ML20037A789
| ML20037A789 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 12/20/1976 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Suhrke K BABCOCK & WILCOX CO. |
| References | |
| NUDOCS 8004070512 | |
| Download: ML20037A789 (1) | |
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.DEC 2 01975 Decknt ::o: 50Jr?" J 0 0
fL Florida Power Corporation U 07 ATrN:
Mr. J. T. Rodgers, Assistant Vice President and Nuclear Project :lanager P. O. Eox 14042 St. Petersburg, Florida 33733 Gontler.en:
TJ3JIC'i': CollPLL'c:CE tilt 11 3 0 CFh PF' 50, APVdDIX 11 (CRYSTAL RIVER 3 - ECCS R F 'H.UATION)
Dur ing +j.n cout sa of our ravian of
- a..nr mency core cooling cyr+.=c (i.;3) evaluation rcuels, va r ecently catarn irea that tne r.odal whic:1 you t efe: ence in yout coolication cos: not coaply -with Sectica I.C.4.e. of ingn.ii.s K to 10 Cc'P. Par
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319 criteria for co.pli nco zith Acconaix K ware ectablianed by *ne imC staf f and wre uiccunsaJ wi*n eaca reactot vandor.
iia have conclux ta2* tan e:C3 cva!uation co#1 u tica voc refercnca can.:e cet tneton witn on!y a s.r.all affnet on tno calculhtad fuel ele.:ent rra.: cicJ tec.orature, and nava so informaa yout reactor venJor airnetly (cae L, closure).
This letter is to inform you that an ECC3 c.odal corraction anu suasecur*
CCC3 reevaluation using that cocol to car:cnStrate emolinnea witn AFenaix K is necess.ry anu rr.ust ba suamittod on your a? plication. Tm naxt licensing action on this acept r.cf o
&layna until your rafatance a
avaluation rio#1, and tha analyses S >$cific to your aoolication Tre catorminaJ by tha staf f to co.?? y wita Ap;>'naix K to 10 CE sort 5U.
l In cruer that wo may evolunta t.v effoct of your scaNuloa ro;;xmsc-en thr. Overall projoct cenauula, cleasa suor. tit your senNule for f.CCS reevaluation on tais application within two we ;3 of your recei,t of r
7 tais letter.
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DEC 2 01976 Florida Power Corporation cc: Mr. S. A. Brandi. ore Vice President and General Counsel P. O. Box 14042 St. Petersburgh, Florida 33733 e
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e, UNITED STATES 3 " Y) j NUCLEAR REGULATORY COMMISSION j
WASHINGTON. D. c'. 20555 DEC 2 193
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t Mr. Kenneth E. Suhrke Manager, Licensing Babcock and Wilcox P.O. Box 1260 Lynchburg, Va.
24505
Dear Mr. Suhrke:
During the course of our review of emergency core cooling system (ECCS) i evaluation models, it has come to our attention that use of a nucleate boiling heat transfer correlation during blowdown after critical heat flux (CHF) is first predicted, may not conform to the requirements of Appendix K to 10 CFR 50.
The criteria for compliance with Appendix K have been established by the NRC staff and were discussed with you.
This is similar to the matter identified with respect to the Combustion Engineering (CE) evaluation model.
Based on our experience in connection with developing a correction for-the CE model, we conclude that there are acceptable correlations which can be used and which w uld have a small effect on calculated peak clad temperature.
We are instructing all operating plants which have been evaluated for ECCS performance using your model to submit a re-evaluation using a model corrected to preclude the use of a nucleate boiling heat transfer cc.rrelation during blowdown after CHF has been predicted by the approved correlation.'
Since the expected effect on peak cladding temperature is small, continued operation of these plants within the limits of the existing Technical Specifications, in the interim until the required recalculations are performed, will continue to provide reasonable assurance that calculated peak clad temperature will remain within the limits of 10 CFP. 50.46 and will result in no undue risk to the public health and safety.
However, it is essential that you submit the corrected model for our evaluation as soon as possiole since new licensing actions involving CP and OL applications or reload cores may be impacted until your evaluition model is fully in compliance with Appendix K.
Sincerely, 4
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Denw
.. Ross, Jr., Assistant Director v
for Reactor Safety Division of Systems Safety Office of Nuclear Reactor Regulation i
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