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1

Exact solutions for stresses in functionally graded pressure vessels  

Microsoft Academic Search

Closed-form solutions for stresses and displacements in functionally graded cylindrical and spherical vessels subjected to internal pressure alone are obtained using the infinitesimal theory of elasticity. The material stiffness obeying a simple power law is assumed to vary through the wall thickness and Poisson's ratio is assumed constant. Stress distributions depending on an inhomogeneity constant are compared with those of

Naki Tutuncu; Murat Ozturk

2001-01-01

2

Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

3

Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifing Philosophy  

NASA Technical Reports Server (NTRS)

The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle's Kevlar-49 fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed non-conservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic-plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23% lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

Thesken, John C.; Murthy, Pappu L. N.; Phoenix, Leigh

2007-01-01

4

Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifting Philosophy  

NASA Technical Reports Server (NTRS)

The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle s Kevlar-49 (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed nonconservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23 percent lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.

2009-01-01

5

Residual stresses in weld deposited clad pressure vessels and nozzles  

SciTech Connect

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

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

1998-04-01

6

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

7

Stress Rupture Life Reliability Measures for Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases onboard spacecraft. Kevlar (DuPont), glass, carbon and other more recent fibers have all been used as overwraps. Due to the fact that overwraps are subjected to sustained loads for an extended period during a mission, stress rupture failure is a major concern. It is therefore important to ascertain the reliability of these vessels by analysis, since the testing of each flight design cannot be completed on a practical time scale. The present paper examines specifically a Weibull statistics based stress rupture model and considers the various uncertainties associated with the model parameters. The paper also examines several reliability estimate measures that would be of use for the purpose of recertification and for qualifying flight worthiness of these vessels. Specifically, deterministic values for a point estimate, mean estimate and 90/95 percent confidence estimates of the reliability are all examined for a typical flight quality vessel under constant stress. The mean and the 90/95 percent confidence estimates are computed using Monte-Carlo simulation techniques by assuming distribution statistics of model parameters based also on simulation and on the available data, especially the sample sizes represented in the data. The data for the stress rupture model are obtained from the Lawrence Livermore National Laboratories (LLNL) stress rupture testing program, carried out for the past 35 years. Deterministic as well as probabilistic sensitivities are examined.

Murthy, Pappu L. N.; Thesken, John C.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie

2007-01-01

8

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

9

Minimization of stress concentration factor in cylindrical pressure vessels with ellipsoidal heads  

Microsoft Academic Search

The paper presents the problem of stress concentration in a cylindrical pressure vessel with ellipsoidal heads subject to internal pressure. At the line, where the ellipsoidal head is adjacent to the circular cylindrical shell, a shear force and bending moment occur, disturbing the membrane stress state in the vessel. The degree of stress concentration depends on the ratio of thicknesses

K Magnucki; W Szyc; J Lewi?ski

2002-01-01

10

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

Microsoft Academic Search

Analyses were performed to determine the impact of weld residual stresses in a reactor pressure vessel (RPV) on (1) the generation of pressure temperature (P-T) curves required for maintaining specified fracture prevention margins during nuclear plant startup and shutdown, and (2) the conditional probability of vessel failure due to pressurized thermal shock (PTS) loading. The through wall residual stress distribution

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

1998-01-01

11

Strain measurements using FBG on composite over wrap pressure vessels (COPV) in stress rupture test  

NASA Astrophysics Data System (ADS)

Thirty six Fiber Optic Braggs Grating sensors were used during an ambient temperature hydrostatic pressurization testing of a Space Transportation System (STS) 40-inch Kevlar Composite Over-wrapped Pressure Vessel (COPV). The 40-inch vessel was of the same design and approximate age as the STS Main Propulsion System (MPS) and Orbiter Maneuvering System (OMS) vessels. The sensors were surfaces mounted to on the vessel to measure strain during a stress rupture event. The Bragg signals were linear with the applied pressure. The results indicated that the vessel was under an uneven force distribution at various locations on the vessel.

Grant, Joseph; Banks, Curtis

2007-03-01

12

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

13

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

SciTech Connect

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

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

1998-01-01

14

Stress analysis and evaluation of a rectangular pressure vessel. [For equipment for sampling Hanford tank radwaste  

SciTech Connect

This study addresses structural analysis and evaluation of an abnormal rectangular pressure vessel, designed to house equipment for drilling and collecting samples from Hanford radioactive waste storage tanks. It had to be qualified according to ASME boiler and pressure vessel code, Section VIII; however, it had the cover plate bolted along the long face, a configuration not addressed by the code. Finite element method was used to calculate stresses resulting from internal pressure; these stresses were then used to evaluate and qualify the vessel. Fatigue is not a concern; thus, it can be built according to Section VIII, Division I instead of Division 2. Stress analysis was checked against the code. A stayed plate was added to stiffen the long side of the vessel.

Rezvani, M.A.; Ziada, H.H. (Westinghouse Hanford Co., Richland, WA (United States)); Shurrab, M.S. (Westinghouse Savannah River Co., Aiken, SC (United States))

1992-10-01

15

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

16

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

17

BENDING STRESSES IN A PRESSURE VESSEL WITH AN INTEGRAL FLAT HEAD  

Microsoft Academic Search

Formulas were derived for maximunn bending stresses in the head and ; cylindrical shell of a pressure vessel with an integral flat head using the thin-; wall theory. Curves were plotted in nondimensional form to facilitate ; computations, and a sample problem was solved. (M.C.G.)

Deagle

1960-01-01

18

Integrity Evaluation of the Pressure Vessels of Angra-2 and Angra-3 Reactors by Stress Analysis.  

National Technical Information Service (NTIS)

The integrity of the reactor pressure vessel of the unit II/III of the Nuclear Power Station at 'Angras do Reis' is evaluated by stress analysis, through the dynamics relaxation method. For the solution of the problem an axisymmetric model is fixed. Initi...

E. Gomes

1978-01-01

19

Stress Analysis of Conical Shell Skirt Support for High Pressure Vessel Using Finite Element Method  

Microsoft Academic Search

Pressure vessel is a closed cylindrical vessel for storing gaseous, liquids or solid products. The stored medium is at a particular pressure and temperature. The cylindrical vessel is closed at both ends by means of dished head, which may be hemispherical, ellipsoidal. The pressure vessels may be horizontal or vertical. The supporting system of this vertical vessel plays an important

K. Tamil Mannan; Rakesh Saxena; R. Murugavel; P. L. Sah

2009-01-01

20

Pressure vessel improvement  

US Patent & Trademark Office Database

A multiple shell pressure vessel is fabricated in modular sections comprising a top head module, a nozzle course module and a bottom shell module, each module utilizing telescoping shells with filled interspaces, each shell being removable for inspection and repair with all modular sections and shells being held in compression by a pair of upper and lower single or multilayer tendon skirts held in place by a number of tension members in combination with hydraulic or mechanical jacks or rams. Both tendons and rams are located outside the pressure vessel. Included is a method of arranging the shell flanges and shell radial supports to reduce or eliminate torsional forces on the flanges and flange seals. A leak detection system monitors for leaks in all shells. A method of adjusting shell stresses during operation uses pumps to adjust the pressure of the filler material in the interspaces between shells. The high thermal conductivity of the outer vessel wall, which is due to good thermal bonding provided by the intershell metallic filler-materials, makes it possible to keep the pressure-carrying outer vessel shells cool during service, by cooling the outer shell by plain water, borated water for nuclear reactor vessels, or other coolant.

1992-02-11

21

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

22

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

23

Stress-intensity-factor influence coefficients for axial and circumferential flaws in reactor pressure vessels  

SciTech Connect

Weight-function techniques in linear elastic fracture mechanics utilize stress-intensity-factor influence coefficients K* and superposition principles to compute stress intensity factors. This paper presents influence coefficients for two flaw geometries often employed in fracture analyses of reactor pressure vessels: (1) infinitely long, axial, inside-surface flaws and (2) 360[degrees], circumferential, inside-surface flaws. Calculations were performed using ABAQUS, a nuclear quality assurance (NQA-1) certified finite-element program which employs a highly accurate crack extension technique for the computation of theJ-integral. Influence coefficients are computed for flaw depths in the range 0.01 [le] a/T [le] 0.9 with particular emphasis on shallow flaws (a/T [le] 0. 1). This study addresses vessels having R/T = 10 which is appropriate for most PWRs in USA. The influence coefficients have been implemented in the FAVOR fracture-mechanics code currently being developed under the NRC-funded HSST Program at ORNL.

Bryson, J.W.; Dickson, T.L.

1993-01-01

24

Stress-intensity-factor influence coefficients for axial and circumferential flaws in reactor pressure vessels  

SciTech Connect

Weight-function techniques in linear elastic fracture mechanics utilize stress-intensity-factor influence coefficients K* and superposition principles to compute stress intensity factors. This paper presents influence coefficients for two flaw geometries often employed in fracture analyses of reactor pressure vessels: (1) infinitely long, axial, inside-surface flaws and (2) 360{degrees}, circumferential, inside-surface flaws. Calculations were performed using ABAQUS, a nuclear quality assurance (NQA-1) certified finite-element program which employs a highly accurate crack extension technique for the computation of theJ-integral. Influence coefficients are computed for flaw depths in the range 0.01 {le} a/T {le} 0.9 with particular emphasis on shallow flaws (a/T {le} 0. 1). This study addresses vessels having R/T = 10 which is appropriate for most PWRs in USA. The influence coefficients have been implemented in the FAVOR fracture-mechanics code currently being developed under the NRC-funded HSST Program at ORNL.

Bryson, J.W.; Dickson, T.L.

1993-03-01

25

Stress-intensity-factor influence coefficients for axial and circumferential flaws in reactor pressure vessels  

NASA Astrophysics Data System (ADS)

Weight-function techniques in linear elastic fracture mechanics utilize stress-intensity-factor influence coefficients K* and superposition principles to compute stress intensity factors. This paper presents influence coefficients for two flaw geometries often employed in fracture analyses of reactor pressure vessels: (1) infinitely long, axial, inside-surface flaws and (2) 360 degree, circumferential, inside-surface flaws. Calculations were performed using ABAQUS, a nuclear quality assurance (NQA-1) certified finite-element program which employs a highly accurate crack extension technique for the computation of the J-integral. Influence coefficients are computed for flaw depths in the range 0.01 less than or = a/T less than or = 0.9 with particular emphasis on shallow flaws (a/T less than or = 0.1). This study addresses vessels having R/T = 10 which is appropriate for most PWR's in USA. The influence coefficients have been implemented in the FAVOR fracture-mechanics code currently being developed under the NRC-funded HSST Program at ORNL.

Bryson, J. W.; Dickson, T. L.

1993-04-01

26

Stress Rupture Testing and Analysis of the NASA WSTF-JPL Carbon Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Carbon composite overwrapped pressure vessels (COPVs) are widely used in applications from spacecraft to life support. COPV technology provides a pressurized media storage advantage over amorphous technology with weight savings on the order of 30 percent. The National Aeronautics and Space Administration (NASA) has been supporting the development of this technology since the early 1970's with an interest in safe application of these components to reduce mass to orbit. NASA White Sands Test Facility (WSTF) has been testing components in support of this objective since the 1980s and has been involved in test development and analysis to address affects of impact, propellant and cryogenic fluids exposure on Kevlar and carbon epoxy. The focus of this paper is to present results of a recent joint WSTF-Jet Propulsion Laboratories (JPL) effort to assess safe life of these components. The WSTF-JPL test articles consisted of an aluminum liner and a carbon fiber overwrap in an industry standard epoxy resin system. The vessels were specifically designed with one plus-minus helical wrap and one hoop wrap over the helical and they measured 4.23 x 11.4 in. long. 120 test articles were manufactured in August of 1998 of one lot fiber and resin and the 110 test articles were delivered to WSTF for test. Ten of the 120 test articles were burst tested at the manufacturer to establish the delivered fiber stress. Figure 1 shows a test article in a pre burst condition and with a hoop fiber failure (no leak of pressurized media) and post burst (failure of liner and loss of pressurized media).

Greene, Nathanael; Yoder, Tommy; Saulsberry, Regor; Grimes, Lorie; Thesken, John; Phoenix, Leigh

2007-01-01

27

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

28

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

29

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

30

Residual stresses at weld repairs in pressure vessels. Quarterly progress report, September 1December 1, 1977  

Microsoft Academic Search

The objective of the research reported is to examine the residual stresses near a weld repair in view of the recent developments in computational modeling for predicting weld-induced residual stresses. A framework for such a study exists through the results of the Heavy Section Steel Technology (HSST) program. Specifically, weld repairs have been conducted on intermediate sized test vessels and

E. F. Rybicki; R. B. Stonesifer

1978-01-01

31

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

32

Strain measurement during stress rupture of composite over-wrapped pressure vessel with fiber Bragg gratings sensors  

Microsoft Academic Search

Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPVs). 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 COPV

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

2008-01-01

33

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

34

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

NASA Astrophysics Data System (ADS)

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

Seifert, H. P.; Ritter, S.

2008-01-01

35

Pressurized Vessel Slurry Pumping  

SciTech Connect

This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

Pound, C.R.

2001-09-17

36

Sapphire tube pressure vessel  

DOEpatents

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, John O. (Cambridge, MA)

2000-01-01

37

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

38

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

39

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

40

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

41

Filament wound pressure vessels - Effects of using liner tooling of low pressure vessels for high pressure vessels development  

NASA Astrophysics Data System (ADS)

High performance pressure vessels have been recently demanded for aerospace and defense applications. Filament wound pressure vessels consist of a metallic thin liner, which also acts as a mandrel, and composite/epoxy overwrap. Graphite/epoxy overwrapped vessels have been developed to obtain the performance ratio, PV/W, as high as one million inches. Under very high pressure the isotropic metallic liner deforms elasto-plastically, and orthotropic composite fibers deform elastically. Sometimes, for the development of ultra high pressure vessels, composite pressure vessels industry uses the existing liner tooling developed for low burst pressure capacity composite vessels. This work presents the effects of various design variables including the low pressure liner tooling for the development of the high burst pressure capacity Brilliant Pebbles helium tanks. Advance stress analysis and development of an ultra high pressure helium tank.

Lal, Krishna M.

42

Finite Element Analysis of Pressure Vessels  

Microsoft Academic Search

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

David Heckman

1998-01-01

43

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

44

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

45

High pressure storage vessel  

SciTech Connect

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

46

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

47

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pressure vessels. 169.249 Section 169.249 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...VESSELS Inspection and Certification Inspections § 169.249 Pressure vessels. Pressure vessels must...

2013-10-01

48

Life prediction of pressure vessel nozzles  

Microsoft Academic Search

When the material yields local stress and strain behaviour changes, especially if there is a notch, determination of the local strain value can be difficult. Therefore it is not easy to predict the life of mechanical components in the low-cycle region. In the present work pressure vessels are considered and fatigue tests carried out. The most stressed zones, which are

M. Giglio; L. Vergani

1995-01-01

49

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

50

Corrosion fatigue characterization of reactor pressure vessel steels. [PWR; BWR  

Microsoft Academic Search

During routine operation, light water reactor (LWR) pressure vessels are subjected to a variety of transients that result in time-varying stresses. Consequently, fatigue and environmentally-assisted fatigue are mechanisms of growth relevant to flaws in these pressure vessels. To provide a better understanding of the resistance of nuclear pressure vessel steels to these flaw growth processes, fracture mechanics data were generated

Van Der Sluys

1982-01-01

51

Image-based biomechanical modeling of aortic wall stress and vessel deformation: response to pulsatile arterial pressure simulations  

NASA Astrophysics Data System (ADS)

Image-based modeling of cardiovascular biomechanics may be very helpful for patients with aortic aneurysms to predict the risk of rupture and evaluate the necessity of a surgical intervention. In order to generate a reliable support it is necessary to develop exact patient-specific models that simulate biomechanical parameters and provide individual structural analysis of the state of fatigue and characterize this to the potential of rupture of the aortic wall. The patient-specific geometry used here originates from a CT scan of an Abdominal Aortic Aneurysm (AAA). The computations are based on the Finite Element Method (FEM) and simulate the wall stress distribution and the vessel deformation. The wall transient boundary conditions are based on real time-dependent pressure simulations obtained from a previous computational fluid dynamics study. The physiological wall material properties consider a nonlinear hyperelastic constitutive model, based on realistic ex-vivo analysis of the aneurismal arterial tissue. The results showed complex deformation and stress distribution on the AAA wall. The maximum stresses occurred at the systole and are found around the aneurismal bulge in regions close to inflection points. Biomechanical modeling based on medical images and coupled with patient-specific hemodynamics allows analysing and quantifying the effects of dilatation of the arterial wall due to the pulsatile aortic pressure. It provides a physical and realistic insight into the wall mechanics and enables predictive simulations of AAA growth and assessment of rupture. Further development integrating endovascular models would help evaluating non-invasively individual treatment strategies for optimal placement and improved device design.

Hazer, Dilana; Bauer, Miriam; Unterhinninghofen, Roland; Dillmann, Rüdiger; Richter, Götz-M.

2008-04-01

52

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

53

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

54

Modeling flow stress constitutive behavior of SA508-3 steel for nuclear reactor pressure vessels  

Microsoft Academic Search

Based on the measured stress–strain curves under different temperatures and strain rates, a series of flow stress constitutive equations for SA508-3 steel were firstly established through the classical theories on work hardening and softening. The comparison between the experimental and modeling results has confirmed that the established constitutive equations can correctly describe the mechanical responses and microstructural evolutions of the

Mingyue Sun; Luhan Hao; Shijian Li; Dianzhong Li; Yiyi Li

2011-01-01

55

Critical fracture stress and fracture strain models for the prediction of lower and upper shelf toughness in nuclear pressure vessel steels  

Microsoft Academic Search

Critical fracture stress and stress modified fracture strain models are utilized to describe the variation of lower and upper\\u000a shelf fracture toughness with temperature and strain rate for two alloy steels used in the manufacture of nuclear pressure\\u000a vessels, namely SA533B-1 (HSST Plate 02) and SA302B (Surveillance correlation heat). Both steels have been well characterized\\u000a with regard to static and

R. O. Ritchie; W. L. Server; R. A. Wullaert

1979-01-01

56

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

Microsoft Academic Search

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

Ernest Y. Robinson

1992-01-01

57

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

58

Mechanical characteristics of filament-wound pressure vessel (burst pressure)  

NASA Technical Reports Server (NTRS)

The finite element method is used to analyze the mechanical characteristics of a pressurized filament-wound (FW) pressure vessel, and to predict its burst pressure. The analysis takes into account the bending moment, the stretch-bend coupling effect, nonlinear stress-strain relations, and finite deflection. The analysis is based on two initial failure criteria for laminae, and two ultimate fracture criteria for laminated structures. The numerical results, obtained by applying the load incremental method to the isotensoid CFRP pressure vessel used in the launching of the Zikiken satellite, are in good agreement with the experimental burst pressure and fracture behaviors.

Iida, H.; Uemura, M.

1987-01-01

59

Modeling flow stress constitutive behavior of SA508-3 steel for nuclear reactor pressure vessels  

NASA Astrophysics Data System (ADS)

Based on the measured stress-strain curves under different temperatures and strain rates, a series of flow stress constitutive equations for SA508-3 steel were firstly established through the classical theories on work hardening and softening. The comparison between the experimental and modeling results has confirmed that the established constitutive equations can correctly describe the mechanical responses and microstructural evolutions of the steel under various hot deformation conditions. We further represented a successful industrial application of this model to simulate a forging process for a large conical shell used in a nuclear steam generator, which evidences its practical and promising perspective of our model with an aim of widely promoting the hot plasticity processing for heavy nuclear components of fission reactors.

Sun, Mingyue; Hao, Luhan; Li, Shijian; Li, Dianzhong; Li, Yiyi

2011-11-01

60

Stress-strain state of the cylindrical shell of a pressure vessel with local heating  

Microsoft Academic Search

Results of calculated and experimental investigations of the stress-strain state of a cylindrical shell subjected to local heating are presented. The solution is obtained by expanding the internal forces into a Fourier series for the circumferential coordinate of the shell. The method of full-scale high-temperature tensometry was used for the experimental investigations. Experimental data and calculation results are compared.

V. N. Mukhin; A. I. Tarovatov; É. I. Él'manovich

1990-01-01

61

A test method to evaluate stress corrosion cracking in pressure vessels  

SciTech Connect

An accelerated laboratory test method was developed to evaluate the stress corrosion cracking (SCC) of kraft continuous digesters. The method uses circular patch test welds made from 38-mm-thick ASTM A516 Grade 70 steel plate. The specimens were exposed to a 110 C solution containing 40 gLNaOH and 20 gLNa/sub 2/S at a controlled electrochemical potential. Several different welding procedures were evaluated for resistance to SCC, along with stress relief, shotpeening, sealed thermal spray coatings, and weld overlays of Inconel/sup (1)/ 82 and AISI 309L stainless steel (SS). Stress relief, shotpeening, and sealed thermal spray coatings prevented SCC during the test. Compared to a control specimen, SCC was less severe after temper-bead welding and after welding with an E6010 capping pass. Severe SCC occurred in a specimen welded with the worst-case welding procedure. Deep, circumferential SCC occurred in the carbon steel at the edge of the Inconel 82 weld overlay. SCC was also observed at the interface between the AISI 309L SS weld overlay and the base plate.

Singbeil, D.; Garner, A.

1988-02-01

62

Common pressure vessel battery performance  

NASA Technical Reports Server (NTRS)

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Otzinger, B.

1978-01-01

63

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

64

Prediction of residual stresses and distortions due to laser beam welding of butt joints in pressure vessels  

Microsoft Academic Search

A two-level three-dimensional Finite Element (FE) model has been developed to predict keyhole formation and thermo-mechanical response during Laser Beam Welding (LBW) of steel and aluminium pressure vessel or pipe butt-joints. A very detailed and localized (level-1) non-linear three-dimensional transient thermal model is initially developed, which simulates the mechanisms of keyhole formation, calculates the temperature distribution in the local weld

G. A. Moraitis; G. N. Labeas

2009-01-01

65

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

66

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

67

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

68

Three-term Asymptotic Stress Field Expansion for Analysis of Surface Cracked Elbows in Nuclear Pressure Vessels  

NASA Astrophysics Data System (ADS)

Elbows with a shallow surface cracks in nuclear pressure pipes have been recognized as a major origin of potential catastrophic failures. Crack assessment is normally performed by using the J-integral approach. Although this one-parameter-based approach is useful to predict the ductile crack onset, it depends strongly on specimen geometry or constraint level. When a shallow crack exists (depth crack-to-thickness wall ratio less than 0.2) and/or a fully plastic condition develops around the crack, the J-integral alone does not describe completely the crack-tip stress field. In this paper, we report on the use of a three-term asymptotic expansion, referred to as the J- A 2 methodology, for modeling the elastic-plastic stress field around a three-dimensional shallow surface crack in an elbow subjected to internal pressure and out-of-plane bending. The material, an A 516 Gr. 70 steel, used in the nuclear industry, was modeled with a Ramberg-Osgood power law and flow theory of plasticity. A finite deformation theory was included to account for the highly nonlinear behavior around the crack tip. Numerical finite element results were used to calculate a second fracture parameter A 2 for the J- A 2 methodology. We found that the used three-term asymptotic expansion accurately describes the stress field around the considered three-dimensional shallow surface crack.

Labbe, Fernando

2007-04-01

69

Material Selection for a Pressure Vessel  

NSDL National Science Digital Library

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

Chattopadhyay, Sonnath

2009-09-24

70

Reactor pressure vessel vented head  

DOEpatents

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

Sawabe, James K. (San Jose, CA)

1994-01-11

71

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

National Technical Information Service (NTIS)

This paper is the result of an effort to design, analyze and evaluate a rectangular pressure vessel. Normally pressure vessels are designed in circular or spherical shapes to prevent stress concentrations. In this case, because of operational limitations,...

M. A. Rezvani H. H. Ziada

1992-01-01

72

Experiments and Analysis of Thermal Stresses around the Nozzle of the Reactor Vessel.  

