressure vessel construction for a metal oxide-hydrogen battery  

SciTech Connect

This patent describes a metal oxide-hydrogen battery. It comprises: an outer vessel, a battery cell disposed within the vessel, the vessel including a flexible inner liner of a material impervious to the passage of hydrogen gas, and an outer layer of fiber reinforced resin disposed in contact with the inner liner, a fitting disposed within an opening in a wall of the vessel and having an opening therethrough, and sealing means for sealing the inner liner to the fitting.

Jones, K.R.; Sindorf, J.F.

1990-05-08

249

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

2014-12-01

250

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

251

Pressure measurements of nonplanar stress waves  

SciTech Connect

A useful gage has been developed for measuring pressure of nonplanar or obliquely incident stress waves. The measurements made with these gages are not as precise as direct strain gage measurements, but are very good considering the conditions under which these gages are used. We feel a need to further develop our ability to measure nonplanar stress waves in the 0 to 10 kbar range. Carbon or ytterbium will probably be chosen for the sensing element.

Carlson, G.H.; Charest, J.A.

1981-02-27

252

INTERNAL WALL COOLING IN PRESSURE VESSELS EXPOSED TO EXTERNAL FIRE IMPINGEMENT  

Microsoft Academic Search

In many applications there is a requirement to retard accidental heating of pressure vessel shells so that loss of pressure carrying capacity due to increasing shell temperature does not occur. For example, hazardous commodity transport and storage vessels are usually thermally insulated so that in the event of accidental fire the shell is not exposed to the full heating effects

A. M. BIRK

1989-01-01

253

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

Code of Federal Regulations, 2013 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...

2013-10-01

254

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

Code of Federal Regulations, 2012 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...

2012-10-01

255

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

256

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

257

Characterizing the effects of cladding on semi-elliptical longitudinal surface flaws in cylindrical vessels subjected to internal pressure  

SciTech Connect

Flaws on the inside surface of cladded reactor vessels are often analyzed by modelling the carbon steel base metal without consideration of a layer of stainless steel cladding material, thus ignoring the effects of this bimetallic discontinuity. Adding cladding material to the inside surface of a finite element model of a vessel raises concerns regarding adequate mesh refinement in the vicinity of the base metal/cladding interface. This paper presents results of three-dimensional linear stress analysis that has been performed to obtain stress intensity factors for clad and unclad reactor vessels subjected to internal pressure loading. The study concentrates on semi-elliptical longitudinal surface flaws with a 6 to 1 length-to-depth ratio and flaw depths of 1/8 and 1/4 of the base metal thickness. Various meshing schemes are evaluated for modelling the crack front profile, with particular emphasis on the region near the inside surface and at the base metal/cladding interface. The shape of the crack front profile through the cladding layer and the number of finite elements used to discretize the cladding thickness are found to have a significant influence on typical fracture mechanic measures of the crack tip stress fields. Results suggest that the stress intensity factor at the inner surface of a cladded vessel may be affected as much by the finite element mesh near the surface as by the material discontinuity between the two parts of the structure.

Killian, D.E.; Yoon, K.K. [Framatome Technologies, Lynchburg, VA (United States)

1996-12-01

258

Distributed sensing of Composite Over-wrapped Pressure Vessels using Fiber-Bragg Gratings  

NASA Technical Reports Server (NTRS)

The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. These materials offer a wide range of possibilities within the space program. But before they can be reliably incorporated into space flight applications, additional understanding is required in the area of damage tolerance of these materials. Efforts to enhance our understanding of failure modes, mechanical properties, long and short term environmental effects, cyclic damage accumulation and residual strength are needed. Thus we have employed the use of fiber optical sensors which offers an excellent opportunity exploit these materials through monitoring and characterizing their mechanical properties and thus the integrity of structures made from such materials during their life cycle. Use of these optical innovations provides an insight into structures that have not been available in the past, as well as the technology available to provide real time health monitoring throughout its life cycle. The embedded fiber optical sensor shows a clearly detectable sensitivity to changes in the near strain and stress fields of the host structure promoted by mechanical or thermal loading or, in certain conditions, structural damage. The last ten years have seen a large increase in the use of FBG based monitoring systems in a broad range of applications. Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in composite structures. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 4400 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Grant, Joseph

2005-01-01

259

A survey of pressure vessel code compliance methods for superconducting radio frequency cryomodules  

NASA Astrophysics Data System (ADS)

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.

Peterson, Thomas J.; Hayano, Hitoshi; Jensch, Kay; Kako, Eiji; Klebaner, Arkadiy; Mammosser, John; Matheisen, Axel; Nakai, Hirotaka; Nicol, Thomas H.; Theilacker, Jay; Yamamoto, Akira

2012-06-01

260

Pressure vessel fracture, fatigue, and life management: PVP-Volume 233  

SciTech Connect

This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on the effects of aging. The papers are organized in the following five areas: (1) pressure vessel life management; (2) fracture characterization using local and dual-parameter approaches; (3) stratification and thermal fatigue; (4) creep, fatigue, and fracture; and (5) integrated approach to integrity assessment of pressure components. Separate abstracts were prepared for 39 papers in this conference.

Bhandari, S.; Milella, P.P.; Pennell, W.E. (eds.)

1992-01-01

261

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

262

46 CFR 52.01-2 - Adoption of section I of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2010 CFR

... Adoption of section I of the ASME Boiler and Pressure Vessel Code. 52...CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-2 Adoption of section I of the ASME Boiler and Pressure Vessel Code....

2010-10-01

263

46 CFR 52.01-2 - Adoption of section I of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2013 CFR

... Adoption of section I of the ASME Boiler and Pressure Vessel Code. 52...CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-2 Adoption of section I of the ASME Boiler and Pressure Vessel Code....

2013-10-01

264

46 CFR 52.01-2 - Adoption of section I of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2011 CFR

... Adoption of section I of the ASME Boiler and Pressure Vessel Code. 52...CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-2 Adoption of section I of the ASME Boiler and Pressure Vessel Code....

2011-10-01

265

46 CFR 52.01-2 - Adoption of section I of the ASME Boiler and Pressure Vessel Code.  

Code of Federal Regulations, 2012 CFR

... Adoption of section I of the ASME Boiler and Pressure Vessel Code. 52...CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-2 Adoption of section I of the ASME Boiler and Pressure Vessel Code....

2012-10-01

266

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

Code of Federal Regulations, 2013 CFR

...Adoption of section IV of the ASME Boiler and Pressure Vessel Code. 53...CONTINUED) MARINE ENGINEERING HEATING BOILERS General Requirements § 53.01-3 Adoption of section IV of the ASME Boiler and Pressure Vessel Code....

2013-10-01

267

ANSI/AIAA S-081A, Pressure Vessel Standards Implementation Guidelines  

NASA Technical Reports Server (NTRS)

The stress rupture specification for Composite Overwrapped Pressure Vessels (COPV) is discussed. The composite shell of the COPV shall be designed to meet the design life considering the time it is under sustained load. A Mechcanical Damage Control Plan (MDCP) shall be created and implemented that assures the COPV will not fail due to mechanical damage due to manufacturing, testing, shipping, installation, or flight. Proven processes and procedures for fabrication and repair shall be used to preclude damage or material degradation during material processing, manufacturing operations, and refurbushment.Selected NDI techniques for the liner and/or boss(es) shall be performed before overwrapping with composite. When visual inspection reveals mechanical damage or defects exceeding manufacturing specification levels (and standard repair procedures), the damaged COPV shall be submitted to a material review board (MRB) for disposition. Every COPV shall be subjected to visual and other non-destructive inspection (NDI), per the inspection plan.

Greene, Nathanael J.

2009-01-01

268

Pressure measurements of nonplanar stress waves  

SciTech Connect

Measuring the pressure of non-planar stress waves using thin piezo-resistive gages requires correcting for induced strain parallel to the sensing elements. A technique has been developed that permits such measurements, making use of a dual element gage. One element, Manganin, is sensitive to stress both parallel and perpendicular to the sensing element; the other element, Constantan, is primarily sensitive to stress parallel to the sensing element. The change in resistance in the Constantan element is thereby used to correct for the strain effect parallel to the Manganin element axis. Individual and combined Manganin and Constantan elements were subjected to controlled gas gun impact tests in the pressure and strain ranges of 0 to 50 kbar and 0 to 7%, respectively. From planar wave tests, the piezoresistivity of Constantan was found to be positive but negligible in comparison with Manganin. From combined stress and strain environments, the compression and tension strain factors of Constantan were found to be constant and equal to 2.06. The strain factors of Manganin were found to increase from 1.2 to 2.0 asymptotically in the range of 0 to 3% strain. It was experimentally demonstrated that, because of the closeness of their strain factors, the Manganin-Constantan dual element gage could be used in the differential recording mode to yield pressure directly. In this mode the gage is a strain compensating gage. Analytical techniques have also been developed for more accurate strain compensation.

Carlson, G.H.; Charest, J.A.

1981-01-01

269

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

270

Evaluation of Progressive Failure Analysis and Modeling of Impact Damage in Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

NASA White Sands Test Facility (WSTF) is leading an evaluation effort in advanced destructive and nondestructive testing of composite pressure vessels and structures. WSTF is using progressive finite element analysis methods for test design and for confirmation of composite pressure vessel performance. Using composite finite element analysis models and failure theories tested in the World-Wide Failure Exercise, WSTF is able to estimate the static strength of composite pressure vessels. Additionally, test and evaluation on composites that have been impact damaged is in progress so that models can be developed to estimate damage tolerance and the degradation in static strength.

Sanchez, Christopher M.

2011-01-01

271

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

Code of Federal Regulations, 2012 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...

2012-10-01

272

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

273

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

274

Fitness-for-service assessment of spherical pressure vessels with hot spots  

Microsoft Academic Search

Spherical shapes are used in industry as hemispherical vessel heads or high-pressure storage vessels due to the inherent strength associated with the shape. Structural integrity of such components needs to be evaluated periodically to prevent failure of the vessels under operating conditions. The paper develops a method for Level 2 (as defined by API 579 [(2000). Fitness-for-service, API 579. Washington,

P. Tantichattanont; S. M. R. Adluri; R. Seshadri

2007-01-01

275

Recent advances in lightweight, filament-wound composite pressure vessel technology  

NASA Technical Reports Server (NTRS)

A review of recent advances is presented for lightweight, high-performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single-cycle burst and cyclic fatigue loading. Filament-wound fiber/epoxy composite vessels were made from S-glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessel structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all-titanium pressure vessels. Significant findings in each area are summarized including data from current NASA-Lewis Research Center contractual and in-house programs.

Lark, R. F.

1977-01-01

276

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

Code of Federal Regulations, 2010 CFR

... 2010-10-01 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,...

2010-10-01

277

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

278

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

279

Study of tearing behaviour of a PWR reactor pressure vessel lower head under severe accident loadings  

Microsoft Academic Search

In PWR severe accident scenarios, involving a relocation of corium (core melt) into the lower head, the possible failure mode of the reactor pressure vessel (RPV), the failure time, the failure location and the final size of the breach are regarded as key elements, since they play an important part in the ex-vessel phase of the accident.Both the LHF and

Vincent Koundy; Cataldo Caroli; Laetitia Nicolas; Philippe Matheron; Jean-Marie Gentzbittel; Michel Coret

2008-01-01

280

High Pressure Composite Overwrapped Pressure Vessel (COPV) Development Tests at Cryogenic Temperatures  

NASA Technical Reports Server (NTRS)

Development tests were conducted to evaluate the performance of 2 COPV designs at cryogenic temperatures. This allows for risk reductions for critical components for a Gaseous Helium (GHe) Pressurization Subsystem for an Advanced Propulsion System (APS) which is being proposed for NASA s Constellation project and future exploration missions. It is considered an advanced system since it uses Liquid Methane (LCH4) as the fuel and Liquid Oxygen (LO2) as the oxidizer for the propellant combination mixture. To avoid heating of the propellants to prevent boil-off, the GHe will be stored at subcooled temperatures equivalent to the LO2 temperature. Another advantage of storing GHe at cryogenic temperatures is that more mass of the pressurized GHe can be charged in to a vessel with a smaller volume, hence a smaller COPV, and this creates a significant weight savings versus gases at ambient temperatures. The major challenge of this test plan is to verify that a COPV can safely be used for spacecraft applications to store GHe at a Maximum Operating Pressure (MOP) of 4,500 psig at 140R to 160R (-320 F to -300 F). The COPVs for these tests were provided by ARDE , Inc. who developed a resin system to use at cryogenic conditions and has the capabilities to perform high pressure testing with LN2.

Ray, David M.; Greene, Nathanael J.; Revilock, Duane; Sneddon, Kirk; Anselmo, Estelle

2008-01-01

281

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

282

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

283

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

284

Workbook for predicting pressure wave and fragment effects of exploding propellant tanks and gas storage vessels  

NASA Technical Reports Server (NTRS)

Technology needed to predict damage and hazards from explosions of propellant tanks and bursts of pressure vessels, both near and far from these explosions is introduced. Data are summarized in graphs, tables, and nomographs.

Baker, W. E.; Kulesz, J. J.; Ricker, R. E.; Bessey, R. L.; Westine, P. S.; Parr, V. B.; Oldham, G. A.

1975-01-01

285

Southwest Research Institute (SwRI) designs, fabricates, and tests pressure vessels,  

E-print Network

simulation chambers Computer strain gage data logger systems Experience High-strength steel, aluminum total of more than 200 years of experience in experi- mental strain measurement and analysis, pressure vessels, submersibles, diving systems, composite housings, titanium instrument housings

Chapman, Clark R.

286

Pressure Vessel and Internals of the International Reactor Innovative and Secure  

SciTech Connect

IRIS (International Reactor Innovative and Secure) is a modular, integral light water cooled, low-to-medium power reactor, which addresses the requirements defined by the US DOE for Generation IV reactors. Its integrated layout features a pressure vessel containing all the main primary circuit components: the internals and the biological shield, here described together with the pressure vessel, plus the steam generators, the pressurizer, and the main coolant pumps described in companion papers. For this reason the pressure vessel is a crucial component of the plant, which deserves the most demanding design effort. The wide inner annulus around the core is exploited to insert steel plates, in order to improve the inner shielding capability up to the elimination of the external biological shielding and to simplify decommissioning activities by having all the irradiated components inside the vessel. (authors)

Lombardi, C.V.; Padovani, E.; Cammi, A. [Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano (Italy); Collado, J.M. [Equipos Nucleares S.A. (Spain); Santoro, R.T.; Barnes, J.M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)

2002-07-01

287

Technology transfer phase of advanced ultrasonic nuclear reactor pressure vessel inspection system. Final report. [PWR; BWR  

SciTech Connect

Between 1976 and 1979, Battelle Northwest (BNW) and Holosonics, Inc., developed and exchanged technology relating to an advanced pressure vessel imaging system under the sponsorship of the Electric Power Research Institute (EPRI). The primary objectives of this program were to develop a system having superior ultrasonic resolution, 3-D isometric imaging capability, and increased inspection speed. Additionally, the system would meet or exceed the requirements of the ASME Boiler and Pressure Vessel Code, Section XI, with the expectation of producing a prototype device.

