Inclusion of unstable ductile tearing and extrapolated crack-arrest toughness data in PWR vessel integrity assessment

A Reassessment of PWR Pressure Vessel Integrity During Overcooling Accidents, Considering 3-D Flaws

Journal of Pressure Vessel Technology ◽

10.1115/1.3264367 ◽

1984 ◽

Vol 106 (4) ◽

pp. 375-382 ◽

Cited By ~ 3

Author(s):

R. D. Cheverton ◽

D. G. Ball

Keyword(s):

Finite Length ◽

Three Dimensional ◽

Crack Arrest ◽

Mechanics Model ◽

Pressurized Thermal Shock ◽

Maximum Crack ◽

Vessel Integrity ◽

Thermal Shock Problem ◽

Arrest Toughness ◽

Plate Type

A continuing analysis of the pressurized-thermal-shock problem associated with PWR postulated overcooling accidents indicates that the previously accepted degree of conservatism in the fracture-mechanics model needs to be more closely evaluated, and, if excessive, reduced. One feature that was believed to be conservative was the use of two-dimensional as opposed to finite-length (three-dimensional) flaws. The degree of conservatism could not be adequately investigated because of computational limitations and a lack of knowledge regarding flaw behavior; however, that situation has changed to the extent that some cases involving finite-length flaws can be studied. A flaw of particular interest is one that is located in an axial weld of a plate-type vessel. For those vessels that suffer relatively high-radiation damage in the welds, the length of the flaw will be no greater than the length of the weld, and recent calculations indicate that a deep flaw of that length (∼2 m) is not effectively infinitely long, contrary to previous thinking. The benefit to be derived from consideration of the 2-m flaw and also a semi-elliptical flaw with length-to-depth ratio of 6/1 was investigated by analyzing several postulated transients. In doing so the sensitivity of the benefit to a specified maximum crack-arrest toughness and to the duration of the transient was investigated. Results of the analysis indicate that for some conditions the benefit in using the 2-m flaw is substantial, but it decreases with increasing pressure, and above a certain pressure there may be no benefit, depending on the duration of the transient and the limit on crack-arrest toughness.

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Crack Arrest Toughness of 4140, 1340 and 4340 Steel

10.21236/ada129837 ◽

1981 ◽

Author(s):

E. J. Ripling ◽

P. B. Crosley

Keyword(s):

Crack Arrest ◽

4340 Steel ◽

Arrest Toughness

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Crack Arrest Toughness of Two High Strength Steels (AISI 4140 and AISI 4340)

Metallurgical Transactions A ◽

10.1007/bf02644431 ◽

1982 ◽

Vol 13 (4) ◽

pp. 657-664 ◽

Cited By ~ 7

Author(s):

E. J. Ripling ◽

J. H. Mulherin ◽

P. B. Crosley

Keyword(s):

High Strength Steels ◽

High Strength ◽

Crack Arrest ◽

Aisi 4140 ◽

Arrest Toughness ◽

Aisi 4340

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French RPV PTS Assessment: An Overview of EDF Research and Development in Progress on Thermalhydraulic, Materials and Mechanical Aspects

Aging Management and Component Analysis ◽

10.1115/pvp2003-2151 ◽

2003 ◽

Author(s):

Dominique Moinereau ◽

Jean-Michel Frund ◽

Henriette Churier-Bossennec ◽

Georges Bezdikian ◽

Alain Martin

Keyword(s):

Structural Integrity ◽

Three Dimensional ◽

Crack Arrest ◽

Pressure Vessels ◽

Short Description ◽

Constraint Effect ◽

Materials Properties ◽

Integrity Assessment ◽

Pressurized Thermal Shock ◽

Reactor Pressure

A significant extensive Research & Development work is conducted by Electricite´ de France (EDF) related to the structural integrity re-assessment of the French 900 and 1300 MWe reactor pressure vessels in order to increase their lifetime. Within the framework of this programme, numerous developments have been implemented or are in progress related to the methodology to assess flaws during a pressurized thermal shock (PTS) event. The paper contains three aspects: a short description of the specific French approach for RPV PTS assessment, a presentation of recent improvements on thermalhydraulic, materials and mechanical aspects, and finally an overview of the present R&D programme on thermalhydraulic, materials and mechanical aspects. Regarding the last aspect on present R&D programme, several projects in progress will be shortly described. This overview includes the redefinition of some significant thermalhydraulic transients based on some new three-dimensional CFD computations (focused at the present time on small break LOCA transient), the assessment of vessel materials properties, and the improvement of the RPV PTS structural integrity assessment including several themes such as warm pre-stress (WPS), crack arrest, constraint effect ....

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