ML20151X367
| ML20151X367 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/04/1986 |
| From: | Zwolinski J Office of Nuclear Reactor Regulation |
| To: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| GL-84-11, IEB-83-02, IEB-83-2, NUDOCS 8602120383 | |
| Download: ML20151X367 (5) | |
Text
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February 4,1966 Docket No. 50-155
, Mr. Kenneth W. Berry Director, Nuclear Licensing Consumers Power Company 1945 West Parnall Road Jackson, Michigan 49201
Dear Mr. Berry:
SUBJECT:
EVALUATION OF CONSUMERS POWER COMPANY'S RESPONSE TO GENERIC LETTER 84-11 FOR STAINLESS STEEL PIPING REINSPECTION Re:
Big Rock Point Plant Consumers Power Company (CPC) submitted the results of augmented inservice inspection required by IE Bulletin 83-02 Stress Corrosion Cracking in Large-Diameter Stainless Steel Recirculation System Piping at BWR Plants, by letter dated August 11, 1983.
CPC's response to Generic Letter (GL) 84-11, " Inspection of BWR Stainless Steel Piping", was submitted by letter dated May 25, 1984. Telephone conversations between respective members of our staffs resulted in additional information being sent to the NRC by letter dated July 2, 1985, to resolve the inspection issues.
Our staff has completed its evaluation of all of your submittals to date regarding GL 84-11 for the Big Rock Point Plant. Our evaluation also considered additional information provided as a result of your 1985 refueling outage inspection activities. Our staff concludes that the Big Rock Point inspection sample size and Technical Specifications leakage surveillance requirements do not meet the guidelines of GL 84-11. The bases for our evaluation are sumarized below.
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Based on the past performance and current inspection results, CPC contends the integranular stress corrosion cracking (IGSCC) in piping is not a problem at the Big Rock Point Plant. The staff's position is that IGSCC is a time-dependent process, and that absence of pipe cracks at this stage of plant life _does not guarantee that the piping will be free of IGSCC in the future. Therefore, the staff does not agree with CPC's position that it j
has been proven that IGSCC is not a problem at Big Rock Point.
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l The staff considers CPC's 20% sampling inadequate for inspectirig a small
-number of welds in differnt pipe sizes, because it will take many fuel cycles to complete a 100% inspection..
For example, it will take four refueling outages to complete the inspection of a total of'four uninspected welds in one pipe line if only the 20% rule is applied. Therefore, to accelerate the l
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Mr. Kenneth W. Berry February 4,1986 completion of inspection and reinspection of welds, Generic Letter 84-11
~ ' ovides guidelines that require the inspection and reinspecti6n'of 20% of pr tfie welds, or a minimum of four uninspected welds and a minimum of two reinspected welds for each pipe size. The inspections sample of 18 welds
. clearly does not mee^ the intention of the GL 84-11 guidelines. Our staff
' has calculated that a total of 31 IGSCC susceptible weld inspections conducted during the 1986 refueling outage would meet the guidelines of GL 84-11 and recommends that CPC incorporate these inspections into the Big Rock Point 1986 refueling outage schedule.
CPC should note that the total number of inspections required to meet the guidelines of GL 84-11 will decrease for each pipe size when weld reinspections are conducted.
The NRC staff has also evaluated the Big Rock Point Technical Specifications for reactor coolant leakage surveillance requirements and has found them to be unacceptable. The GL 84-11 leakage surveillance guidelines are summarized below:
(1) visual inspection of piping leakage during each plant outage, (2) monitoring of the leakage once every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (instead of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />),and (3) the maximum allowed inoperability period of the monitoring system to be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (instead of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />).
The above leakage monitoring frequency of every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is also endorsed by the NRC Piping Review Committee in NUREG-1061 Volume 1 and_ draft NUREG-0313, Revision.2. The staff considers the GL 84-11 guidelines regarding leakage surveillance essential in support of the leak-before-break concept and an important ingredient in the defense-in-depth philosophy.
Therefore, the staff is requesting CPC submit a Technical Specification change for reactor coolant system leakage surveillance for the Big Rock Point Plant incorporating the guidelines provided in GL 84-11.
Based on the results of the IGSCC weld inspections that have been performed for the Big Rock Point Plant and the NRC's Region III inspection report 85-018, dated October 24, 1985, the staff does not have serious concerns regarding the plant's safe operation for the current fuel cycle. Because of the staff's concern of the long term behavior of IGSCC susceptible piping, the discrepancies we have identified herein should be of concern to CPC and remedied by the end of the.1986 refueling outage.
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B 04 1986 Mr. Kenneth W. Berry The reporting and/or recordkeeping requirements contained in this' letter affect fewer than ten respondents; therefore, OMB clearance is no.t required under PL 96-511.
Sincerely, a
W Ihnad nr John A. Zwolinski, Director BWR Project Directorate #1 Division of BWR Licensing cc:
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1 February 4, 1986 Mr. Kenneth W. Berry The reporting and/or recordkeeping requirements containe
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Sincerely,
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w John. Zwolinski, Director BWR Pr ject Directorate #1 Division of BWR Licensing cc: See next page o
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Mr. Kenneth W. Berry Consumers Power Company Big Rock Point Plant cc:
Mr. Thomas A. McNish, Secretary Cohsumers Power Company 217 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Big Rock Point Plant ATTN: Mr. David P. Hoffman Plant Superintendent Route 3 Post Office Box 591 Charlevoix, Michigan 49720 Mr. I. Lee Moerland Chairman, Board of Comissioners P. O. Box 218 Charlevoix, Michigan 49720 Office of the Governor Room 1 - Capitol Building Lansing, Michigan 48913 Regional Administrator Nuclear Regulatory Comission, Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Nuclear Facilities and Environmental Monitoring Section Office Division of Radiological Health P. O. Box 30035 l
Lansing, Michiaar. 48909 l
Resident Ir.spector Big Rock Point Plant c/o U.S. NRC RR #3, Box-600 Charlevoix, Michigan 49720 j
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