ML19322C222

Forwards Proposed Category B Technical Activity Re Loss of Offsite Power Subsequent to Loca,Per ACRS

ML19322C222
Person / Time
Site:	Crane
Issue date:	03/03/1978
From:	Boyd R Office of Nuclear Reactor Regulation
To:	Case E Office of Nuclear Reactor Regulation
References
TASK-TF, TASK-TMR NUDOCS 8001160645
Download: ML19322C222 (2)

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.n 4.A MEMORANDUM FOR:

Edson G. Case, Chairman

~ *lj Technical Activities Steering Committee y.

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Roger S. Boyd, Director

.1, '.h Division of Project Management 54

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SUBJECT:

PROPOSED TECHNICAL ACTIVITY

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~b Enclosed for consideration by the TASC is an additional proposed l

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Category 8 technical activity.

This proposal results from a lingering concern of the ACRS, most recently expressed in a letter from the Committee dated January 18, 1978.

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The Committee is concerned that in the event of a loss of off-site power

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at some time subsequent to a LOCA, the core could be deprived of cooling f3 for that period of time required to transfer the pumps from the off-

.j site power to the diesel generators.

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---1 Roger S. Boyd, Director Division of Project Manageme

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Enclosure:

As stated

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H. Denton R. Mattson V. Stello M. Aycock W. Minners D. Wigginton L. Crocker c'

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TECHil! CAL ACTIVITY q

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Title:

Loss of Of f-Site Power Subsequent to LOCA r,Q This is an ACRS concern, it pertains to the effects

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DescQption:

on the core that could result from a loss of off-

.q i.Lq site power subsequent to a LOCA.

Even though SIS

,gj reset controls are such that a loss of off-site power following a LOCA would result in diesel engine m.{

generator start and pick-up of ESF loads, there

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still remains the question as to the effect on the core during the period of time between the loss of f

the off-site power and the pick-up of ECCS pump loads by the diesels.

If the loss of of f-site jf power were to occur at the end of blowdown, just as

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the ECCS pumps are supposed to start, the core 3!ji could be lef t without cooling water for an addi-

,-ji tional period of time beyond that examined in our 1'!

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analyses.

What is needed is an analysis th:t shows that we need not consider such an event because it is of sufficiently low probability or it does not

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lead to unacceptable consequences, or we need to 7!

come up with some sort of desi,gn fix to assure that i ':! e a

such an event cannot take place.

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Priori ty:

Category B.

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Justification:

This is an extension of the concern described in

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Issue flo. 4 of flVREG-0138.

The ACRS letter of 4

December 12, 1976, which addressed the issues dis-

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cussed in fiUREG-0138, indicated general satisfaction w

1 with the staff position regarding control of SIS 3

reset, except for this question.

In the view of v.

the ACRS, the loss of off-site power following a 3

LOCA would require some time for the pump leids to be transfered to the diesel generators, and this n~

loss of pumps had not been examined by the staff.

'e A copy of the ACRS comments is enclosed.

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Lead Division:

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Manpower Requirement:

Estimated 3 man months.

Technical Assistance I

Funds or RES Support:

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