National Technical Information Service (NTIS)

This report describes the results of analysis and experiments on the thermal stress around the reactor vessel nozzle performed to establish a capability of thermal stress analysis of pressure vessel subjected to thermal loadings. Firstly, heat conduction ...

D. H. Song J. H. Oh H. K. Song D. S. Park K. H. Shon

1981-01-01

73

Spherical Hybrid Matrix Composite Pressure Vessels.  

National Technical Information Service (NTIS)

An exploratory study on the fabrication and behavior of metal and hybrid (metal-resin) matrix composite pressure vessels is described. Spherical vessels were fabricated from boron or stainless steel filaments in aluminum, aluminum-epoxy and epoxy matrices...

F. P. Gerstle T. R. Guess M. Moss

1975-01-01

74

Filament wound pressure vessels - Effects of using liner tooling of low pressure vessels for high pressure vessels development  

Microsoft Academic Search

High performance pressure vessels have been recently demanded for aerospace and defense applications. Filament wound pressure vessels consist of a metallic thin liner, which also acts as a mandrel, and composite\\/epoxy overwrap. Graphite\\/epoxy overwrapped vessels have been developed to obtain the performance ratio, PV\\/W, as high as one million inches. Under very high pressure the isotropic metallic liner deforms elasto-plastically,

Krishna M. Lal

1992-01-01

75

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

76

LPT. EBOR reactor vessel in TAN 646. Pressure vessel head ...  

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

LPT. EBOR reactor vessel in TAN 646. Pressure vessel head being installed in vault. Refueling port extension (right) and control rod nozzles (center). Camera facing northwest. Photographer: Comiskey. Date: January 20, 1965. INEEL negative no. 65-241 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

77

46 CFR 61.10-5 - Pressure vessels in service.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

78

46 CFR 61.10-5 - Pressure vessels in service.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

79

Expanded Fermilab pressure vessel directory program  

SciTech Connect

Several procedures have been written to manage the information pertaining to the vacuum tanks and pressure vessels for which the laboratory is responsible. These procedures have been named TANK1 for the vessels belonging to the Accelerator Division, TANK2 and TANK3 for the vessels belonging to the Research Division and to Technical Support respectively, and TANK4 for the vessels belonging to the Business Division. The operating procedures are otherwise identical in every respect.

Tanner, A.

1983-01-01

80

Formulas and Methods Used in the Analysis of Pressure Vessels.  

National Technical Information Service (NTIS)

The purpose of this report is to make available a compact summary of the formulas and methods used in the stress analysis of thin pressure vessels. The first part deals only with membrane forces and deformations resulting from pressure loading in shells o...

M. Kural

1970-01-01

81

Cyclic crack growth behavior of reactor pressure vessel steels in light water reactor environments  

Microsoft Academic Search

During normal operation light water reactor (LWR) pressure vessels are subjected to a variety of transients resulting in time varying stresses. Consequently, fatigue and environmentally assisted fatigue are growth mechanisms relevant to flaws in these pressure vessels. In order to provide a better understanding of the resistance of nuclear pressure vessel steels to flaw growth process, a series of fracture

W. A. Van Der Sluys; R. H. Emanuelson

1986-01-01

82

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

83

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

84

Pressure vessel burst test program. II  

NASA Technical Reports Server (NTRS)

The current status is disucssed of a program to study the characteristics of blast waves and fragmentation generated by ruptured gas-filled pressure vessels. Current methods for assessing vessel safety and burst parameters are briefly reviewed, and pneumatic burst testing operations and testing results are examined. A comparison is made with current methods for burst assessment. It is tentatively concluded that, at close distances, vessel burst overpressures are less than those of high-explosive (HE) blasts with equivalent energy and are greater than HE far from the vessel. The impulse appears to be the same for both vessel bursts and equivalent energy HE blasts. The functional relationship between shock velocity and overpressure ratio appears to be the same for vessel bursts as for HE blasts. The initial shock overpressure appears to be much less than vessel pressure and may be found using the one-dimensional shock tube equation.

Cain, Maurice R.; Sharp, Douglas E.; Coleman, Michael D.

1991-01-01

85

Method of manufacturing an overwrapped pressure vessel  

NASA Technical Reports Server (NTRS)

A pressure vessel of the type wherein a metallic liner in the shape of a cylindrical portion with a dome-shaped portion at each end thereof is overwrapped by a plurality of layers of resin coated, single fiberglass filaments. A four-step wrapping technique reinforces the vessel with overwrap material at the most likely areas for vessel failure. Overwrapping of the vessel is followed by a sizing pressurization cycle which induces a compressive prestress into the liner and thereby permits the liner to deform elastically through an increased strain range.

Beck, Emory J. (Inventor)

1976-01-01

86

Issues in Reactor Pressure Vessel materials  

Microsoft Academic Search

Reactor Pressure Vessel (RPV) is one of the most important structure in a VHTR. The choice of this material is therefore of a prime importance and necessitates significant work of validation. The purpose of this paper is to make the status of knowledge on different vessel material candidates. The paper will be divided as follows: • Definition of RPV material

B. Riou; C. Escaravage; D. Hittner; D. Pierron

87

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

88

New alloys for pressure vessels and piping  

SciTech Connect

This book describes new alloys for pressure vessels and piping applications. Topics include: Cr-Mo-Si alloys, HAZ liquation cracking in lean 316 stainless steels, copper bearing stainless steels, and Ni-Cr-W-Mo alloys.

Prager, M.; Cantzler, C. (Materials Properties Council, Inc., New York, NY (United States))

1990-01-01

89

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

90

Three-term Asymptotic Stress Field Expansion for Analysis of Surface Cracked Elbows in Nuclear Pressure Vessels  

Microsoft Academic Search

Elbows with a shallow surface cracks in nuclear pressure pipes have been recognized as a major origin of potential catastrophic\\u000a failures. Crack assessment is normally performed by using the J-integral approach. Although this one-parameter-based approach is useful to predict the ductile crack onset, it depends strongly on\\u000a specimen geometry or constraint level. When a shallow crack exists (depth crack-to-thickness wall

Fernando Labbe

2007-01-01

91

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

92

Stressintensity factors for internal surface cracks in cylindrical pressure vessels  

Microsoft Academic Search

This work presents stress-intensity factors for a wide range of semielliptical surface cracks on the inside of pressurized cylinders. The ratio of crack depth to crack length ranged from 0.2 to 1; the ratio of crack depth to wall thickness ranged from 0.2 to 0.8; and the ratio of wall thickness to vessel radius was 0.1 to 0.25. The stress-intensity

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

1980-01-01

93

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

94

Criteria for crack extension in cylindrical pressure vessels  

Microsoft Academic Search

This paper describes three closely related criteria for the extension of axial through-cracks in cylindrical pressure vessels: (1) a fracture-toughness criterion mainly for low- and medium-tough materials, (2) a plastic flow stress criterion for short cracks in tough materials, and (3) a modification of (1) for relatively thin-walled containers. The development couples the Folias theoretical treatment of a pressurized cylindrical

G. T. Hahn; M. Sarrate; A. R. Rosenfield

1969-01-01

95

Determination of stress intensity factors for semielliptical surface cracks in the WWER-1000 reactor pressure vessel from the results of solving thermoelasticity boundary value problems based on the mixed mesh-projection scheme of the finite element method  

Microsoft Academic Search

Results of numerical analysis of stress intensity factors KI for semielliptical surface cracks in the WWER-1000 reactor pressure vessel by emergency cooling simulation with known engineering\\u000a procedures, the equivalent spatial integration and direct methods are presented. Engineering procedures employ the results\\u000a of numerical solution of axially symmetric boundary value problems of thermoelasticity based on the mixed mesh-projection\\u000a scheme of the

V. V. Kharchenko; S. V. Kobel’skii; V. I. Kravchenko; A. Yu. Chirkov; A. A. Zvyagintseva

2007-01-01

96

Stress and Sealing Performance Analysis of Containment Vessel  

Microsoft Academic Search

This paper presents a numerical technique for analyzing the containment vessel subjected to the combined loading of closure-bolt torque and internal pressure. The detailed stress distributions in the O-rings generated by both the torque load and the internal pressure can be evaluated by using this method. Consequently, the sealing performance of the O-rings can be determined. The material of the

TSU-TE

2005-01-01

97

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

98

Guidelines for pressure vessel safety assessment  

NASA Astrophysics Data System (ADS)

A technical overview and information on metallic pressure containment vessels and tanks is given. The intent is to provide Occupational Safety and Health Administration (OSHA) personnel and other persons with information to assist in the evaluation of the safety of operating pressure vessels and low pressure storage tanks. The scope is limited to general industrial application vessels and tanks constructed of carbon or low alloy steels and used at temperatures between -75 and 315 C (-100 and 600 F). Information on design codes, materials, fabrication processes, inspection and testing applicable to the vessels and tanks are presented. The majority of the vessels and tanks are made to the rules and requirements of ASME Code Section VIII or API Standard 620. The causes of deterioration and damage in operation are described and methods and capabilities of detecting serious damage and cracking are discussed. Guidelines and recommendations formulated by various groups to inspect for the damages being found and to mitigate the causes and effects of the problems are presented.

Yukawa, S.

1990-04-01

99

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

100

Reactor pressure vessel with forged nozzles  

DOEpatents

Inlet nozzles for a gravity-driven cooling system (GDCS) are forged with a cylindrical reactor pressure vessel (RPV) section to which a support skirt for the RPV is attached. The forging provides enhanced RPV integrity around the nozzle and substantial reduction of in-service inspection costs by eliminating GDCS nozzle-to-RPV welds.

Desai, Dilip R. (Fremont, CA)

1993-01-01

101

Kendall Analysis of Cannon Pressure Vessels.  

National Technical Information Service (NTIS)

The work of the late U.S. Army Benet Laboratories engineer David P. Kendall encompassed a broad range of design and analysis of high pressure vessels for use as cannons. He used classic results from research in engineering mechanics to develop descriptive...

J. H. Underwood

2012-01-01

102

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

103

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

104

(Irradiation embrittlement of reactor pressure vessels)  

SciTech Connect

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

Corwin, W.R.

1990-09-24

105

Sealing behavior of the HTR-10 pressure vessel flanges  

Microsoft Academic Search

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

Suyuan Yu; Junjie Liu; Weidong Zuo; Shuyan He

2002-01-01

106

Corrosion of steel tendons used in prestressed concrete pressure vessels  

Microsoft Academic Search

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

J. C. Griess; D. J. Naus

1980-01-01

107

High-pressure cryogenic seals for pressure vessels  

NASA Technical Reports Server (NTRS)

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

Buggele, A. E.

1977-01-01

108

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

109

Corrosion fatigue characterization of reactor pressure vessel steels. [PWR; BWR  

SciTech Connect

During routine operation, light water reactor (LWR) pressure vessels are subjected to a variety of transients that result in time-varying stresses. Consequently, fatigue and environmentally-assisted fatigue are mechanisms of growth relevant to flaws in these pressure vessels. To provide a better understanding of the resistance of nuclear pressure vessel steels to these flaw growth processes, fracture mechanics data were generated on the rates of fatigue crack growth for SA508-2 and SA533B-1 steels in both room temperature air and 288/sup 0/C water. Areas investigated were: the relationship of crack growth rate to prior loading history; the effects of loading frequency and R ratio (K/sub min//K/sub max/) on crack growth rate as a function of the stress intensity factor range (..delta..K); transient aspects of the fatigue crack growth behavior; the effect of material chemistry (sulphur content) on fatigue crack; and growth rate; water chemistry effects (high-purity water versus simulated pressurized water reactotr (PWR) primary coolant).

Van Der Sluys, W.A.

1982-12-01

110

Structural durability of a composite pressure vessel  

NASA Technical Reports Server (NTRS)

The effect of local ply fiber fracture on the load-carrying capability and structural behavior of a composite cylindrical shell under internal pressure is investigated, using the CODSTRAN computer code to simulate the composite structural degradation under loading. Results show that an initial outer-surface defect in the vessel begins to grow at a relatively low pressure but exhibits localized gradual damage growth prior to structural fracture and that an initial inner-surface defect shows an overall damage progression and fracture behavior closely similar to that of the outer surface defect. An initial defect located near the mid-thickness of the shell requires a higher pressure to cause damage initiation, but, once the damage initiation pressure is reached, a sudden structural fracture stage is entered by rapid damage propagation at a slightly higher pressure.

Minnetyan, Levon; Chamis, Christos C.; Murthy, Pappu L. N.

1992-01-01

111

Composite Tanks and Pressure Vessel Development  

NASA Technical Reports Server (NTRS)

Pressure vessels and tanks are vital to NASA missions. Tanks need to be lightweight and perform under the operational environments. Design and material limitations make it difficult to contain the fuels and oxidizers. Recent interest in 90% Hydrogen Peroxide adds to the challenge of containment. The majority of current tank technologies are not easily adaptable to conformal shapes. The cost of tooling-up for large tanks are magnified by sudden design changes. New launch vehicle concepts may require tanks and pressure vessels of a non-standard configuration. Scaled versions of new tanks have been fabricated and testing has begun. Second and third generation launch vehicles decisions will effect the path of research and development.

DeLay, Thomas K.; Munafo, Paul M. (Technical Monitor)

2002-01-01

112

Radiation effects on reactor pressure vessel supports  

Microsoft Academic Search

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

R. E. Johnson; R. E. Lipinski

1996-01-01

113

Composite Overwrapped Pressure Vessels (COPV) Materials Aging Issues  

NASA Technical Reports Server (NTRS)

This slide presentation reviews some of the issues concerning the aging of the materials in a Composite Overwrapped Pressure Vessels (COPV). The basic composition of the COPV is a Boss, a composite overwrap, and a metallic liner. The lifetime of a COPV is affected by the age of the overwrap, the cyclic fatigue of the metallic liner, and stress rupture life, a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. There is information about the coupon tests that were performed, and a test on a flight COPV.

2010-01-01

114

Experimental Investigation of Composite Pressure Vessel Performance and Joint Stiffness for Pyramid and Inverted Pyramid Joints  

NASA Technical Reports Server (NTRS)

The focus of this study is on the suitability in the application of classical laminate theory analysis tools for filament wound pressure vessels with adhesive laminated joints in particular: pressure vessel wall performance, joint stiffness and failure prediction. Two 18-inch diameter 12-ply filament wound pressure vessels were fabricated. One vessel was fabricated with a 24-ply pyramid laminated adhesive double strap butt joint. The second vessel was fabricated with the same number of plies in an inverted pyramid joint. Results from hydrostatic tests are presented. Experimental results were used as input to the computer programs GENLAM and Laminate, and the output compared to test. By using the axial stress resultant, the classical laminate theory results show a correlation within 1% to the experimental results in predicting the pressure vessel wall pressure performance. The prediction of joint stiffness for the two adhesive joints in the axial direction is within 1% of the experimental results. The calculated hoop direction joint stress resultant is 25% less than the measured resultant for both joint configurations. A correction factor is derived and used in the joint analysis. The correction factor is derived from the hoop stress resultant from the tank wall performance investigation. The vessel with the pyramid joint is determined to have failed in the joint area at a hydrostatic pressure 33% value below predicted failure. The vessel with the inverted pyramid joint failed in the wall acreage at a hydrostatic pressure within 10% of the actual failure pressure.

Verhage, Joseph M.; Bower, Mark V.; Gilbert, Paul A. (Technical Monitor)

2001-01-01

115

Slideline verification for multilayer pressure vessel and piping analysis  

SciTech Connect

Nonlinear finite element method (FEM) computer codes with slideline algorithm implementations should be useful for the analysis of prestressed multilayer pressure vessels and piping. This paper presents closed form solutions useful for validating slideline implementations for this purpose. The solutions describe stresses and displacements of an internally pressurized elastic-plastic sphere initially separated from an elastic outer sphere by a uniform gap. Comparison of closed form and FEM results evaluates the usefulness of the closed form solution and the validity of the slideline implementation used.

Van Gulick, L.A.

1983-01-01

116

Modeling Scala Media as a Pressure Vessel  

NASA Astrophysics Data System (ADS)

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

Lepage, Eric; Olofsson, A.?Ke

2011-11-01

117

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

118

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

119

Design and Optimization of Filament Wound Composite Pressure Vessels  

Microsoft Academic Search

One of the most important issues for the design of filament-wound pressure vessels reflects on the determination of the most efficient meridian profiles and related fiber architectures, leading to optimal structural performance. To better understand the design and optimization of filament-wound pressure vessels, in this dissertation we present an overview and comprehensive treatment for toroidal and domed pressure vessels. Since

L. Zu

2012-01-01

120

46 CFR 61.10-5 - Pressure vessels in service.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pressure vessels in service. 61.10-5 Section 61.10-5...INSPECTIONS Tests and Inspections of Pressure Vessels § 61.10-5 Pressure vessels in service. (a) Basic requirements....

2013-10-01

121

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

122

Midland reactor pressure vessel flaw distribution  

SciTech Connect

The results of laboratory nondestructive examination (NDE), and destructive cross-sectioning of selected weldment sections of the Midland reactor pressure vessel were analyzed per a previously developed methodology in order to develop a flaw distribution. The flaw distributions developed from the NDE results obtained by two different ultrasonic test (UT) inspections (Electric Power Research Institute NDE Center and Pacific Northwest Laboratories) were not statistically significantly different. However, the distribution developed from the NDE Center`s (destructive) cross-sectioning-based data was found to be significantly different than those obtained through the UT inspections. A fracture mechanics-based comparison of the flaw distributions showed that the cross-sectioning-based data, conservatively interpreted (all defects considered as flaws), gave a significantly lower vessel failure probability when compared with the failure probability values obtained using the UT-based distributions. Given that the cross-sectioning data were reportedly biased toward larger, more significant-appearing (by UT) indications, it is concluded that the nondestructive examinations produced definitively conservative results. In addition to the Midland vessel inspection-related analyses, a set of twenty-seven numerical simulations, designed to provide a preliminary quantitative assessment of the accuracy of the flaw distribution method used here, were conducted. The calculations showed that, in more than half the cases, the analysis produced reasonably accurate predictions.

Foulds, J.R.; Kennedy, E.L. [Failure Analysis Associates, Inc., Menlo Park, CA (United States)] [Failure Analysis Associates, Inc., Menlo Park, CA (United States); Rosinski, S.T. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States)

1993-12-01

123

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

124

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

125

Strength of thick-walled vessels of brittle materials under external pressure  

Microsoft Academic Search

In modern technology use is made of thick-walled vessels of brittle materials such as concrete which are subjected to significant internal pressures. As a result of the poor resistance of brittle materials to tension, in the installation of such vessels those zones of the material in which tensile stresses from service loads are expected are subjected to preliminary strain (compression)

L. K. Luksha

1977-01-01

126

Hydroide Storage Vessel wall stress measurements  

SciTech Connect

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

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

1997-07-31

127

Evaluation of the HSST program intermediate pressure vessel tests in terms of light-water-reactor pressure vessel safety  

Microsoft Academic Search

Eight 6-in.-thick 39-in.-OD steel pressure vessels containing carefully ; prepared and sharpened surface cracks have been tested to provide an improved ; quantitative basis for evaluating the safety margins against fracture of nuclear ; reactor pressure vessels. The cylindrical regions of the test vessels were ; fabricated from either A508 class 2 forging steel or A533, grade B, class 1

J. G. Merkle; G. D. Whitman; R. H. Bryan

1975-01-01

128

High pressure magnetic resonance imaging with metallic vessels  

NASA Astrophysics Data System (ADS)

High pressure measurements in most scientific fields rely on metal vessels given the superior tensile strength of metals. We introduce high pressure magnetic resonance imaging (MRI) measurements with metallic vessels. The developed MRI compatible metallic pressure vessel concept is very general in application. Macroscopic physical systems are now amenable to spatially resolved nuclear magnetic resonance (NMR) study at variable pressure and temperature. Metallic pressure vessels not only provide inherently high tensile strengths and efficient temperature control, they also permit optimization of the MRI RF probe sensitivity. An MRI compatible pressure vessel is demonstrated with a rock core holder fabricated using non-magnetic stainless steel. Water flooding through a porous rock under pressure is shown as an example of its applications. High pressure NMR spectroscopy plays an indispensable role in several science fields. This work will open new vistas of study for high pressure material science MRI and MR.

Han, Hui; Ouellette, Matthew; MacMillan, Bryce; Goora, Frederic; MacGregor, Rodney; Green, Derrick; Balcom, Bruce J.

2011-12-01

129

Nonlinear finite element analysis of mechanical characteristics on CFRP composite pressure vessels  

NASA Astrophysics Data System (ADS)

CFRP(Carbon Fibre Reinforced Plastic) composite pressure vessel was calculated using finite element program of ANSYS for their mechanical characteristics in this paper. The elastic-plastic model and elements of Solid95 were selected for aluminium alloys of gas cylinder. Also liner-elastic model and layer elements of Shell99 were adopted for carbon fibre/epoxy resin. The stress state of CFRP composite pressure vessel was calculated under different internal pressures include pre-stressing pressures, working pressures, test hydraulic pressures, minimum destructive pressures etcetera to determine the size of gas cylinder and layer parameter of carbon fibre. The mechanical characteristics CFRP composite vessel could were using to design and test of gas cylinder. Numerical results showed that finite element model and calculating method were efficient for study of CFRP gas cylinder and useful for engineering design.

Liu, Dong-xia; Liang, Li; Li, Ming

2010-06-01

130

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

131

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

132

High-pressure cryogenic seals for pressure vessels  

NASA Technical Reports Server (NTRS)

Problems associated with maintaining high pressures at cryogenic temperatures in pressure vessels are investigated. The goals were to identify the appropriate materials and design for a seal intended for cryogenic applications at pressures up to 4,080 bars (60,000 psi), and to examine the factors affecting the seal performance. The method employed and the apparatus used in a series of experimental seal system tests, and the test results are described in detail. It is concluded that the common seal designs and extrusion seal-ring materials such as Teflon, tin, and lead are not suitable. However, new seal systems developed using indium seal rings, brass or 304 stainless steel anvil rings, and two 0-rings of silicone rubber or Kel-F did prove suitable.

Buggle, A. E.

1977-01-01

133

Designing of a Fleet-Leader Program for Carbon Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases on board spacecraft when mass saving is a prime requirement. Substantial weight savings can be achieved compared to all metallic pressure vessels. For example, on the space shuttle, replacement of all metallic pressure vessels with Kevlar COPVs resulted in a weight savings of about 30 percent. Mass critical space applications such as the Ares and Orion vehicles are currently being planned to use as many COPVs as possible in place of all-metallic pressure vessels to minimize the overall mass of the vehicle. Due to the fact that overwraps are subjected to sustained loads during long periods of a mission, stress rupture failure is a major concern. It is, therefore, important to ascertain the reliability of these vessels by analysis, since it is practically impossible to show by experimental testing the reliability of flight quality vessels. Also, it is a common practice to set aside flight quality vessels as "fleet leaders" in a test program where these vessels are subjected to slightly accelerated operating conditions so that they lead the actual flight vessels both in time and load. The intention of fleet leaders is to provide advanced warning if there is a serious design flaw in the vessels so that a major disaster in the flight vessels can be averted with advance warning. On the other hand, the accelerating conditions must be not so severe as to be prone to false alarms. The primary focus of the present paper is to provide an analytical basis for designing a viable fleet leader program for carbon COPVs. The analysis is based on a stress rupture behavior model incorporating Weibull statistics and power-law sensitivity of life to fiber stress level.

Murthy, Pappu L.N.; Phoenix, S. Leigh

2009-01-01

134

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

135

Fracture analysis of surface and through cracks in cylindrical pressure vessels  

NASA Technical Reports Server (NTRS)

A previously developed fracture criterion was applied to fracture data for surface- and through-cracked cylindrical pressure vessels to see how well the criterion can correlate fracture data. Fracture data from the literature on surface cracks in aluminum alloy, steel, and epoxy vessels, and on through cracks in aluminum alloy, titanium alloy steel, and brass vessels were analyzed by using the fracture criterion. The criterion correlated the failure stresses to within + or - 10 percent for either surface or through cracks over a wide range of crack size and vessel diameter. The fracture criterion was also found to correlate failure stresses to within + or - 10 percent for flat plates (center-crack or double-edge-crack tension specimens) and cylindrical pressure vessels containing through cracks.

