ML20055C165

Forwards SER Indicating GE 820224 Proposal to Delete Control Rod Drop Accident from Std GE-BWR Reload Package for Banked Position Withdrawal Sequence Plants Acceptable

ML20055C165
Person / Time
Site:	LaSalle
Issue date:	02/15/1983
From:	Rubenstein L Office of Nuclear Reactor Regulation
To:	Lainas G Office of Nuclear Reactor Regulation
Shared Package
ML20055C166	List: ML20055C165
References
TAC-48058, NUDOCS 8303010050
Download: ML20055C165 (4)

Text

SENT BY:LASAllE STATION  : 9-10-93 ; 3:24PM ; C0bOMEALT11 EDIS0F 7086637155;c11/14

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RDQtARD(M FOR: Assistant Director-S.for C.Operat LainisIng teacters, DL FEWl: L. 8. Rubenstein Assistent Director j for Con and PIant Systans, BSI ,,

SUBJECT:

CRW.E5 IN GE ANAL.YS!$ OF THE CONTROL 800 DROP l

ACCIDENT FOR PLAK1 RELO485 (TAC 544058)

! In a letter of February 24,1982 from R. Engel (GE) to 9. Vessallo (NRCl General

Electric presented its proposal to delete the Control Rod Drop Accident (CRDA) from Oe standard CE-BWR reload package for Banted Position Withdrawal Sequence (BPW5) plants. His uns based on e statistical analysis of nsults fram previous

' reload ana13es. This proposal is afaff ar to previous proposals to modify reload sutaittals der the rod withdrawal at power and mislocated assably events. Those previous p sals wre accepted with, however questions ebout future mioad characterist es. Dose questions have been ans,wered and reviewed. The proposal

} for the CRDA submittals have been reviewed and the SER indicating that the pro.

' posal is acceptable is enclosed, nfs reyfew also indicates that the msponses about the future reload characteristics is acceptable for both the previous

events and the CRDA as well.

1 i This completes our efforts for TAC sto. 48058.

L. S. Rubenstein Assistant Director i

for Core and pIant systems. D$1 j Enclosum

l l As stated ec: R. Mattson '

l t. U senhut i L G4Pft

8. Vassalle 4

! 4 l ' ""*?1 i Reactor Physics Section -

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Contact:

N. Richings i X-19465 5

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! etttit THE CADA ANALYS!$ FEM SpW5 puurf SELOAD PAcurds In a letter of February 24,1982 (Reference 1) Eeneral Electric (8t) proposed to l

delete the analysis of the control red drop accident (CADA) fra the standard l

reload pactate for plants using the banked position witWravel sepence (4pv5)

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for control rod withdrawal. This proposal is based on a statistical analysis l

l by St of the resvits of past CRDA analyses for plants using SpWS, and the

! conclusion that with a 95/95 probability / confidence level the peat fuel enthaply mould be (such) less than 280 cal /pn (the staff lisit) with the maxima l

j control red incremental reactivity worth. The GE proposal was to delete the l CNDA analysis from the reload subrnittats beginning April 1982. fne staff review (basis ta be discussed) was favorable, for present populations of l

eesctor nioads, although no formal report as written at the time, l

h This modification of an event analysis for reloads via a statistical analysis of l

previous results is similar to two past GE proposals for reloed salmittal modiff-cations. These proposals were (1) for discontinuing plant-cycle specific mis-

! located bundle analyses (November 1980, see Reference 2), and (2) far a change in the analysis of the tontrol rod withdravel et powr event (May 1981, see

! Reference ?). The staff reviews found both of these modifications to be

! acceptable (see References 4.5,6 and 7) for present populations of reloads, although the reviews continued with questions related to future populations of

reloads. These westions sere responded to by SE (References 8 ans f). The staff has soviewed these responses and finds thw informative and acceptable i

and concledes Oat for the presently foreseeable future the characteristics of i the reload populations appear to be compatible with those considered in the statistical analyses.

i For the statistical analyses of the CRDA analysis K bas empiled the results i fran about to reloads for plants using the BPWS (or those esing siellar f: patterns for part of the withdram1). The control red reactivity wrths used in CRDA analyses at significant points la the startup sequence wre esamined,

! and the statistics of rod worth, incteding average and variance, wre e

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produced. Ilost of the (relevant) red morths are ender 15 a t and all including l ,

a statistically detarsined 95/95 probability / confidence level am well onder l . 3.55 Ak, All red mortAs used result in peak enthalpfes self under 180 cal /gm

esing the St (Imc approved) salculational mothed.

4 The staff review of these results indicate that the red worths and resulting

peak enthalpies are fa an expected range, based on past reviews and staff 1 l consultant (BNL) caleviations. The results are acceptable. In addition staff l j . (SNL) calculations of the CADA (e.g., see Reference 10) with a given red worth

! and vsfag appropriate themal.hdraulle feedback (unlike the SE analysts aAlch i (s. very conservatively, adiabatic) results in such toner peak enthalpfes.

l e.g., well under 150 cal /p for a 1.55 At rod and well under 200 cal /p for a j t.0s,46 rod even when using conservative asswnptions on the initial thermal.  !

j hdraulic stata.

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Thus it is conc 1vJed that for present populations of reloads the expected relevant rod worths and resulting peak enthapies are such that it is reason-f: able not to ine19de the CADA analysis in refoed solumf ttals. Furthermore, i based on the review of information from answers to questions frem the tuo i

prevleus statistical analyses about the characteristics of future i populations as well as the significant margin to liaf ts indicated by the SNL j calculations, there is no apparent need at this time to further exantne the future population characteristics. The allsination of cycle, specific CRDA analyses fras lPW5 plants is ecceptable.

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WERENCG . -

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1. Letter. R. E. Intel. St. to 9. 3. Vassalle. MC. Febtvary 24. 1982  !

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• Control Rod Drop Accident". -

2.' Latter. R. E. Intel. St. to T. A. Ippolf te. MC November 34.1980,

• Change in General Electric Methods for Analysis of Misiocated Sandle 1 l

s Accident *.

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3. Letter. R. E. Inge1. St. to D. B. Vasss11o. NRC. May 18. 1981

• Change in teneral Electric Methods for Analysts of control Rod Withdrawl Erter'.

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4. Mooranden. W. V. Johnston to T. A. Ippelf 3. April 14,1981.

Change in General Electric Analysis of M' ,focated landle Accident'.

i i 5. Letter, l. 5. Rubenstein. NitC. to R. E. Engel CE. May 26. 1981

' Change in General C1tetric Ana1 pes of Mistocated Bendte Acefdent'.

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6. Mesoranda. L. S. Aubenstein to T. M. Novak. November 13. 1981.

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' Evaluation of the 5tatistical Analysis of the RWE for Natch 18

! 7. Letter L. 3. Ilubensteln. NRC. to .R. E. Engel. 8E. November 25. 1981

' Change in General Electric Analysts of Rod Withdrawal Error *. ,

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5.

Letter. R. E. Engel. SE. to D. B. Vassallo. NRC. March 23. 1982, i

' Change in General [1ectric Methods for Attalysis of Mistocated Bundle Accident'.

9. Letter. 8. E. Engel, EE. to L. 5. Rubenstata. WRC. Aprfl 5.1982

' Responses to Questions Rega.rding Change in General Electric Methods j for Analysis of Control Rod Withdrawal Error *. '

10. Menoranda. N. J. Richings to K. Ihfel. April 15,1980. 'The te RM l as Viewed Through BNL Feedback'. .

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