Neeley, V.I.; Collins, H.D.

1980-09-01

288

Analysis and Design of Cryogenic Pressure Vessels for Automotive Hydrogen Storage  

NASA Astrophysics Data System (ADS)

Cryogenic pressure vessels maximize hydrogen storage density by combining the high pressure (350-700 bar) typical of today's composite pressure vessels with the cryogenic temperature (as low as 25 K) typical of low pressure liquid hydrogen vessels. Cryogenic pressure vessels comprise a high-pressure inner vessel made of carbon fiber-coated metal (similar to those used for storage of compressed gas), a vacuum space filled with numerous sheets of highly reflective metalized plastic (for high performance thermal insulation), and a metallic outer jacket. High density of hydrogen storage is key to practical hydrogen-fueled transportation by enabling (1) long-range (500+ km) transportation with high capacity vessels that fit within available spaces in the vehicle, and (2) reduced cost per kilogram of hydrogen stored through reduced need for expensive structural material (carbon fiber composite) necessary to make the vessel. Low temperature of storage also leads to reduced expansion energy (by an order of magnitude or more vs. ambient temperature compressed gas storage), potentially providing important safety advantages. All this is accomplished while simultaneously avoiding fuel venting typical of cryogenic vessels for all practical use scenarios. This dissertation describes the work necessary for developing and demonstrating successive generations of cryogenic pressure vessels demonstrated at Lawrence Livermore National Laboratory. The work included (1) conceptual design, (2) detailed system design (3) structural analysis of cryogenic pressure vessels, (4) thermal analysis of heat transfer through cryogenic supports and vacuum multilayer insulation, and (5) experimental demonstration. Aside from succeeding in demonstrating a hydrogen storage approach that has established all the world records for hydrogen storage on vehicles (longest driving range, maximum hydrogen storage density, and maximum containment of cryogenic hydrogen without venting), the work also demonstrated a methodology for computationally efficient detailed modeling of cryogenic pressure vessels. The work continues with support of the US Department of Energy to demonstrate a new generation of cryogenic vessels anticipated to improve on the hydrogen storage performance figures previously imposed in this project. The author looks forward to further contributing to a future of long-range, inexpensive, and safe zero emissions transportation.

Espinosa-Loza, Francisco Javier

289

Multilayer Pressure Vessel Materials Testing and Analysis Phase 2  

NASA Technical Reports Server (NTRS)

To provide NASA with a suite of materials strength, fracture toughness and crack growth rate test results for use in remaining life calculations for the vessels described above, Southwest Research Institute® (SwRI®) was contracted in two phases to obtain relevant material property data from a representative vessel. An initial characterization of the strength, fracture and fatigue crack growth properties was performed in Phase 1. Based on the results and recommendations of Phase 1, a more extensive material property characterization effort was developed in this Phase 2 effort. This Phase 2 characterization included additional strength, fracture and fatigue crack growth of the multilayer vessel and head materials. In addition, some more limited characterization of the welds and heat affected zones (HAZs) were performed. This report

Popelar, Carl F.; Cardinal, Joseph W.

2014-01-01

290

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

291

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 heat absorption.

DeLay, Thomas K. (Inventor)

2005-01-01

292

Structural considerations in design of lightweight glass-fiber composite pressure vessels  

NASA Technical Reports Server (NTRS)

The design concepts used for metal-lined glass-fiber composite pressure vessels are described, comparing the structural characteristics of the composite designs with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. The discussion centers around two distinctly different design concepts, which provide the basis for defining metal lined composite vessels as either (1) thin-metal lined, or (2) glass fiber reinforced (GFR). Both concepts are described and associated development problems are identified and discussed. Relevant fabrication and testing experience from a series of NASA-Lewis Research Center development efforts is presented.

Faddoul, J. R.

1973-01-01

293

HFIR Vessel Pressure/Temperature Limits Corresponding to the Upgrade Design  

SciTech Connect

Pressure/temperature limits were calculated for the HFIR pressure vessel for a temperature range of 40 to 120 F. New values were necessary for the upgrade design of the reactor and were calculated using a probabilistic fracture mechanics approach that accounts for the success of periodic hydrostatic proof testing. The range of calculated pressure corresponding to the specific range of temperatures is 634 to 987 psi for ''pressure safety limit'' and 564 to 895 psi for the ''limiting conditions for operation.''

Cheverton, R.D.; Bryson, J.W.

2000-03-01

294

Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment  

Microsoft Academic Search

The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding\\u000a automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F)\\u000a and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure

P. K. Liaw; W. A. Logsdon; J. A. Begley

1989-01-01

295

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

296

Cross Section of Coils & Shielding Vessels; Stresses & Deformations Preliminary Results  

E-print Network

the five resistive and upstream eight superconducting coils of Magnet Design IDS120h. Most annular disks, including conical one). #12; Fig. 3: Isometric view (longitudinal axis compressed) of inner and outer shielding vessels (blue) of design "Shields50mm.mph". Outlined are the five resistive and upstream eight

McDonald, Kirk

297

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

298

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

299

HFIR Vessel Maximum Permissible Pressures for Operating Period 26 to 50 EFPY (100 MW)  

SciTech Connect

Extending the life of the HFIR pressure vessel from 26 to 50 EFPY (100 MW) requires an updated calculation of the maximum permissible pressure for a range in vessel operating temperatures (40-120 F). The maximum permissible pressure is calculated using the equal-potential method, which takes advantage of knowledge gained from periodic hydrostatic proof tests and uses the test conditions (pressure, temperature, and frequency) as input. The maximum permissible pressure decreases with increasing time between hydro tests but is increased each time a test is conducted. The minimum values that occur just prior to a test either increase or decrease with time, depending on the vessel temperature. The minimum value of these minimums is presently specified as the maximum permissible pressure. For three vessel temperatures of particular interest (80, 88, and 110 F) and a nominal time of 3.0 EFPY(100 MVV)between hydro tests, these pressures are 677, 753, and 850 psi. For the lowest temperature of interest (40 F), the maximum permissible pressure is 295 psi.

Cheverton, R.D.; Inger, J.R.

1999-01-01

300

Distributed Sensing of Carbon-Epoxy Composites and Filament Wound Pressure Vessels Using Fiber-Bragg Gratings  

NASA Technical Reports Server (NTRS)

Multiple Fiber Bragg-gratings are embedded in carbon-epoxy laminates as well as in composite wound pressure vessel. Structural properties of such composites are investigated. The measurements include stress-strain relation in laminates and Poisson's ratio in several specimens with varying orientation of the optical fiber Bragg-sensor with respect to the carbon fiber in an epoxy matrix. Additionally, fiber Bragg gratings are bonded on the surface of these laminates and cylinders fabricated out of carbon-epoxy composites and multiple points are monitored and compared for strain measurements at several locations.

Grant, J.; Kaul, R.; Taylor, S.; Myer, G.; Jackson, K.; Osei, A.; Sharma, A.

2003-01-01

301

Influence of lumen shape and vessel geometry on plaque stresses: possible role in the increased vulnerability of a remodelled vessel and the “shoulder” of a plaque  

PubMed Central

Objective: To use finite element modelling to look at the impact of lumen shape and vessel geometry on stress distribution in a vessel. Methods: A finite element model of an atherosclerotic plaque in a coronary artery was created and a non-linear analysis with Ogden strain energy function was done. The three most common shapes seen in an artery with an eccentric plaque—namely an elliptical lumen inside a circular vessel (A), a circular lumen inside an elliptical vessel, typical of a vessel with positive remodelling (B), and a circular lumen inside a circular vessel (C)—were modelled with and without lipid. Stress was analysed in the region of the fibrous cap separating the lumen from the plaque and the region of maximum stress along the circumference of the lumen was noted. Results: In a normal circular shaped coronary artery, the haemodynamic stresses were uniformly distributed all around the circle. However, if the circle was changed to an ellipse, the stresses were redistributed along the major axis and dropped substantially along the minor axis. The stresses in a positively remodelled vessel (B) were significantly greater than in A and C, by almost 100%. Moreover, the haemodynamic stresses increased significantly towards the major axis or the shoulder in A and B, due to lumen shape and vessel geometry alone, even in the absence of lipid in the model. The stresses also had a direct relation with the thickness of the lipid pool and an inverse relation with cap thickness and lumen stenosis. Conclusions: The increased vulnerability of the shoulder region of a plaque and a remodelled coronary artery are due, apart from other factors, to increased biomechanical stresses as a result of lumen shape and vessel geometry. PMID:15774611

Krishna Kumar, R; Balakrishnan, K R

2005-01-01

302

J-integral patch for finite element analysis of dynamic fracture due to impact of pressure vessels  

NASA Technical Reports Server (NTRS)

Prediction of whether a pressurized cylinder will fail catastrophically when impacted by a projectile has important applications ranging from perforation of an airplane's skin by a failed turbine blade to meteorite impact of a space station habitation module. This report summarizes the accomplishment of one task for a project whose aim is to simulate numerically the outcome of a high velocity impact of pressure vessels. A finite element patch covering the vicinity of a growing crack has been constructed to estimate the J-integral (crack driving force) during the impact. Explicit expressions for the J-integral through the nodal values of displacement, strain, and stress have been written. The patch is to be used repeatedly to estimate the amount of crack growth during the time of the impact. The resulting crack size is to be compared to an estimated critical crack size for the pressurized cylinder.

Kunin, Boris I.

1993-01-01

303

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

304

Development of composite pressure vessels with nonmetallic liners  

NASA Astrophysics Data System (ADS)

Brunswick composites has developed metallic liners and composite cylinders for use in military and civilian aircraft, missiles, inflation systems and space applications. At present an all-composite pressurant tank is being developed for use in the natural gas vehicle (NGV). This tank uses a plastic liner of high density polyethylene (HDPE) as a leak-tight permeation barrier. Tank characteristics and testing are described. HDPE reduces cost, meets all space and missile pressurant tank requirements, and is readily availble. Test results indicate that an all-composite pressurant tank with an HDPE liner provides a tough, high cycle life, lightweight, environmentally stable pressurant tank with very low permeability. HDPE offers a viable, low cost alternative to conventional metal liners as well as many design advantages.

Murray, Con F.; Newhouse, Norman L.; Schimenti, John D.; Tiller, Dale B.

1992-07-01

305

Monitoring of Radiation Load of Pressure Vessels of Russian Vver in Compliance with License Amendments  

NASA Astrophysics Data System (ADS)

The neutron fluence, fluence rate and spectrum monitoring of reactor pressure vessels of Russian VVERs is considered under view of license amendments. Such monitoring over the whole reactor operation of all VVER units based on validated calculational procedures and tested by ex-vessel measurements at every unit is a matter of present analysis. Results, some of which are presented in this paper, allow us to improve uncertainty of fluence monitoring and fluence prediction on end of RPV lifetime.

Borodkin, G.; Khrennikov, N.; Gordon, B.; Borodkin, P.; Miroshnichenko, M.; Khlebtsevich, V.; Ryabinin, Yu.

2009-08-01

306

Thermal-hydraulic analyses of pressurized-thermal-shock-induced vessel ruptures. [PWR  

SciTech Connect

A severe overcooling transient was postulated to produce vessel wall temperatures below the nil-ductility transition temperature which in conjunction with system repressurization, led to vessel rupture at the core midplane. Such transients are referred to as pressurized-thermal-shock transients. A wide range of vessel rupture sizes were investigated to assess the emergency system's ability to cool the fuel rods. Ruptures greater than approximately 0.015 m/sup 2/ produced flows greater than those of the emergency system and resulted in core uncovery and subsequent core damage.

Dobranich, D.

1982-05-01

307

Reactor pressure vessel head vents and methods of using the same  

DOEpatents

Internal head vents are usable in nuclear reactors and include piping inside of the reactor pressure vessel with a vent in the reactor upper head. Piping extends downward from the upper head and passes outside of the reactor to permit the gas to escape or be forcibly vented outside of the reactor without external piping on the upper head. The piping may include upper and lowers section that removably mate where the upper head joins to the reactor pressure vessel. The removable mating may include a compressible bellows and corresponding funnel. The piping is fabricated of nuclear-reactor-safe materials, including carbon steel, stainless steel, and/or a Ni--Cr--Fe alloy. Methods install an internal head vent in a nuclear reactor by securing piping to an internal surface of an upper head of the nuclear reactor and/or securing piping to an internal surface of a reactor pressure vessel.

Gels, John L; Keck, David J; Deaver, Gerald A

2014-10-28

308

Aging results for PRD 49 III/epoxy and Kevlar 49/epoxy composite pressure vessels  

NASA Technical Reports Server (NTRS)

Kevlar 49/epoxy composite is growing in use as a structural material because of its high strength-to-weight ratio. Currently, it is used for the Trident rocket motor case and for various pressure vessels on the Space Shuttle. In 1979, the initial results for aging of filament-wound cylindrical pressure vessels which were manufactured with preproduction Kevlar 49 (Hamstad, 1979) were published. This preproduction fiber was called PRD 49 III. This report updates the continuing study to 10-year data and also presents 7.5-year data for spherical pressure vessels wound with production Kevlar 49. For completeness, this report will again describe the specimens of the original study with PRD 49 as well as specimens for the new study with Kevlar 49.

Hamstad, M. A.

1983-01-01

309

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

310

Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures  

SciTech Connect

Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X.

Swindeman, R.W.; Brinkman, C.R.

1981-01-01

311

Development of composite pressure vessels with nonmetallic liners  

Microsoft Academic Search

Brunswick composites has developed metallic liners and composite cylinders for use in military and civilian aircraft, missiles, inflation systems and space applications. At present an all-composite pressurant tank is being developed for use in the natural gas vehicle (NGV). This tank uses a plastic liner of high density polyethylene (HDPE) as a leak-tight permeation barrier. Tank characteristics and testing are

Con F. Murray; Norman L. Newhouse; John D. Schimenti; Dale B. Tiller

1992-01-01

312

Managing Pressure Vessel Equipment as a Capital Asset.  

ERIC Educational Resources Information Center

Argues the importance of treating facility pressure equipment as capital assets and discusses three steps in their management process. The following steps are discussed: understanding the condition of all major equipment; altering maintenance practices and procedures; and developing a long-term equipment strategy such as increased monitoring,…

Robinson, Glenn; Trombley, Robert; Shultes, Kenneth

1999-01-01

313

New Developments in Nickel-Hydrogen Dependent Pressure Vessel (DPV) Cell and Battery Design  

NASA Technical Reports Server (NTRS)

THe Dependent Pressure Vessel (DPV) Nickel-Hydrogen (NiH2) design is being developed as an advanced battery for military and commercial, aerospace and terrestrial applications. The DPV cell design offers high specific energy and energy density as well as reduced cost, while retaining the established Individual Pressure Vessel (IPV) technology flight heritage and database. This advanced DPV design also offers a more efficient mechanical, electrical and thermal cell and battery configuration and a reduced part count. The DPV battery design promotes compact, minimum volume packaging and weight efficiency, and delivers cost and weight savings with minimal design risk.

Caldwell, Dwight B.; Fox, Chris L.; Miller, Lee E.

