ML20198F812

Informs of Impact on Facility Schedule Due to Major Changes in Applicant Assumptions Re Subcompartment Analysis in post- SER Stage of Review.Applicant Changed Assumptions Used to Determine Peak Differential Pressure Response

ML20198F812
Person / Time
Site:	Washington Public Power Supply System
Issue date:	12/30/1974
From:	Tedesco R US ATOMIC ENERGY COMMISSION (AEC)
To:	Moore V US ATOMIC ENERGY COMMISSION (AEC)
References
CON-WNP-1029 NUDOCS 8605290101
Download: ML20198F812 (2)

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V. A. Moore, Assistant Director for Light Water Reactors, Group 2, L l

VAS!!INGTON NUCLEAR 1 & 4 I

i In our draf t Safety Evaluation Report to you en Noveetbar 26, 1974, we

• indicated that the applicant had not provided sufficient iafomation related to his analyses of containment pressure response and subcotapart-cent pressure response. On December 12, 1974, we indicated that we were reviewing additional information from the applicant on these matters.

We recommended that the applicant provide an analysis of the containment pressure response using the mass and energy release methods that ue have found acceptable for similar plants; e.g., Bellefonte 1 & 2 and Greenwood 2 & 3, if we were to avoid irmacting the schedule for Washington Nuclear 1 & 4.

We also indicated that we were reviewing the applicant's analysis of the subcompartment pressure response and would provide the Project

!anager the results of our evaluations. These concerns we're discussed with the applicant by telephone during the past two weeks regarding the containment pressure and subconpartr.ent preneure responses and below is the current status of these areas.

For the containnent pressure response, the applicant han not followed our recommendation, but has proposed determining the maus and energy release ratas to the containconc differently than the method described in our ne.no to you of Decenher 12, 1974.

Because the applicant has not followed our rococesondation we cannot assure you that the schedule for Washington Nuclear 1 & 4 will not be impacted.

In our review of the new information provided by the applicant, with regard to the subcompartment analysis, we have discovered that the applicant has mado major changes in the assumptions used to determine the peak differential pressure response for the various subcompartments without justification.

In particular, for three out of four subcompartments the applicant has not, justified the worst case with regard to break size, break location (hot or cold leg), and break type (oplit or guillotine). We have requested (by telephone) as a nininun, the following information from thu applicant in order for us to evaluate the adequacy of the subcompartment desi:;ns 1.

The maximun calculated and design differential prossure for each subcompartment; i.e.,

the pressurizer, stean generator, reactor cavity, and pipe penetration.

2.

Justification that the worst cases with regard to break size, break location and break type have been detemined for each subcompartment.

8605290101 741230 PDR ADOCK 05000460 A

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Tables of mass and enthalpy release rates for all combinations i

in Item 2.

Tables should state that the information was obtained by B&W using the CRAIT computer code and is for vent valve plants.

I 4.

Flow loss coefficients for all vent flow paths for the various subcompartment models used in the analysis. A statement is required that the flow coefficients have been compared to the geoisatry of the various subcompartments and that they are con-se rvative.

f Because the applicant has made major changes in his asstaptions with regard to the subcompartment analysis in the pogt-SER stage of the review, the schedule for Washington Nuclear 1 & 4 will be impacted. He cannot at this time determine the extent of schedule slippage because va do not know when the applicant will provido the additional information. When thu Froject Manager provides us with this date we can then provide you with the extent of tua alippagu.

Or:gir.r.1 si.med tF:

n.mrt L Te '+xo Robert L. Tedesco, Asaistant Director for Cdntainnent Safety Directorate of Licensing cc; J. Kudrick J. Shapaker i

G. Lainas T. Greene T. Cox l

0. Parr i

A. Schwencer

• W. Jensen A. Giambusso W. Mcdonald F. Schroeder I

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