ML20216D665
| ML20216D665 | |
| Person / Time | |
|---|---|
| Issue date: | 04/09/1998 |
| From: | Sheron B NRC (Affiliation Not Assigned) |
| To: | Liberatori L WESTINGHOUSE OPERATING PLANTS OWNERS GROUP |
| References | |
| PROJECT-694 IEIN-98-011, IEIN-98-11, NUDOCS 9804150382 | |
| Download: ML20216D665 (5) | |
Text
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2 NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 206 5 0001
- April 9, 1998 l
Mr. Lou Liberatori, Chairman i WOG Steering Committee l Indian Point Unit 2 Broadway & Bleakley Ave.
l Buchanan, NY 10511 l l
SUBJECT:
BAFFLE BARREL BOLTING PROGRAM Dear M This letter is a followup to recent conversations between Mr. Roger Newton and members of the Westinghouse Owners Group (WOG), and Mr. Richard Wessman, Ms. Claudia Craig and other members of the NRC staff regarding the WOG baffle barrel botting issue. On ,
March 31,1998, representatives of the WOG summarized this issue at the semi-annual senior i management meeting. On April 3,1998, the staff requested postponement of a meeting I between WOG and NRC, scheduled for April 8,1998, until the staff could better estimate i resources needed to complete the review with current priorities, and WOG could resolve certain j uncertainties in the approach to this issue.
Indications of baffle former bolt cracking have been identified in European reactors as early as 1988 and this problem continues to occur. Although this cracking is not fully understood, testing of cracked bolts suggests an age-related intergranular stress-corrosion cracking process i influenced by bolt material, fluence, stress, and temperature. On March 25,1998, the NRC issued Information Notice (lN) 98-11, " Cracking of Reactor Vesse! Intemal Baffle Former Bolts in Foreign Pl ants," to alert addressees to the foreign experience and to inform addressees of actions taken and planned by dornestic pressurized water reactor (PWR) owners' groups in response to this experience. The WOG has been proactive in addressing the baffle barrel bolt issue, committed substantial resources to this effort, and has been interacting with the staff on this issue since mid-1997. During the initial meeting with the staff in August 1997, the WOG identified topical report submittals for which NRC approval would be requested in order to ;
support a planned industry program. Prior to performing baffle bolting inspection / replacement and testing on the WOG lead plant candidate (Point Beach Unit 2), W'G requested approval of the inspection scope, inspection method, and acceptance criteria and t,ases. In a September 25,1997, meeting with the staff, WOG stated that potential bolt degradation did not represent a substantial safety hazard for WOG plants. In a February 26,1998, meeting with the staff, WOG presented two-loop risk-informed evaluation results and stated that the incremental core damage frequency contribution associated with degraded baffle barrel bolts was 4.9 E-07 and that it was appropriate to treat potential baffle barrel bolt degradation as an aging management issue.
l WOG has submitted several topical reports to the NRC in support of the baffle barrel bolt program. Recent submittals include WCAP-9735, "Multiflex 3.0: A Fortran IV Computer Program for Analyzing Thermal Hydraulic Structural System Dynamics, Advanced Beam Model" (received February 20,1998), WCAP-15029, " Westinghouse Methodology for Evaluating the \O 9804150382 980409 PDR TOPRP EMVWEST C PDR 9f- 27 m
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I L Liberatori 2 April 4, 1998 i
Acceptability of Baffle-Former-Barrel Bolting Distributions Under Faulted Load Conditions" l (received March 12,1998), and WCAP-15036 " Determination of Acceptable Bame Barrel Bolting for Two-Loop Westinghouse Domestic Plants" (dated March 31,1998, but not received yet). Related submittals undergoing staff review deal with increased postulated break opening times and the COBRA / TRAC computer code for two-phase loads. WOG submittals yet to be received deal with the acceptable bame barrel bolting for the three-loop group of plants l and properties of irradiated bolt material. Completion of all of these reviews is necessary for the l staff to approve WOG's proposed program. WOG has requested expedited staff review of the entire group of submittals by mid-September 1998 and stated that the program would be first applied in conjunction with a planned bolt inspection at Point Beach Unit 2 in l- September / October 1998.
Subsequent to the March 31,1998, semi-annual management meeting, the staff received a March 27,1998, letter, from Southern Nuclear Operating Company (SNC) advising NRC of its intent to proceed with a bame former bolt inspection and replacement activity at the Farley Nuclear Plant Unit i during the fall 1998 outage pending approval of the WOG WCAPs. The SNC letter of intent states that the WCAP for the three-loop plants will be submitted in June 1998, and requests staff approval prior to September 15,1998.
The NRC staff has interacted with WOG and reviews of submittals already received are in progress. More recently-received submittals have only received a scoping review. The staff has determined that, in the absence of a compelling high safety significance argument and based on the current status of the review effort, completion of the overall effort would not be likely before mid to late 1999, considering current staff resources and competing review priorities.
Additionally, the staff notes that only a letter of intent regarding WOG's approach for the three-loop group has been received and that the lead plant for the two-loop group suggested by the WOG faces uncertainties regarding core off-load capability due to fuel storage cask issues. The staff notes, however, that bolt inspection and repair, if necessary, could be accomplished under L existing code and license provisions.
WOG and the staff have tentatively scheduled a meeting on the baffle barrel bolt issue for April 23,1998. In the light of the staff's review schedule and the uncertainties regarding WOG's implementation of a baffle barrel bolt program, WOG is requested to respond to this letter and provide the fobowing:
- 1. An assessment of the safety significance of the bame bolt issue for operating U.S. 1 Westinghouse PWRs.
- 2. Recommended and attemate approaches and proposed implementation plan to address .
the bame bolt issue including inspections, application of the proposed analytical l l
approach, and repair contingencies.
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- 3. Expected schedule for plant-specific submittals, if required. ;
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I L. Liberatori 3 April 9, 1908 NRC commends WOG for their proactive approach to this issue and we encourage continued dialogue with the staff, Please contact Ms. Craig, of the Generic issues and Environmental Projects Branch, or Mr. Wessman, of the Mechanical Engineering Branch, if you have any questions.
l Sincerely, 0 0 j%Ld . C6 %w%
Brian W. Sheron Acting Associate Director for Technical Review i Office of Nuclear Reactor Regulation i Project No. 694 i l
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3 L. Liberatori April 9, 1990 i
l NRC commends WOG for their proactive approach to this issue and we encourage continued
! dialogue with the staff. Please contact Ms. Craig, of the Generic issues and Environmental l Projects Branch, or Mr. Wessman, of the Mechanical Engineering Branch, if you have any questions.
l Sincerely, 4
Origin-1 Signed By:
l Brian W. Sheron .
l Acting Associate Director for Technical Review
- Office of Nuclear Reactor Regulation Project No. 694 cc
- See next page L Document Name: A:BBBSCHED.LTR l
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cc:
Mr. Nicholas J. Liparuto, Manager Regulatory and Engineering Networks Westinghouse Electric Corporation Mail Stop ECE 4-15 P.O. Box 355 Pittsburgh, PA 13520-0355 Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering Westinghouse Electric Corporation Mail Stop ECE 4-07A P.O. Box 355 Pittsburgh, PA 13520-0355 Mr. Roger Newton, Chairman Westinghouse Owners Group Baffle Barrel Working Group Wisconsin Electric Power Corp.
231 West Michigan Milwaukee,WI 53201 Mr. Andrew Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation Mail ECE 5-16 P.O. Box 355 Pittsburgh, PA 15320-0355