ML19254B363

Forwards Request for Addl Info Re Override of Containment Purge Isolation

ML19254B363
Person / Time
Site:	Millstone
Issue date:	08/29/1979
From:	Lainas G Office of Nuclear Reactor Regulation
To:	Reid R Office of Nuclear Reactor Regulation
References
TAC-42588, NUDOCS 7909270376
Download: ML19254B363 (2)

Text

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AUG 2 91979 MEMORANDUM FOR:

R. Reid, Chief, Operating Reactors Branch #4, D0R FROM:

G."Lainas, Chief, Plant Systems Branch, DOR

SUBJECT:

MILLSTONE 2 - OVERRIDE OF CONTAINMENT PURGE ISOLATION (TAC 10819)

We have prepared the enclosed request for additional infomation. As indicated by the first three questions, we have determined that signifi-cant design changes are necessary. The other questions might also involve design changes. -

It is anticipated that these changes might have a significant impact on the licensee. Therefore, we suggest that this request be discussed with the licensee prior to transmitting the request fomally. We will be glad to participate in a. conference call, if you desire.

A G. Laina, Ch,ef Plant Sy tems Branch Division of Operating Reactors

Enclosure:

As stated

Contact:

J.T. Beard X-28077 cc w/ enclosure:

D. Eisenhut

.J.T. Beard (2)

W. Gamill P. Shemanski B. Grimes V. Panciera G. Lainas W. Russell D. Tondi E. Reeves E. L. Conner M densam 7909270T7(o 1046 272

ENCLOSURE

, REQUEST FOR ADDITIONAL INFORMATION MILLSTONE UNIT 2 0VERRIDE OF CONTAINMENT PURGE ISOLATION 1.

We understand that the overriding of the high-radiation safety actuation signal to a purge isolation valve will cause the blocking of the safety injection actuation signal, which should cause isolation of the purge valve. This design feature is not acceptable. Describe (including approprjate electrical schematic diagrams) the design changes you propose' to rectify this deficiency.

2.

The design feature of cycling of the normal control switch for a purge isolation valve to override a safety actuation signal to the valve does not facilitate an acceptable degree of administrative control over the use of the override.

Describe the design changes you propose to rectify this deficiency.

3.

The fact that a safety actuation signal to ESF equipment is overriden must be " annunciated" whenever such an override is active. Valve position (" status") lights are not sufficient.

Describc. the design changes you propose to rectify the present deficiency.

4 4.

Purge valve isolation must be initiated by diverse safety signals.

Specifically, we require that purge isolation be automatically initiated by any of the following: (a) containment high radiation, (b) contain-ment high pressure, and (c) the safety injection actuation signal.

Discuss the type signals which will initiate purge isolation at Millstone 2.

Describe any design changes necessary to achieve full compliance with this requirement.

5.

We require that all the equipment which senses plant conditions and initiates purge isolation be designed and appropriately qualified as Class 1E equipment. Discuss the qualification of all such equipment at Millstone 2.

Describe any changes necessary to achieve full compliance with this requirement.

6.

The overriding of a safety actuation signal to a purge isolation valve must not, by itself, result in the automatic opening of any isolation valve. After considering items 1 and 2, above, discuss the physical factors involving in re-opening a purge isolation valve. Describe any design changes needed to preclude automatic re-opening.

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