ML20128G575
| ML20128G575 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Palisades, Kewaunee, Harris, Saint Lucie, Robinson  |
| Issue date: | 10/03/1996 |
| From: | Rosalyn Jones NRC (Affiliation Not Assigned) |
| To: | Thadani A NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9610090071 | |
| Download: ML20128G575 (2) | |
Text
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l October 3, 1996 i
MEMORANDUM T0: Ashok C. Thadani, Associate Director for Technical Review Office of Nuclear Reactor regulation THRU:
Gary M. Holahan, Director i
Division of Systems Safety and Analysis l
FROM:
Robert C. Jones, Branch Chief Reactor Systems Branch Division of Systems Safety and Analysis i
SUBJECT:
WAIVER OF CRGR REVIEW 0F GENERIC LETTER TO SIX LICENSEES i
CONCERNING THE SIEMENS' LOSS-0F-COOLANT ACCIDENT EMERGENCY CORE COOLING SYSTEM EVALUATION 7
Attached is one of the letters to be sent to the licensees of the six pressurized water reactor plants that have used fuel manufactured by Siemens Power Corporation (SPC) since 1986:
H.B. Robinson 2, Kewaunee, Millstone 2, Palisades, Shearon Harris 1, and St. Lucie 1.
In an inspection conducted in August 1995, the Reactor Systems Branch identified that SPC had made significant changes to the NRC-approved Fuel Cooling Test Facility (FCTF) reflood heat transfer correlation used in the T00DEE2 computer code used for LOCA analysis and did not report some of the code changes and code errors to the Commission, as licensees are required to do under 10 CFR 50.46(a)(3)(ii).
Also, SPC in their annual reports to NRC, did not properly assess the significance of the code changes in some cases and may have incorrectly characterized the changes as being minor.
We have determined that Siemens made significant changes to the code without staff approval and may have incorporated these model changes to plant specific calculations for the noted pants. The net impact of the unapproved model changes for some plants where the Siemens 1991 methodology was used exceeded 50 degrees F in the calculation of PCT used in the LOCA analysis. We are concerned that these plants may be operating in violation of 10 CFR 50.46.
In j
addition to potential violation of the reporting requirements for "significant changes" in the approved model, Appendix K requires that when a significant change is made to the evaluation model (decrease of 50 degrees F) the evaluation model must, at the same time be modified to delete the use of the l
Dougall-Rohsenow film boiling correlation. The Dougall-Rohsenow correlation was not deleted when the above changes were made to the code. Therefore, we
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prepared the attached letter to the licensees to inform them of their potential violation of 10 CFR 50.46. The letters request the licensees to do the following:
(1) address the code changes and their impact on the PCT for their plant; (2) report the codes changes if they are significant and include 090011 DFOT o '
CONTACT:
GThomas, SRXB/DSSA415-1814
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Wlyd Di n -) - ct % lL i
9610090071 961003 PDR REVGP NRCCRG CORRESPONDENCE PDR
Ashok C. Thadani 2
a proposed schedule for providing a reanalysis or for taking other cetion, as may be needed, to show compliance with 10 CFR 50.46; and (3) discuss whether the model used for their plant meets the requirements of Appendix K with respect to the Dougall-Rohsenow correlation.
I According to the CRGR charter III. B "The CRGR shall consider---staff approval of topical reports---and all other documents, letters or communications of a i
ceneric nature which reflect or interpret NRC staff positions, un]Sss such documents refer only to or staff oositions previously aoolicable to the affected licensees and approved by the appropriate officials," (ref: NRR Office letter No.500, Rev.2 dated June 21,1993).
The purpose of the letter is to request that licensees verify that they are in compliance with the regulations, especially 10 CFR 50.46. The letters do not impose new requirements on licensees, nor do they represent a change in the staff's position regarding compliance with 100FR 50.46 and 10CFR 50, Appendix K.
Therefore, the staff's action does not constitute a backfit.
For the reasons above, we believe that CRGR review is not required.
j If you agree that a CRGR review is not necessary, please indicate your agreement by signing below.
Otherwise, we shall proceed with preparation of an appropriate CRGR package.
Attachment:
As stated M
Ashok C. Thadani Approved: CRGR review is not necessary.
4 DISTRIBUTION Central Files PUBLIC SRXB R/F GHolahan RJones RIngram TCollins GThomas GThomas R/F
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