Newman, J. C., Jr.

1976-01-01

136

Pressure vessel burst test program - Initial program paper  

NASA Technical Reports Server (NTRS)

The current status of a pressure vessel burst test program, aimed at the study of the blast waves and fragmentation characteristics of ruptured gas-filled pressure vessels, is reported. The program includes a series of test plans, each involving multiple bursts with burst pressures ranging to 7500 psig. The discussion covers the identification of concerns and hazards, application of the data generated, and a brief review of the current methods for assessing vessel safety and burst parameters. Attention is also given to pretest activities, including completed vessel and facility/instrumentation preparation and results of completed preliminary burst tests.

Cain, Maurice R.; Sharp, Douglas E.; Coleman, Michael D.; Webb, Bobby L.

1990-01-01

137

Radiation embrittlement and annealing of VVER pressure vessels  

Microsoft Academic Search

Pressure vessels of the Soviet-designed VVERs are exposed to up to 10X the fast flux of the vessels of US PWRs. They are fabricated of 2 1\\/2% Cr, 1% Mo or 2 1\\/2% Cr, 1% Ni steels developed for that purpose. Consequently, the data base on irradiation effects differs somewhat from that of Western-designed pressure vessels. The role of phosphorus,

1989-01-01

138

Radiation embrittlement of nuclear reactor pressure vessel steels  

Microsoft Academic Search

A critical issue in assuring the safety of nuclear power plants involves the integrity of the primary pressure vessel of light water reactors, which are the nuclear source of choice in most nations. Such integrity depends upon no serious degradation of the steel in the pressure vessel, which, in turn, depends upon the knowledge of neutron irradiation embrittlement and the

Steele

1989-01-01

139

Integral hydro-bulge forming of pressure vessel heads  

Microsoft Academic Search

A new process has been proposed to form pressure vessel heads by hydro-bulging circular flat plates as an alternative to traditional processes. This new process is especially intended for the manufacture of pressure vessel heads of very large diameter that may not be possible to form by traditional processes, and also for products of various sizes or very small production

S. H. Zhang; J. Danckert; K. B. Nielsen

1998-01-01

140

Fatigue of weldments in nuclear pressure vessels and piping  

Microsoft Academic Search

Current (ASME) Code fatigue design rules for nuclear pressure vessels and piping include no special considerations for weldments other than purely geometric factors. Research programs aimed at nonnuclear applications have found weldments to display fatigue behavior inferior to that of pure base material. Available information on fatigue of weldments relevant to nuclear pressure vessels and piping was reviewed and determined

M. K. Booker; B. L. P. Booker; H. B. Meieran; Heuschkel J

1980-01-01

141

Recent development in nuclear prestressed concrete pressure vessels in France  

Microsoft Academic Search

From 2nd international congress for pressure vessel and piping ; technology; San Antonio, Texas, USA (1 Oct 1973) See CONF731003-P1. Experience ; in France in the use of prestressed concrete pressure vessels (PCPV's) for gas-; cooled reactors, such as the Marcoule built in 1956-57, is reviewed by ; considering the special characteristics of PCPV's, resistance of PCPV's to ; accidents,

D. Costes; R. Riquois; R. Lacroix

1973-01-01

142

Large boron--epoxy filament-wound pressure vessels  

NASA Technical Reports Server (NTRS)

Advanced composite material used to fabricate pressure vessel is prepeg (partially cured) consisting of continuous, parallel boron filaments in epoxy resin matrix arranged to form tape. To fabricate chamber, tape is wound on form which must be removable after composite has been cured. Configuration of boron--epoxy composite pressure vessel was determined by computer program.

Jensen, W. M.; Bailey, R. L.; Knoell, A. C.

1973-01-01

143

Ex vivo lymphatic perfusion system for independently controlling pressure gradient and transmural pressure in isolated vessels.  

PubMed

In addition to external forces, collecting lymphatic vessels intrinsically contract to transport lymph from the extremities to the venous circulation. As a result, the lymphatic endothelium is routinely exposed to a wide range of dynamic mechanical forces, primarily fluid shear stress and circumferential stress, which have both been shown to affect lymphatic pumping activity. Although various ex vivo perfusion systems exist to study this innate pumping activity in response to mechanical stimuli, none are capable of independently controlling the two primary mechanical forces affecting lymphatic contractility: transaxial pressure gradient, [Formula: see text], which governs fluid shear stress; and average transmural pressure, [Formula: see text], which governs circumferential stress. Hence, the authors describe a novel ex vivo lymphatic perfusion system (ELPS) capable of independently controlling these two outputs using a linear, explicit model predictive control (MPC) algorithm. The ELPS is capable of reproducing arbitrary waveforms within the frequency range observed in the lymphatics in vivo, including a time-varying [Formula: see text] with a constant [Formula: see text], time-varying [Formula: see text] and [Formula: see text], and a constant [Formula: see text] with a time-varying [Formula: see text]. In addition, due to its implementation of syringes to actuate the working fluid, a post-hoc method of estimating both the flow rate through the vessel and fluid wall shear stress over multiple, long (5 s) time windows is also described. PMID:24809724

Kornuta, Jeffrey A; Brandon Dixon, J

2014-08-01

144

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

145

Explosion pressures of hydrocarbon-air mixtures in closed vessels.  

PubMed

An experimental study on pressure evolution during closed vessel explosions of several gaseous fuel-air mixtures was performed, at various initial pressures within 0.3-1.2 bar and ambient initial temperature. Explosion pressures and explosion times are reported for methane-, n-pentane-, n-hexane-, propene-, butene-, butadiene-, cyclohexane- and benzene-air mixtures. The explosion pressures measured in a spherical vessel (Phi=10 cm) and in three cylindrical vessels with different diameter/height ratios are examined in comparison with the adiabatic explosion pressures, computed by assuming chemical equilibrium within the flame front. The influence of initial pressure, fuel concentration and heat losses during propagation (determined by the size and shape of the explosion vessel and by the position of the ignition source) on explosion pressures and explosion times are discussed for some of the examined systems. PMID:16386834

Razus, Domnina; Movileanu, Codina; Brinzea, Venera; Oancea, D

2006-07-31

146

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

147

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

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

Burst-Pressure Test Fixture for Pressure Vessels Dynamic Rocket Motors.  

National Technical Information Service (NTIS)

A method for burst testing a vented pressure vessel is disclosed which accurately measures the true burst pressure of the vented pressure vessel. The method employs a burst-pressure test fixture which is comprised of a plug and a gauge adapter member for ...

R. E. Betts

1981-01-01

150

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

151

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

Code of Federal Regulations, 2010 CFR

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

2009-07-01

152

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

153

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

154

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

155

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

156

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

157

Crashworthy sealed pressure vessel for plutonium transport  

SciTech Connect

A rugged transportation package for the air shipment of radioisotopic materials was recently developed. This package includes a tough, sealed, stainless steel inner containment vessel of 1460 cc capacity. This vessel, intended for a mass load of up to 2 Kg PuO/sub 2/ in various isotopic forms (not to exceed 25 watts thermal activity), has a positive closure design consisting of a recessed, shouldered lid fastened to the vessel body by twelve stainless-steel bolts; sealing is accomplished by a ductile copper gasket in conjunction with knife-edge sealing beads on both the body and lid. Follow-on applications of this seal in newer, smaller packages for international air shipments of plutonium safeguards samples, and in newer, more optimized packages for greater payload and improved efficiency and utility, are briefly presented.

Andersen, J.A.

1980-01-01

158

Investigation of pressure vessel neutron fluence calculation with Monte Carlo  

Microsoft Academic Search

The life of a reactor and its possible extension are strongly dependent on the embrittlement of the pressure vessel under neutron irradiation. Therefore, in order to assess pressure vessel radiation damage, the neutron fluence must be accurately determined. The S[sub N] transport method, is currently used to determine a synthetic three-dimensional flux distribution based on one- and two-dimensional transport calculations.

J. C. Wagner; A. Haghighat; B. G. Petrovic

1993-01-01

159

Bursting of shielded pressure vessels subject to hypervelocity impact  

Microsoft Academic Search

During the 30-year lifetime of the Space Station, NASA is concerned that a large piece of orbital debris could strike one of the inhabited or laboratory modules. The modules are basically cylindrical pressure vessels, 4.3 meters in diameter and 9.1 meters long, made of Al 2219-T87. There is a potential for unstable crack growth (“unzipping”) in these pressure vessels if

Scott A. Mullin; Herve Couque; Burton G. Cour-Palais; Donald J. Grosch; James D. Walker

1997-01-01

160

Life cycle considerations for pressurized water reactor vessels  

SciTech Connect

This paper reports on the pressurized water reactor (PWR) reactor vessel identified by the Surry 1 life extension project as a critical element for life extension considerations. This ranking was based on a prioritization of all the plant systems, components, and structures taking into account difficulty to repair/replace and wear out considerations. The study also determined the vessel has a high probability for extended service life based on best estimate analysis of actual usage, maintenance, in-service inspection programs, and presently available methods for prolonging vessel life. Feasibility studies have also been performed for PWR reactor pressure vessels designed by the three domestic vendors. All of these studies concluded that the reactor vessel has a high probability for extended service life beyond the original license period.

Walker, R.S.; Hostetler, D.R. (Grove Engineering, Inc., Rockville, MD (United States))

1991-01-01

161

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

162

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

163

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

164

Low-Cost, Lightweight Pressure Vessel Proof Test  

NASA Astrophysics Data System (ADS)

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

Chanez, Eric

165

Time-dependent response of filamentary composite spherical pressure vessels  

NASA Technical Reports Server (NTRS)

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

Dozier, J. D.

1983-01-01

166

Radiation embrittlement and annealing of VVER pressure vessels  

SciTech Connect

Pressure vessels of the Soviet-designed VVERs are exposed to up to 10X the fast flux of the vessels of US PWRs. They are fabricated of 2 1/2% Cr, 1% Mo or 2 1/2% Cr, 1% Ni steels developed for that purpose. Consequently, the data base on irradiation effects differs somewhat from that of Western-designed pressure vessels. The role of phosphorus, which is high in the older VVER steels, is especially important. Newer grades of steels, low in copper and phosphorus, have been developed. Pressure vessels fabricated before about 1980 were unclad. The embrittlement of these can be tested in situ with a remote microhardness measuring device. Hydrogen pickup from corrosion does not increase the embrittlement due to irradiation. Considerable research has been performed on pressure vessel annealing, and anneals of the core weld region of the pressure vessels of three operating VVERs have been completed at temperatures 160-185{degree}C higher than the irradiation temperature for 150 hours to one week. Recoveries, monitored with a remote microhardness tester, have ranged upward from 70%.

Weeks, J.R. (Brookhaven National Lab., Upton, NY (USA))

1989-01-01

167

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

168

Elastic analysis of heterogeneous thick-walled spherical pressure vessels with parabolic varying properties  

NASA Astrophysics Data System (ADS)

On the basis of plane elasticity theory (PET), the displacement and stress components in a thick-walled spherical pressure vessels made of heterogeneous materials subjected to internal and external pressure is developed. The mechanical properties except the Poisson's ratio are assumed to obey the parabolic variations throughout the thickness. Effect of material inhomogeneity on the elastic deformations and stresses is investigated. The analytical solutions and the solutions carried out through the FEM have a good agreement. The values used in this study are arbitrary chosen to demonstrate the effect of inhomogeneity on displacements, and stresses distributions.

Karami, Keyhan; Abedi, Majid; Zamani Nejad, Mohammad; Lotfian, Mohammad Hassan

2012-12-01

169

Oxygen recombination in individual pressure vessel nickel-hydrogen batteries  

SciTech Connect

An improved metal-hydrogen (H/sub 2/) cell is described of the type comprising a pressure vessel pressurized with H/sub 2/ and including an electrolyte and a stack of electrical cell units disposed in the pressure vessel in back-to-back relationship with gas screens positioned between adjacent electrical units; the improvement comprising one or more sites of catalytic material disposed on the inner surface of the pressure vessel. Each electrical cell unit includes a separator plate having edges in contact with a porous ceramic wick coating disposed on a portion of the pressure vessel interior and partially immersed in a supply of electrolyte whereby electrolyte is wicked to the separators, the separator edges being notched whereby gases in the cell flow adjacent to the catalytic sites to maximize recombination of O/sub 2/ generated by operation of the cell with H/sub 2/ outside of the electrical cell units on the pressure vessel catalytic sites whereby the heat of recombination is effectively removed from the cell.

Smithrick, J.J.

1986-04-22

170

Proceedings of the 13. international conference on NDE in the nuclear and pressure vessel industries  

SciTech Connect

This book is divided into the following sections: plenary session; role of NDE (nondestructive evaluation) 1; x-ray technology; role of NDE 2; piping and major components; reactor pressure vessel inspection; advanced ultrasonic inspection technologies 1; performance demonstration initiative and inspection qualification approaches; electromagnetic technologies; advanced ultrasonic inspection technologies 2; advanced inspection technologies 1; advanced inspection technologies 2; material characterization 1; material characterization 2; steam generators 1; steam generators 2; BWR reactor pressure vessel inspection; modelling of NDE inspections; turbine inspection; stress measurement; and control rod drive mechanism. Separate abstracts were prepared for 66 papers in this book.

Iida, Kunihiro [ed.] [Shibaura Inst. of Technology, Tokyo (Japan); Light, G.M [ed.] [Southwest Research Inst., San Antonio, TX (United States); Whittle, M.J. [ed.] [John Whittle and Associates, Cheshire (United Kingdom)

1995-08-01

171

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

172

Pressure suppression system for a nuclear reactor safety vessel  

Microsoft Academic Search

A pressure suppression system for a safety vessel is described. It ; consists of a pressure enclosure of steel or concrete for a liquid-cooled nuclear ; reactor with a condensation chamber with toroidal floor (flooring, platform, ; ceiling) in the form of a circular cylinder in the interior of which parallel to ; the axis, not filling the entire cylinder,

W. Ullrich; K. H. Lohse; J. Leuteritz; G. Zeitzschel; R. Fassl

1970-01-01

173

Calibrating Droplet Generator for Pressurized Testing Vessel  

NASA Technical Reports Server (NTRS)

Device helps to aline laser for droplet-sizing interferometer. Monodispersing Droplet Generator creates uniformly sized droplets. Laser source and receiver of interferometer alined and focused on droplets. MDG mounted in high-pressure flange on tank. Line extensions pass through flange to outside. Flange allows MDG to operate at high injector back pressures used for tests.

Defever, G. J.; Exposito, T.

1985-01-01

174

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

175

Advanced technology for minimum weight pressure vessel system  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

176

Transportable, small high-pressure preservation vessel for cells  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

177

Deformation behavior in reactor pressure vessel steels as a clue to understanding irradiation hardening  

Microsoft Academic Search

In this paper, we examine the post-yield true stress vs true strain behavior of irradiated pressure vessel steels and iron-based alloys to reveal differences in strain-hardening behavior associated with different irradiating particles (neutrons and electrons) and different alloy chernky. It is important to understand the effects on mechanical properties caused by displacement producing radiation of nuclear reactor pressure steels. Critical

R. J. DiMelfi; D. E. Alexander; L. E. Rehn

1999-01-01

178

FAVOR: A new fracture mechanics code for reactor pressure vessels subjected to pressurized thermal shock  

SciTech Connect

This report discusses probabilistic fracture mechanics (PFM) analysis which is a major element of the comprehensive probabilistic methodology endorsed by the NRC for evaluation of the integrity of Pressurized Water Reactor (PWR) pressure vessels subjected to pressurized-thermal-shock (PTS) transients. It is anticipated that there will be an increasing need for an improved and validated PTS PFM code which is accepted by the NRC and utilities, as more plants approach the PTS screening criteria and are required to perform plant-specific analyses. The NRC funded Heavy Section Steel Technology (HSST) Program at Oak Ridge National Laboratories is currently developing the FAVOR (Fracture Analysis of Vessels: Oak Ridge) PTS PFM code, which is intended to meet this need. The FAVOR code incorporates the most important features of both OCA-P and VISA-II and contains some new capabilities such as PFM global modeling methodology, the capability to approximate the effects of thermal streaming on circumferential flaws located inside a plume region created by fluid and thermal stratification, a library of stress intensity factor influence coefficients, generated by the NQA-1 certified ABAQUS computer code, for an adequate range of two and three dimensional inside surface flaws, the flexibility to generate a variety of output reports, and user friendliness.

Dickson, T.L.

1993-04-01

179

FAVOR: A new fracture mechanics code for reactor pressure vessels subjected to pressurized thermal shock  

SciTech Connect

This report discusses probabilistic fracture mechanics (PFM) analysis which is a major element of the comprehensive probabilistic methodology endorsed by the NRC for evaluation of the integrity of Pressurized Water Reactor (PWR) pressure vessels subjected to pressurized-thermal-shock (PTS) transients. It is anticipated that there will be an increasing need for an improved and validated PTS PFM code which is accepted by the NRC and utilities, as more plants approach the PTS screening criteria and are required to perform plant-specific analyses. The NRC funded Heavy Section Steel Technology (HSST) Program at Oak Ridge National Laboratories is currently developing the FAVOR (Fracture Analysis of Vessels: Oak Ridge) PTS PFM code, which is intended to meet this need. The FAVOR code incorporates the most important features of both OCA-P and VISA-II and contains some new capabilities such as PFM global modeling methodology, the capability to approximate the effects of thermal streaming on circumferential flaws located inside a plume region created by fluid and thermal stratification, a library of stress intensity factor influence coefficients, generated by the NQA-1 certified ABAQUS computer code, for an adequate range of two and three dimensional inside surface flaws, the flexibility to generate a variety of output reports, and user friendliness.

Dickson, T.L.

1993-01-01

180

Fractographic study of a thick wall pressure vessel failure  

Microsoft Academic Search

The pressure vessel described in this paper is identified as Intermediate Test Vessel 1 (ITV-1) and was fabricated of SA508, Class 2 Steel. It was tested to failure at 54°C (130°F). The gross failure appeared to be a brittle fracture although accompanied by a measured strain of 0.9%. Seven regions of the fracture were examined in detail and the observed

D. A. Canonico; R. S. Crouse; T. J. Henson

1979-01-01

181

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

182

Cyclic crack growth behavior of reactor pressure vessel steels in light water reactor environments  

SciTech Connect

During normal operation light water reactor (LWR) pressure vessels are subjected to a variety of transients resulting in time varying stresses. Consequently, fatigue and environmentally assisted fatigue are growth mechanisms relevant to flaws in these pressure vessels. In order to provide a better understanding of the resistance of nuclear pressure vessel steels to flaw growth process, a series of fracture mechanics experiments were conducted to generate data on the rate of cyclic crack growth in SA508-2 and SA533b-1 steels in simulated 550/sup 0/F boiling water reactor (BWR) and 550/sup 0/F pressurized water reactor (PWR) environments. Areas investigated over the course of the test program included the effects of loading frequency and r ratio (Kmin-Kmax) on crack growth rate as a function of the stress intensity factor (deltaK) range. In addition, the effect of sulfur content of the test material on the cyclic crack growth rate was studied. Cyclic crack growth rates were found to be controlled by deltaK, R ratio, and loading frequency. The sulfur impurity content of the reactor pressure vessel steels studied had a significant effect on the cyclic crack growth rates. The higher growth rates were always associated with materials of higher sulfur content. For a given level of sulfur, growth rates were in a 550/sup 0/F simulated BWR environment than in a 550/sup 0/F simulated PWR environment. In both environments cyclic crack growth rates were a strong function of the loading frequency.

Van Der Sluys, W.A.; Emanuelson, R.H.

1986-01-01

183

Pressure vessel burst test program - Progress paper No. 3  

NASA Technical Reports Server (NTRS)

An updated progress report is provided on a program developed to study through test and analysis, the characteristics of blast waves and fragmentation generated by ruptured gas filled pressure vessels. Prior papers on this USAF/NASA/General Physics program were presented to the AIAA in July 1990 and June 1991. Ten pressure vessels have been burst using pneumatic pressure. Tests were designed to explore burst characteristics and used an instrumented arena. Data trends for current experiments are presented. This paper is the third progress report on the program and addresses: (1) a brief review of current methods for assessing vessel safety and burst parameters, (2) a review of pneumatic burst testing operations and testing results, including a comparison to current methods for burst assessment, and (3) a review of the basis for the current test program including planned testing.

Cain, Maurice R.; Sharp, Douglas E.; Coleman, Michael D.

1992-01-01

184

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

185

Technical Appendix to Cryogenic Pressure Vessels  

SciTech Connect

The 20,000 gls. Liquid Argon dewar stores up to 15,000 gls. of high purity (<1.0 ppm O{sub 2}, 0.999995) LAr for use in the Liquid Argon calorimeters of E740, the D0 collider detector, at elevation 707-feet. The dewar provides for the total detector volume of 11,000 gls and a 4,000 gls. storage inventory. The large gas volume ({ge}5,000 gls.) serves operational needs and guards against overfill concerns. The LAr dewar functions in two modes: (1) low pressure (16 psi relief) storage, and liquid and gas transfer operations to and from the low pressure (13 psi relief) detector cryostats, and (2) high pressure (65 psi relief) liquid transfer operations to and from a delivery trailer at elevation 743-feet. The storage function is intended to be long term and nonventing. The dewar is equipped with a 40 kW LN{sub 2} condenser that operates to maintain the pressure constant in the storage mode. This service exactly parallels the NeH{sub 2} and D{sub 2} storage dewar services provided at the 15-feet bubble chamber for its operation.

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

1990-02-22

186

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

2012-01-01

187

Procurement of replacement pressure vessels for MURR  

Microsoft Academic Search

The University of Missouri Research Reactor Facility (MURR) located in Columbia, Missouri, is the highest powered, highest steady-state flux university research reactor in the United States. The reactor is a 10-MW pressurized loop, in-pool-type, light-water-moderated, beryllium-reflected, flux trap reactor. MURR has a compact core (0.033 m³) composed of eight fuel elements of the materials test reactor type arranged as an

W. A. Jr. Meyer; C. B. Jr. Edwards; J. C. McKibben; A. R. Schoone

1989-01-01

188

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

2010-03-01

189

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

NASA Technical Reports Server (NTRS)

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

Miller, Thomas B.; Lewis, Harlan L.

2004-01-01

190

IMPROVEMENTS IN OR RELATING TO REACTOR PRESSURE VESSELS  

Microsoft Academic Search

A reactor pressure vessel with a group of nozzles projecting into the ; interior is provided with thermal insulation for ensuring that the welds joining ; the nozzles to the vesse do not become too hot. The insulation includes a ; plurality of units, each having an insulating sleeve encircling a nozzle and an ; insulating flange connected to the

Sturley

1962-01-01

191

Temperature transients in a cylindrical pressure vessel filled from vacuum  

Microsoft Academic Search

The spatially averaged temperature of the gas inside a cylindrical pressure vessel during the time that it is being filled from vacuum has been predicted theoretically and investigated experimentally. The theory, which yields analytic formulas, is based on a heat-transfer model developed from physical and dimensional reasoning. It includes corrections for slow changes in the injection gas reservoir conditions and

David R. Dowling; Victor R. Buonadonna; Robert E. Breidenthal

1990-01-01

192

Radiation Hardening in Magnox Pressure-Vessel Steels  

Microsoft Academic Search

The ferritic steels used for reactor pressure vessels undergo a marked transition from ductile to brittle fracture behaviour over a relatively narrow temperature range. For most unirradiated mild steels the ductile to brittle transition temperature (d.b.t.t.) is between -50 degrees and 20 degrees C. The process of irradiation hardening, through the formation of clusters of intersitial or vacancy defects, increases

S. B. Fisher; J. E. Harbottle; N. Aldridge

1985-01-01

193

Relating surveillance capsule measurements to pressure vessel damage  

SciTech Connect

As part of the pressure vessel (PV) materials surveillance program, surveillance capsules including material specimens and neutron flux dosimeters are generally required to monitor changes in the fracture toughness properties of the reactor vessel materials. These capsules are withdrawn sequentially according to a predetermined schedule covering the service life of the vessel, and specimen material changes and dosimeter activation measured. The neutron fluence accumulated by the flux dosimeters is determined from the measured dosimeter activation and known reaction cross section (in practice, the /sup 54/Fe(n,p)/sup 54/Mn reaction.) The capsule fluence and material changes are then extrapolated to the pressure vessel using a fluence lead-factor determined from detailed multigroup neutron transport calculations. Typically, in this extrapolation changes in neutron spectrum are neglected. The purpose of this study is twofold; first, to determine the effect of including spectral changes in the extrapolation from capsule to vessel and second, to evaluate the effect of using the latest ENDF/B-V /sup 54/Fe(n,p)/sup 54/Mn cross sections in converting dosimeter activation to fluence.