1997-01-01

314

Performance features of 22-cell, 19Ah single pressure vessel nickel hydrogen battery  

NASA Technical Reports Server (NTRS)

Two 22-cells 19Ah Nickel-Hydrogen (Ni-H2) Single Pressure Vessel (SPV) Qual batteries, one each from EPI/Joplin and EPI/Butler, were designed and procured. The two batteries differ in the cell encapsulation technology, stack preload, and activation procedure. Both the Butler and Joplin batteries met the specified requirements when subjected to qualification testing and completed 2100 and 1300 LEO cycles respectively, with nominal performance. This paper discusses advantages, design features, testing procedures, and results of the two single pressure vessel Ni-H2 batteries.

Rao, Gopalakrishna M.; Vaidyanathan, Hari

1996-01-01

315

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

316

Correlation of mechanical property changes in neutron irradiated pressure vessel steels on the basis of spectral effects  

SciTech Connect

Defect production functions derived from atomistic modeling were evaluated for use in correlating yield stress changes of A212B and A302B pressure vessel steels irradiated in a wide variety of neutron spectra at low temperatures (40--90{degree}C) and low doses (<0.1 dpa). The irradiations were performed in RTNS-II, OWR, ORR and the HFIR pressure vessel surveillance positions. The data from RTNS-II, OWR and ORR are correlated fairly well on the basis of dpa, but the data from HFIR show that only one tenth as many dpa are needed to produce the same radiation-induced yield stress changes as in the other neutron spectra. About 96% of the neutrons in the HFIR surveillance position are thermal neutrons, and a significant fraction of the displacements is produced by recoils from thermal neutron captures. The best correlation of all the data is achieved when the property changes are compared on the basis of the production of freely migrating self-interstitial defects, which better represents the defects participating in the radiation strengthening process.

Heinisch, H.L.

1989-05-01

317

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

318

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.  

SciTech Connect

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

Nibur, Kevin A.

2010-11-01

319

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

320

Boat sampling and inservice inspections of the reactor pressure vessel weld No. 4 at Kozloduy NPP, Unit 1  

Microsoft Academic Search

The paper deals with reactor pressure vessel (RPV) boat sampling performed at Kozloduy Nuclear Power Plant, Unit 1, from August to November 1996. Kozloduy NPP, Unit 1 has no reactor vessel material surveillance program. Changes in the material fracture toughness resulting from the fast neutron irradiation which cannot be monitored without removal of the vessel material. Therefore, the main objective

Mato Cvitanovic; Elido Oreb; Vedran Mudronja; Vladimir Zado; Hrvoje Bezlaj; Miladin Petkov; Jonko Gledatchev; Stefan Radomirski; Teodara Ribarska; Bert Kroes

1999-01-01

321

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

322

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

323

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

324

EQUATIONS FOR GAS RELEASING PROCESS FROM PRESSURIZED VESSELS IN ODH EVALUATION.  

SciTech Connect

IN THE EVALUATION OF ODH, THE CALCULATION OF THE SPILL RATE FROM THE PRESSURIZED VESSEL IS THE CENTRAL TASK. THE ACCURACY OF THE ENGINEERING ESTIMATION BECOMES ONE OF THE SAFETY DESIGN ISSUES. THIS PAPER SUMMARIZES THE EQUATIONS FOR THE OXYGEN CONCENTRATION CALCULATION IN DIFFERENT CASES, AND DISCUSSES THE EQUATIONS FOR THE GAS RELEASE PROCESS CALCULATION BOTH FOR THE HIGH-PRESSURE GAS TANK AND THE LOW-TEMPERATURE LIQUID CONTAINER.

JIA,L.X.; WANG,L.

2001-07-16

325

Study on spherical pressure vessel of ceramics for deep-sea buoyancy module applications  

Microsoft Academic Search

Remotely operated vehicles (ROVs) for deep-sea operation should be as light as possible for Improvement of maneuverability and payload increase. Engineering ceramics has been one of the candidate materials for deep-sea pressure vessels because of its high compressive strength. The plan, which lessens its specific gravity and enlarges its pressure tolerance, had been prepared with installation of ceramic macro-spheres into

Yusuke Yano; Shinichi Takagawa

2004-01-01

326

Numerical modeling of the behaviour of high pressure vessel under hypervelocity impact  

Microsoft Academic Search

The increase of the number of space debris, particularly in LEO, has become a menace for space missions, and Space Agencies such as CNES (French Space Agency) are worried about this phenomenon. Because high pressure vessels are critical components onboard satellites, it is important to know their behaviour under hypervelocity impact induced by space debris. The aim of the study

C. Maveyraud; J. P. Vila; D. Sornette; C. Le Floc'h; J. M. Dupillier; R. Salomé

2001-01-01

327

Walking and Climbing Service Robots for Safety Inspection of Nuclear Reactor Pressure Vessels  

E-print Network

Walking and Climbing Service Robots for Safety Inspection of Nuclear Reactor Pressure Vessels B of Electronics and Computer Science, University of Southampton, Southampton, UK Abstract: Nuclear reactor and the usefulness of these robots for improving safety inspection of nuclear reactors in general are discussed

Chen, Sheng

328

Intergranular and intragranular phosphorus segregation in Russian pressure vessel steels due to neutron irradiation  

Microsoft Academic Search

Russian reactor pressure vessel steels have been studied in three conditions: initial, irradiated and annealed. It has been established that irradiation induces both intergranular as well as intragranular phosphorus segregation. Fractographic studies demonstrated that brittle intergranular and ductile intergranular fracture surfaces of Charpy specimens appear as a result of intergranular and intragranular segregation, respectively. Transmission electron microscope (TEM) studies have

B. A Gurovich; E. A Kuleshova; Ya. I Shtrombakh; O. O Zabusov; E. A Krasikov

2000-01-01

329

Pipeline and Pressure Vessel R&D under the Hydrogen Regional Infrastructure  

E-print Network

Pipeline and Pressure Vessel R&D under the Hydrogen Regional Infrastructure Program In Pennsylvania Kevin L. Klug, Ph.D. 25 September 2007 DOE Hydrogen Pipeline Working Group Meeting, Aiken, SCPerComp Engineering Inc. (HEI) ­ American Society Of Mechanical Engineers (ASME) ­ Pipeline Working Group (PWG) #12

330

Nuclear Technology. Course 30: Mechanical Inspection. Module 30-7, Pressure Vessel Inspection.  

ERIC Educational Resources Information Center

This seventh in a series of eight modules for a course titled Mechanical Inspection is devoted to the design and fabrication of the reactor pressure vessel. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject matter, (6)…

Kupiec, Chet; Espy, John

331

Radiation embrittlement modelling for reactor pressure vessel steels: I. Brittle fracture toughness prediction  

Microsoft Academic Search

Modelling for the irradiation effect on brittle fracture toughness of reactor pressure vessel (RPV) steel is performed on the basis of the probabilistic model for fracture toughness prediction proposed by the authors earlier. The irradiation effect on parameters controlling plastic deformation and brittle fracture of RPV steels is analyzed. The physical mechanisms are considered which control the cleavage microcrack nucleation

B. Z. Margolin; V. A. Shvetsova; A. G. Gulenko

1999-01-01

332

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

333

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

334

2 1\\/4 chrome1 molybdenum steel in pressure vessels and piping. Symposium held at Denver, Colorado, September 16--17, 1970  

Microsoft Academic Search

The publication presents eight papers that were assembled from the 21st ; Annual Petroleum- Mechanical Engineering Conference of ASME and the Second Annual ; Pressure Vessels and Piping Conference. The papers were entitled: The Strength ; of 21\\/4 Cr-- 1 Mo Steel at Elevated Temperatures; Notched Stress-Rupture Data for ; Quenched-and-Tempered 21\\/4 Cr- 1 Mo Steel; Welding of Heavy Wall

1971-01-01

335

Characteristics of Turbulent Premixed Flames under the Pressure Rising Process in a Closed Vessel  

NASA Astrophysics Data System (ADS)

In a closed vessel such as SI engines, the internal pressure increases due to dilatation during the combustion after the ignition. To clarify quantitative characteristics of turbulent premixed flames under the pressure rising process, direct numerical simulation (DNS) of turbulent premixed flames in a closed vessel at relatively high Reynolds number has been conducted. Detailed kinetic mechanism for hydrogen-air mixtures is used. Because of the local pressure rise, turbulence is enhanced at the unburnt side and flame surface is distorted, which results in increase of the flame surface. Heat release rate of each flame element is augmented since the pressure rise makes flame thickness thin. Under this pressure rising process, the flame thickness, the flame front curvature and the local heat release rate can be scaled by laminar flame thickness and the maximum heat release rate obtained from one dimensional DNS of laminar flame propagation by using averaged temperature in the unburnt region of the vessel as the inlet temperature. The tangential strain rate on the flame front can be scaled by Taylor micro scale averaged in the unburnt side. The local heat release rate is positively correlated with the curvature and the tangential strain. The time evolution of the flame surface area is also investigated quantitatively.

Fukushima, Naoya; Yenerdag, Basmil; Shimura, Masayasu; Tanahashi, Mamoru; Miyauchi, Toshio

2011-11-01

336

Influence of pore pressure and production-induced changes in pore pressure on in situ stress  

SciTech Connect

Knowledge of in situ stress and how stress changes with reservoir depletion and pore pressure drawdown is important in a multi-disciplinary approach to reservoir characterization, reservoir management, and improved oil recovery projects. This report summarizes a compilation of in situ stress data from six fields showing the effects of pore pressure and production-induced changes in pore pressure on the minimum horizontal stress. The in situ stress data and corresponding pore pressure data were obtained from field records of the operating companies and published reports. Horizontal stress was determined from closure pressure data of hydraulic fractures and leak-off tests. The stress measurements clearly demonstrate that the total minimum-horizontal stress is dependent on pore pressure. A decrease in pore pressure either by geologic processes or production of a reservoir will result in a decrease in the total minimum-horizontal stress. The magnitude of changes in stress state with net changes in pore pressure is dependent on local field conditions and cannot be accurately predicted by the uniaxial strain model that is commonly used by the petroleum industry.

Teufel, L.W.

1996-02-01

337

Standard practice for examination of seamless, gas-filled, steel pressure vessels using angle beam ultrasonics  

E-print Network

1.1 This practice describes a contact angle-beam shear wave ultrasonic technique to detect and locate the circumferential position of longitudinally oriented discontinuities and to compare the amplitude of the indication from such discontinuities to that of a specified reference notch. This practice does not address examination of the vessel ends. The basic principles of contact angle-beam examination can be found in Practice E 587. Application to pipe and tubing, including the use of notches for standardization, is described in Practice E 213. 1.2 This practice is appropriate for the ultrasonic examination of cylindrical sections of gas-filled, seamless, steel pressure vessels such as those used for the storage and transportation of pressurized gasses. It is applicable to both isolated vessels and those in assemblies. 1.3 The practice is intended to be used following an Acoustic Emission (AE) examination of stacked seamless gaseous pressure vessels (with limited surface scanning area) described in Test Met...

American Society for Testing and Materials. Philadelphia

2007-01-01

338

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

339

Assessment of fire damage to pressure vessels in a refinery unit  

SciTech Connect

A systematic approach is proposed to assess the fitness of pressure vessels in the alkylation unit of a refinery after fire damage. Techniques used to study a Jan. 11, 1991, fire included in-situ metallography; hardness testing; crack detection; and measurements of thicknesses, plumb, circumference, and straightness. Emphasis is placed not on conventional techniques such as hardness testing and in-situ metallography, but on methods of measuring the affected vessels and effectively detecting and sizing distortions caused by the fire. Though these methods have been available in the past, they are not used in typical damage assessments.

Hau, J.L. (Petroleos de Venezuela, Curacao (Netherlands Antilles))

1993-05-01

340

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

341

Urethral closure pressure with stress--a comparison between stress-incontinent and continent women.  

PubMed

Stress incontinence has been said to occur as a consequence of a low urethral pressure and defective pressure transmission from the abdomen to the urethra due to descent of the bladder neck area. Equipment suitable for dynamic pressure measurements has been used to analyse the losses of urethral pressure that lead to incontinence. The pressure transmission from abdomen to urethra was found to be incomplete in both continent and stress-incontinent women. There was also significant loss of smooth muscle tone in the urethral wall after repeated straining, leading to a still narrower margin between the urethral pressure and the leakage treshold in both continent and stress-incontinent women. The main factor determining the degree of continence or incontinence seemed to be the urethral closure pressure at rest . As long as this pressure is sufficiently high, leakage during sudden stress will not occur. PMID:568337

Bunne, G; Obrink, A

1978-01-01

342

Biaxial loading effects on fracture toughness of reactor pressure vessel steel  

SciTech Connect

The preliminary phases of a program to develop and evaluate fracture methodologies for assessing crack-tip constraint effects on fracture toughness of reactor pressure vessel (RPV) steels have been completed by the Heavy-Section Steel Technology (HSST) Program. Objectives were to investigate effect of biaxial loading on fracture toughness, quantify this effect through existing stress-based, dual-parameter, fracture-toughness correlations, or propose and verify alternate correlations. A cruciform beam specimen with 2-D, shallow, through-thickness flaw and a special loading fixture was designed and fabricated. Tests were performed using biaxial loading ratios of 0:1 (uniaxial), 0.6:1, and 1:1 (equi-biaxial). Critical fracture-toughness values were calculated for each test. Biaxial loading of 0.6:1 resulted in a reduction in the lower bound fracture toughness of {approximately}12% as compared to that from the uniaxial tests. The biaxial loading of 1:1 yielded two subsets of toughness values; one agreed well with the uniaxial data, while one was reduced by {approximately}43% when compared to the uniaxial data. Results were evaluated using J-Q theory and Dodds-Anderson (D-A) micromechanical scaling model. The D-A model predicted no biaxial effect, while the J-Q method gave inconclusive results. When applied to the 1:1 biaxial data, these constraint methodologies failed to predict the observed reduction in fracture toughness obtained in one experiment. A strain-based constraint methodology that considers the relationship between applied biaxial load, the plastic zone width in the crack plane, and fracture toughness was formulated and applied successfully to the data. Evaluation of this dual-parameter strain-based model led to the conclusion that it has the capability of representing fracture behavior of RPV steels in the transition region, including the effects of out-of-plane loading on fracture toughness. This report is designated as HSST Report No. 150.

McAfee, W.J.; Bass, B.R.; Bryson, J.W. Jr.; Pennell, W.E. [Oak Ridge National Lab., TN (United States)

1995-03-01

343

Develop Critical Profilometers to Meet Current and Future Composite Overwrapped Pressure Vessel (COPV) Interior Inspection Needs  

NASA Technical Reports Server (NTRS)

The objective of this project is to develop laser profilometer technology that can efficiently inspect and map the inside of composite pressure vessels for flaws such as liner buckling, pitting, or other surface imperfections. The project will also provide profilometers that can directly support inspections of flight vessels during development and qualification programs and subsequently be implemented into manufacturing inspections to screen out vessels with "out of family" liner defects. An example interior scan of a carbon overwrapped bottle is shown in comparison to an external view of the same bottle (Fig. 1). The internal scan is primarily of the cylindrical portion, but extends about 0.15 in. into the end cap area.

Saulsberry, Regor L.

