ML20037A229

Response to NRC Question 2.2 on Cycle 3 Safety Analysis, Nonproprietary Version

ML20037A229
Person / Time
Site:	Millstone
Issue date:	05/02/1979
From:	ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
To:
Shared Package
ML19292H571	List: ML20037A228 ML20037A229
References
CEN-110(N)-NP, TAC-46174, NUDOCS 7905080407
Download: ML20037A229 (4)

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.f Ii CEft-l10(N)-NP RESP 0t15E TO N.R.C.

QUESTION 2.2 ON THE MILLSTONE UllIT N0. 2 CYCLE 3 RELOAD APPLICATION, DOCKET NO, 50-336.

MAY 2, 1979 JJ Combustion Engineering, Inc.

Nuclear Power Systems Windsor, Connecticut s

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i Cell-110(;1),-t!P QUESTION 2.2 ON THE RESP 0t15E T0 ti.R.C.MILLST0!!E UttIT N0. 2 APPLICATI0ti, DOCKET tt0. 50-336, 1%Y 2,1979 k

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Combustion Engineering, Inc.

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Nuclear Power Systems I

Windsor, Connecticut 1

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LEGAL NOTICE THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY. COMBUSTION ENGINEERING, INC. NEITHER COMBUSTION ENGINEERING NOR ANY PERSON ACTING ON ITS BEHALF:

A.

MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY, WITH RESPECT TO THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATI;',N CONTAINED IN THIS REPORT, OR THAT THE USE OF ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS;OR B. ASSUMES ANY LIABILITIES WITH RESPECT TO THE USE OF,OR FCR DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, METHOD OR PROCESS DISCLOSED IN THIS REPORT.

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P,esponse to NRC Question 2.2 on the iillistone Unit 2 Reload Application 9

Question 2.2: (Section 7.1.1, CEA Withdrawal Event)

The Time delay Adjus.tment Bias (TAB) for the TM-LP parameter is,-in principle,, determined by.the transient, for which DNBR suffers the greatest degradation after core ' conditions have reached the TM-LP setp'oint.

All potentially limiting transients should be considered in computing the TAB.

(The Loss of Flow, Seized Rotor, CEA Drop, CEA Ejection, Steam Line Rupture, and l

Malfunction of One Steam Generator Events do not require the TM-LP trip, and hence, are excluded from consideration in the i

determination of the TAB.) Ordinarily, the limiting transient is either CEA Withdrawal or RCS Depressurization. However, all l

transients (except those noted above) should be examined to ascertain that they are, in fact, not more limiting than those two.

For those other transients,'it is ordinarily not necessary to compute the TAB, but only to demonstrate that they produce substantially slower degradation in DNBR that the two limiting transients.

Provide answers to the three following questions.

I a.

Was the comparison of' speed of degradation described above 1

performed?

If so, what transients were considered?

i b.

If this comparison was performed, what is your criterion for saying that one transient produces substantially slower DNBR degradatica than another transient?

c.

The transient with the fastest degradation in DNBR dops not necessarily produce the limiting TAB because the shap!of the turnaround in DNBR vs Time curve is a function of the particular transient being analyzed.

(This is why both CEA Withdrawal and RCS Depressurization are normally both analyzed, and not simply the one with the fastest degradation in DNBR.) Explain how the criterion of questions b above is justified in view of the above consideration.

Do this in numerical terms to demon-l strate the confidence we can put on your criterion.

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Response

2.2.a f-As stated in section 5.6.1 of CENPD-199-P, and as indicated in Table 1-3 of the same report, [-

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1 l1 2.2.b The pur pose of the bias factor is to accommodate the trip delays for the most

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2.2.c Contrary to what is implic.d'in this question and as already stated in answering 2.2.a and 2.2 b, the [

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