Carew, J.F.; Min, D.K.; Aronson, A.L.

1980-01-01

194

Parametric equations for maximum stresses in cylindrical vessels subjected to thermal expansion loading  

Microsoft Academic Search

This paper derives a set of parametric equations for finding the maximum stresses developed in a cylindrical vessel which is supported by two saddles firmly secured to the foundation and subjected to thermal expansion loading. Three types of stresses are considered: maximum stress intensity, maximum circumferential stress and maximum axial stress. The maximum stresses in the vessel are found to

L. S. Ong; J. S. T. Cheung; H. W. Ng; A. S. Tooth

1998-01-01

195

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

196

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

197

Dynamic strain aging in SA508-class 3 pressure vessel steel  

Microsoft Academic Search

The influence of dynamic strain aging (DSA) on deformation and fracture was investigated on ASME SA508-class 3 pressure vessel steel. Serrated flow in stress-strain curves was observed between about 140 and 340°C, which was varied by the strain rate and microstructural condition. The onset temperature of serration for the pearlite-ferrite microstructural condition was lower than that for the as-received, tempered

I. S. Kim; S. S. Kang

1995-01-01

198

Effect of hydrogenation on the fracture mode of a reactor pressure-vessel steel  

Microsoft Academic Search

The conditions for hydrogen-induced intergranular fracture in an artificially embrittled, low-alloy reactor pressure-vessel\\u000a steel were investigated by using fracture toughness and stress-corrosion cracking tests. The specimens were taken from two\\u000a locations: the heat-affected zone beneath the cladding and the base material directly below the heat-affected zone. A hydrogenating\\u000a system allowed the tests to be carried out on both prehydrogenated specimens

N. Taylor; H. M. Nykyforchyn; O. T. Tsyrulnyk; O. Z. Student

2009-01-01

199

Evaluation of Acoustic Emission NDE of Kevlar Composite Over Wrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Pressurization and failure tests of small Kevlar/epoxy COPV bottles were conducted during 2006 and 2007 by Texas Research Institute Austin, Inc., at TRI facilities. This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. Results of some of the tests indicate a possibility that AE can be used to track the stress-rupture degradation of COPV vessels.

Horne, Michael R.; Madaras, Eric I.

2008-01-01

200

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

201

Behavior of a Corium Jet in High Pressure Melt Ejection from a Reactor Pressure Vessel,  

National Technical Information Service (NTIS)

The report provides results from analytical and experimental investigations on the behavior of gas supersaturated molten jet expelled from a pressurized vessel. Models are developed for jet expansion, primary breakup of the jet, and secondary fragmentatio...

W. Frid

1988-01-01

202

Behavior of a corium jet in high pressure melt ejection from a reactor pressure vessel.  

National Technical Information Service (NTIS)

This report provides results from analytical and experimental investigations on the behavior of a gas supersaturated molten jet expelled from a pressurized vessel. Aero-hydrodynamic stability of liquid jets in gas, stream degassing of molten metals and ga...

W. Frid

1987-01-01

203

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

Microsoft Academic Search

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

Jeffrey S. Paine; Craig A. Rogers

1995-01-01

204

Application of Negligible Creep Criteria to Candidate Materials for HTGR Pressure Vessels  

SciTech Connect

Two of the proposed High Temperature Gas Reactors (HTGRs) under consideration for a demonstration plant have the design object of avoiding creep effects in the reactor pressure vessel (RPV) during normal operation. This work addresses the criteria for negligible creep in Subsection NH, Division 1 of the ASME B&PV (Boiler and Pressure Vessel) Code, Section III, other international design codes and some currently suggested criteria modifications and their impact on permissible operating temperatures for various reactor pressure vessel materials. The goal of negligible creep could have different interpretations depending upon what failure modes are considered and associated criteria for avoiding the effects of creep. It is shown that for the materials of this study, consideration of localized damage due to cycling of peak stresses results in a lower temperature for negligible creep than consideration of the temperature at which the allowable stress is governed by creep properties. In assessing the effect of localized cyclic stresses it is also shown that consideration of cyclic softening is an important effect that results in a higher estimated temperature for the onset of significant creep effects than would be the case if the material were cyclically hardening. There are other considerations for the selection of vessel material besides avoiding creep effects. Of interest for this review are (1) the material s allowable stress level and impact on wall thickness (the goal being to minimize required wall thickness) and (2) ASME Code approval (inclusion as a permitted material in the relevant Section and Subsection of interest) to expedite regulatory review and approval. The application of negligible creep criteria to two of the candidate materials, SA533 and Mod 9Cr-1Mo (also referred to as Grade 91), and to a potential alternate, normalized and tempered 2 Cr-1Mo, is illustrated and the relative advantages and disadvantages of the materials are discussed.

Jetter, Robert I [Consultant; Sham, Sam [ORNL; Swindeman, Robert W [Consultant

2011-01-01

205

Corrosion of steel tendons used in prestressed concrete pressure vessels  

Microsoft Academic Search

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

J. C. Griess; D. J. Naus

2009-01-01

206

Temperature and pressure influence on explosion pressures of closed vessel propane-air deflagrations.  

PubMed

An experimental study on pressure evolution during closed vessel explosions of propane-air mixtures was performed, for systems with various initial concentrations and pressures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.2 bar). The explosion pressures and explosion times were measured in a spherical vessel (Phi=10 cm), at various initial temperatures (T(0)=298-423 K) and in a cylindrical vessel (Phi=10 cm; h=15 cm), at ambient initial temperature. The experimental values of explosion pressures are examined against literature values and compared to adiabatic explosion pressures, computed by assuming chemical equilibrium within the flame front. The influence of initial pressure, initial temperature and fuel concentration on explosion pressures and explosion times are discussed. At constant temperature and fuel/oxygen ratio, the explosion pressures are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, both the measured and calculated (adiabatic) explosion pressures are linear functions of reciprocal value of initial temperature. Such correlations are extremely useful for predicting the explosion pressures of flammable mixtures at elevated temperatures and/or pressures, when direct measurements are not available. PMID:19818553

Razus, Domnina; Brinzea, Venera; Mitu, Maria; Oancea, Dumitru

2010-02-15

207

Peak stress and fatigue assessment at the saddle support of a cylindrical vessel  

Microsoft Academic Search

The maximum stress in a saddle-supported cylindrical storage vessel is often the circumferential stress developed at the tips (or horns) of the saddle support. Although the peak stress at the support is not immediately detrimental to the integrity of a vessel, it would have a long-term effect on the fatigue life of the vessel. This article provides a parametric equation

L. S. Ong

1995-01-01

208

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

209

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

210

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

211

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

212

Slideline verification for multilayer pressure vessel and piping analysis including tangential motion. [LMFBR  

SciTech Connect

Nonlinear finite element method (FEM) computer codes with slideline algorithm implementations should be useful for the analysis of prestressed multilayer pressure vessels and piping. This paper presents closed form solutions including the effects of tangential motion useful for verifying slideline implementations for this purpose. The solutions describe stresses and displacements of a long internally pressurized elastic-plastic cylinder initially separated from an elastic outer cylinder by a uniform gap. Comparison of closed form and FEM results evaluates the usefulness of the closed form solution and the validity of the sideline implementation used.

Van Gulick, L.A.

1984-01-01

213

Slideline verification for multilayer pressure vessels and piping analysis including strain hardening  

SciTech Connect

Nonlinear finite element computer codes with slideline algorithm implementations are useful for the analysis of prestressed pressure vessels and piping. This paper presents closed form solutions including the effects of linear strain hardening useful for verifying slideline implementations for this application. The solutions describe stresses and displacements of an internally pressurized inner sphere initially separated from an outer sphere by a uniform gap. Linear strain hardening material behavior following yield for the inner sphere and elastic material behavior for the outer sphere are assumed. Comparison of closed form and finite element results evaluates the usefulness of the closed form solutions and the validity of the slideline implementation used. 9 refs., 9 figs.

Van Gulick, L.A.

1985-01-01

214

Method and Device for Inserting a Linear Array Module into Long Small Diameter Pressure Vessels.  

National Technical Information Service (NTIS)

A method and apparatus for loading a linear array module into a pressure vessel includes a first rotatable winch positioned adjacent a first end of the pressure vessel, a second rotatable winch positioned adjacent a second end of the pressure vessel, a mo...

A. Kanel

1996-01-01

215

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

Microsoft Academic Search

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

Zoran Sterjovski

2003-01-01

216

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

217

Dual shell pressure balanced reactor vessel. Final project report  

SciTech Connect

The Department of Energy`s Office of Energy Research (OER) has previously provided support for the development of several chemical processes, including supercritical water oxidation, liquefaction, and aqueous hazardous waste destruction, where chemical and phase transformations are conducted at high pressure and temperature. These and many other commercial processes require a pressure vessel capable of operating in a corrosive environment where safety and economy are important requirements. Pacific Northwest Laboratory (PNL) engineers have recently developed and patented (U.S. patent 5,167,930 December 1, 1992) a concept for a novel Dual Shell Pressure Balanced Vessel (DSPBV) which could solve a number of these problems. The technology could be immediately useful in continuing commercialization of an R&D 100 award-winning technology, Sludge-to-oil Reactor System (STORS), originally developed through funding by OER. Innotek Corporation is a small business that would be one logical end-user of the DSPBV reactor technology. Innotek is working with several major U.S. engineering firms to evaluate the potential of this technology in the disposal of wastes from sewage treatment plants. PNL entered into a CRADA with Innotek to build a bench-scale demonstration reactor and test the system to advance the economic feasibility of a variety of high pressure chemical processes. Hydrothermal processing of corrosive substances on a large scale can now be made significantly safer and more economical through use of the DSPBV. Hydrothermal chemical reactions such as wet-air oxidation and supercritical water oxidation occur in a highly corrosive environment inside a pressure vessel. Average corrosion rates from 23 to 80 miles per year have been reported by Rice (1994) and Latanision (1993).

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

1994-10-01

218

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

219

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

220

Differential Global Gene Expression Response Patterns of Human Endothelium Exposed to Shear Stress and Intraluminal Pressure  

Microsoft Academic Search

We investigated the global gene expression response of endothelium exposed to shear stress and intraluminal pressure and tested the hypothesis that the two biomechanical forces induce a differential gene expression response pattern. Intact living human conduit vessels (umbilical veins) were exposed to normal or high intraluminal pressure, or to low or high shear stress in combination with a physiological level

Maria Andersson; Lena Karlsson; Per-Arne Svensson; Erik Ulfhammer; Mikael Ekman; Margareta Jernås; Lena M. S. Carlsson; Sverker Jern

2005-01-01

221

Jam proof closure assembly for lidded pressure vessels  

DOEpatents

An expendable closure assembly is provided for use (in multiple units) with a lockable pressure vessel cover along its rim, such as of an autoclave. This assembly is suited to variable compressive contact and locking with the vessel lid sealing gasket. The closure assembly consists of a thick walled sleeve insert for retention in the under bores fabricated in the cover periphery and the sleeve is provided with internal threading only. A snap serves as a retainer on the underside of the sleeve, locking it into an under bore retention channel. Finally, a standard elongate externally threaded bolt is sized for mating cooperation with the so positioned sleeve, whereby the location of the bolt shaft in the cover bore hole determines its compressive contact on the underlying gasket.

Cioletti, Olisse C. (Pittsburgh, PA)

1992-01-01

222

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

Code of Federal Regulations, 2011 CFR

...expected to experience significant thermal or stress effects during the thermal annealing operation...the effects of mechanical and thermal stresses and temperatures on the vessel, containment...that localized temperatures, thermal stress gradients, and subsequent...

2011-01-01

223

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

...expected to experience significant thermal or stress effects during the thermal annealing operation...the effects of mechanical and thermal stresses and temperatures on the vessel, containment...that localized temperatures, thermal stress gradients, and subsequent...

2014-01-01

224

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

Code of Federal Regulations, 2012 CFR

...expected to experience significant thermal or stress effects during the thermal annealing operation...the effects of mechanical and thermal stresses and temperatures on the vessel, containment...that localized temperatures, thermal stress gradients, and subsequent...

2012-01-01

225

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

226

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

227

Treating asphericity in fuel particle pressure vessel modeling  

NASA Astrophysics Data System (ADS)

The prototypical nuclear fuel of the New Production Modular High Temperature Gas-Cooled Reactor (NP-MHTGR) consists of spherical TRISO-coated particles suspended in graphite cylinders. The coating layers surrounding the fuel kernels in these particles consist of pyrolytic carbon layers and a silicon carbide layer. These coating layers act as a pressure vessel which retains fission product gases. In the operating conditions of the NP-MHTGR, a small percentage of these particles (pressure vessels) are expected to fail due to the pressure loading. The fuel particles of the NP-MHTGR deviate to some degree from a true spherical shape, which may have some effect on the failure percentages. A method is presented that treats the asphericity of the particles in predicting failure probabilities for particle samples. It utilizes a combination of finite element analysis and Monte Carlo sampling and is based on the Weibull statistical theory. The method is used here to assess the effects of asphericity in particles of two common geometric shapes, i.e. faceted particles and ellipsoidal particles. The method presented could be used to treat particle anomalies other than asphericity.

Miller, Gregory K.; Wadsworth, Derek C.

1994-07-01

228

Fabrication Flaws in Reactor Pressure Vessel Repair Welds  

SciTech Connect

This paper describes the fabrication flaw distribution and characterization in the repair weld metal of reactor pressure vessels. This work indicates that the large flaws occur in these repairs. These results show that repair flaws are complex in composition and sometimes include cracks on the repair ends. Parametric analysis using an exponential fit is performed on the data. A description of repair flaw morphology is provided. Fabrication flaws in repairs are characterized using high sensitivity nondestructive ultrasonic testing, validation by other nondestructive evaluation (NDE) techniques, and complemented by destructive testing.

Schuster, George J.; Doctor, Steven R.

2007-12-01

229

A nickel hydrogen common pressure vessel battery spaceflight experiment  

NASA Astrophysics Data System (ADS)

The Naval Research Laboratory-Johnson Controls Inc. Cooperative Research and Development Agreement, the NiH2 CPV (common pressure vessel) battery experiment design, and the qualification test program are described. The NiH2 CPV battery experiment is to fly as the primary energy storage system on a host spacecraft. The existing NiCd battery is to fly as a backup battery. Experiment electronics to provide switching between the two batteries and fault detection have been developed. The NiH2 CPV battery and the experiment components have been subjected to a rigorous qualification test program and have passed all tests with some minor exceptions.

Garner, J. C.

230

Evaluation of the reactor pressure vessel steels by positron annihilation  

NASA Astrophysics Data System (ADS)

This paper presents a comparison of commercially used German and Russian reactor pressure vessel steels from the positron annihilation spectroscopy (PAS) point of view, having in mind knowledge obtained also from other techniques from the last decades. The second generation of Russian RPV steels seems to be fully comparable with German steels and their quality allows prolongation of NPP operating lifetime over projected 40 years. The embrittlement of CrMoV steels is relatively low due to effect of higher temperature which implies partial in situ annealing of primary microstructural point defects and therefore delays the degradation processes caused by neutron irradiation.

Sluge?, V.; Hein, H.; Sojak, S.; Simeg Veterníková, J.; Petriska, M.; Sabelová, V.; Pavúk, M.; Hinca, R.; Stacho, M.

2013-11-01

231

DOMPAC Dosimetry Experiment: Neutron Simulation of the Pressure Vessel of a Pressurized-Water Reactor Characterization of Irradiation Damage.  

National Technical Information Service (NTIS)

The DOMPAC dosimetry experiment is an irradiated PWR pressure vessel simulation and has been performed in the pool of TRITON reactor (Fontenay-aux-Roses). It was designed for radiation damage characterization inside the vessel (neutron spectrum variation)...

A. Alberman M. Faure M. Thierry O. Hoclet A. Le Dieu de Ville

1983-01-01

232

Pressure vessel components design and analysis; Proceedings of the Pressure Vessels and Piping Conference, New Orleans, LA, June 23-26, 1985  

Microsoft Academic Search

The present conference on pressure vessels and piping encompasses topics in the design and analysis of tubesheet, bolted flange design advancements, computational methods for nonlinear problems, the design and analysis of valve applications, and computation methods for composite pipes and pressure vessels. Specific attention is given to the design of fixed tubesheet heat exchangers, the elastoplastic analysis of U-tube heat

1985-01-01

233

A Theoretical Investigation of Composite Overwrapped Pressure Vessel (COPV) Mechanics Applied to NASA Full Scale Tests  

NASA Technical Reports Server (NTRS)

A theoretical investigation of the factors controlling the stress rupture life of the National Aeronautics and Space Administration's (NASA) composite overwrapped pressure vessels (COPVs) continues. Kevlar (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of a load sharing liner, the manufacturing induced residual stresses and the complex mechanical response, the state of actual fiber stress in flight hardware and test articles is not clearly known. This paper is a companion to a previously reported experimental investigation and develops a theoretical framework necessary to design full-scale pathfinder experiments and accurately interpret the experimentally observed deformation and failure mechanisms leading up to static burst in COPVs. The fundamental mechanical response of COPVs is described using linear elasticity and thin shell theory and discussed in comparison to existing experimental observations. These comparisons reveal discrepancies between physical data and the current analytical results and suggest that the vessel s residual stress state and the spatial stress distribution as a function of pressure may be completely different from predictions based upon existing linear elastic analyses. The 3D elasticity of transversely isotropic spherical shells demonstrates that an overly compliant transverse stiffness relative to membrane stiffness can account for some of this by shifting a thin shell problem well into the realm of thick shell response. The use of calibration procedures are demonstrated as calibrated thin shell model results and finite element results are shown to be in good agreement with the experimental results. The successes reported here have lead to continuing work with full scale testing of larger NASA COPV hardware.

Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.; Greene, N.; Palko, Joseph L.; Eldridge, Jeffrey; Sutter, James; Saulsberry, R.; Beeson, H.

2009-01-01

234

A Theoretical Investigation of Composite Overwrapped Pressure Vessel (COPV) Mechanics Applied to NASA Full Scale Tests  

NASA Technical Reports Server (NTRS)

A theoretical investigation of the factors controlling the stress rupture life of the National Aeronautics and Space Agency's (NASA) composite overwrapped pressure vessels (COPVs) continues. Kevlar(TradeMark) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar(TradeMark) filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However, due to the presence of a load sharing liner, the manufacturing induced residual stresses and the complex mechanical response, the state of actual fiber stress in flight hardware and test articles is not clearly known. This paper is a companion to the experimental investigation reported in [1] and develops a theoretical framework necessary to design full-scale pathfinder experiments and accurately interpret the experimentally observed deformation and failure mechanisms leading up to static burst in COPVs. The fundamental mechanical response of COPVs is described using linear elasticity and thin shell theory and discussed in comparison to existing experimental observations. These comparisons reveal discrepancies between physical data and the current analytical results and suggest that the vessel's residual stress state and the spatial stress distribution as a function of pressure may be completely different from predictions based upon existing linear elastic analyses. The 3D elasticity of transversely isotropic spherical shells demonstrates that an overly compliant transverse stiffness relative to membrane stiffness can account for some of this by shifting a thin shell problem well into the realm of thick shell response. The use of calibration procedures are demonstrated as calibrated thin shell model results and finite element results are shown to be in good agreement with the experimental results. The successes reported here have lead to continuing work with full scale testing of larger NASA COPV hardware.

Greene, N.; Thesken, J. C.; Murthy, P. L. N.; Phoenix, S. L.; Palko, J.; Eldridge, J.; Sutter, J.; Saulsberry, R.; Beeson, H.

2006-01-01

235

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

236

Analysis of the failure of nuclear reactor pressure vessel closure studs  

Microsoft Academic Search

From 2nd international congress for pressure vessel and piping ; technology; San Antonio, Texas, USA (1 Oct 1973). See CONF-731003-P1. Two A-; 437 B4B closure studs of a nuclear reactor pressure vessel failed during the head ; removal operation. The service history of the vessel and the results of an in-; depth investigation of the failure are reviewed. It was

H. C. Jr. Burghard; A. G. Pickett

1973-01-01

237

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

238

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

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

239

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

PubMed Central

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

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

2014-01-01

240

Influence of crack depth on the fracture toughness of reactor pressure vessel steel  

SciTech Connect

The Heavy Section Steel Technology Program (HSST) at Oak Ridge National Laboratory (ORNL) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. Recently, it has been shown that, in notched beam testing, shallow cracks tend to exhibit an elevated toughness as a result of a loss of constraint at the crack tip. The loss of constraint takes place when interaction occurs between the elastic-plastic crack-tip stress field and the specimen surface nearest the crack tip. An increased shallow-crack fracture toughness is of interest to the nuclear industry because probabilistic fracture-mechanics evaluations show that shallow flaws play a dominant role in the probability of vessel failure during postulated pressurized-thermal-shock (PTS) events. Tests have been performed on beam specimens loaded in 3-point bending using unirradiated reactor pressure vessel material (A533 B). Testing has been conducted using specimens with a constant beam depth (W = 94 mm) and within the lower transition region of the toughness curve for A533 B. Test results indicate a significantly higher fracture toughness associated with the shallow flaw specimens compared to the fracture toughness determined using deep-crack (a/W = 0.5) specimens. Test data also show little influence of thickness on the fracture toughness for the current test temperature ({minus}60{degree}C). 21 refs., 5 figs., 3 tabs.

Theiss, T.J.; Bryson, J.W.

1991-01-01

241

Some mechanistic observations on the crack growth characteristics of pressure vessel and piping steels in PWR environment  

Microsoft Academic Search

The fatigue crack growth behavior of A533B and A508 pressure vessel steel and AISI Types 304 and 316 steels used in reactor coolant piping have been studied in a pressurized water reactor environment at 288°C (550°F). The influence of stress ratio (P\\/sub min\\/\\/P\\/sub max\\/), frequency, ramp times, specimen orientation and material microstructures were included in the study. While none of

W. H. Bamford; D. M. Moon

1979-01-01

242

Stress concentration factors of flat end to cylindrical shell connection with a fillet or stress relief groove subjected to internal pressure  

Microsoft Academic Search

For fatigue assessment of pressure vessels (parts), as proposed by the CEN Technical Committee 54, the knowledge of some stress quantities in the structure is necessary, e.g. equivalent stresses according to Tresca's yield criterion and principal stresses at welds. In this article, these quantities are given in the form of stress concentration factors for the flat end to cylindrical shell

Reinhard Preiss

1997-01-01

243

New methods of analysis of materials strength data for the ASME Boiler and Pressure Vessel Code  

SciTech Connect

Tensile and creep data of the type used to establish allowable stress levels for the ASME Boiler and Pressure Vessel Code have been examined for type 321H stainless steel. Both inhomogeneous, unbalanced data sets and well-planned homogeneous data sets have been examined. Data have been analyzed by implementing standard manual techniques on a modern digital computer. In addition, more sophisticated techniques, practical only through the use of the computer, have been applied. The result clearly demonstrates the efficacy of computerized techniques for these types of analyses.

Booker, M.K.; Booker, B.L.P.