2010-01-01

344

Overall evaluation light-weight composite pressure vessel with alloy liner by acoustic emission and Bragg grating  

NASA Astrophysics Data System (ADS)

Light-weight carbon fiber composite pressure vessel with inner thin-wall aluminum alloy liner has main problem of local buckling during manufacture and working process. The approach of acoustic emission and Bragg grating are adapted to monitoring the light-weight composite vessel under water pressure. Two channels of acoustic emission (AE) were bonded to front dome and cylinder to monitoring the performance of the vessel withstanding maximum 4.5MPa water pressure during loading, maintaining and unloading. Meantime six fiber Bragg sensors (FBG)were attached to front dome and cylinder of the outer surface by hoop and meridian direction respectively in order to monitor the vessel behavior. Analysis indicated Bragg sensors can evaluate outer surface behavior of the vessel with pressure. AE character parameters analysis illustrated the local buckling of inner thin-wall liner.

Zhao, Jun-qing; He, Xiao-dong; Wang, Rong-guo; Liu, Wen-bo

2013-04-01

345

Zero-dimensional model of compressible gas flow in networks of pressure vessels: Program TRIC  

NASA Astrophysics Data System (ADS)

A computational tool that models the flow of real gases of arbitrary equation of state in networks of pressure vessels connected by various flow components is described. The conservation equations in zero dimensions are applied to the vessels, which are treated as either constant or deformable control volumes, to produce a set of time dependent, ordinary differential equations. A flow model is developed for an isentropic process, appropriate to nozzles and short orifices, with the flow rate modified by a flow coefficient. For long ducts, the code solves the boundary value problem resulting from the one dimensional conservation equations. Friction and heat transfer in the duct are included in this flow model and a loss of total pressure is predicted, obviating a flow coefficient.

Clark, G. L.

1983-07-01

346

Evaluation of Agency Non-Code Layered Pressure Vessels (LPVs). Corrected Copy, Aug. 25, 2014  

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

347

Fragmentations caused by hypervelocity collisions of debris particles with pressurized vessels  

Microsoft Academic Search

Collisions and orbital breakups are considered to play the most important role in determining the scenario of debris evolution in low Earth orbits and in geostationary orbit. Hypervelocity collisions with debris fragments could be very dangerous for spacecrafts. Most of spacecrafts contain pressurized gas-filled or fluid-filled vessels as structural elements. Fragmentation of a gas-filled or fluid-filled containment in hypervelocity collision

N. N. Smirnov; A. B. Kiselev; V. F. Nikitin

2001-01-01

348

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

Microsoft Academic Search

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

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

1996-01-01

349

A Reactor Pressure Vessel Dosimetry Calculation Using ATTILA, An Unstructured Tetrahedral Mesh Discrete-Ordinates Code  

SciTech Connect

Recently, a new state-of-the-art discrete-ordinates code, ATTILA, was developed. ATTILA provides the capabilities to solve geometrically complex 3-D transport problems by using an unstructured tetrahedral mesh. In this paper we describe the application of ATTILA to a 3-D reactor pressure vessel dosimetry problem. We provide numerical results from ATTILA and the Monte Carlo code, MCNP. The results demonstrate the effectiveness and efficiency of ATTILA for such calculations.

Wareing, T.A.; Parsons, D.K. [Los Alamos National Lab., NM (United States); Pautz, S. [Texas A and M Univ., College Station, TX (United States). Dept. of Nuclear Engineering

1997-12-31

350

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

351

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

352

Neutron radiation embrittlement studies in support of continued operation, and validation by sampling of Magnox reactor steel pressure vessels and components  

SciTech Connect

Magnox steel reactor pressure vessels differ significantly from US LWR vessels in terms of the type of steel used, as well as their operating environment (dose level, exposure temperature range, and neutron spectra). The large diameter ferritic steel vessels are constructed from C-Mn steel plates and forgings joined together with manual metal and submerged-arc welds which are stress-relieved. All Magnox vessels are now at least thirty years old and their continued operation is being vigorously pursued. Vessel surveillance and other programmes are summarized which support this objective. The current understanding of the roles of matrix irradiation damage, irradiation-enhanced copper impurity precipitation and intergranular embrittlement effects is described in so far as these influence the form of the embrittlement and hardening trend curves for each material. An update is given on the influence of high temperature exposure, and on the role of differing neutron spectra. Finally, the validation offered by the results of an initial vessel sampling exercise is summarized together with the objectives of a more extensive future sampling programme.

Jones, R.B.; Bolton, C.J. [Magnox Electric plc, Berkeley Centre, Glos (United Kingdom)

1997-02-01

353

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

354

Environmental crack-growth behavior of high strength pressure vessel alloys  

NASA Technical Reports Server (NTRS)

Results of sustained-load environmental crack growth threshold tests performed on six spacecraft pressure vessel alloys are presented. The alloys were Inconel 718, 6Al-4V titanium, A-286 steel, AM-350 stainless steel, cryoformed AISI 301 stainless steel; and cryoformed AISI 304L steel. The test environments for the program were air, pressurized gases of hydrogen, oxygen, nitrogen, and carbon dioxide, and liquid environments of distilled water, sea water, nitrogen tetroxide, hydrazine, aerozine 50, monomethyl hydrazine, and hydrogen peroxide. Surface flaw type specimens were used with flaws located in both base metal and weld metal.

Forman, R. G.

1975-01-01

355

Comparison of Irradiation Conditions of VVER-1000 Reactor Pressure Vessel and Surveillance Specimens for Various Core Loadings  

NASA Astrophysics Data System (ADS)

The comparative analysis of irradiation conditions of surveillance specimens and pressure vessel of VVER-1000 reactor has been carried out for various configurations of the core. It is proved the fluences onto specimens and a pressure vessel don't correlate with each other but only the spectral indexes do. It is revealed that in the case of the specimen reconstitution technique application the data on the assembly orientation to the reactor core is sufficient to complete four representative groups from the samples of any container assembly. It is shown that the standard surveillance program of VVER-1000 allows obtaining reliable information on the reactor pressure vessel state.

Bukanov, V. N.; Diemokhin, V. L.; Grytsenko, O. V.; Vasylieva, O. G.; Pugach, S. M.

2009-08-01

356

REACTOR PRESSURE VESSEL TEMPERATURE ANALYSIS OF CANDIDATE VERY HIGH TEMPERATURE REACTOR 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. Because PEBBED-THERMIX has not been extensively validated, confirmatory calculations were also performed with RELAP5-3D for the pebble-bed design. During normal operation, the predicted axial profiles in reactor vessel temperature were similar with both codes and the predicted maximum values were within 2 °C. The trends of the calculated vessel temperatures were similar during the depressurized conduction cooldown accident. The maximum value predicted with RELAP5-3D during the depressurized conduction cooldown accident was about 40 °C higher than that predicted with PEBBED. This agreement is considered reasonable based on the expected uncertainty in either calculation. The differences between the PEBBED and RELAP5-3D calculations were not large enough to affect conclusions concerning comparisons between calculated and allowed maximum temperatures during normal operation and the depressurized conduction cooldown accident.

Hans D. Gougar; Cliff B. Davis; George Hayner; Kevan Weaver

2006-10-01

357

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

358

Pressure and stress analysis for an underwater vehicle  

Microsoft Academic Search

Underwater vehicles are widely used in both military and civilian operations for more than 60 years. They are the best tools to perform dull, dangerous and dirty tasks in the water. So the distribution principles of static pressure and stress along the vehicle hull must be found out when designing hull shape and choosing the materials. The static pressure and

Yanhui Ai

2011-01-01

359

FAST NEUTRON FLUX MEASUREMENT OUTSIDE THE PWR PRESSURE VESSEL. SHIPPINGPORT PWR-1 SEED 3. DLCS-40201 DLCS-40202. Test Evaluation  

Microsoft Academic Search

Results and evaluations concerning fast neutron flux measurements made ; outside the pressure vessel in a source-range instrument well during PWR-1 seed 3 ; life are presented. These measurements were made to obtain data from which to ; calculate the fast neutron exposure inside the PWR vessel. It is concluded that ; the fast flux on the inside of the

K. P. Barr; J. H. Leonard; G. G. Smith

1962-01-01

360

Definition of mutually optimum NDI and proof test criteria for 2219 aluminum pressure vessels. Volume 1: Methods  

NASA Technical Reports Server (NTRS)

The requirements for proof testing and nondestructive inspection of aluminum pressure vessels were discussed. The following conclusions are (1) lack-of-fusion weld defects are sufficiently tight in the as-welded condition to be considered undetectable; (2) proof-level loads are required to fully open lack-of-fusion weld defects; (3) significant crack opening occurs at subproof levels so that an inspection enhancement loading treatment designed to avoid catastrophic failure is feasible; (4) currently used proof levels for 2219 pressure vessels are adequate for postproof inspection; (5) quantification of defect size and location using collimated ultrasonic pitch-catch techniques appears sufficiently feasible for tankage to warrant developmental work; (6) for short-time single-cycle pressure-vessel applications, postproof inspection is desirable; and (7) for long-term multiple-cycle pressure-vessel applications, postproof inspection is essential for life assurance.

Schwartzberg, F. R.; King, R. G.; Todd, P. H., Jr.

1979-01-01

361

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

362

Estimation of mechanical properties of irradiated nuclear pressure vessel steel by use of subsized CT specimen and small punch specimen  

Microsoft Academic Search

This paper reports on the 2-1\\/4 Cr-1Mâ steel that has been selected as the material for the reactor pressure vessel (RPV) of a multipurpose experimental high temperature gas cooled reactor designed by JAERI. The 2-1\\/4 Cr-1Mâ steel has successful records for high temperature pressure vessels in the petrochemical industries and the ASME Code Case authorizes the use of the steel

X. Mao; H. Takahashi; T. Kodaira

1991-01-01

363

RADIATION DOSIMETRY OF THE PRESSURE VESSEL INTERNALS OF THE HIGH FLUX BEAM REACTOR.  

SciTech Connect

In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, both measurements and calculations of the decay gamma-ray dose rate have been performed for the reactor pressure vessel and vessel internal structures which included the upper and lower thermal shields, the transition plate, and the control rod blades. The measurements were made using Red Perspex{trademark} polymethyl methacrylate high-level film dosimeters, a Radcal ''peanut'' ion chamber, and Eberline's high-range ion chamber. To compare with measured gamma-ray dose rate, the Monte Carlo MCNP code and geometric progressive Microshield code were used to model the gamma transport and dose buildup.

HOLDEN,N.E.; RECINIELLO,R.N.; HU,J.P.; RORER,D.C.

2002-08-18

364

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

365

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

366

Neural Network Burst Pressure Prediction in Graphite/Epoxy Pressure Vessels from Acoustic Emission Amplitude Data  

NASA Technical Reports Server (NTRS)

Acoustic emission (AE) data were taken during hydroproof for three sets of ASTM standard 5.75 inch diameter filament wound graphite/epoxy bottles. All three sets of bottles had the same design and were wound from the same graphite fiber; the only difference was in the epoxies used. Two of the epoxies had similar mechanical properties, and because the acoustic properties of materials are a function of their stiffnesses, it was thought that the AE data from the two sets might also be similar; however, this was not the case. Therefore, the three resin types were categorized using dummy variables, which allowed the prediction of burst pressures all three sets of bottles using a single neural network. Three bottles from each set were used to train the network. The resin category, the AE amplitude distribution data taken up to 25 % of the expected burst pressure, and the actual burst pressures were used as inputs. Architecturally, the network consisted of a forty-three neuron input layer (a single categorical variable defining the resin type plus forty-two continuous variables for the AE amplitude frequencies), a fifteen neuron hidden layer for mapping, and a single output neuron for burst pressure prediction. The network trained on all three bottle sets was able to predict burst pressures in the remaining bottles with a worst case error of + 6.59%, slightly greater than the desired goal of + 5%. This larger than desired error was due to poor resolution in the amplitude data for the third bottle set. When the third set of bottles was eliminated from consideration, only four hidden layer neurons were necessary to generate a worst case prediction error of - 3.43%, well within the desired goal.

Hill, Eric v. K.; Walker, James L., II; Rowell, Ginger H.

1995-01-01

367

Intergranular and intragranular phosphorus segregation in Russian pressure vessel steels due to neutron irradiation  

NASA Astrophysics Data System (ADS)

Russian reactor pressure vessel steels have been studied in three conditions: initial, irradiated and annealed. It has been established that irradiation induces both intergranular as well as intragranular phosphorus segregation. Fractographic studies demonstrated that brittle intergranular and ductile intergranular fracture surfaces of Charpy specimens appear as a result of intergranular and intragranular segregation, respectively. Transmission electron microscope (TEM) studies have revealed radiation-induced precipitates on interface boundaries to which intragranular phosphorus segregation occurs. Auger electron spectroscopy (AES) has been applied to detect phosphorus enrichment of fracture surfaces in the regions of brittle and ductile intergranular fractures.

Gurovich, B. A.; Kuleshova, E. A.; Shtrombakh, Ya. I.; Zabusov, O. O.; Krasikov, E. A.

2000-06-01

368

On the uncertainity of neutron transport calculations for reactor pressure vessel surveillance  

SciTech Connect

One of the primary concerns of the aging nuclear power plants is the radiation-induced embrittlement of the reactor pressure vessels (PVs). In the current methodology, the PV material embrittlement is determined from the prescribed (regulatory) or plant-specific trend curves, which give the increase of reference nil-ductility transition (NDT) temperature ({Delta}RT{sub NDT}) of the materials as a function of material chemical composition and fast (E > 1 MeV) neutron fluence. Therefore, accurate and reliable fast fluence values in the PV and surveillance capsule locations must be known.

Remec, I. [Oak Ridge National Laboratory, TN (United States)

1996-12-31

369

Overview of NASA White Sands Test Facility Composite Overwrapped Pressure Vessel Testing  

NASA Technical Reports Server (NTRS)

This viewgraph presentation examines the White Sands Test Facility testing of Composite overwrapped pressure vessel (COPV). A COPV is typically a metallic liner overwrapped with a fiber epoxy matrix. There is a weight advantage over the traditional all metal design. The presentation shows pictures of the facilities at White Sands, and then examines some of the testing performed. The tests include fluids compatibility, and Kevlar COPV. Data for the Kevlar tests are given, and an analysis is reviewed. There is also a comparison between Carbon COPVs and the Kevlar COPVs.

Greene, Nathanael; Saulsberry, Regor; Thesken, John; Phoenix, Leigh

2006-01-01

370

Fiber/epoxy filament-wound vessels. Final report  

SciTech Connect

The present investigation has provided a valuable insight into the design, fabrication and performance of filament-wound pressure vessels. The long-term stress rupture data generated under the contract is perhaps the only available lifetime data of its kind for Kevlar 49/epoxy pressure vessels. Now, it is clear that Kevlar 49/epoxy pressure vessels can be made to last at least 9 years at 50% of the static burst pressure.

Chiao, T.T.; Moore, R.L.

