Reactor Pressure Vessel Status Report (NUREG-1511, Supplement 2)
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Manuscript Completed: September 2000
Date Published: October 2000
C. E. Carpenter, B. J. Elliot, A. L. Hiser, Jr.,
M. J. Khanna, A. D. Lee, J. Medoff,
M.A. Mitchell, S. C. F. Sheng, K. R. Wichman,
J. K Strosnider, W. H. Bateman
Division of Engineering
Office of Nuclear Reactor Regulation
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
On May 18, 1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 92-01, Revision 1, Supplement 1, "Reactor Vessel Structural Integrity," requesting that addressees: (1) identify, collect, and report any new data pertinent to the analysis of structural integrity for the reactor pressure vessels (RPVs) at their nuclear power plants, and (2) assess the impact of those data on their RPV integrity analyses relative to the requirements of 10 CFR 50.61, "Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events," and to the requirements of Appendix G to 10 CFR Part 50, "Fracture Toughness Requirements," which is used to evaluate the upper shelf energy (USE) values for RPV materials and pressure-temperature (P-T) limits for RPVs.
Since the issuance of GL 92-01, Revision 1, Supplement 1, the industry completed a major initiative to collect all available alloying chemistry and materials property data for the various forging, plate and weld materials used to fabricate the RPVs. This represents the first time that a comprehensive, integrated assessment of all alloying chemistry and surveillance data has been completed for the materials that have been used to fabricate the RPVs in U.S. lightwater nuclear power plants. These efforts should minimize surprises regarding the alloying chemistries for domestic RPV beltline materials. In addition, as a result of the industry's efforts in response to GL 92-01, Revision 1, Supplement 1, licensees and staff will be able to perform reactor vessel integrity evaluations more efficiently and more effectively. However, the staff expects additional surveillance data will become available after fracture toughness testing is performed on surveillance capsules that are presently being irradiated in domestic RPVs. The staff will incorporate the additional surveillance data into the existing database after it becomes available for review.
In the summer and fall of 1998, the staff issued a series of requests for additional information (RAIs) regarding the industry's responses to GL 92-01, Revision 1, Supplement 1. In the RAIs, the staff requested that the addressees assess how the updated alloying chemistry and materials property data would affect the results of the RPV integrity analyses for their plants.
This report summarizes both the industry's and the NRC's efforts to address how all of the new chemistry and surveillance data, when integrated, could affect the plant specific RPV integrity analyses for the RPVs of U.S. light-water nuclear power plants. Specifically, this report discusses the following: (1) the basis for issuing and reviewing the responses to the RAIs on GL 92-01, Revision 1, Supplement 1, (2) the activities conducted by the industry owners groups to collect weld chemistry data for the materials used to fabricate the RPVs at U.S. nuclear plants, (3) the activities conducted by the industry owners groups to collect data from RPV surveillance capsules on behalf of the industry, (4) the staff's efforts to update plant-specific data into the Reactor Vessel Integrity Database, and to make Version 2 of the database accessible via the World-Wide Web, (5) the staff's current regulatory and research activities regarding RPV integrity, (6) the staff's activities regarding RPV weld inspection reduction, as documented in the NRC final safety evaluation on Topical Report BWRVIP-05, (7) the staff's review of the thermal annealing project at the Marble Hill facility and the status of the Palisades thermal annealing application, and (8) the results of significant plant-specific RPV integrity reviews that could have an impact on the industry.