1980-01-01

244

Tribology Aspects of a Pressure Vessel Closure Subjected to Pressure Cycling.  

National Technical Information Service (NTIS)

A repair method being considered for a steel pressure vessel is to cut away the faulty part leaving an unreinforced circular hole in the curved wall and cover it with a sealed plate placed inside. In order to investigate the structural properties of such ...

A. F. George M. E. Williams

1988-01-01

245

Simply actuated closure for a pressure vessel - Design for use to trap deep-sea animals  

NASA Technical Reports Server (NTRS)

A pressure vessel is described that can be closed by a single translational motion within 1 sec. The vessel is a key component of a trap for small marine animals and operates automatically on the sea floor. As the vessel descends to the sea floor, it is subjected both internally and externally to the high pressures of the deep sea. The mechanism for closing the pressure vessel on the sea floor is activated by the timed release of the ballast which was used to sink the trap. As it rises to the sea surface, the internal pressure of the vessel remains near the value present on the sea floor. The pressure vessel has been used in simulated ocean deployments and in the deep ocean (9500 m) with a 75%-85% retention of the deep-sea pressure. Nearly 100% retention of pressure can be achieved by using an accumulator filled with a gas.

Yayanos, A. A.

1977-01-01

246

Role of Crack Arrest in the Evaluation of PWR Pressure Vessel Integrity During PTS Transients.  

National Technical Information Service (NTIS)

The PWR pressurized thermal-shock (PTS) issue, which is concerned with the integrity of the reactor pressure vessel during postulated overcooling transients, is under intensive investigation by the USNRC. The USNRC-sponsored Integrated Pressurized Thermal...

R. D. Cheverton D. G. Ball

1984-01-01

247

Burst prediction by acoustic emission in filament-wound pressure vessels  

NASA Technical Reports Server (NTRS)

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

Gorman, Michael R.

1990-01-01

248

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 vessels 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.

Lark, R. F.

1977-01-01

249

Robust stress-classification of pressure components using the GLOSS and GLOSS r-node methods  

SciTech Connect

The GLOSS and GLOSS r-mode methods are used to classify stresses in pressure components. The classification scheme is akin to the prevailing ASME Boiler and Pressure Vessel Code procedures. The proposed method is applied to a cylinder flat-head configuration for thin as well as thick heads, and the stress classification methodology is outlined. The methods described in this paper can be readily applied to a general three-dimensional pressure component configuration.

Seshadri, R. [Memorial Univ. of Newfoundland, St. John`s (Canada). Faculty of Engineering and Applied Science

1996-05-01

250

Neutron irradiation embrittlement of reactor pressure-vessel steels. [BWR; PWR  

Microsoft Academic Search

The future of nuclear power depends importantly on the assurance of safety and reliability. The primary pressure boundary, especially the core-region pressure vessel, must withstand the usual service conditions plus neutron radiation, which embrittles, hardens, and strengthens the steel used in the pressure vessel. The article presented reviews the critical factors associated with radiation embrittlement and the measures that can

Steele

1976-01-01

251

Techniques for Embedding Instrumentation in Pressure Vessel Test Articles  

NASA Technical Reports Server (NTRS)

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

Cornelius, Michael

2006-01-01

252

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

253

ASTM Standards for Reactor Dosimetry and Pressure Vessel Surveillance  

SciTech Connect

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

GRIFFIN, PATRICK J.

1999-09-14

254

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.

2014-03-01

255

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

256

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

257

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

258

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

NASA Technical Reports Server (NTRS)

The development of structurally efficient, metal-lined, glass-fiber composite pressure vessels. Both the current state-of-the-art and current problems are discussed along with fracture mechanics considerations for the metal liner. The design concepts used for metal-lined, glass-fiber, composite pressure vessels are described and the structural characteristics of the composite designs are compared with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. Results of a current program to evaluate flaw growth and fracture characteristics of the metal liners are reviewed and the impact of these results on composite pressure vessel designs is discussed.

Faddoul, J. R.

1973-01-01

259

Deformation behavior in reactor pressure vessel steels as a clue to understanding irradiation hardening.  

SciTech Connect

In this paper, we examine the post-yield true stress vs true strain behavior of irradiated pressure vessel steels and iron-based alloys to reveal differences in strain-hardening behavior associated with different irradiating particles (neutrons and electrons) and different alloy chernky. It is important to understand the effects on mechanical properties caused by displacement producing radiation of nuclear reactor pressure steels. Critical embrittling effects, e.g. increases in the ductile-to-brittle-transition-temperature, are associated with irradiation-induced increases in yield strength. In addition, fatigue-life and loading-rate effects on fracture can be related to the post-irradiation strain-hardening behavior of the steels. All of these properties affect the expected service life of nuclear reactor pressure vessels. We address the characteristics of two general strengthening effects that we believe are relevant to the differing defect cluster characters produced by neutrons and electrons in four different alloys: two pressure vessel steels, A212B and A350, and two binary alloys, Fe-0.28 wt%Cu and Fe-0.74 wt%Ni. Our results show that there are differences in the post-irradiation mechanical behavior for the two kinds of irradiation and that the differences are related both to differences in damage produced and alloy chemistry. We find that while electron and neutron irradiations (at T {le} 60 C) of pressure vessel steels and binary iron-based model alloys produce similar increases in yield strength for the same dose level, they do not result in the same post-yield hardening behavior. For neutron irradiation, the true stress flow curves of the irradiated material can be made to superimpose on that of the unirradiated material, when the former are shifted appropriately along the strain axis. This behavior suggests that neutron irradiation hardening has the same effect as strain hardening for all of the materials analyzed. For electron irradiated steels, the post-yield hardening rate is clearly greater than that of the unirradiated material, and the flow curves cannot be made to superimpose. The binary iron-base model alloys studied here show a less pronounced difference in flow behavior for neutrons and electrons than exhibited by the steels, implicating the effect of alloy chemistry. Our results are analyzed in the context of classical theories dealing with the interaction between the deformation microstructure, i.e. glide dislocations, and irradiation-produced defects. Our findings provide clues about the way different alloy constituents interact with the different kinds of irradiation damage to strengthen the material differently.

DiMelfi, R. J.; Alexander, D. E.; Rehn, L. E.

1999-10-25

260

Microorganism inactivation using high-pressure generation in sealed vessels under sub-zero temperature  

Microsoft Academic Search

In order to test the possibility of utilizing high pressure in bioscience and biotechnology, a simple method for high-pressure\\u000a generation and its use for microbial inactivation have been studied. When a pressure vessel was filled with water, sealed\\u000a tightly and cooled to sub-zero temperatures, high pressure was generated in the vessel. The pressure generation was 60?MPa\\u000a at ?5?C, 103?MPa at

K. Hayakawa; Y. Ueno; S. Kawamura; T. Kato; R. Hayashi

1998-01-01

261

Risk identification and control of stationary high-pressure hydrogen storage vessels  

Microsoft Academic Search

The number of hydrogen fueling stations is steadily growing as the number of hydrogen fueled vehicles increases. Stationary high-pressure hydrogen storage vessels are key equipment in hydrogen fueling station. The safety of these vessels should be first considered during the design of hydrogen infrastructure because the vessel failure will cause huge damage and losses. This paper analyzes the potential hazards

Ping Xu; Jinyang Zheng; Pengfei Liu; Rui Chen; Fangming Kai; Lei Li

2009-01-01

262

Impact of Radiation Embrittlement on Integrity of Pressure Vessel Supports for Two PWR (Pressurized-Water-Reactor) Plants.  

National Technical Information Service (NTIS)

Recent pressure-vessel surveillance data from the High Flux Isotope Reactor (HFIR) indicate an embrittlement fluence-rate effect that is applicable to the evaluation of the integrity of light-water reactor (LWR) pressure vessel supports. A preliminary eva...

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

1988-01-01

263

A Neural Network/Acoustic Emission Analysis of Impact Damaged Graphite/Epoxy Pressure Vessels  

NASA Technical Reports Server (NTRS)

Acoustic emission (AE) signal analysis has been used to measure the effects of impact damage on burst pressure in 5.75 inch diameter, inert propellant filled, filament wound pressure vessels. The AE data were collected from fifteen graphite/epoxy pressure vessels featuring five damage states and three resin systems. A burst pressure prediction model was developed by correlating the AE amplitude (frequency) distribution, generated during the first pressure ramp to 800 psig (approximately 25% of the average expected burst pressure for an undamaged vessel) to known burst pressures using a four layered back propagation neural network. The neural network, trained on three vessels from each resin system, was able to predict burst pressures with a worst case error of 5.7% for the entire fifteen bottle set.

Walker, James L.; Hill, Erik v. K.; Workman, Gary L.; Russell, Samuel S.

1995-01-01

264

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

NASA Astrophysics Data System (ADS)

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

Cherniaev, Aleksandr; Telichev, Igor

2014-02-01

265

Teaching evolutionary biology: Pressures, stress, and coping  

Microsoft Academic Search

Understanding what teachers need to be more comfortable and confident in their profession is crucial to the future of effective teachers and scientific literacy in public schools. This study focuses on the experiences of Arizona biology teachers in teaching evolution, using a clinical model of stress to identify sources of pressure, the resulting stresses, and coping strategies they employ to

Joyce A. Griffith; Sarah K. Brem

2004-01-01

266

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

Microsoft Academic Search

This report discusses development on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels containing flaws. Fracture mechanics tests on reactor pressure vessel steel have shown that local brittle zones do not significantly degrade the material fracture toughness, constraint relaxation at the crack tip of shallow surface flaws results in increased fracture toughness, and biaxial loading

W. E. Pennell; W. R. Corwin

1994-01-01

267

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

SciTech Connect

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

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

1995-03-01

268

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

269

Experimental investigation into water-filled pressurized vessels damaged by high-velocity projectile impact  

NASA Astrophysics Data System (ADS)

All spacecraft in orbit are susceptible to high velocity impact by meteoroid and space debris. Pressure vessels are the most critical components onboard spacecraft. Impacts of meteoroid or space debris on pressure vessels can indeed lead to the rupturing failure of the vessel and terminate prematurely spacecraft mission. The aim of this work is to explore experimentally the condition and the limit between simple perforation and rupturing damage of pressure vessels under high velocity impacts. Preliminary results are presented from high-velocity impact tests on thin-walled aluminum and steel cylindrical pressurized vessels filled with different percent volume of water and different pressure of gas. Damage patterns and mechanisms leading to rupturing failure are discussed.

Pang, Baojun; Zhang, Wei; Luo, Dekun; Zhang, Zehua

2001-10-01

270

Shallow-crack toughness results for reactor pressure vessel steel  

SciTech Connect

The Heavy Section Steel Technology Program (HSST) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. To complete this investigation, techniques were developed to determine the fracture toughness from shallow-crack specimens. A total of 38 deep and shallow-crack tests have been performed on beam specimens about 100 mm deep loaded in 3-point bending. Two crack depths (a {approx} 50 and 9 mm) and three beam thicknesses (B {approx} 50, 100, and 150 mm) have been tested. Techniques were developed to estimate the toughness in terms of both the J-integral and crack-tip opening displacement (CTOD). Analytical J-integral results were consistent with experimental J-integral results, confirming the validity of the J-estimation schemes used and the effect of flaw depth on fracture toughness. Test results indicate a significant increase in the fracture toughness associated with the shallow flaw specimens in the lower transition region compared to the deep-crack fracture toughness. There is, however, little or no difference in toughness on the lower shelf where linear-elastic conditions exist for specimens with either deep or shallow flaws. The increase in shallow-flaw toughness compared with deep-flaw results appears to be well characterized by a temperature shift of 35{degree}C.

Theiss, T.J.; Shum, D.K.M. (Oak Ridge National Lab., TN (United States)); Rolfe, S.T. (Kansas Univ., Lawrence, KS (United States))

1992-01-01

271

Shallow-crack toughness results for reactor pressure vessel steel  

SciTech Connect

The Heavy Section Steel Technology Program (HSST) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. To complete this investigation, techniques were developed to determine the fracture toughness from shallow-crack specimens. A total of 38 deep and shallow-crack tests have been performed on beam specimens about 100 mm deep loaded in 3-point bending. Two crack depths (a {approx} 50 and 9 mm) and three beam thicknesses (B {approx} 50, 100, and 150 mm) have been tested. Techniques were developed to estimate the toughness in terms of both the J-integral and crack-tip opening displacement (CTOD). Analytical J-integral results were consistent with experimental J-integral results, confirming the validity of the J-estimation schemes used and the effect of flaw depth on fracture toughness. Test results indicate a significant increase in the fracture toughness associated with the shallow flaw specimens in the lower transition region compared to the deep-crack fracture toughness. There is, however, little or no difference in toughness on the lower shelf where linear-elastic conditions exist for specimens with either deep or shallow flaws. The increase in shallow-flaw toughness compared with deep-flaw results appears to be well characterized by a temperature shift of 35{degree}C.

Theiss, T.J.; Shum, D.K.M. [Oak Ridge National Lab., TN (United States); Rolfe, S.T. [Kansas Univ., Lawrence, KS (United States)

1992-09-01

272

Shallow-crack toughness results for reactor pressure vessel steel  

NASA Astrophysics Data System (ADS)

The Heavy Section Steel Technology Program (HSST) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. To complete this investigation, techniques were developed to determine the fracture toughness from shallow-crack specimens. A total of 38 deep and shallow-crack tests have been performed on beam specimens about 100 mm deep loaded in 3-point bending. Two crack depths (a is approximately equal to 50 and 9 mm) and three beam thicknesses (B is approximately equal to 50, 100, and 150 mm) have been tested. Techniques were developed to estimate the toughness in terms of both the J-integral and crack-tip opening displacement (CTOD). Analytical J-integral results were consistent with experimental J-integral results, confirming the validity of the J-estimation schemes used and the effect of flaw depth on fracture toughness. Test results indicate a significant increase in the fracture toughness associated with the shallow flaw specimens in the lower transition region compared to the deep-crack fracture toughness. There is, however, little or no difference in toughness on the lower shelf where linear-elastic conditions exist for specimens with either deep or shallow flaws. The increase in shallow-flaw toughness compared with deep-flaw results appears to be well characterized by a temperature shift of 35 C.

Theiss, T. J.; Shum, D. K. M.; Rolfe, S. T.

273

Advances in crack-arrest technology for reactor pressure vessels  

SciTech Connect

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

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

1988-01-01

274

Coordinated sensing and autonomous repair of pressure vessels and structures  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

275

Three-dimensional analysis of thermal shock effect on inner semi-elliptical surface cracks in a cylindrical pressure vessel  

Microsoft Academic Search

Transient mode I stress intensity factors (KIT) distributions along semi-elliptical crack fronts resulting from thermal shock typical to a firing gun are investigated. KIT distributions for various crack arrays of n=2 to 48 cracks, bearing cracks of relative depths of a\\/W=0.1 to 0.4 and with ellipticities of a\\/c=0.5, 1.0 and 1.5 are evaluated for a cylindrical pressure vessel of radii

M. Perl; Y. Greenberg

1999-01-01

276

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

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

2009-10-01

277

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

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

2010-10-01

278

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

NASA Technical Reports Server (NTRS)

Introducing composite vessels into the Space Shuttle Program represented a significant technical achievement. Each Orbiter vehicle contains 24 (nominally) Kevlar tanks for storage of pressurized helium (for propulsion) and nitrogen (for life support). The use of composite cylinders saved 752 pounds per Orbiter vehicle compared with all-metal tanks. The weight savings is significant considering each Shuttle flight can deliver 54,000 pounds of payload to the International Space Station. In the wake of the Columbia accident and the ensuing Return to Flight activities, the Space Shuttle Program, in 2005, re-examined COPV hardware certification. Incorporating COPV data that had been generated over the last 30 years and recognizing differences between initial Shuttle Program requirements and current operation, a new failure mode was identified, as composite stress rupture was deemed credible. The Orbiter Project undertook a comprehensive investigation to quantify and mitigate this risk. First, the engineering team considered and later deemed as unfeasible the option to replace existing all flight tanks. Second, operational improvements to flight procedures were instituted to reduce the flight risk and the danger to personnel. Third, an Orbiter reliability model was developed to quantify flight risk. Laser profilometry inspection of several flight COPVs identified deep (up to 20 mil) depressions on the tank interior. A comprehensive analysis was performed and it confirmed that these observed depressions were far less than the criterion which was established as necessary to lead to liner buckling. Existing fleet vessels were exonerated from this failure mechanism. Because full validation of the Orbiter Reliability Model was not possible given limited hardware resources, an Accelerated Stress Rupture Test of a flown flight vessel was performed to provide increased confidence. A Bayesian statistical approach was developed to evaluate possible test results with respect to the model credibility and thus flight rationale for continued operation of the Space Shuttle with existing flight hardware. A non-destructive evaluation (NDE) technique utilizing Raman Spectroscopy was developed to directly measure the overwrap residual stress state. Preliminary results provide optimistic results that patterns of fluctuation in fiber elastic strains over the outside vessel surface could be directly correlated with increased fiber stress ratios and thus reduced reliability.

Kezirian, Michael T.

2010-01-01

279

Fatigue performance of metal-lined graphite/epoxy pressure vessels  

NASA Technical Reports Server (NTRS)

Using an ultrahigh-strength graphite fiber, a program was started to develop a thin metal-lined fiber/epoxy pressure vessel that would have a fatigue life of over 1000 cycles. First, the performance factor of the fiber/epoxy composite was found to be 351 kN m/kg from the average of 18 rubber-lined pressure vessels. Then, both aluminum- and titanium-lined vessels were filament wound with the graphite fiber in an epoxy matrix. Several of these metal-lined vessels were subjected to hydraulic fatigue testing to about 50% of their expected burst pressures. The average fatigue life of the aluminum-lined vessels was 462 cycles; the average for the titanium-lined vessels was 2190 cycles.

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

1975-01-01

280

Design of a standalone-type beryllium vessel for high-pressure protein crystallography  

NASA Astrophysics Data System (ADS)

A standalone-type beryllium (Be) high-pressure crystallography vessel has been developed. Using a coupler-joint unit and a pressure valve, we could keep the pressure in the vessel constant at 100+/-1 MPa for more than 24 h without connecting to a pressure-generating apparatus. Diffraction spots of a glucose isomerase (GI) crystal under 100 MPa were collected using the vessel and a rotating copper-anode in-house x-ray generator (0.8 kW). We successfully collected a 2.0 A? resolution data set of a 0.5 mm size GI crystal in an aqueous solution at 100 MPa.

Suzuki, Yoshihisa; Tsukamoto, Masayuki; Sakuraba, Haruhiko; Matsumoto, Masamitsu; Nagasawa, Makoto; Tamura, Katsuhiro

2010-08-01

281

Pressure vessels and piping codes and standards: Volume 1. PVP-Volume 338  

SciTech Connect

The role of Codes and Standards for pressure vessels and piping has increased significantly over the past decade. More and more, developments in Codes and Standards are accommodating the increasing sophistication of analysis methods, the need to address post-construction and operating plant issues, and the efficiencies that may be gained by focusing codes and standards on the areas that present the greatest risk. Codes and Standards for new construction also have had to accommodate greater challenges and more extreme environments imposed by more escalating requirements on piping and pressure vessel design and fabrication. This volume on Codes and Standards has focused on these challenges faced by Codes and Standards development. The topics in this volume include: (1) Socket Welds and Stress Intensification Factors; (2) Developments in Piping Code and Standards; (3) Root Cause Analysis; (4) B31.1 Code Developments and Applications; (5) Flow-Accelerated Corrosion Developments and Applications; (6) Advanced Analysis Methods and the ASME Code; and (7) Application of Advanced Analysis Methods for ASME Code Evaluation. Separate abstracts were prepared for most of the papers in this volume.

Esselman, T.C. [ed.] [Altran Corp., Boston, MA (United States); Adams, T.M. [ed.] [Stevenson and Associates, Cleveland, OH (United States); Bhavnani, D. [ed.] [Public Service Electric and Gas Co., Hancock`s Bridge, NJ (United States); Cofie, N.G. [ed.] [Structural Integrity Associates, Inc., San Jose, CA (United States); Jones, D.P. [ed.] [Westinghouse Electric Corp., West Mifflin, PA (United States); Olson, D.E. [ed.] [Sargent and Lundy, Chicago, IL (United States); Thailer, H.J. [ed.] [Pacific Gas and Electric Co., San Francisco, CA (United States)

1996-12-01

282

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

SciTech Connect

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

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

1982-01-01

283

International pressure vessels and piping codes and standards. Volume 2: Current perspectives; PVP-Volume 313-2  

SciTech Connect

The topics in this volume include: (1) Recent or imminent changes to Section 3 design sections; (2) Select perspectives of ASME Codes -- Section 3; (3) Select perspectives of Boiler and Pressure Vessel Codes -- an international outlook; (4) Select perspectives of Boiler and Pressure Vessel Codes -- ASME Code Sections 3, 8 and 11; (5) Codes and Standards Perspectives for Analysis; (6) Selected design perspectives on flow-accelerated corrosion and pressure vessel design and qualification; (7) Select Codes and Standards perspectives for design and operability; (8) Codes and Standards perspectives for operability; (9) What`s new in the ASME Boiler and Pressure Vessel Code?; (10) A look at ongoing activities of ASME Sections 2 and 3; (11) A look at current activities of ASME Section 11; (12) A look at current activities of ASME Codes and Standards; (13) Simplified design methodology and design allowable stresses -- 1 and 2; (14) Introduction to Power Boilers, Section 1 of the ASME Code -- Part 1 and 2. Separate abstracts were prepared for most of the individual papers.

Rao, K.R.; Asada, Yasuhide; Adams, T.M. [eds.] [and others

1995-12-01

284

Computational methods for fracture analysis of heavy-section steel technology (HSST) pressure vessel experiments  

SciTech Connect

This paper summarizes the capabilities and applications of the general-purpose and special-purpose computer programs that have been developed for use in fracture mechanics analyses of HSST pressure vessel experiments. Emphasis is placed on the OCA/USA code, which is designed for analysis of pressurized-thermal-shock (PTS) conditions, and on the ORMGEN/ADINA/ORVIRT system which is used for more general analysis. Fundamental features of these programs are discussed, along with applications to pressure vessel experiments.

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

1983-01-01

285

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

286

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

287

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

288

Non-invasive method and apparatus for measuring pressure within a pliable vessel  

NASA Technical Reports Server (NTRS)

A non-invasive method and apparatus is disclosed for measuring pressure within a pliable vessel such as a blood vessel. The blood vessel is clamped by means of a clamping structure having a first portion housing a pressure sensor and a second portion extending over the remote side of the blood vessel for pressing the blood vessel into engagement with the pressure sensing device. The pressure sensing device includes a flat deflectable diaphragm portion arranged to engage a portion of the blood vessel flattened against the diaphragm by means of the clamp structure. In one embodiment, the clamp structure includes first and second semicylindrical members held together by retaining rings. In a second embodiment the clamp structure is of one piece construction having a solid semicylindrical portion and a hollow semicylindrical portion with a longitudinal slot in the follow semicylindrical portion through which a slip the blood vessel. In a third embodiment, an elastic strap is employed for clamping the blood vessel against the pressure sensing device.

Shimizu, M. (inventor)

1983-01-01

289

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

290

HFIR Pressure Vessel and Structural Components Materials Surveillance Program  

SciTech Connect

A proposal has been made to increase the size of the HFIR HB-2 and HB-4 beam tubes and to extend the life of the vessel to 50 EFPY(100 MW). Studies indicate that the increase in radiation-induced embrittlement of the vessel can be tolerated, and an appropriate expanded vessel-materials surveillance program has been devised. This program, which is the subject of this report, includes additional beam-tube nozzle-material surveillance specimens, relocation of existing specimens of all materials, and additional dosimetry. As an aid in the placement of specimens and dosimeters, extensive two- and three-dimensional neutron and gamma flux/dpa transport calculations were made. Surveillance data will be added to the HFIR vessel (delta)NDTT vs dpa data base, and dosimetry will be used to normalize the calculated fluxes. The updated (delta)NDTT vs dpa correlation and the normalized dpa values will be used in the calculation of the probability of vessel failure. This procedure, in conjunction with periodic hydrostatic proof testing, is used to determine the useful life of the vessel.