1986-08-14

371

Effect of neutron irradiation on tensile properties of materials for pressure vessel internals of WWER type reactors  

NASA Astrophysics Data System (ADS)

Tensile properties of austenitic stainless steels used for pressure vessel internals of WWER type reactors (18Cr-10Ni-Ti steel and its weld metal) in the initial and irradiated conditions were investigated. Based on the presented original investigations and generalization of the available experimental data the dependences of yield strength and ultimate strength on a neutron damage dose up to 108 dpa, irradiation temperature range 320-450 °C and test temperature range 20-450 °C were obtained. The method of determination of the stress-strain curve parameters was proposed which does not require uniform elongation of a specimen as an input parameter. The dependences was proposed allowing one to calculate the stress-strain curve parameters for 18Cr-10Ni-Ti steel and its weld metal for different test temperatures, different irradiation temperatures and doses. The dependences were obtained to describe the fracture strain decrease under irradiation at a temperature range 320-340 °C when irradiation swelling is absent.

Sorokin, A. A.; Margolin, B. Z.; Kursevich, I. P.; Minkin, A. J.; Neustroev, V. S.

2014-01-01

372

Predictive Reactor Pressure Vessel Steel Irradiation Embrittlement Models: Issues and Opportunities  

SciTech Connect

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 (RPV) 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 fi ts to the existing surveillance database. However, an important challenge is developing advanced embrittlement models for low fl ux-high fl uence 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, verifi cation 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, George Robert [UCSB; Nanstad, Randy K [ORNL

2009-01-01

373

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

NASA Astrophysics Data System (ADS)

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 past an array of plates, stochastic finite elements for automotive impact, numerical simulation in the deployment of space structures, axial buckling of a thin cylindrical shell, applying FEM to the prediction of vibrations of liquid propelled launch vehicles, analysis of a large bore piping system supported with viscodampers, stochastic simulation of lubricant depletion on a magnetic storage disk, and two-dimensional crak inclusion interaction effects. Additional topics include analyzing damage mechanisms using the energy release rate, the suspension of solid particles in an aerospace plane's slush hydrogen tanks, modal methods for the analysis of vibrations of structures coupled with fluids, the elastic-plastic behavior of fibrous metal matrix composites, and stochastic finite element analysis of nonlinear media.

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

1989-06-01

374

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

375

Recovering strain readings from chirping fiber Bragg gratings in composite overwrapped pressure vessels  

NASA Astrophysics Data System (ADS)

This study reports on signal recovery of optical fiber Bragg gratings embedded in a carbon fiber composite overwrapped pressure vessel's (COPV) structure which have become chirped due to microcracks. COPVs are commonly used for the storage of high pressure liquids and gases. They utilize a thin metal liner to seal in contents, with a composite overwrap to strengthen the vessel with minimal additional mass. A COPV was instrumented with an array of surface mounted and embedded fiber Bragg gratings (FBGs) for structural health monitoring (SHM) via strain sensing of the material. FBGs have been studied as strain sensors for the last couple decades. Many of the embedded FBGs reflected a multi-peak, chirped response which was not able to be interpreted well by the current monitoring algorithm. Literature and this study found that the chirping correlated with microcracks. As loading increases, so does the number of chirped FBGs and microcracks. This study uses optical frequency domain reflectometry (OFDR) to demultiplex the array of FBGs, and then sub- divide individual FBGs. When a FBG is sub-divided using OFDR, the gratings' strain along its length is recovered. The sub-divided chirped FBGs have strain gradients along their length from microcracks. Applying this to all chirped gratings, nearly the entirety of the embedded sensors' readings can be recovered into a series of single peak responses, which show very large local strains throughout the structure. This study reports on this success in recovering embedded FBGs signal, and the strain gradient from microcracks.

Strutner, Scott M.; Pena, Frank; Piazza, Anthony; Parker, Allen R.; Richards, W. Lance; Carman, Gregory P.

2014-04-01

376

Standard Master Matrix for Light-Water Reactor Pressure Vessel Surveillance Standards, E706(0)  

E-print Network

1.1 This master matrix standard describes a series of standard practices, guides, and methods for the prediction of neutron-induced changes in light-water reactor (LWR) pressure vessel (PV) and support structure steels throughout a pressure vessel's service life (Fig. 1). Some of these are existing ASTM standards, some are ASTM standards that have been modified, and some are proposed ASTM standards. General requirements of content and consistency are discussed in Section 6 . More detailed writers' and users' information, justification, and specific requirements for the nine practices, ten guides, and three methods are provided in Sections 3-5. Referenced documents are discussed in Section 2. The summary-type information that is provided in Sections 3 and 4 is essential for establishing proper understanding and communications between the writers and users of this set of matrix standards. It was extracted from the referenced documents, Section 2 and references (1-106) for use by individual writers and users. 1...

American Society for Testing and Materials. Philadelphia

2002-01-01

377

Irradiation effects on toughness behaviour and microstructure of VVER-type pressure vessel steels  

NASA Astrophysics Data System (ADS)

The irradiation sensitivity and the annealing behaviour were studied on seven different heats from VVER 440 and VVER 1000-type reactor pressure vessel steels. The specimens were irradiated at the Rheinsberg prototype VVER 2 reactor to mean neutron fluences between 43 and 127.6×10 18 n/cm2[E>0.5 MeV] . Toughness and strength properties were determined and the microstructure was analysed using the small angle neutron scattering (SANS) technique. There is an obvious correlation between the irradiation-induced changes of transition temperature, hardness and volume fraction of microstructural features of radii up to 2 nm. The main parameters of influence are the neutron fluence and the nickel content. The nickel-containing VVER 1000-type pressure vessel steel is more sensitive to irradiation than the VVER 440-type steel which has a low nickel content. For the latter, the sensitivity to radiation embrittlement depends on the copper and phosphorus contents. Annealing at 475°C (100 h) reduces the irradiation effect but not completely in every case.

Böhmert, J.; Viehrig, H.-W.; Ulbricht, A.

2001-09-01

378

Radiation damage characterization in reactor pressure vessel steels with nonlinear ultrasound  

SciTech Connect

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. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Kim, J.-Y. [School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Wall, J. J. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 and Nuclear Sector, The Electric Power Research Institute, Charlotte, NC 28262 (United States); Qu, J. [Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208 (United States); Jacobs, L. J. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2014-02-18

379

Plain bearing stresses due to forming and oil film pressure  

NASA Astrophysics Data System (ADS)

This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

Burke-Veliz, A.; Wang, D.; Wahdy, N.; Reed, P. A. S.; Merritt, D.; Syngellakis, S.

2009-08-01

380

Measurement of Averaged Heat Transfer Coefficients in High-Pressure Vessel during Charging with Hydrogen, Nitrogen or Argon Gas  

NASA Astrophysics Data System (ADS)

Heat transfer to the wall of a small pressure vessel during filling with some different kinds of gas was investigated experimentally. The vessel was orientated vertically with the inlet at the top. The space-averaged Nusselt number for the curved wall was found to be a function of both the Reynolds and Rayleigh numbers indicating a mixed convection heat transfer situation. A correlation is proposed for the heat transfer coefficient during charging of the vessel. For the six positions where measurements were taken, the local heat transfer coefficient typically did not differ from the space-averaged value by more than about 30 percent. Measurements were also taken during discharging to atmospheric pressure. For discharging, some of the data was found to agree with a correlation for natural convection in cylindrical geometry. Local Nusselt numbers for discharging tended to be higher towards the bottom of the vessel.

Woodfield, Peter Lloyd; Monde, Masanori; Mitsutake, Yuichi

381

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

382

Anterior cingulate activity correlates with blood pressure during stress  

PubMed Central

The anterior cingulate cortex presumptively regulates blood pressure reactions to behavioral stressors. There is little evidence in humans, however, that stressor-evoked changes in blood pressure correlate with concurrent changes in anterior cingulate activity. Using fMRI, we tested whether changes in mean arterial blood pressure correlate with ongoing changes in blood oxygen level dependent (BOLD) activation in 9 women and 11 men who completed a stressful Stroop color-word interference task. Higher mean arterial pressure during the Stroop task correlated with greater BOLD activation in two regions of the cingulate cortex (perigenual and mid-anterior) and in other networked brain regions, including the insula, thalamus, and periaqueductal gray. These results support the hypothesis that the anterior cingulate cortex regulates blood pressure reactions to behavioral stressors in humans. PMID:16364058

Gianaros, Peter J.; Derbyshire, Stuart W. G.; May, J. Christopher; Siegle, Greg J.; Gamalo, Mark A.; Jennings, J. Richard

2008-01-01

383

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.

384

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

385

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

386

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

Code of Federal Regulations, 2014 CFR

...pressure vessels and reports of repairs or accidents by chief engineer-TB/ALL. 35...pressure vessels and reports of repairs or accidents by chief engineer—TB/ALL...be made. (b) In the event of an accident to a boiler, unfired pressure...

2014-10-01

387

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

...pressure vessels and reports of repairs or accidents by chief engineer-TB/ALL. 35...pressure vessels and reports of repairs or accidents by chief engineer—TB/ALL...be made. (b) In the event of an accident to a boiler, unfired pressure...

2013-10-01

388

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

Code of Federal Regulations, 2011 CFR

...pressure vessels and reports of repairs or accidents by chief engineer-TB/ALL. 35...pressure vessels and reports of repairs or accidents by chief engineer—TB/ALL...be made. (b) In the event of an accident to a boiler, unfired pressure...

2011-10-01

389

Pore pressure and poroelasticity effects in Coulomb stress analysis of earthquake interactions  

E-print Network

that pore pressure is proportional to fault- normal stress leads to the widely used concept of an effective the effective normal stress change within the fault as a weighted linear combination of mean stress and fault- normal stress changes in the surroundings. Pore pressure changes are determined by fault-normal stress

390

Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment  

SciTech Connect

The fatigue crack growth rate (FCGR) properties of SA508 Cl 2a and SA533 Gr A Cl 2 pressure vessel steels and the corresponding automatic submerged arc weldments were developed in a high-temperature pressurized water (HPW) environment at 288{degrees} C (550{degrees} F) and 7.2 MPa (1044 psi) at load ratios of 0.20 and 0.50. The properties were generally conservative compared to American Society of Mechanical Engineers Section XI water environment reference curve. The growth rate of fatigue cracks in the base materials, however, was faster in the HPW environment than in a 288{degrees} C (550{degrees} F) base line air environment. The growth rate of fatigue cracks in the two submerged arc weldments was also accelerated in the HPW environment but to a lesser degree than that demonstrated by the base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials compared the weldments attributed to a different sulfide composition and morphology.

Liaw, P.K.; Logsdon, W.A.; Begley, J.A. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Research and Development Center)

1989-10-01

391

Neural Network Prediction of Failure of Damaged Composite Pressure Vessels from Strain Field Data Acquired by a Computer Vision Method  

NASA Technical Reports Server (NTRS)

This effort used a new and novel method of acquiring strains called Sub-pixel Digital Video Image Correlation (SDVIC) on impact damaged Kevlar/epoxy filament wound pressure vessels during a proof test. To predict the burst pressure, the hoop strain field distribution around the impact location from three vessels was used to train a neural network. The network was then tested on additional pressure vessels. Several variations on the network were tried. The best results were obtained using a single hidden layer. SDVIC is a fill-field non-contact computer vision technique which provides in-plane deformation and strain data over a load differential. This method was used to determine hoop and axial displacements, hoop and axial linear strains, the in-plane shear strains and rotations in the regions surrounding impact sites in filament wound pressure vessels (FWPV) during proof loading by internal pressurization. The relationship between these deformation measurement values and the remaining life of the pressure vessels, however, requires a complex theoretical model or numerical simulation. Both of these techniques are time consuming and complicated. Previous results using neural network methods had been successful in predicting the burst pressure for graphite/epoxy pressure vessels based upon acoustic emission (AE) measurements in similar tests. The neural network associates the character of the AE amplitude distribution, which depends upon the extent of impact damage, with the burst pressure. Similarly, higher amounts of impact damage are theorized to cause a higher amount of strain concentration in the damage effected zone at a given pressure and result in lower burst pressures. This relationship suggests that a neural network might be able to find an empirical relationship between the SDVIC strain field data and the burst pressure, analogous to the AE method, with greater speed and simplicity than theoretical or finite element modeling. The process of testing SDVIC neural network analysis and some encouraging preliminary results are presented in this paper. Details are given concerning the processing of SDVIC output data such that it may be used as back propagation neural network (BPNN) input data. The software written to perform this processing and the BPNN algorithm are also discussed. It will be shown that, with limited training, test results indicate an average error in burst pressure prediction of approximately six percent,

Russell, Samuel S.; Lansing, Matthew D.

1997-01-01

392

Pump and pressure vessel considerations for nuclear-heated steam rockets  

SciTech Connect

The purpose of this work is to estimate the pump and nuclear reactor pressure vessel masses for a reactor-type decision, between a pressurized water reactor (PWR) and a boiling water reactor (BWR). The main objective is to estimate pump performance, given that its mass must be limited to under 300 kg. The Lunar Prospector spacecraft found water ice at permanently shadowed, 80 K regions inside crater basins at the North and South Poles of the moon. Either a PWR or a BWR would power a nuclear-heated steam rocket, using water from the moon as propellant. A nuclear-heated steam rocket offers an exceptionally simple and presumably inexpensive system to shuttle people and payloads to and from the moon`s surface. Previous work determined the specific power required to develop sufficient thrust for liftoff: Each ton of nuclear rocket engine must deliver at least 150 MW into 1,100 K, or hotter, steam. The scaled pump mass (3,850 kg) for a PWR exceeds budget (300 kg). This implies that the PWR cannot be used unless pump-specific mass can be lowered by an order of magnitude. The scaled pump mass for a BWR would provide acceptable pressure (1.7 MPa).

Zuppero, A.C.; Richins, W.D. [Lockheed Martin Idaho Technologies, Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.

1998-09-01

393

Irradiation-induced Cu aggregations in Fe: An origin of embrittlement of reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

Very dilute Fe-Cu systems, model alloys of nuclear reactor pressure vessel (RPV) steels, irradiated by fast neutrons, are studied by positron annihilation experiments and simple calculations. The ultrafine Cu precipitates, which are never formed by thermal aging in the dilute alloys, are observed clearly and are strongly suggested to be responsible for irradiation-induced embrittlement of RPV steels. The formation and recovery process of the precipitates are revealed: (i) irradiation-induced Cu-vacancy complexes aggregate into microvoids; (ii) around 400 °C the dissociation of vacancies from the microvoids leads to the formation of the Cu precipitates of about 1 nm in size; and (iii) the Cu precipitates anneal out at about 650 °C.

Nagai, Y.; Tang, Z.; Hassegawa, M.; Kanai, T.; Saneyasu, M.

2001-04-01

394

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

395

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. 6 figs.

Challberg, R.C.; Gou, P.F.; Chu, C.L.; Oliver, R.P.

1999-07-27

396

Prediction of the effects of thermal ageing on the embrittlement of reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

A new method has been proposed for prediction of the effects of thermal ageing on the embrittlement of reactor pressure vessel (RPV) steels. The method is based on the test results for materials in two conditions, namely, aged at temperatures of temper embrittlement and annealed after irradiation. The prediction is based on the McLean's equation and the dependencies describing thermally activated and radiation-enhanced phosphorus diffusion. Experimental studies have been carried out for estimation of thermal ageing of the WWER-1000 RPV 2Cr-Ni-Mo-V steel. The ductile to brittle transition temperature shift ?Tk due to phosphorus segregation has been estimated on the basis of experimental data processed by the proposed method for the time t = 5 × 105 h (more than 60 years of operation) for the base and weld metals of the WWER-1000 RPV.

