ML20009A368
| ML20009A368 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/30/1981 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| Shared Package | |
| ML18046B418 | List: |
| References | |
| TAC-7545, NUDOCS 8107100314 | |
| Download: ML20009A368 (5) | |
Text
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Docket flo. 50-336 lir. W. G. Counsil. Vice President 2
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Hartford, Connec+.icut 16101
Dear Mr. Couns11:
By letters dated April 25, 1978 and August 29, 1979, Florida Power and Light Comparty and Northeast Nuclear Energy Company provided technical reports on two different Loop Current Step Response (LCSR) methods for determining the resistance temperature detector (RTD) response time at St. Lucie, Unit No. I and Millstone, Unit No. 2, respectively. These methods are similar in most respects, but have a few differences which are discussed in the enclosed Safety Evaluation (SE). Based on our review of both reference reports, we find the LCSR methods to determine RTD time response as described in each report and docunented in the SE to be acceptable. We plan to issue the SE as a NUREG in the near future.
Extensive testing has shown the LCSR method to be extremely reliable and provide results with an accuracy of 10% (naximun error). This conpares very favorably with the older plunge test method, which often has inaccuracies as high as a factor of 3.
Since the LCSR method offers a significant improvement in RTD response time testing, we recommend you consider its use at your facili ty.
It appears to us that use of the LCSR method would also result in a reduction in personnel radiation exposure.
The extensive RTD ti'ne response testing which has been done in conjunction with the development of the LCSR method has revealed that the RTDs in operating reactors suffer time response degradation as they age. Current Standard Technical Spet.ifications (STS) require that one quarter of the safety systen RTDs be tested each 18 months. This corresponds to testing each RTD once every six years.
In view of the RTD time response degradation observed in our study, it is clear that the present RTD surveillance testing schedule is not adequate. We request that you make application for TS changes to require the time response testing of all safaty system PTDs within one conth of operation for newly installed RTD and once every 18 nonths thereafter. This application should be made before or as a part of your application for the next core reload.
If you plan to use the provisions of 10 CFR 50.59 for the next core reload, please submit the application for such a chance at least 90 days ahead of the next planned reactor shutdown. This request is independent of whether you plan to use the LCSR or some other trethod (plunge test for exanple) of determining the RTD response time.
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-2 If you have any questions on this subject, please contact your assigned HRC project manager.
Sincerely, Dri inal Signed by 8
Robert A. ClarV.
Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
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JUN 3 01981 D:cket No. 50-336 Mr. W. G. Counsit, Vice President Nuclear Engineering & Operations Northeast Nuclear Energy Company P. O. Box 270 Hartford, Connecticut 16101
Dear Mr. Counsil:
By letters dated April 25, 1978 and August 29, 1979, Florida Power and Light Company and Northeast Nuclear Energy Company provided technical reports on two different Loop Current Step Response (LCSR) methods for determining the resistance temperature detector (RTD) response time at St. Lucie, Unit No. I and Millstone, Unit No. 2, respectively. These methods are si'nilar in most re aects, but have a few differences which are discussed in the enclosed Safety Evaluation (SE). Based on our review of both reference reports, we find the LCSR methods to detennine RTD time response as described in each report and documented in the SE to be acceptable. We plan to issue the SE as a NUREG in the near future.
Extensive testing has shown the LCSR method to be extremely reliable and provide results with an accuracy of 10*. (maximum error). This compares very favorably with the older plunge test method, which often has inaccuracies as high as a factor of 3.
Since the LCSR method offers a significant improvement in RTD response time testing, we recommend you consider its use at your f acility.
It appears to us that use of the LCSR method would also result in a reduction in personnel radiation exposure.
The extensive RTD time response testing which has been done in conjunction with the development of the LCSR method has revealed that the RTDs in operating reactors suffer time response degradation as they age. Current Standard Technical Specifications (STS) require that one quarter of the safety system RTDs be tested each 18 months. This corresponds to testing each RTD once every six years.
In view of the RTD time response degradation observed in our study, it is clear that the present RTD surveillance testing schedule is not adequate. We request that you make application for TS changes to require the time response testing of all safety system RTDs within one month of operation for newly installed RTD and once every 18 months thereafter. This application should be made before or as a part of your application for the next core reload.
If you plan to use the provisions of 10 CFR 50.59 for the next core reload, please submit the application for such a change at least 90 days anead of the next planned reacter shutdown. This request is independent of whether you plan to use the LCSR or some other method (plunge test for example) of detennining the RTD response time.
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Robert A.-Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
As stated cc:
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r, Northeast Nuclear Energy Company cc:
William H. Cuddy, Esquire Mr. John Shedicsky Cay,- Berry & Howard Resident Inspector / Millstone Counselors at Lew c/o U.S.N.R.C.
One Constitution Plaza P. O. Drawer KK Hartford, Connecticut 06103 Niantic, CT 06357 Anthony Z. Roisman Mr. Charles Brinkman Natural Resources Defense Council Manager - Washington Nuclear 91715th Street, N.W.
Operations Washington, D. C.
20005 C-E Power Systems Combustion Engineering, Inc.
Mr. Lawrence Bettencourt, First Selectman 4853 Cordell Aven., Suite A-1 Town of Waterford Bethesda, MD 20014 Hall of Records - 200 Boston Post Road Waterford, Connecticut 06385 Northeast Nuclear Energy Cobpany ATTN: Superintendent Millstone Plant Connecticut Energy Agency Post Office Box 128 ATTN: Assistant Director, Research Waterford, Connecticut 06385 and Policy Development Department of Planning and Energy Waterford Public Library Policy Rope Ferry Road, Route 156 20 Grand Street Waterford, Connecticut 06385 Hartford, CT 06106 Director, Criteria and Standards Division Office of Radiation Prograns (ANR-460)
U.S. Environmental Protection Agency Washington, D. C.
20460 U. S. Environmental Protection Agnecy Region I Office ATTN: EIS COORDINATOR John F. Kennedy Federal Building Boston, Massachusetts 02203 Northeast Utilities Service Conpany ATTN: Mr. Janes R. Himmelwright Nuclear Engineering and Operations P. O. Box 270 Hartford, Connecticut 06101 6
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