Blakeman, E.D.; Cheverton, R.D.; Nanstad, R.K.

1999-08-01

291

Finite-element and fracture-mechanics analyses of filament-wound pressure vessels with thin metallic liners  

SciTech Connect

The theoretical background and concept are provided for analyzing the filament-wound pressure vessels with thin metallic liners. The thin metallic liner serves mainly as a permeation barrier to hold liquid or gas, while the composite is sized to carry most of the pressure loads. The bilinear material model is selected to simulate the material stress-strain curve that governs the metal linear behavior. Subjects investigated are classical lamination theory, quadratic failure criterion, bilinear material model, finite-element analysis for axisymmetric solids, and linear elastic fracture mechanics. Four sample cases are analyzed to demonstrate the capabilities of the developed finite-element program FEASY4ND in solving the axisymmetric shell problems. The cases investigated include the parametric study on Poisson's ratio, the thick-walled and thin-walled sphere analyses, and analysis of a sample filament-wound pressure vessel with a thin metallic liner. The filament-wound pressure vessel is analyzed at proof, operating, and design burst pressures. The liner cycle life is calculated based on the principle of linear elastic fracture mechanics.

Shy, D.S.

1987-01-01

292

Fatality Assessment and Control Evaluation (FACE) Report for California: Fitter/Welder is Crushed Between Two Pressure Vessels and Dies.  

National Technical Information Service (NTIS)

A 42-year old male fitter/welder (decedent) died when he was crushed between a stationary pressure vessel (a type of unfired, cylindrical tank) and a pressure vessel that had tipped up. The decedent was on top of the pressure vessel that tipped while he w...

2000-01-01

293

DEVELOPMENT OF ASME SECTION X CODE RULES FOR HIGH PRESSURE COMPOSITE HYDROGEN PRESSURE VESSELS WITH NON-LOAD SHARING LINERS  

SciTech Connect

The Boiler and Pressure Vessel Project Team on Hydrogen Tanks was formed in 2004 to develop Code rules to address the various needs that had been identified for the design and construction of up to 15000 psi hydrogen storage vessel. One of these needs was the development of Code rules for high pressure composite vessels with non-load sharing liners for stationary applications. In 2009, ASME approved new Appendix 8, for Section X Code which contains the rules for these vessels. These vessels are designated as Class III vessels with design pressure ranging from 20.7 MPa (3,000 ps)i to 103.4 MPa (15,000 psi) and maximum allowable outside liner diameter of 2.54 m (100 inches). The maximum design life of these vessels is limited to 20 years. Design, fabrication, and examination requirements have been specified, included Acoustic Emission testing at time of manufacture. The Code rules include the design qualification testing of prototype vessels. Qualification includes proof, expansion, burst, cyclic fatigue, creep, flaw, permeability, torque, penetration, and environmental testing.

Rawls, G.; Newhouse, N.; Rana, M.; Shelley, B.; Gorman, M.

2010-04-13

294

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

295

Comparison between classical and substructuring finite-element stress analysis of a complex vacuum vessel shell.  

National Technical Information Service (NTIS)

In this study, the middle part of a vacuum vessel was considered for stress analysis. This section consisted of a cylindrical shell with flanges at the ends to be connected to the other parts of the vessel. Because of the nature of the design, many penetr...

M. A. Rezvani H. H. Ziada

1991-01-01

296

BENCHMARKING OF SYNTHESIZED 3-D SN TRANSPORT METHODS FOR PRESSURE VESSEL FLUENCE CALCULATIONS WITH MONTE CARLO  

Microsoft Academic Search

Monte Carlo calculations of pressure vessel (PV) neutron fluence have been performed to benchmark discrete ordinates (SN) transport methods. These calculations, along with measured data at the ex-vessel cavity dosimeter, provide a means to examine various uncertainties associated with the SN transport calculations. For the purpose of the PV fluence calculations, synthesized 3-D deterministic models are shown to produce results

J. C. Wagner; A. Haghighat; B. G. Petrovic; H. L. Hanshaw

297

DOMPAC Dosimetry. PWR Pressure Vessel Neutronic Simulation and Radiation Damage Characterization.  

National Technical Information Service (NTIS)

The DOMPAC dosimetry experiment is an irradiated PWR pressure vessel simulation and has been performed in the pool of TRITON reactor (Fontenay-aux-Roses). A 20-cm thick ferritic steel block simulated the vessel and was equipped with graphite (GAMIN) and t...

A. Alberman M. Faure M. Thierry O. Hoclet A. Le Dieu de Ville

1983-01-01

298

Metodi i priblizheniya za opredelyane na neutronniya fluens vyrkhu korpusa na VVER. (Methods and assumptions for determination of neutron fluence onto the WWER pressure vessel).  

National Technical Information Service (NTIS)

The determination of neutron fluence onto the WWER pressure vessel is considered as an essential part of the Pressure Vessel Surveillance Program. The main tools for determining the pressure vessel fluence are the neutron transport calculations. From metr...

K. Ilieva T. Apostolov

1993-01-01

299

Teaching Evolutionary Biology: Pressures, Stress, and Coping  

ERIC Educational Resources Information Center

Understanding what teachers need to be more comfortable and confident in their profession is crucial to the future of effective teachers and scientific literacy in public schools. This study focuses on the experiences of Arizona biology teachers in teaching evolution, using a clinical model of stress to identify sources of pressure, the resulting…

Griffith, Joyce A.; Brem, Sarah K.

2004-01-01

300

Evaluation of polyimide/glass fiber composites for construction of light weight pressure vessels for cryogenic propellants  

NASA Technical Reports Server (NTRS)

The application of polyimide resin as a matrix for glass filament-wound thin metal-lined pressure vessels was studied over a temperature range of (minus) 320 to 600 F. Keramid 601 polyimide was found to perform quite well over the entire range of temperature. Hoop stress values of 425 ksi were determined at 75 F which is equivalent to epoxy resin in similar structures. At -320 and 600 F, 125 and 80% of this strength was retained. Thermal ageing at 500 F for up to 50 hours was studied with severe reduction in strength, but there is evidence that this reduction could be improved. Another polyimide resin studied was P10PA which was found to have processing characteristics inappropriate for filament-winding. NOL ring tensile and shear data was determined from both resins with S-glass. Pressure vessel design, fabrication and test procedures are described in detail.

Petker, I.; Segimoto, M.

1973-01-01

301

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

302

Fracture Toughness Data for Ferritic Nuclear Pressure Vessel Materials. Task B - Laboratory Testing.  

National Technical Information Service (NTIS)

A comprehensive testing program on production heats of ferritic nuclear pressure vessel steel has recently been completed and the results from this program are documented in this report. Mechanical tests performed include tensile, drop weight NDTT, Charpy...

W. L. Server J. W. Sheckherd R. A. Wullaert

1976-01-01

303

Assessment of Materials Technology of Pressure Vessels and Piping for Coal Conversion Systems.  

National Technical Information Service (NTIS)

The current technology of the materials, fabrication, and inspection of pressure vessels and piping for commercial coal conversion systems is reviewed. Comparison is made between the various codes applicable to these conversion systems. Areas of concern, ...

D. A. Canonico, R. H. Cooper, B. E. Foster, R. W. McClung, R. K. Nanstad

1978-01-01

304

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

305

DOMPAC Dosimetry Experiment. Neutronic Simulation of the Thickness of a PWR Pressure Vessel. Irradiation Damages.  

National Technical Information Service (NTIS)

For suitable extrapolation of irradiated PWR ferritic steel results, proper irradiation of the pressure vessel has been 'simulated' in test reactor. For this purpose, a huge steel block (20 cm in depth) was loaded with Saclay's graphite (GAMIN) and tungst...

A. Alberman M. Faure M. Thierry O. Hoclet A. Le Dieu de Ville

1979-01-01

306

Development of a Mechanistic Understanding of Radiation Embrittlement in Reactor Pressure Vessel Steels.  

National Technical Information Service (NTIS)

The microstructures of a series of reactor pressure vessel (RPV) steels and model iron alloys with various Cu, Ni, and P contents were examined in unirradiated and neutron-irradiated conditions using high resolution analytical microscopy. Fractography tec...

D. Venables D. T. Hoelzer F. Ebrahimi V. Krishnamoorthy

1988-01-01

307

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

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

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

308

Dosimetry and Fluence Calculations on French PWR (Pressurized Water Reactor) Vessels Comparisons Between Experiments and Calculations.  

National Technical Information Service (NTIS)

Fluence and damage calculations on PWR pressure vessels and irradiation test specimens are presented for two types of reactor: the Franco-Belgian (reactor CHOOZ) and the French reactors (CPY program). Comparisons with measurements are given for activation...

J. C. Nimal L. Bourdet R. Lloret A. Abevilaqua

1988-01-01

309

Low Cycle-Fatigue and Fracture Behaviour as Parameters for the Dimensioning of High Pressure Vessels.  

National Technical Information Service (NTIS)

The behavior under cyclic elastic and plastic deformations, the crack propagation, and the brittle fracture of a high-pressure vessel steel with different values for ultimate strength and yielding point are discussed and their application for the dimensio...

V. Grubisic

1977-01-01

310

Oxidative stress in hypobaric hypoxia and influence on vessel-tone modifying mediators.  

PubMed

Increased pulmonary artery pressure is a well-known phenomenon of hypoxia and is seen in patients with chronic pulmonary diseases, and also in mountaineers on high altitude expedition. Different mediators are known to regulate pulmonary artery vessel tone. However, exact mechanisms are not fully understood and a multimodal process consisting of a whole panel of mediators is supposed to cause pulmonary artery vasoconstriction. We hypothesized that increased hypoxemia is associated with an increase in vasoconstrictive mediators and decrease of vasodilatators leading to a vasoconstrictive net effect. Furthermore, we suggested oxidative stress being partly involved in changement of these parameters. Oxygen saturation (Sao2) and clinical parameters were assessed in 34 volunteers before and during a Swiss research expedition to Mount Muztagh Ata (7549 m) in Western China. Blood samples were taken at four different sites up to an altitude of 6865 m. A mass spectrometry-based targeted metabolomic platform was used to detect multiple parameters, and revealed functional impairment of enzymes that require oxidation-sensitive cofactors. Specifically, the tetrahydrobiopterin (BH4)-dependent enzyme nitric oxide synthase (NOS) showed significantly lower activities (citrulline-to-arginine ratio decreased from baseline median 0.21 to 0.14 at 6265 m), indicating lower NO availability resulting in less vasodilatative activity. Correspondingly, an increase in systemic oxidative stress was found with a significant increase of the percentage of methionine sulfoxide from a median 6% under normoxic condition to a median level of 30% (p<0.001) in camp 1 at 5533 m. Furthermore, significant increase in vasoconstrictive mediators (e.g., tryptophan, serotonin, and peroxidation-sensitive lipids) were found. During ascent up to 6865 m, significant altitude-dependent changes in multiple vessel-tone modifying mediators with excess in vasoconstrictive metabolites could be demonstrated. These changes, as well as highly significant increase in systemic oxidative stress, may be predictive for increase in acute mountain sickness score and changes in Sao2. PMID:24067187

Pichler Hefti, Jacqueline; Sonntag, Denise; Hefti, Urs; Risch, Lorenz; Schoch, Otto D; Turk, Alexander J; Hess, Thomas; Bloch, Konrad E; Maggiorini, Marco; Merz, Tobias M; Weinberger, Klaus M; Huber, Andreas R

2013-09-01

311

Neutron-irradiated model alloys and pressure-vessel steels studied using positron spectroscopy  

Microsoft Academic Search

We have used positron-annihilation-lifetime spectroscopies to examine microstructural evolution of pressure vessel steels and model alloys that have systematically varied amounts of copper, nickel, and phosphorus during neutron irradiation and post-irradiation annealing. The objective of this work was to characterize the neutron-irradiation induced microstructural features that cause the embrittlement of nuclear reactor pressure-vessel steel. We used positron annihilation lifetime spectroscopy

Stephen Eric Cumblidge

2002-01-01

312

Heat transfer analysis of the LWR pressure vessel steel irradiation capsules in the Oak Ridge research reactor-pressure vessel benchmark facility  

Microsoft Academic Search

The purpose of this study was to determine a design for irradiation capsules for the Light Water Reactor (LWR) Pressure Vessel Wall Simulation (PVWS) experiment in the Poolside Facility of the Oak Ridge Research Reactor. The experiment's structural configuration is based on the actual configuration of an LWR PV wall, the surveillance specimen capsule, and the thermal shield. The design

Siman-Tov

1982-01-01

313

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

314

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

315

Constriction of isolated collecting lymphatic vessels in response to acute increases in downstream pressure.  

PubMed

Collecting lymphatic vessels generate pressure to transport lymph downstream to the subclavian vein against a significant pressure head. To investigate their response to elevated downstream pressure, collecting lymphatic vessels containing one valve (incomplete lymphangion) or two valves (complete lymphangion) were isolated from the rat mesentery and tied to glass cannulae capable of independent pressure control. Downstream pressure was selectively raised to various levels, either stepwise or ramp-wise, while keeping upstream pressure constant. Diameter and valve positions were tracked under video microscopy, while intralymphangion pressure was measured concurrently with a servo-null micropipette. Surprisingly, a potent lymphatic constriction occurred in response to the downstream pressure gradient due to (1) a pressure-dependent myogenic constriction and (2) a frequency-dependent decrease in diastolic diameter. The myogenic index of the lymphatic constriction (-3.3 ± 0.6, in mmHg) was greater than that of arterioles or collecting lymphatic vessels exposed to uniform increases in pressure (i.e. upstream and downstream pressures raised together). Additionally, the constriction was transmitted to the upstream lymphatic vessel segment even though it was protected from changes in pressure by a closed intraluminal valve; the conducted constriction was blocked by loading only the pressurized half of the vessel with either ML-7 (0.5 mm) to block contraction, or cromakalim (3 ?m) to hyperpolarize the downstream muscle layer. Finally, we provide evidence that the lymphatic constriction is important to maintain normal intraluminal valve closure during each contraction cycle in the face of an adverse pressure gradient, which probably protects the lymphatic capillaries from lymph backflow. PMID:23045335

Scallan, Joshua P; Wolpers, John H; Davis, Michael J

2013-01-15

316

Constriction of isolated collecting lymphatic vessels in response to acute increases in downstream pressure  

PubMed Central

Collecting lymphatic vessels generate pressure to transport lymph downstream to the subclavian vein against a significant pressure head. To investigate their response to elevated downstream pressure, collecting lymphatic vessels containing one valve (incomplete lymphangion) or two valves (complete lymphangion) were isolated from the rat mesentery and tied to glass cannulae capable of independent pressure control. Downstream pressure was selectively raised to various levels, either stepwise or ramp-wise, while keeping upstream pressure constant. Diameter and valve positions were tracked under video microscopy, while intralymphangion pressure was measured concurrently with a servo-null micropipette. Surprisingly, a potent lymphatic constriction occurred in response to the downstream pressure gradient due to (1) a pressure-dependent myogenic constriction and (2) a frequency-dependent decrease in diastolic diameter. The myogenic index of the lymphatic constriction (?3.3 ± 0.6, in mmHg) was greater than that of arterioles or collecting lymphatic vessels exposed to uniform increases in pressure (i.e. upstream and downstream pressures raised together). Additionally, the constriction was transmitted to the upstream lymphatic vessel segment even though it was protected from changes in pressure by a closed intraluminal valve; the conducted constriction was blocked by loading only the pressurized half of the vessel with either ML-7 (0.5 mm) to block contraction, or cromakalim (3 ?m) to hyperpolarize the downstream muscle layer. Finally, we provide evidence that the lymphatic constriction is important to maintain normal intraluminal valve closure during each contraction cycle in the face of an adverse pressure gradient, which probably protects the lymphatic capillaries from lymph backflow.

Scallan, Joshua P; Wolpers, John H; Davis, Michael J

2013-01-01

317

Safety-Valve Mechanism For Pressure-Vessel Window  

NASA Technical Reports Server (NTRS)

Pressure-activated valve mechanism seals small window in pressure chamber if window cracks or breaks, thereby preventing continued leakage or sudden decompression. Window used in experiments involving optical observation of processes in chamber. Valve mechanism activated by pressure from gas leaking through window.

Mccoomb, E. J.

1994-01-01

318

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

SciTech Connect

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

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

1995-05-01

319

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

320

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

SciTech Connect

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

Cheverton, R.D.

1982-01-01

321

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

SciTech Connect

A severe accident in a nuclear power plant could result in the relocation of large quantities of molten core material onto the lower head of he reactor pressure vessel (RPV). In the absence of inherent cooling mechanisms, failure of the RPV ultimately becomes possible under the combined effects of system pressure and the thermal heat-up of the lower head. Sandia National Laboratories has performed seven experiments at 1:5th scale simulating creep failure of a RPV lower head. This paper describes a modeling program that complements the experimental program. Analyses have been performed using the general-purpose finite-element code ABAQUS-5.6. In order to make ABAQUS solve the specific problem at hand, a material constitutive model that utilizes temperature dependent properties has been developed and attached to ABAQUS-executable through its UMAT utility. Analyses of the LHF-1 experiment predict instability-type failure. Predicted strains are delayed relative to the observed strain histories. Parametric variations on either the yield stress, creep rate, or both (within the range of material property data) can bring predictions into agreement with experiment. The analysis indicates that it is necessary to conduct material property tests on the actual material used in the experimental program. The constitutive model employed in the present analyses is the subject of a separate publication.

Pilch, M.M.; Ludwigsen, J.S.; Chu, T.Y. [Sandia National Labs., Albuquerque, NM (United States); Rashid, Y.R. [Anatech, San Diego, CA (United States)

1998-08-01

322

Influence of long-time stress relief treatments on the dynamic fracture toughness properties of ASME SA508 C1 2a and ASME SA533 GR B C12 pressure vessel steels  

SciTech Connect

Dynamic fracture toughness tests were performed on materials which had been subjected to one of three long-time post weld type stress relief heat treatments: 48 hours at 1000/degree/F (538/degree/C), 24 hours at 1125/degree/F (607/degree/C), and 48 hours at 1125/degree/F (607/degree/C). Linear elastic K/sub Id/ results were obtained at low temperatures while J-integral techniques were utilized to evaluate dynamic fracture toughness over the transition and upper shelf temperature ranges. Tensile, Charpy impact, and drop weight nil-ductility transition tests as well as room temperature, air environment fatigue crack growth rate tests (SA508 Cl 2a only) were also performed. The fracture toughness of both materials exceeded the ASME specified minimum reference toughness K/sub IR/ curve. 17 refs.

Logsdon, W.A.

1982-03-01

323

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 automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) 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

324

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

325

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

326

THE DEVELOPMENT OF RADIATION EMBRITTLEMENT MODELS FOR U.S. POWER REACTOR PRESSURE VESSEL STEELS  

Microsoft Academic Search

The information fusion technique is used to develop radiation embrittlement prediction models for reactor pressure vessel (RPV) steels from U.S. power reactors, including boiling water reactors and pressurized water reactors. The Charpy transition temperature-shift data is used as the primary index of RPV radiation embrittlement in this study. Six parameters Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature

Jy-An John Wang; Nageswara S Rao

2006-01-01

327

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

Microsoft Academic Search

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

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

1998-01-01

328

Design of a standalone-type beryllium vessel for high-pressure protein crystallography.  

PubMed

A standalone-type beryllium (Be) high-pressure crystallography vessel has been developed. Using a coupler-joint unit and a pressure valve, we could keep the pressure in the vessel constant at 100+/-1 MPa for more than 24 h without connecting to a pressure-generating apparatus. Diffraction spots of a glucose isomerase (GI) crystal under 100 MPa were collected using the vessel and a rotating copper-anode in-house x-ray generator (0.8 kW). We successfully collected a 2.0 A resolution data set of a 0.5 mm size GI crystal in an aqueous solution at 100 MPa. PMID:20815618

Suzuki, Yoshihisa; Tsukamoto, Masayuki; Sakuraba, Haruhiko; Matsumoto, Masamitsu; Nagasawa, Makoto; Tamura, Katsuhiro

2010-08-01

329

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

330

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

331

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

NASA Astrophysics Data System (ADS)

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.

1993-11-01

332

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

333

Role of crack arrest in the evaluation of PWR pressure vessel integrity during PTS transients  

Microsoft Academic Search

The PWR pressurized thermal-shock (PTS) issue, which is concerned with the integrity of the reactor pressure vessel during postulated overcooling transients, is under intensive investigation by the USNRC. The USNRC-sponsored Integrated Pressurized Thermal-Shock (IPTS) and Heavy-Section Steel Technology (HSST) Programs are dedicated to a better understanding and a timely resolution of the problem. The HSST program is investigating flaw behavior

R. D. Cheverton; D. G. Ball

1984-01-01

334

Considerations for acoustic emission monitoring of spherical Kevlar/epoxy composite pressure vessels  

NASA Technical Reports Server (NTRS)

We are continuing to research the applications of acoustic emission testing for predicting burst pressure of filament-wound Kevlar 49/epoxy pressure vessels. This study has focused on three specific areas. The first area involves development of an experimental technique and the proper instrumentation to measure the energy given off by the acoustic emission transducer per acoustic emission burst. The second area concerns the design of a test fixture in which to mount the composite vessel so that the acoustic emission transducers are held against the outer surface of the composite. Included in this study area is the calibration of the entire test setup including couplant, transducer, electronics, and the instrument measuring the energy per burst. In the third and final area of this study, we consider the number, location, and sensitivity of the acoustic emission transducers used for proof testing composite pressure vessels.

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

1977-01-01

335

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

NASA Astrophysics Data System (ADS)

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

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

1994-01-01

336

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

SciTech Connect

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

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

1994-02-01

337

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

338

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

339

Elastic-Plastic Analysis of Some Pressure Vessel Heads.  

National Technical Information Service (NTIS)

Sixteen ASME standard torispherical heads attached to cylinders and subjected to internal pressure are analyzed as elastic and/or elastic-plastic shells using a new finite element. As basic elements, thin-walled frusta with curved meridians having common ...

E. P. Popov M. Khojasteh-Bakht P. Sharifi

1969-01-01

340

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

341

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

342

Analysis of the effect of partial vitrification on stress development in cryopreserved blood vessels.  