Margolin, B. Z.; Yurchenko, E. V.; Morozov, A. M.; Chistyakov, D. A.

2014-04-01

397

Numerical analysis of the effect of torispherical head on the buckling of pressure vessels  

NASA Astrophysics Data System (ADS)

Effect of torispherical head on the buckling of pressure vessels was investigated by finite element (FE) method. The FE method with use of nonlinear buckling analysis was applied to predict the critical buckling Load. The influences of geometrical parameter such as thickness, knuckle radius and diameter of cylindrical part, on the buckling of heads have been studied. The Arc Length method which can control the load level, the length of the displacement increment and the maximum displacement was been used. By verification performed with the European Convention for Constructional Steelwork (ECCS) code, it was confirmed that the nonlinear buckling analysis could assure accurate results for buckling strength. It was shown that geometrical imperfections had little effect on buckling strength.

Khoshravan, M. R.; Rahmani, A.

2009-08-01

398

United States Department of Energy projects related to reactor pressure vessel annealing optimization  

SciTech Connect

Light water reactor pressure vessel (RPV) material properties reduced by long-term exposure to neutron irradiation can be recovered through a thermal annealing treatment. This technique to extend RPV life, discussed in this report, provides a complementary approach to analytical methodologies to evaluate RPV integrity. RPV annealing has been successfully demonstrated in the former Soviet Union and on a limited basis by the US (military applications only). The process of demonstrating the technical feasibility of annealing commercial US RPVs is being pursued through a cooperative effort between the nuclear industry and the US Department of Energy (USDOE) Plant Lifetime Improvement (PLIM) Program. Presently, two projects are under way through the USDOE PLIM Program to demonstrate the technical feasibility of annealing commercial US RPVS, (1) annealing re-embrittlement data base development and (2) heat transfer boundary condition experiments.

Rosinski, S.T.; Nakos, J.T.

1993-09-01

399

Characterization of phosphorus segregation in neutron-irradiated Russian pressure vessel steel weld  

NASA Astrophysics Data System (ADS)

An atom probe field ion microscopy characterization of three Russian pressure vessel steels has been performed. Field ion micrographs of several lath boundaries have indicated that they are decorated with a semicontinuous film of discrete brightly-imaging precipitates that were identified as molybdenum carbonitrides. In addition, extremely high phosphorus levels were measured at the lath boundaries. The phosphorus was found to be confined to an extremely narrow region indicative of monolayer type segregation. The phosphorus coverage determined from the atom probe results of the unirradiated materials agree with predictions based on McLean's equilibrium model of grain boundary segregation. The boundary phosphorus coverage of a neutron-irradiated weld material was significantly higher than in the unirradiated material. Ultrafine darkly-imaging copper- and phosphorus-enriched precipitates were also observed in the matrix of the neutron-irradiated material.

Miller, M. K.; Jayaram, R.; Russell, K. F.

1995-08-01

400

Research and Development Roadmaps for Nondestructive Evaluation of Cables, Concrete, Reactor Pressure Vessels, and Piping Fatique  

SciTech Connect

To address these research needs, the MAaD Pathway supported a series of workshops in the summer of 2012 for the purpose of developing R&D roadmaps for enhancing the use of Nondestructive Evaluation (NDE) technologies and methodologies for detecting aging and degradation of materials and predicting the remaining useful life. The workshops were conducted to assess requirements and technical gaps related to applications of NDE for cables, concrete, reactor pressure vessels (RPV), and piping fatigue for extended reactor life. An overview of the outcomes of the workshops is presented here. Details of the workshop outcomes and proposed R&D also are available in the R&D roadmap documents cited in the bibliography and are available on the LWRS Program website (http://www.inl.gov/lwrs).

Clayton, Dwight A [ORNL] [ORNL; Bakhtiari, Sasan [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Smith, Cyrus M [ORNL] [ORNL; Simmons, Kevin [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Coble, Jamie [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Brenchley, David [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Meyer, Ryan [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL)

2013-01-01

401

PIONEER VENUS 2 MULTI-PROBE PARACHUTE TESTS IN VAB PRIOR TO ATTACHING PRESSURE VESSEL  

NASA Technical Reports Server (NTRS)

A parachute system, designed to carry an instrument-laden probe down through the dense atmosphere of torrid, cloud-shrouded Venus, was tested in KSC's Vehicle Assembly Building. The tests are in preparation for a Pioneer multi-probe mission to Venus scheduled for launch from KSC in 1978. Full-scale (12-foot diameter) parachutes with simulated pressure vessels weighing up to 45 pounds were dropped from heights of up to 450 feet tot he floor of the VAB where the impact was cushioned by a honeycomb cardboard impact arrestor. The VAB offers an ideal, wind-free testing facility at no additional construction cost and was used for similar tests of the parachute system for the twin Viking spacecraft scheduled for launch toward Mars in August.

1975-01-01

402

A Unified Cohesive Zone Approach to Model Ductile Brittle Transition in Reactor Pressure Vessel Steels  

SciTech Connect

In this study, a unified cohesive zone model has been proposed to predict, Ductile to Brittle Transition, DBT, in Reactor Pressure Vessel, RPV, steels. A general procedure is described to obtain the Cohesive Zone Model, CZM, parameters for the different temperatures and fracture probabilities. In order to establish the full master-curve, the procedure requires three calibration points with one at the upper-shelf for ductile fracture and two for the fracture probabilities, Pf, of 5% and 95% at the lower-shelf. In the current study, these calibrations were carried out by utilizing the experimental fracture toughness values and flow curves. After the calibration procedure, the simulations of fracture behavior (ranging from completely unstable to stable crack extension behavior) in one inch thick compact tension specimens at different temperatures yielded values that were comparable to the experimental fracture toughness values, indicating the viability of such unified modeling approach.

Pritam Chakraborty; S. Bulent Biner

2014-08-01

403

A review of the state-of-the-art of the non-destructive testing of flight pressure vessels  

NASA Technical Reports Server (NTRS)

The design of flight vessels is based on a nominal stress requirement and a fracture mechanics approach, and optimization of the weight of the vessel is based on the smallest size defect that can be detected with a high degree of confidence. The wide variety of metals used for fabrication, and the different defects that may be present in them at every stage, up to completion of the vessel, is described. Techniques currently being used for NDT are described along with their advantages, limitations and limits of detectability at high levels of confidence. Techniques considered for use in the future to improve the limits of the minimum flaw size that can currently be detected include the Delta Scan and Acoustic Emission techniques. The construction of space vessels for use in the future has been modified to reduce the presence of critical defects and so to improve the cost effectiveness of projected NDT requirements.

Noronha, P. J.; Mckannan, E. C.

1975-01-01

404

Integrated use of design aspects of new ASME pressure vessel code with requalification aspects of the ASME High Pressure Systems Standard  

SciTech Connect

This paper implements various procedures in the design articles of the proposed ASME BPV Section VIII, Division 3 to re-evaluate the compound shell of a 15 year old large hot isostatic high pressure vessel. The analysis then is subjected to the requalification procedures of the ASME High Pressure Systems Standard (HPS-1994) to create an updated periodic examination program. The purpose of the paper is to show how the two codes mesh for either new or existing vessels to provide rational guidance for obtaining optimum cyclic service performance.

Fryer, D.M. [High Pressure Engineering and Safety, Fairview, PA (United States); Aggarwal, M.C. [Gannon Univ., Erie, PA (United States). Mechanical Engineering Dept.

1996-12-01

405

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

406

Effects of Hyperbaric Pressure on a Deep-Sea Archaebacterium in Stainless Steel and Glass-Lined Vessels  

PubMed Central

The effects of hyperbaric helium pressures on the growth and metabolism of the deep-sea isolate ES4 were investigated. In a stainless steel reactor, cell growth was completely inhibited but metabolic gas production was observed. From 85 to 100°C, CO2 production proceeded two to three times faster at 500 atm (1 atm = 101.29 kPa) than at 8 atm. At 105°C, no CO2 was produced until the pressure was increased to 500 atm. Hydrogen and H2S were also produced biotically but were not quantifiable at pressures above 8 atm because of the high concentration of helium. In a glass-lined vessel, growth occurred but the growth rate was not accelerated by pressure. In most cases at temperatures below 100°C, the growth rate was lower at elevated pressures; at 100°C, the growth rates at 8, 250, and 500 atm were nearly identical. Unlike in the stainless steel vessel, CO2 production was exponential during growth and continued for only a short time after growth. In addition, relatively little H2 was produced in the glass-lined vessel, and there was no growth or gas production at 105°C at any pressure. The behavior of ES4 as a function of temperature and pressure was thus very sensitive to the experimental conditions. PMID:16348606

Nelson, Chad M.; Schuppenhauer, Michael R.; Clark, Douglas S.

1991-01-01

407

Correlation among maximal urethral closure pressure, retrograde leak point pressure, and abdominal leak point pressure in men with postprostatectomy stress incontinence  

Microsoft Academic Search

ObjectivesTo assess the correlation among abdominal leak point pressure (ALPP), maximal urethral closure pressure (MUCP), and retrograde leak point pressure (RLPP) in the evaluation of men with stress urinary incontinence (SUI) after radical prostatectomy.

Craig V. Comiter; Maryrose P. Sullivan; Subbarao V. Yalla

2003-01-01

408

Risk Assessment for Titanium Pressure Vessels Operating Inside the ARES I's Liquid Hydrogen Tank Environment  

NASA Technical Reports Server (NTRS)

Titanium alloy (Ti-6-4) is currently being proposed for the manufacturing of pressure vessels (PV) for storage of compressed helium gas, which are mounted inside the ARES I's liquid hydrogen (LH2) tank. At cryogenic temperature, titanium alloys usually have the highest strength-to-weight ratio property and have been considered as the metallic materials of choice for lightweight PV operating in LH2 environment. Titanium PV s are also considered as heritage hardware because they have been used by NASA for the Saturn IV-B rocket s LH2 tank in the mid 1960 s. However, hydrogen embrittlement is possible if Ti-6-4 alloy is exposed to gaseous hydrogen at certain pressure and temperature during the LH2 tank filling and draining operations on the launch pad, and during the J2X engine burn period for the ARES I s upper stage. Additionally, the fracture toughness and ductility properties of Ti-6-4 are significantly decreased at cryogenic temperature. These factors do not necessary preclude the use of titanium PV in hydrogen or at cryogenic applications; however, their synergistic effects and the material damage tolerance must be accounted for in the mission life assessment for PV s, which are considered as fracture critical hardware. In this paper, an overview of the risk assessment for Ti-6-4 alloy, strategy to control hydrogen embrittlement and brief metallic material trade study for PV operating in LH2 tank will be presented.

Lee, Jonathan A.

2008-01-01

409

Dome Shape Optimization of Composite Pressure Vessels Based on Rational B-Spline Curve and Genetic Algorithm  

NASA Astrophysics Data System (ADS)

This paper presents an algorithm for shape optimization of composite pressure vessels head. The shape factor which is defined as the ratio of internal volume to weight of the vessel is used as an objective function. Design constrains consist of the geometrical limitations, winding conditions, and Tsai-Wu failure criterion. The geometry of dome shape is defined by a B-spline rational curve. By altering the weights of control points, depth of dome, and winding angle, the dome shape is changed. The proposed algorithm uses genetic algorithm and finite element analysis to optimize the design parameters. The algorithm is applied on a CNG pressure vessel and the results show that the proposed algorithm can efficiently define the optimal dome shape. This algorithm is general and can be used for general shape optimization.

Vafaeesefat, Abbas

2009-10-01

410

Simplified modeling of a PWR reactor pressure vessel lower head failure in the case of a severe accident  

Microsoft Academic Search

In order to characterize the timing, mode and size of a possible lower head failure (LHF) of the reactor pressure vessel (RPV) in the event of a core meltdown accident, several large-scale LHF experiments were performed under the USNRC\\/SNL LHF program. The experiments examined lower head failure at high pressures (10MPa in most cases) and with small throughwall temperature differentials.

V. Koundy; M. Durin; L. Nicolas; A. Combescure

2005-01-01

411

Surface spectroscopy of pressure vessel steel fatigue fracture surface films formed in PWR (pressurized water reactor) environments  

SciTech Connect

The composition and structure of corrosion products formed on corrosion fatigue fracture surfaces of pressure vessel steels tested in PWR-water conditions have been analyzed by using X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) techniques. This was the first time these electron spectroscopic techniques have been applied to corrosion fatigue fracture surface studies. The oxide phase on the corrosion fatigue fracture surfaces was Fe/sub 3/O/sub 4/ (magnetite) in all the specimens. Small amounts of sulfur (typically about 3 atomic percent) were present in the oxide film mainly as FeS/sub 2/. In specimens showing the highest crack growth rates, the amount of sulfur was about doubled near the crack tip as compared to the value obtained further behind the crack tip in the middle of the fracture surface. It was possible to locate the crack-tip condition on the high-temperature Pourbaix diagram in the area where both magnetite and FeS/sub 2/ are stable phases. The anticipated crack-tip conditions are that the corrosion potential is about -500 mV(SHE) or less and the pH value is neutral or slightly acid. XPS and AES analyses of the corrosion fatigue fracture surfaces were found to reveal the possible water chemistry impurities during the corrosion fatigue tests, like Cl, Na, Ca, etc.

Hanninen, H.E.; Vulli, M.; Cullen, W.H.

1987-07-01

412

Direct measurement of reactor pressure vessel steels fracture toughness: Master Curve concept and instrumented Charpy-V test  

Microsoft Academic Search

One of the key issues concerning the structural integrity of reactor pressure vessel is the effect of neutron irradiation on the material fracture toughness. At present, this is achieved indirectly by means of correlation between Charpy and fracture toughness due to neutron irradiation. The uncertainties associated with this indirect determination have increased the need for a direct measurement of the

M. Serrano; F. J. Perosanz; J. Lapeña

2000-01-01

413

REACTOR PRESSURE VESSEL REMOVAL AT A BOILING WATER REACTOR WITH SPENT FUEL IN THE ADJACENT FUEL POOL  

Microsoft Academic Search

A Reactor Pressure Vessel Removal Feasibility Study was prepared for use in the decommissioning planning for the Oyster Creek Nuclear Generating Station. The primary consideration of this study was to determine if the RPV could be safely removed from a boiling water reactor with spent fuel in the adjacent spent fuel storage pool. The scope of the study included: ?

