This paper is concerned with round-robin analyses of probabilistic fracture mechanics (PFM) problems of aged RPV material. Analyzed here is a plate with a semi-elliptical surface crack subjected to various cyclic tensile and bending stresses. A depth and an aspect ratio of the surface crack are assumed to be probabilistic variables. Failure probabilities are calculated using the Monte Carlo methods with the importance sampling or the stratified sampling techniques. Material properties are chosen from the Marshall report, the ASME Code Section XI, and the experiments on a Japanese RPV material carried out by the Life Evaluation (LE) subcommittee of the Japan Welding Engineering Society (JWES), while loads are determined referring to design loading conditions of pressurized water reactors (PWR). Seven organizations participate in this study. At first, the procedures for obtaining reliable PFM solutions with low failure probabilities are examined by solving a unique problem with seven computer programs. The seven solutions agree very well with one another, i.e., by a factor of 2 to 5 in failure probabilities. Next, sensitivity analyses are performed by varying fracture toughness values, loading conditions, and pre and in-service inspections. Finally, life extension simulations based on the PFM analyses are performed. It is clearly demonstrated from these analyses that failure probabilities are so sensitive to the change of fracture toughness values that the degree of neutron irradiation significantly influences the judgment of plant life extension.

1.
Akiyama
M.
, et al.,
1991
, “
Technical Challenge Toward Safe and Long-Lived Nuclear Power Plant
,” (in Japanese),
Journal of Atomic Energy Society of Japan
, Vol.
33
, pp.
205
242
.
2.
ASME Boiler & Pressure Vessel Code, 1973, Section XI, Appendix A.
3.
Broom, J. M., 1984, “Probabilistic Fracture Mechanics—A State-of the-Art Review,” ASME PVP-Vol. 92, pp. 1–19.
4.
Fujioka
T.
, and
Kashima
K.
,
1990
. “
A Sensitivity Study of Probabilistic Fracture Analysis of Light Water Reactor Carbon Steel Pipe
,”
International Journal of Pressure Vessels and Piping
, Vol.
52
, pp.
403
416
.
5.
Handa, N., and Uno, T., 1991, “Application of the Probabilistic Fracture Mechanics to the Multiple Crack Problem and Inelastic Behavior Problem,” Proceedings 11th SMiRT, Tokyo, Japan, Vol. G2, pp. 349–355.
6.
Harris, D. O., Lim, E. Y., and Dedhia, D. D., 1981. “Probabilistic Pipe Fracture in the Primary Coolant Loop of a PWR Plant,” Vol. 5, NUREG/CR-2189, UCRL-18967.
7.
Harris, D. O., Balkey, K. R., 1993. “Probabilistic Considerations in Life Extension and Aging,” Technology for the 90s, ASME PVP Division, pp. 243–269.
8.
Hojo
K.
,
Takenaka
M.
,
Kaguchi
H.
,
Yagawa
G.
, and
Yoshimura
S.
,
1993
. “
Application of Probabilistic Fracture Mechanics to FBR Components
,”
Nuclear Engineering and Design
, Vol.
42
, pp.
43
49
.
9.
JWES-AE-9003, 1990, Report of Atomic Energy Research Committee (in Japanese), Japan Welding Engineering Society.
10.
Lo, T. Y., et al., 1984, “Probability of Pipe Failure in the Reactor Coolant Loop of Combustion Engineering PWR Plants,” Vol. 2, NUREG/CR-3663, UCRL-53500.
11.
Marshall, W., 1982, “An Assessment of the Integrity of PWR Pressure Vessels,” UKAEA.
12.
Newman, J. C., Jr., and Raju, L. S., 1984, “Stress Intensity Factor Equations for Cracks in 3D Finite Bodies Subjected to Tension and Bending Loads,” NASA-TM-85793.
13.
Pennell, W. E., 1991, “Heavy-Section Steel Technology Program Fracture Issues,” Proceedings 1991 ASME PVP Conference, San Diego, CA, PVP-Vol. 213/MPC-Vol. 32, pp. 15–23.
14.
Tipping, P., 1987, “Study of a Possible Plant Life Extension by Intermediate Annealing of the Reactor Pressure Vessel II—Confirmation by Further Annealing Schedules,” Proceedings NEA-UNIPEDE Specialist Meeting on Life-Limiting and Regulatory Aspects of Reactor Core Internals and Pressure Vessels, Sweden.
15.
Ueda, H., and Oyama, T., 1991, “Embedded Crack Modeling for PFM Analysis of FBR Structural Components,” Proceedings 11th SMiRT, Tokyo, Japan, Vol. G2, pp. 369–374.
16.
Watashi, K., and Furuhashi, I., 1991, “Probabilistic Fracture Mechanics Analysis Code CANIS-P,” Proceedings 11th SMiRT, Tokyo, Japan, Vol. G2, pp. 343–348.
17.
Woo, H. H., et al., 1982, “Piping and Reliability Model Validation and Potential Use for Licensing Regulation Development,” NUREG/CR-2801.
18.
Yagawa
G.
,
1988
, “
Structural Integrity Assessment of Nuclear Power Plants Using Probabilistic Fracture Mechanics
,” (in Japanese),
Nuclear Engineering
, Vol.
34
, pp.
19
30
.
19.
Yagawa
G.
, and
Ye
G.-W.
,
1993
, “
Probabilistic Fracture Mechanics Analysis for Cracked Pipe Using 3-D Model
,”
Reliability Engineering and System Safety
, Vol.
41
, pp.
189
196
.
20.
Ye, G.-W., Yagawa, G., Yoshimura, S., and Zhang, M-Y., 1991, “Efficient Nonlinear Probabilistic Fracture Mechanics Analysis Based on Fast Monte-Carlo Algorithm,” Proceedings 11th SMiRT, Tokyo, Japan, Vol. G2, pp. 357–362.
21.
Ye
G.-W.
,
Yagawa
G.
, and
Yoshimura
S.
,
1993
, “
Probabilistic Fracture Mechanics Analysis Based on Three-Dimensional J-Integral Database
,”
Engineering Fracture Mechanics
, Vol.
44
, pp.
887
893
.
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