PubMed

Thermal stress development in blood vessels, during processes associated with vitrification (vitreous means glassy in Latin), is studied. This paper addresses the limiting case where the specimen completely crystallizes, while the cryoprotectant medium (CPA) completely vitrifies. This case is expected to provide upper boundary estimates for stresses for the more common problem of a partially vitrified sample. The CPA is modeled as a linear viscoelastic medium, with viscosity increasing exponentially with decreasing temperature; given the assumption of complete crystallization, the blood vessel is modeled as linear elastic below the freezing temperature. Consistent with previous observations, the CPA is found to behave linear elastically below a set-temperature, at which point the viscosity rises sufficiently quickly with further cooling. This observation reduces computational efforts and allows for parametric studies based on suitably chosen wholly elastic models. Both 2D concentric cylinder models of the blood vessel in a straight configuration and a 3D model of the vessel curled in a vial of CPA are studied; 2D models are shown to bound the results of the more general 3D problem. It is found that stress in the CPA decreases with increase in CPA volume, at least under conditions where the temperature can be viewed as uniform. Planar cracks are predicted to form transverse to the vessel axis, and to propagate right up to the blood vessel wall. Should such cracks propagate into the vessel, even over only a few mum, the mechanical damage to the lumen, or to endothelial cells, may cause the blood vessel to completely loose its functionality at the end of the cryopreservation protocol. PMID:16996295

Steif, Paul S; Palastro, Matthew C; Rabin, Yoed

2007-07-01

343

Prediction of magnitude of minimum horizontal stress from extended leak-off test conducted by the riser vessel CHIKYU  

NASA Astrophysics Data System (ADS)

By means of introduction of the drilling vessel 'CHIKYU', riser drilling operations using mud fluid will be carried out in NanTroSEIZE Stage 2 for the first time as an oceanic scientific-drilling. For determining drilling operation parameter such as a mud density, a downhole experiment, leak-off test (LOT) or extended leak-off test (XLOT), is going to be implemented next to casing and cementing at each casing shoe during the drilling process. Data of the downhole experiment aimed for operation can also be used for an important scientific application to obtain in-situ stress information which is necessary for various cases of scientific drillings such as seismogenic zone drillings etc. In order to examine feasibility of the application of the LOT or XLOT data, we analyzed an example of XLOT conducted by the riser vessel CHIKYU during its Shimokita shakedown cruise, 2006; and then estimated magnitude of minimum principal stress in horizontal plane, Shmin. Moreover, we will propose the test procedures to possibly improve the quality of stress result from the applications of LOT or XLOT. The XLOT of Shimokita cruise was conducted under following conditions; 1180 m water depth, 525 mbsf (meter below seafloor) depth, 1030 kg/m3 fluid density (seawater) and 80 litter/min injection flow-rate. Estimated magnitude of the Shmin is equal to 18.3 MPa based on the assumption that fracture closure pressure balances with the minimum principal stress perpendicular to the fracture plane. For comparison, the vertical stress magnitude at the depth was estimated from density profile of core samples retrieved from the same borehole; and was equal to 20 MPa approximately. These two values can be considered to be not disagreement. Therefore, we can say that the XLOT data is valuable and practical for estimating the magnitude of minimum horizontal stress. From the viewpoint of determining stress magnitude, the XLOT is more essential rather than the LOT because it might be hardly to obtain reliable Shmin magnitude only by leak-off pressure which is exclusive stress-related parameter obtained from the latter. In addition, implementation of the LOT/XLOT multi-cycles (3 cycles) is preferable if possible. The first cycle with a lower maximum injection pressure is for knowing permeable property of the formation and for examining whether there is pre-existing fracture(s). The second cycle is a normal XLOT; and the third one is the repeat of the second one for confirm the pressure values obtained from the XLOTs.

Lin, W.; Masago, H.; Yamamoto, K.; Kawamura, Y.; Saito, S.; Kinoshita, M.

2007-12-01

344

Impact fragment cloud propagating in a pressure vessel  

Microsoft Academic Search

The propagation of fragment clouds in a pressurized steel container with PMMA (polymethylmethacrylate) side-windows was investigated. The fragment clouds were generated by hypervelocity impact of aluminum projectiles on 1 mm thick AlMg3 plates. Projectile diameters ranged from 2.0 mm to 4.4 mm. At impact velocities of around 7 km s?1, kinetic energies varied between 269 J and 2950 J. Container

Frank K. Schaefer; Eberhard E. Schneider; Michel Lambert

1997-01-01

345

Mechanical design of heat exchangers and pressure vessel components  

SciTech Connect

The twenty-two chapters in this book are prefaced by brief descriptions of the computer codes referenced or listed within the pages that follow. The first chapter, which contains an outline of the more accepted heat-exchanger types and basic design considerations, is followed by another outlining various design-stress criteria. The next twenty chapters contain considerable detailed information concerning the design and operation of heat exchangers. The authors devote 121 pages to one of the most important design considerations, flow-induced vibration. Another chapter is dedicated to methods of seismic analysis. The remaining chapters address mechanical and thermal design as well as manufacturing.

Singh, K.P.; Soler, A.I.

1984-01-01

346

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

347

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

348

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

349

Fast neutron fluence of yonggwang nuclear unit 1 reactor pressure vessel  

SciTech Connect

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

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

2006-07-01

350

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

351

Stress-Strain Measurements and Viscoelastic Response of Blood Vessels Cryopreserved by Vitrification  

Microsoft Academic Search

To gain increased insight into thermo-mechanical phenomena during cryopreservation, tensile stress relaxation experiments\\u000a were conducted on vitrified blood vessels (vitreous in Latin means Glassy), and the results compared with various viscoelastic\\u000a models. Using a recently presented device, isothermal stress-relaxation results were obtained for a bovine carotid artery\\u000a model, permeated with the cryoprotectant cocktail VS55 and a reference solution of 7.05 M

Jorge L. Jimenez Rios; Paul S. Steif; Yoed Rabin

2007-01-01

352

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

353

Fundamentals of heat exchanger and pressure vessel technology  

SciTech Connect

More than 1200 questions and answers provide access to information on process design, mechanical design, vibration analysis, construction, installation, operation, maintenance, and repair; quality control, inspection, and testing; codes and standards; corrosion, erosion, fouling, and water treatment. The question-and-answer format offers solutions to common heat exchanger problems. Supplemented by more than 200 illustrations and over 500 references, this book addresses directly such topics as; tie-rods and various types of baffles; procedures to take when the calculated pressure drop is higher than the allowable value; comparative value of various types of multipass exchangers, multiple segmental baffles, and tube layouts; the effects of laminar and turbulent flows; flow stratification; mechanical design and failure analysis; nondestructive testing methods; nozzle reinforcements; tube cleaning methods; types of corrosion and failing and standard preventive methods; and the causes and prevention of vibration and vibrational damage.

Gupta, J.P.

1986-01-01

354

Computational methods for fracture analysis of heavy-section steel technology (HSST) pressure vessel experiments  

Microsoft Academic Search

This paper summarizes the capabilities and applications of the general-purpose and special-purpose computer programs that have been developed for use in fracture mechanics analyses of HSST pressure vessel experiments. Emphasis is placed on the OCA\\/USA code, which is designed for analysis of pressurized-thermal-shock (PTS) conditions, and on the ORMGEN\\/ADINA\\/ORVIRT system which is used for more general analysis. Fundamental features of

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

1983-01-01

355

APFIM investigation of clustering in neutron-irradiated Fe Cu alloys and pressure vessel steels  

Microsoft Academic Search

Pressure vessel steels used in PWRs are known to be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are commonly supposed to result from the formation of point defects, dislocation loops, voids and copper-rich precipitates. However, the real nature of the irradiation induced damage, in these particularly low copper steels (A new experimental work has

P. Auger; P. Pareige; M. Akamatsu; D. Blavette

1995-01-01

356

The Information Fusion Embrittlement Models for U.S. Power Reactor Pressure Vessel Steels  

Microsoft Academic Search

The complex nonlinear dependencies observed in typical reactor pressure vessel (RPV) material embrittlement data, as well as the inherent large uncertainties and scatter in the radiation embrittlement data, make prediction of radiation embrittlement a difficult task. Conventional statistical and deterministic approaches have only resulted in rather large uncertainties, in part because they do not fully exploit domain-specific mechanisms. The domain

Jy-An John Wang; Nageswara S Rao; Savanthi Konduri; R. Lott; S. W. Dean

2007-01-01

357

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

Microsoft Academic Search

Nanostructural features that form in reactor pressure vessel steels under neutron irradiation at around 290°C are responsible for significant hardening and embrittlement. It is well established that the nanostructural features can be separated into well formed precipitates and matrix features comprised of point defect clusters complexed with solutes, which may also include regions of solute enrichment that are not well

Brian David Wirth

1998-01-01

358

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

Microsoft Academic Search

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

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

1998-01-01

359

THEORETICAL ASPECTS OF RADIATION DAMAGE AND BRITTLE FRACTURE IN STEEL PRESSURE VESSELS  

Microsoft Academic Search

The problem of the radiation embrittlement of structural steel and its ; relation to reactor pressure vessels is discussed. Clustered lattice defects ; produced by knock-on collisions from fast neutrons harden steel by a process ; analogous to precipitation hardening. It is shown that for the amount of ; hardening produced, the increase of the ductile-brittle transition temperature by ;

1962-01-01

360

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

Microsoft Academic Search

The International Atomic Energy Agency (IAEA) has conducted a series of Coordinated Research Projects (CRPs) that have focused on irradiated reactor pressure vessel (RPV) steel fracture toughness properties and approaches for assuring structural integrity of RPVs throughout operating life. A series of nine CRPs have been sponsored by the IAEA, starting in the early 1970s, focused on neutron radiation effects

William L. Server; Randy K. Nanstad; Jeremy T. Busby; Brady Hanson; S. W. Dean

2009-01-01

361

Development of a mechanistic understanding of radiation embrittlement in reactor pressure vessel steels: Final report  

Microsoft Academic Search

The microstructures of a series of reactor pressure vessel (RPV) steels and model iron alloys with various Cu, Ni, and P contents were examined in unirradiated and neutron-irradiated conditions using high resolution analytical microscopy. Fractography techniques were also applied. Objectives were to isolate and identify the mechanisms by which these elements affect steel radiation embrittlement sensitivity as evidenced by notch

F. Ebrahimi; D. T. Hoelzer; D. Venables; V. Krishnamoorthy

1988-01-01

362

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

Microsoft Academic Search

A new approach of utilizing information fusion technique is developed to predict the radiation embrittlement of reactor pressure vessel steels. The Charpy transition temperature shift data contained in the Power Reactor Embrittlement Database is used in this study. Six parameters-Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature are used in the embrittlement prediction models. The results indicate that

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

2007-01-01

363

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

Microsoft Academic Search

A new approach of utilizing information fusion technique is developed to predict the radiation embrittlement of reactor pressure vessel steels. The Charpy transition temperature shift data contained in the Power Reactor Embrittlement Database is used in this study. Six parameters-Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature – are used in the embrittlement prediction models. The results indicate

Jy-An John Wang; Nageswara S Rao; Savanthi Konduri

2007-01-01

364

Influence of hydrogen on the toughness of irradiated reactor pressure vessel steels  

Microsoft Academic Search

The influence of hydrogen on the mechanical behaviour of different reactor pressure vessel (RPV) steels was investigated by tensile tests in correlation to the chemical composition, the neutron fluence, the hydrogen charging condition, the strain rate, and the temperature. Small-angle neutron scattering (SANS) experiments, hydrogen analyses and thermal desorption investigations were performed to prove the evidence of hydrogen trapping at

G. Müller; M. Uhlemann; A. Ulbricht; J. Böhmert

2006-01-01

365

Protection of storage pressure vessels in the flames; the watering by running and the fireproofing.  

National Technical Information Service (NTIS)

The bursting of petroleum pressure vessel in case of fire on the storage site may produce the boiling liquid expanding vapor explosion extremely damaging for the environment. The research is to find safety means to have enough time to get under control. T...

R. Guillemet

1992-01-01

366

Regulatory Activities Related to Circumferential Cracking of Reactor Pressure Vessel Head Penetration Nozzles  

Microsoft Academic Search

The recent discoveries of cracked and leaking Alloy 600 vessel head penetration (VHP) nozzles, including control rod drive mechanism (CRDM) and thermocouple nozzles, at four pressurized water reactors (PWRs) have raised concerns about the structural integrity of VHP nozzles throughout the PWR industry. Nozzle cracking at Oconee Nuclear Station Unit 1 in November 2000 and Arkansas Nuclear One Unit 1

Hiser; Allen L. Jr

2002-01-01

367

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

368

Applicability of the ferromagnetic resonance for the neutron irradiated degradation in the reactor pressure vessel  

Microsoft Academic Search

In this paper, to explore the applicability of nondestructive test to detect radiation embrittlement in reactor pressure vessel, we investigate ferromagnetic resonance supplemented by vibrating sample magnetometer. Specimens used in this investigation were SA508-3 low alloy steels with different refining process. Magnetization as a function of the applied field was measured.

Seung Sik Park; Y. H. Cho; D. G. Park; W. S. Park; C. O. Kim

2003-01-01

369

Reactor Pressure Vessel Steels Asme Sa533b and SA508 C 1.2.  

National Technical Information Service (NTIS)

Information needed to assess the structural integrity of reactor pressure vessels made of the steels SA533B and SA508 C 1-2 was collected. Microstructural characteristics and basic mechanical properties as a function of varying heat treatments were evalua...

R. Pelli K. Toerroenden

1985-01-01

370

Underclad cracking of pressure vessel steels for light-water reactors  

Microsoft Academic Search

Although fracture mechanics analyses have shown that underclad cracks have no detrimental effect on the integrity of thick walled pressure vessels (40 year service), in order to avoid unexpected failures the US Nuclear Regulatory Commission has issued Regulatory Guide 1.43 which sets limits on the extent of fissures permitted and describes acceptable means of controlling the weld cladding processes. Cavitation

H LOPEZ

1987-01-01

371

Significance of reheat cracks to the integrity of pressure vessels for light-water reactors  

Microsoft Academic Search

Reheat cracks manifest themselves as macroscopic defects detectable by nondestructive testing (NDT) procedures or as microscopic grain boundary decohesions (GBD) that are beyond the limit of detection by NDT. The significance of the microscopic cracks that may go undetected are discussed. The probability that GBD exist in the heat-affected zones (HAZ) of weldments of pressure vessel steels is high; particularly

Canonico

1979-01-01

372

Role of crack arrest in the evaluation of PWR pressure vessel integrity during PTS transients  

SciTech Connect

The PWR pressurized thermal-shock (PTS) issue, which is concerned with the integrity of the reactor pressure vessel during postulated overcooling transients, is under intensive investigation by the USNRC. The USNRC-sponsored Integrated Pressurized Thermal-Shock (IPTS) and Heavy-Section Steel Technology (HSST) Programs are dedicated to a better understanding and a timely resolution of the problem. The HSST program is investigating flaw behavior in large cylinders and is also obtaining fracture-mechanics-related material properties, while the IPTS program is primarily concerned with an estimation of the overall frequency of vessel failure and identification of dominant transients and design and operating features contributing thereto for specific nuclear plants. One important component of the IPTS study is a probabilistic fracture-mechanics analysis of the reactor vessel, and a point of particular interest therein is the role of crack arrest in mitigating the consequences of the postulated PTS transients. The HSST program has provided crack-arrest data from small specimens and large thermally and pressure-loaded cylinders that tend to establish the validity of the crack-arrest concept for application to the PTS problem. Unfortunately, recent results of the IPTS studies indicate that the inclusion of crack arrest in the probabilistic fracture-mechanics model does not substantially influence the calculated frequency of vessel failure. However, there are still significant questions regarding flaw behavior at upper-shelf temperatures, and the HSST program is continuing to pursue this area of uncertainty.

Cheverton, R.D.; Ball, D.G.

1984-01-01

373

Experimental and analytical investigation of the shallow-flaw effect in reactor pressure vessels  

SciTech Connect

The Heavy-Sections Steel Technology (HSST) Program is investigating the increase in effective fracture toughness of A 533 B steel associated with shallow flaws and the implications of the shallow-flaw effect on reactor pressure vessel (RPV) life assessments. This document provides a description of test methodology and test results of this study.

Theiss, T.J.; Shum, D.K. (Oak Ridge National Lab., TN (United States)); Rolfe, S.T. (Kansas Univ., Lawrence, KS (United States))

1992-07-01

374

Fracture Behavior of a Pressure Vessel Steel in the Ductile-to-Brittle Transition Region,  

National Technical Information Service (NTIS)

The reasons for the scatter of fracture toughness in the ductile-to-brittle transition region, as well as the mechanisms leading to cleavage fracture, have been investigated for a quenched and tempered pressure vessel steel, DIN 20 MnMoNi 55. The fracture...

J. Heerens D. T. Read

1988-01-01

375

Test Results Using a Bell Jar to Measure Containment Vessel Pressurization  

SciTech Connect

A bell jar is used to determine containment vessel pressurization due to outgassing of plutonium materials. Fifteen food cans containing plutonium bearing materials, including plutonium packaged in direct contact with plastic and plutonium contaminated enriched oxide have been tested to date.

Hensel, S.J.

2002-05-10

376

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

National Technical Information Service (NTIS)

A severe accident in a nuclear power plant could result in the relocation of large quantities of molten core material onto the lower head of he reactor pressure vessel (RPV). In the absence of inherent cooling mechanisms, failure of the RPV ultimately bec...

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

1998-01-01

377

Critical Experiments, Measurements and Analyses to Establish a Crack Arrest Methodology for Nuclear Pressure Vessel Steels.  

National Technical Information Service (NTIS)

Results of a program aimed at (1) dynamic analyses of crack arrest in test pieces thermally shocked nuclear pressure vessels, (2) a practical laboratory test method for measuring the crack arrest toughness, and (3) a crack arrest data base for nuclear ste...

H. T. Corten K. S. Kim C. P. Debel C. W. Marschall P. C. Gehlen

1978-01-01

378

Low-cycle fatigue of piping and pressure vessel steels in LWR environments  

Microsoft Academic Search

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figure I-90 of Appendix I to Section III of the Code specifies fatigue design curves for structural materials. Although effects of reactor coolant environments are not explicitly addressed by the design curves, test data suggest that the Code fatigue curves may not always

Omesh K. Chopra; William J. Shack

1998-01-01

379

Catheter-induced errors in pressure measurements in vessels: an in-vitro and numerical study.  

PubMed

Accurate measurement of blood pressure is important because it is a biomarker for cardiovascular disease. Diagnostic catheterization is routinely used for pressure acquisition in vessels despite being subject to significant measurement errors. To investigate these errors, this study compares pressure measurement using two different techniques in vitro and numerical simulations. Pressure was acquired in a pulsatile flow phantom using a 6F fluid-filled catheter and a 0.014'' pressure wire, which is considered the current gold standard. Numerical simulations of the experimental set-up with and without a catheter were also performed. Despite the low catheter-to-vessel radius ratio, the catheter traces showed a 24% peak systolic pressure overestimation compared to the wire. The numerical models replicated this difference and indicated the cause for overestimation was the increased flow resistance due to the presence of the catheter. Further, the higher frequency pressure oscillations observed in the wire and numerical data were absent in the catheter, resulting in an overestimation of the pulse wave velocity with the latter modality. These results show that catheter geometry produces significant measurement bias in both the peak pressure and the waveform shape even with radius ratios considered acceptable in clinical practice. The wire allows for more accurate pressure quantification, in agreement with the numerical model without a catheter. PMID:24845294

de Vecchi, Adelaide; Clough, Rachel E; Gaddum, Nicholas R; Rutten, Marcel C M; Lamata, Pablo; Schaeffter, Tobias; Nordsletten, David A; Smith, Nicolas P

2014-06-01

380

Optimization of Composite Material System and Lay-up to Achieve Minimum Weight Pressure Vessel  

NASA Astrophysics Data System (ADS)

The use of composite pressure vessels particularly in the aerospace industry is escalating rapidly because of their superiority in directional strength and colossal weight advantage. The present work elucidates the procedure to optimize the lay-up for composite pressure vessel using finite element analysis and calculate the relative weight saving compared with the reference metallic pressure vessel. The determination of proper fiber orientation and laminate thickness is very important to decrease manufacturing difficulties and increase structural efficiency. In the present work different lay-up sequences for laminates including, cross-ply [ 0 m /90 n ] s , angle-ply [ ±?] ns , [ 90/±?] ns and [ 0/±?] ns , are analyzed. The lay-up sequence, orientation and laminate thickness (number of layers) are optimized for three candidate composite materials S-glass/epoxy, Kevlar/epoxy and Carbon/epoxy. Finite element analysis of composite pressure vessel is performed by using commercial finite element code ANSYS and utilizing the capabilities of ANSYS Parametric Design Language and Design Optimization module to automate the process of optimization. For verification, a code is developed in MATLAB based on classical lamination theory; incorporating Tsai-Wu failure criterion for first-ply failure (FPF). The results of the MATLAB code shows its effectiveness in theoretical prediction of first-ply failure strengths of laminated composite pressure vessels and close agreement with the FEA results. The optimization results shows that for all the composite material systems considered, the angle-ply [ ±?] ns is the optimum lay-up. For given fixed ply thickness the total thickness of laminate is obtained resulting in factor of safety slightly higher than two. Both Carbon/epoxy and Kevlar/Epoxy resulted in approximately same laminate thickness and considerable percentage of weight saving, but S-glass/epoxy resulted in weight increment.

Mian, Haris Hameed; Wang, Gang; Dar, Uzair Ahmed; Zhang, Weihong

2013-10-01

381

Development and Systematic Application of Surface Inspection Methods Used for In-Service Inspection of Reactor Pressure Vessel  

Microsoft Academic Search

Both from the mechanics of fracture and from actual instances of defects observed in reactor pressure vessels, it is indicated that greater importance should be attached to surface than to internal defects in the in-service inspection of these components.In the JPDR, the reactor pressure vessel has undergone ISI three times since 1968, with emphasis placed on surface inspection, and using

Yoshiaki FUTAMURA; Hiroshi KAMATA

1979-01-01

382

Detection and characterization of indications in segments of reactor pressure vessels  

SciTech Connect

Studies have been conducted to estimate flaw density in segments cut from light water reactor (LWR) pressure vessels as part of the Oak Ridge National Laboratory's Heavy-Section Steel Technology (HSST) Program. Segments from the Hope Creek Unit 2 vessel and the Pilgrim Unit 2 vessel were purchased from salvage dealers. Hope Creek was a boiling water reactor (BWR) design and Pilgrim was a pressurized water reactor (PWR) design. Neither were ever placed in service. Objectives were to evaluate these LWR segments for flaws with ultrasonic and liquid penetrant techniques and to compare the results with current assumptions related to probabilistic risk assessment. Both objectives were successfully completed. Ultrasonic techniques beyond those required by the 1986 edition of the ASME Boiler and Pressure Vessel Code were necessary for the detection and reporting of the detected discontinuities. Extra care and analysis must be exercised when conducting ultrasonic examination through cladding. The detection of the discontinuities in the arbitrarily selected sections implies that the Marshall report estimates (and others) are nonconservative for such small flaws. 8 refs., 9 figs.

Cook, K.V.; Cunningham, R.A. Jr.; McClung, R.W.

1989-08-01

383

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

384

A new hybrid pressure-coring system for the drilling vessel Chikyu  

NASA Astrophysics Data System (ADS)

Retrieving core samples without releasing the in situ hydrostatic pressure during core recovery is one of the many technical challenges in scientific drilling. We report here a newly developed hybrid pressure-coring system for the use on the drilling vessel Chikyu and its successful use during expeditions 906 and 802 in the Nankai Trough of Japan. The system is gas-tight and hence enables researchers to study in situ geophysical and geochemical characteristics of sediments containing gaseous components, such as methane hydrates that cannot be reliably recovered with nonpressure coring systems. In addition, pressure coring is a powerful tool, not only for scientific but also for hydrocarbon resources research.

Kubo, Y.; Mizuguchi, Y.; Inagaki, F.; Yamamoto, K.

2014-04-01

385

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

386

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

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

387

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

388

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

389

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

SciTech Connect

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

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-07-22

390

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

391

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

SciTech Connect

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

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

2006-02-15

392

(Implications of radiation-induced embrittlement for the integrity of pressure vessels)  

SciTech Connect

The traveler lectured at the International Course on Implications of Radiation-Induced Embrittlement for the Integrity of Pressure Vessels held at Mar del Plata, Argentina, October 26 through November 13, 1987. The course was jointly sponsored by the International Atomic Energy Agency (IAEA) and the Argentinean Commission Nacional de Energia Atomica (CNEA). The 30 student'' participants were from 17 nations and the 9 lecturers were from the United Kingdom, Germany, Czechoslovakia, and the United States. The traveler lectures on several topics dealing with various aspects of experimental and analytical fracture mechanics using experience gained during a 14-year association with the US Nuclear Regulatory Commission (NRC) sponsored Heavy-Section Steel Technology (HSST) Program. This may contribute to an increased awareness of some of the safety-related issues of pressure vessel integrity. The cost of this trip was borne by the IAEA.

Iskander, S.K.

1987-11-30

393

Improvements in ENDF/B-VI iron and possible impacts on pressure vessel surveillance dosimetry  

SciTech Connect

The ENDF/B-VI cross-section evaluations for the four iron isotopes are summarized, emphasizing the major improvements over ENDF/B-V. The evaluations were mostly based on a preliminary file generated in 1986 for natural iron that has been used for re-calculating several neutron-transport experiments, of all which showed improved agreement. These re-analyses, including those for pressure-vessel surveillance dosimetry, are also discussed. 20 refs., 3 figs.