Albert A. Freitag

2000-01-01

414

An experimental study of assessment of weld quality on fatigue reliability analysis of a nuclear pressure vessel  

Microsoft Academic Search

The steam generator in a PWR primary coolant system is one of the pieces of equipment made in China for the Qinshan nuclear power plant, Zhejiang. It is a crucial unit belonging to the category of nuclear pressure vessel. The purpose of this research work is to carry out an examination of the weld quality of the steam generator under

Shu-Ho Dai; Shuho

1993-01-01

415

Influences of welding processes on fatigue life of cruciform joints of pressure vessel grade steels containing LOP defects  

Microsoft Academic Search

The influences of two welding processes, namely, shielded metal arc welding (SMAW) and flux cored arc welding (FCAW), on fatigue life of cruciform joints, containing lack of penetration (LOP) defects, have been studied. Load carrying cruciform joints were fabricated from high strength, quenched and tempered steels of pressure vessel (ASTM 517 ‘F’) grade. Fatigue crack growth experiments were carried out

V Balasubramanian; B Guha

2000-01-01

416

Instability and "Sausage-String" Appearance in Blood Vessels during High Blood Pressure  

E-print Network

A new Rayleigh-type instability is proposed to explain the `sausage-string' pattern of alternating constrictions and dilatations formed in blood vessels under influence of a vasoconstricting agent. Our theory involves the nonlinear elasticity characteristics of the vessel wall, and provides predictions for the conditions under which the cylindrical form of a blood vessel becomes unstable.

Alstrøm, P; Colding-Jorgensen, M; Gustafsson, F; Holstein-Rathlou, N H; Alstrom, Preben; Eguiluz, Victor M.; Colding-Jorgensen, Morten; Gustafsson, Finn; Holstein-Rathlou, Niels-Henrik

1999-01-01

417

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

418

Radiological characterization of the pressure vessel internals of the BNL High Flux Beam Reactor.  

PubMed

In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, measurements and calculations of the decay gamma-ray dose-rate were performed in the reactor pressure vessel and on vessel internal structures such as the upper and lower thermal shields, the Transition Plate, and the Control Rod blades. Measurements of gamma-ray dose rates were made using Red Perspex polymethyl methacrylate high-dose film, a Radcal "peanut" ion chamber, and Eberline's RO-7 high-range ion chamber. As a comparison, the Monte Carlo MCNP code and MicroShield code were used to model the gamma-ray transport and dose buildup. The gamma-ray dose rate at 8 cm above the center of the Transition Plate was measured to be 160 Gy h (using an RO-7) and 88 Gy h at 8 cm above and about 5 cm lateral to the Transition Plate (using Red Perspex film). This compares with a calculated dose rate of 172 Gy h using Micro-Shield. The gamma-ray dose rate was 16.2 Gy h measured at 76 cm from the reactor core (using the "peanut" ion chamber) and 16.3 Gy h at 87 cm from the core (using Red Perspex film). The similarity of dose rates measured with different instruments indicates that using different methods and instruments is acceptable if the measurement (and calculation) parameters are well defined. Different measurement techniques may be necessary due to constraints such as size restrictions. PMID:15220719

Holden, Norman E; Reciniello, Richard N; Hu, Jih-Perng

2004-08-01

419

Neutron spectra at different High Flux Isotope Reactor (HFIR) pressure vessel surveillance locations  

SciTech Connect

This project addresses the potential problem of radiation embrittlement of reactor pressure vessel (RPV) supports. Surveillance specimens irradiated at the High Flux Isotope Reactor (HFIR) at relatively low neutron flux levels (about 1.5E + 8 cm{sup {minus}2}.s{sup {minus}1}) and low temperatures (about 50{degrees}C) showed embrittlement more rapidly than expected. Commercial power reactors have similar flux levels and temperatures at the level vessel support structures. The purposes of this work are to provide the neutron fluence spectra data that are needed to evaluate previously measured mechanical property changes in the HFIR, to explain the discrepancies in neutron flux levels between the nickel dosimeters and two other dosimeters, neptunium and beryllium, and to address any questions or peculiarities of the HFIR reactor environment. The current work consists of neutron and gamma transport calculations, dosimetry measurements, and least-squares logarithmic adjustment to obtain the best estimates for the neutron spectra and the related neutron exposure parameters. The results indicate that the fission rates in neptunium-237 (Np-237) and uranium-238 (U-238) and the helium production rates in beryllium-9 (Be-9) are dominated by photo-induced reactions. The displacements per atom rate for iron (dpa/s) from gamma rays is five times higher than the dpa/s from neutrons. The neutron fluxes in key 7, position 5 do not show any significant gradient in the surveillance capsule, but key 4 and key 2 showed differences in magnitude as well as in the shape of the spectrum. The stainless steel monitor in the V-notch of the Charpy specimens of the surveillance capsules is adequate to determine the neutron flux above 1.0 MeV at the desired V-notch location. Simultaneous adjustment of neutron and gamma fluxes with the measurements has been demonstrated and should avoid future problems with photo-induced reactions.

Remec, I. [Josef Sefan Inst., Ljubljana (Slovenia); Kam, F.B. [Oak Ridge National Lab., TN (United States)

1993-12-01

420

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

421

Vessel failure time for a low-pressure short-term station blackout in a BWR-4  

SciTech Connect

A low-pressure, short-term station blackout severe accident sequence has been analyzed using the MELCOR code, version 1.8.1, in a boiling water reactor (BWR)-4. This paper presents a sensitivity study evaluating the effect of several MELCOR input parameters on vessel failure time. Results using the MELCOR/CORBH package and the BWRSAR code are also presented and compared to the MELCOR results. These calculated vessel failure times are discussed, and a judgment is offered as to which is the most realistic.

Carbajo, J.J. (Martin Marietta Energy System, Oak Ridge, TN (United States))

1993-01-01

422

Discrete Element Simulations of Floor Pressure due to a Granular Material in a Cylindrical Vessel  

NASA Astrophysics Data System (ADS)

At the end of the 19th century, H. A. Janssen discovered that the floor pressure in a cylindrical container of granular material asymptotes exponentially to a value less than the weight of the material i.e., the pressure becomes independent of the fill height of the column. This phenomenon is investigated using discrete element simulations of inelastic, frictional spheres in a cylindrical vessel having a particle-to-cylinder diameter ratio at approximately 13.3 or 26.6, with varying bed heights in both cases. The load experienced by a piston that is supporting the granular column are computed. In order to activate frictional forces at the wall contacts either the piston (or equivalently the cylinder wall), is slowly displaced at a constant rate so as to maintain quasi-static conditions. Various combinations of wall and inter-particle friction coefficients are examined. The simulated behavior of the load vs. fill level was found to fit well to the functional form of Janssen's theory. Moreover, quantitative comparisons are in agreement with experimental measurements from the literature. The effect of a tangential force applied to the surface of the particles at the contact point rather than the center of the particle is also analyzed. The tangential force causes a torque on the particle, which consequently causes a rotation of the particle. The rate of rotation is proportional to the wall friction coefficient. It is shown that an increase in the wall friction coefficient may not increase the resistance to sliding. However, the increase in wall friction coefficient causes a higher particle angular velocity, which acts like lubrication at the wall causing a higher load then expected. These rotations cause a violation of Janssen's assumption that frictional forces are fully activated.

Chester, Shawn; Cui, Meng; Rosato, Anthony; Walton, Otis

2009-06-01

423

Evolution of Nickel-Manganese-Silicon Dominated Phases in Highly Irradiated Reactor Pressure Vessel Steels  

SciTech Connect

Formation of a high density of Ni-Mn-Si nm-scale precipitates in irradiated reactor pressure vessel steels, both with and without Cu, could lead to severe embrittlement. Models long ago predicted that these precipitates, which are not treated in current embrittlement regulations, would emerge only at high fluence. However, the mechanisms and variables that control Ni-Mn- Si precipitate formation, and their detailed characteristics, have not been well understood. High flux irradiations of six steels with systematic variations in Cu and Ni were carried out at ˜ 295±5°C to high and very high neutron fluences of ˜ 1.3x1020 and 1.1x1021 n/cm2. Atom probe tomography (APT) shows that significant mole fractions of these precipitates form in the Cu bearing steels at ˜ 1.3x1020 n/cm2, while they are only beginning to develop in Cu-free steels. However, large mole fractions, far in excess of those found in previous studies, are observed at 1.1x1021 n/cm2 at all Cu levels. The precipitates diffract, and in one case are compositionally and structurally consistent with the Mn6Ni16Si7 G-phase. At the highest fluence, the large precipitate mole fractions primarily depend on the steel Ni content, rather than Cu, and lead to enormous strength increases up to about 700 MPa. The implications of these results to light water reactor life extension are discussed briefly.

Peter B Wells; Yuan Wu; Tim Milot; G. Robert Odette; Takuya Yamamoto; Brandon Miller; James Cole

2014-11-01

424

Metallographic and hardness examinations of TMI-2 lower pressure vessel head samples  

SciTech Connect

Fifteen steel samples were removed from the lower pressure vessel head of the damaged TMI-2 nuclear reactor to assess the thermal threat to the head posed by 15 to 20 metric tons of molten core debris relocating there during the accident. Full sections of thirteen of the samples and partial sections of the other two samples underwent hardness and metallographic examinations at the Idaho National Engineering Laboratory. These examinations have shown that eleven of the fifteen samples did not exceed the ferrite-austenite transformation temperature of 727 C during the accident. The remaining four samples did show evidence of having a much more severe thermal history. The samples from core grid positions F-10 and G-8 are believed to have experienced temperatures of 1,040 to 1,060 C for about 30 minutes. Samples from positions E-8 and E-6 appear to have been subjected to 1,075 to 1,100 C for approximately 30 minutes.

Korth, G. E. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

1994-03-01

425

Effects of thermal annealing and reirradiation on toughness of reactor pressure vessel steels  

SciTech Connect

One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response, or {open_quotes}recovery,{close_quotes} of several irradiated RPV steels; it also includes recent results from both ORNL and the Russian Research Center-Kurchatov Institute (RRC-KI) on a cooperative program of irradiation, annealing and reirradiation of both U.S. and Russian RPV steels. The cooperative program was conducted under the auspices of Working Group 3, U.S./Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS). The materials investigated are an RPV plate and various submerged-arc welds, with tensile, Charpy impact toughness, and fracture toughness results variously determined. Experimental results are compared with applicable prediction guidelines, while observed differences in annealing responses and reirradiation rates are discussed.

Nanstad, R.K.; Iskander, S.K.; Sokolov, M.A. [and others

1996-12-31

426

Effects of thermal annealing and reirradiation on toughness of reactor pressure vessel steels  

SciTech Connect

One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response, or {open_quotes}recovery,{close_quotes} of several irradiated RPV steels; it also includes recent results from both ORNL and the Russian Research Center-Kurchatov Institute (RRC-KI) on a cooperative program of irradiation, annealing and reirradiation of both U.S. and Russian RPV steels. The cooperative program was conducted under the auspices of Working Group 3, U.S./Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS). The materials investigated are an RPV plate and various submerged-arc welds, with tensile, Charpy impact toughness, and fracture toughness results variously determined. Experimental results are compared with applicable prediction guidelines, while observed differences in annealing responses and reirradiation rates are discussed.

Nanstad, R.K.; Iskander, S.K.; Sokolov, M.A. [Oak Ridge National Lab., TN (United States)] [and others

1997-02-01

427

Use of CPXSD for generation of effective fast multigroup libraries for pressure vessel fluence calculations  

SciTech Connect

Multigroup (i.e., broad-group) libraries play a significant role in the accuracy of transport calculations. There are several broad-group libraries available for particular applications. For example the 47-neutron (26 fast groups), 20-gamma-group BUGLE libraries are commonly used for light water reactor shielding and pressure vessel dosimetry problems. However, there is no publicly available methodology to construct group structures for a problem and objective of interest. Therefore, we have developed the Contribution and Point-wise Cross-Section Driven (CPXSD) methodology, which constructs effective fine-and broad-group structures. In this paper, we use the CPXSD methodology to construct broad-group structures for fast neutron dosimetry problems. It is demonstrated that the broad-group libraries generated from CPXSD constructed group structures, while only 14 groups (rather than 26 groups) in the fast energy range are in good agreement (similar to 1 %-2 %) with the fine-group library from which they were derived, in reaction rate calculations.

Alpan, F Arzu [ORNL; Haghighat, Alireza [University of Florida

2008-01-01

428

Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels  

SciTech Connect

One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 10{sup 19} n/cm{sup 2} (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 10{sup 19} n/cm{sup 2} (>l MeV). In both cases, irradiations were conducted at {approximately}290 C and annealing treatments were conducted at {approximately}454 C. The ORNL and RRC-RI experiments have shown generally good agreement for both the Russian and U.S. steels. While recoveries of the Charpy 41-J transition temperatures were substantial in all cases, significantly less recovery of the lateral expansion and shear fracture in some cases (no recovery in one case) deserves further attention. The RRC-KI results for the U.S. steels showed reirradiation embrittlement rates which are conservative relative to the lateral shift prediction based on Charpy impact energy.

Chernobaeva, A.A.; Korolev, Y.N.; Nanstad, R.K.; Nikolaev, Y.A.; Sokolov, M.A.

1998-06-16

429

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

430

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

431

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

432

Effects of neutron-irradiation-induced intergranular phosphorus segregation and hardening on embrittlement in reactor pressure vessel steels  

Microsoft Academic Search

The effects of intergranular P segregation and hardening on the ductile-to-brittle transition temperature (DBTT) in several neutron-irradiated reactor pressure vessel steels with different bulk contents of P and Cu have been investigated using a scanning Auger microbe, a local electrode atom probe and positron annihilation spectroscopy. Increasing the neutron fluence at 563K promotes intergranular P segregation, particularly in steels with

Y. Nishiyama; K. Onizawa; M. Suzuki; J. W. Anderegg; Y. Nagai; T. Toyama; M. Hasegawa; J. Kameda

2008-01-01

433

Peripheral Microvascular Responses to Whole-Body Tilting, G(z) Centrifugation, and Lower Body Negative Pressure Stresses in Humans  

NASA Technical Reports Server (NTRS)

The response of the cutaneous microcirculation to orthostatic stress varies along the length of the body due to the interaction of central controls with regional responses to local blood pressure. We hypothesize that artificial orthostatic stresses such as Gz centrifugation and LBNP differ from whole-body tilting in terms of the distribution of microvascular blood flow. Cutaneous microvascular flows were measured by laser Doppler flowmetry at the neck, thigh, and leg of 15 normal subjects. Volunteers underwent stepwise head-up tilt (HUT) and short- and long-arm centrifugation protocols from supine control (0 Gz) to 0.2, 0.4, 0.6, 0.8, 1.0, 0.8, 0.6, 0.4, 0.2, and 0 Gz at the feet, for 30-s periods with 10-s transitions between levels. The same subjects underwent a corresponding supine LBNP protocol, up to 100 mmHg (in 20 mmHg increments) and back to zero pressure, which produced transmural pressure across blood vessels in the foot approximately equal to the HUT protocol. In general, application of all orthostatic stresses produced significant flow reductions in the lower body (p less than 0.05) and inconsistent changes in the neck. At low levels of each stress (0.4 Gz, 40 mmHg), LBNP generated the greatest relative reduction in flow in the lower body (-66.9+/-5.7%, thigh; -60.6 +/-5.7%, leg, mean +/- SE). HUT caused a less severe flow reduction than LBNP at the thigh and leg (-39.9 +/- 8.1% and -55.9+/-4.8%), while the effects induced by both forms of centrifugation were the least profound. Higher levels of each stress generally resulted in similar responses. These responses exhibit a consistent relationship to hypothesized changes in local microvascular transmural pressure, suggesting that myogenic and veno-arteriolar reflexes play a significant role in determining microvascular perfusion during orthostatic stress.

