ML20211G583

Anticipates Completion of Steam Generator Analysis & App R Modeling Reanalysis Work by Feb 1987,per 860918 Telcon W/Nrc Re Steam Generator Cool Down Studies for App R

ML20211G583
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/22/1986
From:	Robert Williams PUBLIC SERVICE CO. OF COLORADO
To:	Berkow H Office of Nuclear Reactor Regulation
References
P-86585, TAC-54373, TAC-63576, NUDOCS 8611040079
Download: ML20211G583 (2)

Text

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Public Service ~

nh P.o. Box 840 October 22, 1986 Denver. co so201-os40 Fort St. Vrain Unit No. I R.O. WILLIAMS, JR.

P-86585 E"e"$sgeudrions c

Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.

20555 Attention: Mr. H. N. Berkow, Director Standardization and Special Projects Directorate Docket No. 50-267

SUBJECT:

Steam Generator Cool Down Studies for Appendix R

REFERENCES:

1) NRC letter Butcher to Lee dated November 1, 1985 (G-85459)

2) PSC letter Walker to Berkow dated December 20, 1985 (P-85488)

3) PSC letter Walker to Berkow dated March 14, 1986 (P-86209)

4) PSC letter Gahm to NRC Document Control dated October 17, 1986 (P-86587)

Dear Mr. Berkow:

During a'

recent (September 18, 1986) telephone conversation with various members of the NRC Staff, it was suggested that PSC submit a letter stating our current assessment of our Appendix R Shutdown Cooling model with respect to our recent Steam Generator cool down

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PDR ADOCK 05000267 F

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P-86585 Page 2 October 22, 1986 l

studies as noted in References 1 through 3 above. We acknowledge that the recent discoveries with the Economizer-Evaporator-Superheater (EES) section during an EQ. shutdown may impact the-Appendix R shutdown model. The EES discoveries were reported to you in our LER 86-026 transmitted to you by Reference 4.

As we stated to you, although the EES cannot support the safe shutdown cooling conditions as represented in the FSAR, we are confident that the EES sections can support safe shutdown cooling given alternative conditions or some reduced power level.

We-are performing analyses to confirm this. We will address the EQ shutdown cooling separately from the Appendix R shutdown model and deal with the " safety grade" safe shutdown cooling with the steam generators as the first priority as suggested by the Staff. We will then. move to resolve the Appendix R shutdown cooling -model.

Given the many uncertainties involved, it is not possible to predict a firm schedule, but we would anticipate having both the Steam Generator analysis and the Appendix-R modeling reanalysis. work completed by February 1987, which is revised from the connitment made in Reference 3.

If you have any questions concerning this matter, please contact Mr. M. H. Holmes at (303) 480-6960.

Very truly yours, A

R. O. Williams, Jr.

-Vice President Nuclear Operations R0W'FT:pa c

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