Fu, C.Y.; Hetrick, D.M.; Perey, C.M.; Perey, F.G.; Larson, N.M.; Larson, D.C.

1990-01-01

394

Effect of neutron flux on low temperature irradiation embrittlement of reactor pressure vessel steel  

Microsoft Academic Search

Miniature Charpy V-notch impact test specimens of commercial reactor pressure vessel (RPV) steels having high and low copper contents were irradiated at the different irradiation positions with neutron flux levels of ?6×1014, ?7×1015, and ?8×1016 n m?2 s?1 (E>1 MeV) to fluence levels ranging from ?6×1021 to ?7×1022 n m?2 (E>1 MeV) at temperatures of about 50°C to 150°C in

K. Dohi; T. Onchi; F. Kano; K. Fukuya; M. Narui; H. Kayano

1999-01-01

395

Brittle fracture local criterion and radiation embrittlement of reactor pressure vessel steels  

Microsoft Academic Search

The application of local criteria for predicting brittle fracture of reactor pressure vessel steels is discussed with an emphasis\\u000a on radiation embrittlement. An association of the radiation-induced damages and the processes of initiation and propagation\\u000a of cleavage microcracks is analyzed from the standpoint of the local criterion for fracture. Physical-mechanical models are\\u000a put forward to describe the influence of radiation

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

2010-01-01

396

Characterisation of creep cavitation damage in a stainless steel pressure vessel using small angle neutron scattering  

Microsoft Academic Search

Grain-boundary cavitation is the dominant failure mode associated with initiation of reheat cracking, which has been widely observed in austenitic stainless steel pressure vessels operating at temperatures within the creep range (>450 °C). Small angle neutron scattering (SANS) experiments at the LLB PAXE instrument (Saclay) and the V12 double-crystal diffractometer of the HMI-BENSC facility (Berlin) are used to characterise cavitation

P. J. Bouchard; F. Fiori; W. Treimer

2002-01-01

397

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

398

New manufacturing techniques of large forged shell rings for pressure vessels  

Microsoft Academic Search

A 250 ton hollow ingot was made for experimental purposes so that the properties of a large-sized hollow ingot could be simulated.\\u000a The investigation results indicated that this ingot was suitable for forged shell rings of nuclear reactor pressure vessels\\u000a (RPV). They were used in the manufacture of forged shell rings for an RPV of a 1300 MW type PWR

K. Saito; A. Namba; K. Aso; N. Abe; J. Nagai; A. Ejima

1987-01-01

399

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

400

Role of crack arrest in the evaluation of PWR pressure vessel integrity during PTS transients  

Microsoft Academic Search

The HSST program is investigating flaw behavior in large cylinders and is also obtaining fracture-mechanics-related material properties, while the Integrated Pressurized Thermal-Shock (IPTS) program is primarily concerned with an estimation of the overall frequency of vessel failure and identification of dominant transients and design and operating features contributing thereto for specific nuclear plants. One important component of the IPTS study

R. D. Cheverton; D. G. Ball

1984-01-01

401

Tensile properties of irradiated nuclear grade pressure vessel welds for the third HSST irradiation series  

Microsoft Academic Search

The Heavy Section Steel Technology (HSST) Program conducted a series of experiments to investigate the effect of neutron irradiation on the fracture toughness of nuclear pressure vessel materials. Four welds of A 508 class 2 steel were examined in this Third HSST Irradiation Series. The welds were fabricated according to ''early'' (pre-1972) light-water reactor weld practice (i.e., copper-coated electrodes). As

McGowan

1985-01-01

402

Application of Master Curve fracture toughness for reactor pressure vessel integrity assessment in the USA  

Microsoft Academic Search

The Master Curve fracture toughness approach has been used in the USA for better defining the transition temperature fracture toughness of irradiated reactor pressure vessel (RPV) steels for end-of-life (EOL) and EOL extension (EOLE) time periods. The first application was for the Kewaunee plant in which the life-limiting material was a circumferential weld metal. Fracture toughness testing of this weld

William Server; Stan Rosinski; Randy Lott; Charles Kim; Dennis Weakland

2002-01-01

403

Holographic determination of the yield strength of a welded stainless steel pressure vessel  

Microsoft Academic Search

The strength and toughness of a high energy rate formed (HERF'ed) stainless steel, as influenced by the heat input from a variety of welds, are being measured. Using holographic interferometry, a welded spherical pressure vessel constructed from HERF'ed stainless steel with a composition of 21 percent Cr, 6 percent Ni, 9 percent Mn, 0.23 percent N, balance Fe was examined.

1976-01-01

404

Simplified Design Techniques for Laminated Cylindrical Pressure Vessels under Stiffness and Strength Constraints  

Microsoft Academic Search

This paper treats the optimum design of graphite\\/epoxy laminated composite cylindrical pressure vessels under stiffness and strength constraints based upon the membrane theory. Stiffness constraints are specified as strain conditions both in the axial and circumferential directions. Tsai-Wu failure criterion is used for determining a first-ply-failure strength. The stiffness and strength characteristics of the laminate are discussed based upon the

Hisao Fukunaga; Tsu-Wei Chou

1988-01-01

405

A study on probabilistic fracture mechanics for nuclear pressure vessels and piping  

Microsoft Academic Search

This paper describes some recent research activities on probabilistic fracture mechanics (PFM) for nuclear pressure vessels and piping (PV&P) performed by the RC111 research committee of the Japan Society of Mechanical Engineers (JSME) under a subcontract of the Japan Atomic Energy Research Institute (JAERI). To establish standard procedures for evaluating failure probabilities of nuclear PV&P, we have set up the

Genki Yagawa; Shinobu Yoshimura

1997-01-01

406

Analysis of pressurized resistance vessel diameter changes with a low cost digital image processing device  

Microsoft Academic Search

A low cost digital image processing device (frame grabber) together with a program running under MS-WINDOWS for automatic on-line analysis of diameter changes of in vitro pressurized blood vessels with an inner diameter of 80–400 ?m is presented. The frame grabber is designed to receive light microscopic images either from a video camera or from a VCR and to present

Jörg-Gerald Fischer; Hartmut Mewes; Hans-Heinrich Hopp; Rudolf Schubert

1996-01-01

407

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

Microsoft Academic Search

Fifteen prism-shaped steel samples were removed from the lower head of the damaged TMI-2 reactor pressure vessel to assess the effects of approximately 19 metric tons of molten core debris that had relocated there during the 1979 loss-of-coolant accident. Metallographic examinations of the samples revealed that inside surface temperatures of 800 to 1,100°C were attained during the accident in an

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

1993-01-01

408

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

Microsoft Academic Search

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

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

1997-01-01

409

Measuring occupational stress: Development of the Pressure Management Indicator  

Microsoft Academic Search

The study of occupational stress is hindered by the lack of compact and comprehensive standardized measurement tools. The Pressure Management Indicator (PMI) is a 120-item self-report questionnaire developed from the Occupational Stress Indicator (OSI). The PMI is more reliable, more comprehensive, and shorter than the OSI. It provides an integrated measure of the major dimensions of occupational stress. The outcome

Stephen Williams; Cary L. Cooper

1998-01-01

410

High pressure deuterium-tritium gas target vessels for muon-catalyzed fusion experiments  

SciTech Connect

In experimental studies of muon-catalyzed fusion, the density of the hydrogen gas mixture is an important parameter. Catalysis of up to 150 fusions per muon has been observed in deuterium-tritium gas mixtures at liquid hydrogen density; at room temperature, such densities require a target gas pressure of the order of 1000 atmospheres (100 MPa, 15,000 psi). We report here the design considerations for hydrogen gas target vessels for muon-catalyzed fusion experiments that operate at 1000 and 10,000 atmospheres. The 1000 atmosphere high pressure target vessels are fabricated of Type A-286 stainless steel and lined with oxygen-free, high-conductivity (OFHC) copper to provide a barrier to hydrogen permeation of the stainless steel. The 10,000 atmosphere ultrahigh pressure target vessels are made from 18Ni (200 grade) maraging steel and are lined with OFHC copper, again to prevent hydrogen permeation of the steel. In addition to target design features, operating requirements, fabrication procedures, and secondary containment are discussed. 13 refs., 3 figs., 1 tab.

Caffrey, A.J.; Spaletta, H.W.; Ware, A.G.; Zabriskie, J.M.; Hardwick, D.A.; Maltrud, H.R.; Paciotti, M.A. (EG and G Idaho, Inc., Idaho Falls, ID (USA); Los Alamos National Lab., NM (USA))

1989-01-01

411

Instrumented impact properties of some advanced nuclear reactor pressure vessel steels  

SciTech Connect

Steels used to construct nuclear reactor pressure vessels are low-alloy ferritic steels. These steels should have good impact properties, i.e., low transition temperature and high upper shelf energy, both before and during service conditions. The most important service condition is the neutron irradiation. Extensive research and development was conducted to develop such steels. Instrumented impact testing was conducted on three advanced pressure vessel steels and, for comparison, a conventional pressure vessel steel. Both microstructures and fracture surfaces were examined using optical and scanning electron microscopic (SEM) techniques. In general, the advanced steels showed much better impact properties (lower ductile-brittle transition temperature and higher upper shelf energy) than the conventional steel. Load-time traces showed that increase in the fracture energy was mainly due to increase in the fracture propagation energy rather than the initiation energy. Improvement in the toughness level of the advanced steels compared to that of the HSST steel was related to the difference in chemical composition, microstructure, and fracture surface morphology.

Ghoneim, M.M.; Nasreldin, A.M.; Elsayed, A.A.; Hammad, F.H. [Atomic Energy Authority, Cairo (Egypt); Pachur, D. [KFA, Juelich (Germany)

1996-06-01

412

Instrumented impact properties of some advanced nuclear reactor pressure vessel steels  

NASA Astrophysics Data System (ADS)

Steels used to construct nuclear reactor pressure vessels are low-alloy ferritic steels. These steels should have good impact properties, i.e., low transition temperature and high upper shelf energy, both before and during service conditions. The most important service condition is the neutron irradiation. Extensive research and development was conducted to develop such steels. Instrumented impact testing was conducted on three advanced pressure vessel steels and, for comparison, a conventional pressure vessel steel. Both microstructures and fracture surfaces were examined using optical and scanning electron microscopic (SEM) techniques. In general, the advanced steels showed much better impact properties (lower ductile-brittle transition temperature and higher upper shelf energy) than the conventional steel. Loadtime traces showed that increase in the fracture energy was mainly due to increase in the fracture propagation energy rather than the initiation energy. Improvement in the toughness level of the advanced steels compared to that of the HSST steel was related to the difference in chemical composition, microstructure, and fracture surface morphology.

Ghoneim, Mm.; Nasreldin, A. M.; Elsayed, A. A.; Pachur, D.; Hammad, F. H.

1996-06-01

413

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

414

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

PubMed Central

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

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

2012-01-01

415

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

416

Assessment of uncertainties for PWR pressure vessel surveillance-French Experience  

SciTech Connect

A characteristic of the French nuclear installations that differs from those in most other countries with an important nuclear industry is their high degree of standardization. Two main types of pressurized water reactors (PWRs) are the 900-MW(electric) CPY and the 1300-MW(electric) P4 reactors produced by a single manufacturer, Electricite de France (EdF). Loading schemes are very standardized, although greater diversification has been introduced in recent years due to implementation of some new loading schemes (LLLP, mixed oxide, extended fuel cycle). This report describes the pressure vessel surveillance program.

Kodeli, I. [GIST, Sevres (France); Nimal, J.C.

1996-12-31

417

Pore-pressure gradients, stresses, and induced earthquakes  

Microsoft Academic Search

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

Segall

1992-01-01

418

Equations for gas releasing process from pressurized vessels in ODH evaluation  

NASA Astrophysics Data System (ADS)

The evaluation of Oxygen Deficiency Hazard (ODH) is a critical part in the design of any cryogenic system. The high-pressure gas tank or low-temperature liquid container that contain asphyxiated fluid could be the sources to bring about the oxygen deficiency hazard. 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. Some simplified formulas for engineering estimation are presented along with the theoretical background that involves the process analyses under variable mass, variable pressure and variable temperature. .

Jia, L. X.; Wang, L.

2002-05-01

419

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 division 1 of section VIII of the ASME Boiler and Pressure Vessel Code. 54.01-2...division 1 of section VIII of the ASME Boiler and Pressure Vessel Code. (a...accordance with section VIII of the ASME Boiler and Pressure Vessel Code...

2013-10-01

420

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

421

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

NASA Astrophysics Data System (ADS)

The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure vessel steels and submerged arc weldments were generally conservative, compared with the approrpriate American Society of Mechanical Engineers (ASME) Section XI water environmental reference curve. The growth rate of fatigue cracks in the base materials, however, was considerably faster in the HPW environment than in a corresponding 288°C (550°F) base line air environment. The growth rate of fatigue cracks in the two submerged are weldments was also accelerated in the HPW environment but to a significantly lesser degree than that demonstrated by the corresponding 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, as compared with the weldments, was attributed to a different sulfide composition and morphology.

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

1989-10-01

422

Role of crack arrest in the evaluation of PWR pressure vessel integrity during PTS transients  

SciTech Connect

The HSST program is investigating flaw behavior in large cylinders and is also obtaining fracture-mechanics-related material properties, while the Integrated Pressurized Thermal-Shock (IPTS) program is primarily concerned with an estimation of the overall frequency of vessel failure and identification of dominant transients and design and operating features contributing thereto for specific nuclear plants. One important component of the IPTS study is a probabilistic fracture-mechanics analysis of the reactor vessel, and a point of particular interest therein is the role of crack arrest in mitigating the consequences of the postulated PTS transients. The HSST program has provided crack-arrest data from small specimens and large thermal- and pressure-loaded cylinders that tend to establish the validity of the crack-arrest concept for application to the PTS problem. Unfortunately, recent results of the IPTS studies indicate that the inclusion of crack arrest in the probabilistic fracture-mechanics model does not substantially influence the calculated frequency of vessel failure. However, there are still significant questions regarding flaw behavior at upper-shelf temperatures, and the HSST program is continuing to pursue this area of uncertainty.

Cheverton, R.D.; Ball, D.G.

1984-01-01

423

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

NASA Technical Reports Server (NTRS)

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

Klimcak, C.; Jaduszliwer, B.

1995-01-01

424

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

425

Interrelationship of Nondestructive Evaluation Methodologies Applied to Testing of Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Composite Overwrapped Pressure Vessels (COPVs) are commonly used in spacecraft for containment of pressurized gases and fluids, incorporating strength and weight savings. The energy stored is capable of extensive spacecraft damage and personal injury in the event of sudden failure. These apparently simple structures, composed of a metallic media impermeable liner and fiber/resin composite overwrap are really complex structures with numerous material and structural phenomena interacting during pressurized use which requires multiple, interrelated monitoring methodologies to monitor and understand subtle changes critical to safe use. Testing of COPVs at NASA Johnson Space Center White Sands T est Facility (WSTF) has employed multiple in-situ, real-time nondestructive evaluation (NDE) methodologies as well as pre- and post-test comparative techniques to monitor changes in material and structural parameters during advanced pressurized testing. The use of NDE methodologies and their relationship to monitoring changes is discussed based on testing of real-world spacecraft COPVs. Lessons learned are used to present recommendations for use in testing, as well as a discussion of potential applications to vessel health monitoring in future applications.

Leifeste, Mark R.

2007-01-01

426

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

427

Reactor Pressure Vessel Steels Asme sa 533B and SA508.C1.2: Microstructural Investigations.  

National Technical Information Service (NTIS)

The as-quenched and variably tempered microstructures of pressure vessel steels were studied with optical, scanning and transmission electron microscopes. The microstructure consists mainly of granular bainite. Tempering transforms the martensite-austenit...

R. Pelli P. Nenonen M. Kemppainen K. Toerroenen

1983-01-01

428

The high pressure high shear stress rheology of liquid lubricants  

NASA Astrophysics Data System (ADS)

A limiting shear stress model of liquid lubricant shear rheology is offered which accurately represents all available primary data. The model is of the nonlinear Maxwell type with shear modulus taken into the time derivative and broadening of the viscous-plastic transition with pressure. Property relations for viscosity, limiting stress and shear modulus are refined for a polyphenyl ether in particular. The model, with simplifying assumptions, is compared with disk machine results. This model, with change of yield criterion, may be applicable to some shear thinning liquids at low pressure. Limiting shear stress varies with pressure in the same manner as the ultimate shear strength of solid polymers.

Bair, S.; Winer, W. O.

1992-01-01

429

Stress and Thermal Analysis of the In-Vessel RMP Coils in HL-2M  

NASA Astrophysics Data System (ADS)

A set of in-vessel resonant magnetic perturbation (RMP) coils for MHD instability suppression is proposed for the design of a HL-2M tokamak. Each coil is to be fed with a current of up to 5 kA, operated in a frequency range from DC to about 1 kHz. Stainless steel (SS) jacketed mineral insulated cables are proposed for the conductor of the coils. In-vessel coils must withstand large electromagnetic (EM) and thermal loads. The support, insulation and vacuum sealing in a very limited space are crucial issues for engineering design. Hence finite element calculations are performed to verify the design, optimize the support by minimizing stress caused by EM forces on the coil conductors and work out the temperature rise occurring on the coil in different working conditions, the corresponding thermal stress caused by the thermal expansion of materials is evaluated to be allowable. The techniques to develop the in-vessel RMP coils, such as support, insulation and cooling, are discussed.

Cen, Yishun; Li, Qiang; Ding, Yonghua; Cai, Lijun; Jiang, Jiaming; Li, Guangsheng; Liu, Yi

2013-09-01

430

Weld repair of Heavy Section Steel Technology program vessel V-7. Final report  

Microsoft Academic Search

The in situ repair of a flaw in a large nuclear pressure vessel is likely to be a complex undertaking. Normally, a thermal stress relief is required to reduce peak welding stresses; however, accomplishing this task under field conditions can result in difficulties related to warpage of the vessel. Consequently, Section XI of the ASME Boiler and Pressure Vessel Code

W. D. Goins; D. L. Butler

1976-01-01

431

D-Zero Central Calorimeter Technical Appendix to Cryogenic Pressure Vessels  

SciTech Connect

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

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

1990-11-19

432

Radiation Dosimetry of the Pressure Vessel Internals of the High Flux Beam Reactor  

NASA Astrophysics Data System (ADS)

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™ 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 rates, the Monte Carlo MCNP code and geometric progressive MicroShield code were used to model the gamma-ray transport and dose buildup.

Holden, Norman E.; Reciniello, Richard N.; Hu, Jih-Perng; Rorer, David C.

2003-06-01

433

Research and Development of Automated Eddy Current Testing for Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Eddy current testing (ET) was used to scan bare metallic liners used in the fabrication of composite overwrapped pressure vessels (COPVs) for flaws which could result in premature failure of the vessel. The main goal of the project was to make improvements in the areas of scan signal to noise ratio, sensitivity of flaw detection, and estimation of flaw dimensions. Scan settings were optimized resulting in an increased signal to noise ratio. Previously undiscovered flaw indications were observed and investigated. Threshold criteria were determined for the system software's flaw report and estimation of flaw dimensions were brought to an acceptable level of accuracy. Computer algorithms were written to import data for filtering and a numerical derivative filtering algorithm was evaluated.

Carver, Kyle L.; Saulsberry, Regor L.; Nichols, Charles T.; Spencer, Paul R.; Lucero, Ralph E.

2012-01-01

434

Weld Repair of a Stamped Pressure Vessel in a Radiologically Controlled Zone  

SciTech Connect

In September 2012 an ASME B&PVC Section VIII stamped pressure vessel located at the DOE Hanford Site Effluent Treatment Facility (ETF) developed a through-wall leak. The vessel, a steam/brine heat exchanger, operated in a radiologically controlled zone (by the CH2MHill PRC or CHPRC), had been in service for approximately 17 years. The heat exchanger is part of a single train evaporator process and its failure caused the entire system to be shut down, significantly impacting facility operations. This paper describes the activities associated with failure characterization, technical decision making/planning for repair by welding, logistical challenges associated with performing work in a radiologically controlled zone, performing the repair, and administrative considerations related to ASME code requirements.

Cannell, Gary L. [Fluor Enterprises, Inc.; Huth, Ralph J. [CH2MHill Plateau Remediation Company; Hallum, Randall T. [Fluor Government Group

2013-08-26

435

Prestressed-concrete pressure vessels and their applicability to advanced-energy-system concepts  

SciTech Connect

Prestressed concrete pressure vessels (PCPVs) are, in essence, spaced steel structures since their strength is derived from a multitude of steel elements made up of deformed reinforcing bars and prestressing tendons which are present in sufficient quantities to carry tension loads imposed on the vessel. Other major components of a PCPV include the concrete, liner and cooling system, and insulation. PCPVs exhibit a number of advantages which make them ideally suited for application to advanced energy concepts: fabricability in virtually any size and shape using available technology, improved safety, reduced capital costs, and a history of proven performance. PCPVs have many applications to both nuclear- and non-nuclear-based energy systems concepts. Several of these concepts will be discussed as well as the research and development activities conducted at ORNL in support of PCPV development.

Naus, D.J

1983-01-01

436

Potential impact of enhanced fracture-toughness data on fracture mechanics assessment of PWR vessel integrity for pressurized thermal shock  

Microsoft Academic Search

The Heavy Section Steel Technology (HSST) Program is involved with the generation of enhanced fracture-initiation toughness and fracture-arrest toughness data of prototypic nuclear reactor vessel steels. These two sets of data are enhanced because they have distinguishing characteristics that could potentially impact PWR pressure vessel integrity assessments for the pressurized-thermal shock (PTS) loading condition which is a major plant-life extension

T. L. Dickson; T. J. Theiss

1991-01-01

437

Model testing conducted to benchmark the Shippingport Reactor Pressure Vessel\\/Neutron Shield Tank package safety analysis  

Microsoft Academic Search

The decommissioned Shippingport Reactor Pressure Vessel (RPV) and its integral Neutron Shield Tank (NST) were transported from Shippingport, Pennsylvania, via barge to Hanford, Washington for burial in the Hanford Site Radioactive Waste Disposal Area. To ensure that the Reactor Pressure Vessel\\/Neutron Shield Tank (RPV\\/NST) assembly could be shipped safely, without undue risk to the public or the environment, the RPV\\/NST

D. L. Becker; D. M. Burgess; W. W. Bowen; B. V. Winkel

1989-01-01

438

Numerical investigation of the reactor pressure vessel behaviour under severe accident conditions taking into account the combined processes of the vessel creep and the molten pool natural convection  

Microsoft Academic Search

Analysis of the WWER lower head behaviour and its failure has been performed for several molten pool structures and internal overpressure levels in a reactor pressure vessel (RPV). The different types of the molten pools (homogeneous, conventionally homogeneous, conventionally stratified, stratified) cover the bounding scenarios during a hypothetical severe accident. The parametric investigations of the failure mode and RPV behaviour

V. D. Loktionov; E. S. Mukhtarov; N. I. Yaroshenko; V. E. Orlov

1999-01-01

439

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

440

Effect of Pressure and Deviatoric Stress on Rock Magnetism.  

National Technical Information Service (NTIS)

Experiments were performed on many rock types to examine the effect of pressure and stress on their magnetic properties. The effects of loading path on thermoremanent magnetization (TRM) and magnetic susceptibility were examined in detail. For samples wit...

R. J. Martin

1988-01-01

441

The classical pressure vessel problems for linear elastic materials with voids  

Microsoft Academic Search

The traditional problems of the thick walled spherical and circular cylindrical shells under internal and external pressure are solved in the context of the theory of linear elastic materials with voids. The solutions are quasi-static. The stress distributions are those predicted by isotropic linear elasticity. The displacement and solid volume fraction charge fields exhibit a volumetric viscoelasticity induced by a

S. C. Cowin; P. Puri

1983-01-01

442

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

Microsoft Academic Search

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

1977-01-01