Breit, G. A.; Watenpaugh, D. E.; Buckley, T. M.; Ballard, R. E.; Murthy, G.; Hargens, A. R.

1994-01-01

434

Pressure Raman effects and internal stress in network glasses  

E-print Network

Raman scattering from binary GexSe1-x glasses under hydrostatic pressure shows onset of a steady increase in the frequency of modes of corner-sharing GeSe4 tetrahedral units when the external pressure P exceeds a threshold value Pc. The threshold pressure Pc(x) decreases with x in the 0.15 < x < 0.20 range, nearly vanishes in the 0.20 < x < 0.25 range, and then increases in the 0.25 < x < 1/3 range. These Pc(x) trends closely track those in the non-reversing enthalpy, DHnr(x), near glass transitions (Tgs), and in particular, both DHnr(x) and Pc(x) vanish in the reversibility window (0.20 < x < 0.25). It is suggested that Pc provides a measure of stress at the Raman active units; and its vanishing in the reversibility window suggests that these units are part of an isostatically rigid backbone. Isostaticity also accounts for the non-aging behavior of glasses observed in the reversibility window.

Fei Wang; S. Mamedov; P. Boolchand; B. Goodman; Meera Chandrasekhar

2007-09-27

435

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

436

Spin-rolling, welding, and heat treatment of aluminium 2219 for Ariane 5 GAM high pressure vessel liners  

NASA Astrophysics Data System (ADS)

Cylindrical liners made of Al 2219 may be spinrolled if both recrystallization and metastable precipitates can be avoided during forging or preparatory heat treatment. So welding is to be limited to circumferential joints. Pore-free welds are attainable immediately after hydroxide layer removal by diamond cutting without grease application. The EB vacuum is favorable to porosity suppression. A complete heat treatment of the liner incorporating solutionizing, water quenching and ageing leads to 100 percent weld efficiency. Pressure stabilization avoids buckling. Subsequent carbon fiber winding, curing and plastic prestressing of the liner results in an efficient high pressure vessel for hydrogen service.

Radtke, W.

1992-10-01

437

Blood pressure regulation V: in vivo mechanical properties of precapillary vessels as affected by long-term pressure loading and unloading.  

PubMed

Recent studies are reviewed, concerning the in vivo wall stiffness of arteries and arterioles in healthy humans, and how these properties adapt to iterative increments or sustained reductions in local intravascular pressure. A novel technique was used, by which arterial and arteriolar stiffness was determined as changes in arterial diameter and flow, respectively, during graded increments in distending pressure in the blood vessels of an arm or a leg. Pressure-induced increases in diameter and flow were smaller in the lower leg than in the arm, indicating greater stiffness in the arteries/arterioles of the leg. A 5-week period of intermittent intravascular pressure elevations in one arm reduced pressure distension and pressure-induced flow in the brachial artery by about 50%. Conversely, prolonged reduction of arterial/arteriolar pressure in the lower body by 5 weeks of sustained horizontal bedrest, induced threefold increases of the pressure-distension and pressure-flow responses in a tibial artery. Thus, the wall stiffness of arteries and arterioles are plastic properties that readily adapt to changes in the prevailing local intravascular pressure. The discussion concerns mechanisms underlying changes in local arterial/arteriolar stiffness as well as whether stiffness is altered by changes in myogenic tone and/or wall structure. As regards implications, regulation of local arterial/arteriolar stiffness may facilitate control of arterial pressure in erect posture and conditions of exaggerated intravascular pressure gradients. That increased intravascular pressure leads to increased arteriolar wall stiffness also supports the notion that local pressure loading may constitute a prime mover in the development of vascular changes in hypertension. PMID:24318655

Eiken, Ola; Mekjavic, Igor B; Kölegård, Roger

2014-03-01

438

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

NASA Astrophysics Data System (ADS)

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; Lam, Poh-Sang

1995-02-01

439

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

440

46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).  

Code of Federal Regulations, 2011 CFR

...boilers must be constructed in accordance with part 52 of this subchapter. (b) Vessels known as “Evaporators” or “Heat Exchangers” are not classified as unfired steam boilers. They shall be fitted with an approved safety device as required...

2011-10-01

441

46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).  

Code of Federal Regulations, 2012 CFR

...boilers must be constructed in accordance with part 52 of this subchapter. (b) Vessels known as “Evaporators” or “Heat Exchangers” are not classified as unfired steam boilers. They shall be fitted with an approved safety device as required...

2012-10-01

442

46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).  

Code of Federal Regulations, 2010 CFR

...boilers must be constructed in accordance with part 52 of this subchapter. (b) Vessels known as “Evaporators” or “Heat Exchangers” are not classified as unfired steam boilers. They shall be fitted with an approved safety device as required...

2010-10-01

443

Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV using Temperature and Pressure Acceleration  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessel (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Sometimes lifetime testing is performed on an actual COPV in service in an effort to validate the reliability model that is the basis for certifying the continued flight worthiness of its sisters. Currently, testing of such a Kevlar49(registered TradeMark)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the data base and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one nine , that is, reducing the probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several would be necessary.

Phoenix, S. Leigh; Kezirian, Michael T.; Murthy, Pappu L. N.

2009-01-01

444

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

445

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

446

Contact Pressure and Shear Stress Analysis on Conforming Contact Problem  

NASA Astrophysics Data System (ADS)

Two methods to solve a conforming contact problem are proposed. First method is general and can be applicable to the contact case between elastic arbitrary shape bodies. For verification FEA is performed on the convex-concave sphere contact, and the result of this method is well corresponding to the FEA result. However, the accuracy deteriorates when the mesh aspect ratio is extremely large. This phenomenon is caused by the usage of numerical integration for the calculation of influence coefficient. The second method is devised to avoid this problem, while this improved method is applicable only to the case when the contact area can be considered to be on a cylinder surface. By using this method, the contact pressure can be obtained without the deterioration even in the case of edge load occurring between ball bearing race shoulder and ball. The results of the contact pressure and the shear stress that is necessary for bearing life estimation are compared with the FEA result, which showed well correspondence.

Nagatani, Haruo; Imou, Akitoshi

447

A New Computerized Biomechanical Perfusion Model for ex vivo Study of Fluid Mechanical Forces in Intact Conduit Vessels  

Microsoft Academic Search

We have developed a new computerized biomechanical ex vivo perfusion system for intact conduit vessels in which a wide range of combinations of intraluminal pressure, fluid flow and shear stress could be set and maintained at target levels in mammalian conduit vessels under controlled metabolic conditions. Mean wall shear stress is calculated using the formula:Accuracy of the wall shear stress

Li-ming Gan; Lena Selin Sjögren; Roya Doroudi; Sverker Jern

1999-01-01

448

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

449

Proof test criteria for thin-walled 2219 aluminum pressure vessels. Volume 1: Program summary and data analysis  

NASA Technical Reports Server (NTRS)

This experimental program was undertaken to investigate the crack growth behavior of deep surface flaws in 2219 aluminum. The program included tests of uniaxially loaded surface flaw and center crack panels at temperatures ranging from 20K (-423 F) to ambient. The tests were conducted on both the base metal and as-welded weld metal material. The program was designed to provide data on the mechanisms of failure by ligament penetration, and the residual cyclic life, after proof-testing, of a vessel which has been subjected to incipient penetration by the proof test. The results were compared and analyzed with previously developed data to develop guidelines for the proof testing of thin walled 2219 pressure vessels.

Finger, R. W.

1976-01-01

450

Blood Pressure Reactions to Acute Psychological Stress and Future Blood Pressure Status: A 10Year Follow-Up of Men in the Whitehall II Study  

Microsoft Academic Search

Objective: The aim of this study was to examine whether blood pressure reactions to mental stress predicted future blood pressure and hypertension. Methods: Blood pressure was recorded at an initial medical screening examina- tion after which blood pressure reactions to a mental stress task were determined. A follow-up screening assessment of blood pressure and antihypertensive medication status was undertaken 10

DOUGLAS CARROLL; GEORGE DAVEY SMITH; MARTIN J. SHIPLEY; ERIC J. BRUNNER; MICHAEL G. MARMOT

451

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

452

Differential effects of alprazolam and clonazepam on the immune system and blood vessels of non-stressed and stressed adult male albino rats  

PubMed Central

Benzodiazepines belongs to one of the most commonly used anxiolytic and anticonvulsant drugs in the world. Full description of toxic effects on different organs is lacking for nearly all the current benzodiazepines. The aim of the current work was to study the immunologic and vascular changes induced by sub-chronic administration of alprazolam and clonazepam in non-stressed and stressed adult male albino rats. Forty-two adult male albino rats were divided into 6 groups (I): (Ia) Negative control rats, (Ib): Positive control rats received distilled water, (II): Stressed rats, (III): Non-stressed rats received daily oral dose of clonazepam (0.5 mg/kg), (IV): Stressed rats received daily oral dose of clonazepam (0.5 mg/kg), (V): Non-stressed rats received daily oral dose of alprazolam (0.3 mg/kg). (VI): Stressed rats received daily oral dose of alprazolam (0.3 mg/kg). At the end of the 4th week, total leukocyte count (WBCs) and differential count were determined, anti-sheep RBC antibody (Anti-SRBC) titer and interleukin-2 (IL-2) level were assessed, thymus glands, lymph nodes, spleens and abdominal aortae were submitted to histopathological examination. Alprazolam was found to induce a significant increase in neutrophil count and a significant decrease in lymphocytes, anti-SRBC titer and IL-2 level with severe depletion of the splenic, thymal and nodal lymphocytes, accompanied by congestion and eosinophilic vasculitis of all organs tested in comparison to clonazepam treated rats. Stress enhanced the toxic effects. It was concluded that the immune system and blood vessels can be adversely affected to a greater extent by short-term chronic administration of alprazolam than by clonazepam, and these toxic effects are aggravated by stress. PMID:22058654

Elmesallamy, Ghada E.; Abass, Marwa A.; Ahmed Refat, Nahla A.G.; Atta, Amal H.

2011-01-01

453

Blood pressure regulation VIII: resistance vessel tone and implications for a pro-atherogenic conduit artery endothelial cell phenotype.  

PubMed

Dysfunction of the endothelium is proposed as the primary initiator of atherosclerotic peripheral artery disease, which occurs mainly in medium- to large-sized conduit arteries of the lower extremities (e.g., iliac, femoral, popliteal arteries). In this review article, we propose the novel concept that conduit artery endothelial cell phenotype is determined, in part, by microvascular tone in skeletal muscle resistance arteries through both changes in arterial blood pressure as well as upstream conduit artery shear stress patterns. First, we summarize the literature supporting the involvement of sympathetic nerve activity (SNA) and nitric oxide (NO) in the modulation of microvascular tone and arterial blood pressure. We then focus on the role of elevated blood pressure and shear stress profiles in modulating conduit artery endothelial cell phenotype. Last, we discuss findings from classic and emerging studies indicating that increased vascular resistance, as it occurs in the context of increased SNA and/or reduced NO bioavailability, is associated with greater oscillatory shear stress (e.g., increased retrograde shear) in upstream conduit arteries. The ideas put forth in this review set the stage for a new paradigm concerning the mechanistic link between increased microvascular tone and development of conduit artery endothelial dysfunction and thus increased risk for peripheral artery disease. Indeed, a vast amount of evidence supports the notion that excessive blood pressure and oscillatory shear stress are potent pro-atherogenic signals to the endothelium. PMID:23860841

Padilla, Jaume; Jenkins, Nathan T; Laughlin, M Harold; Fadel, Paul J

2014-03-01

454

10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.  

Code of Federal Regulations, 2014 CFR

...Charpy upper-shelf energy due to the thermal annealing treatment...the actual vessel thermal anneal. The recovery...Charpy upper-shelf energy provide the basis...profiles of the actual thermal annealing; ...Charpy upper-shelf energy values of the...

2014-01-01

455

10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.  

Code of Federal Regulations, 2011 CFR

...Charpy upper-shelf energy due to the thermal annealing treatment...the actual vessel thermal anneal. The recovery...Charpy upper-shelf energy provide the basis...profiles of the actual thermal annealing; ...Charpy upper-shelf energy values of the...

2011-01-01

456

10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.  

Code of Federal Regulations, 2010 CFR

...Charpy upper-shelf energy due to the thermal annealing treatment...the actual vessel thermal anneal. The recovery...Charpy upper-shelf energy provide the basis...profiles of the actual thermal annealing; ...Charpy upper-shelf energy values of the...

2010-01-01

457

10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.  

Code of Federal Regulations, 2012 CFR

...Charpy upper-shelf energy due to the thermal annealing treatment...the actual vessel thermal anneal. The recovery...Charpy upper-shelf energy provide the basis...profiles of the actual thermal annealing; ...Charpy upper-shelf energy values of the...

2012-01-01

458

10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.  

Code of Federal Regulations, 2013 CFR

...Charpy upper-shelf energy due to the thermal annealing treatment...the actual vessel thermal anneal. The recovery...Charpy upper-shelf energy provide the basis...profiles of the actual thermal annealing; ...Charpy upper-shelf energy values of the...

2013-01-01

459

Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR plants  

SciTech Connect

Recent data from the HFIR vessel surveillance program indicate a substantial radiation embrittlement rate effect at low irradiation temperatures (/approximately/120/degree/F) for A212-B, A350-LF3, A105-II, and corresponding welds. PWR vessel supports are fabricated of similar materials and are subjected to the same low temperatures and fast neutron fluxes (10/sup 8/ to 10/sup 9/ neutrons/cm/sup 2//center dot/s, E > 1.0 MeV) as those in the HFIR vessel. Thus, the embrittlement rate of these structures may be greater than previously anticipated. A study sponsored by the NRC is under way at ORNL to determine the impact of the rate effect on PWR vessel-support life expectancy. The scope includes the interpretation and application of the HFIR data, a survey of all light-water-reactor vessel support designs, and a structural and fracture-mechanics analysis of the supports for two specific PWR plants of particular interest with regard to a potential for support failure as a result of propagation of flaws. Calculations performed thus far indicate best-estimate critical flaw sizes, corresponding to 32 EFPY, of /approximately/0.2 in. for one plant and /approximately/0.4 in. for the other. These flaw sizes are small enough to be of concern. However, it appears that low-cycle fatigue is not a viable mechanism for creation of flaws of this size, and thus, presumably, such flaws would have to exist at the time of fabrication. 59 refs., 128 figs., 49 tabs.

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

1989-01-01

460

Comparison of microstructural features of radiation embrittlement of VVER-440 and VVER-1000 reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

Comparative microstructural studies of both surveillance specimens and reactor pressure vessel (RPV) materials of VVER-440 and VVER-1000 light water reactor systems have been carried out, following irradiation to different fast neutron fluences and of the heat treatment for extended periods at the operating temperatures. It is shown that there are several microstructural features in the radiation embrittlement of VVER-1000 steels compared to VVER-440 RPV steels that can cause changes in the contributions of different radiation embrittlement mechanisms for VVER-1000 steel.

Kuleshova, E. A.; Gurovich, B. A.; Shtrombakh, Ya. I.; Erak, D. Yu.; Lavrenchuk, O. V.

2002-02-01