ML20045D583

LAR Proposing Changes to Seabrook Station Tech Specs to Reduce Frequency of Surveillances Which Are Required to Verify Integrity of CST Enclosure

ML20045D583
Person / Time
Site:	Seabrook
Issue date:	06/18/1993
From:	Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20045D578	List: ML20045D576 ML20045D583 ML20045D584
References
NUDOCS 9306290176
Download: ML20045D583 (3)

Text

- - - _ _ . . . _ _ - _ _ _ _

1 4

, M North sesenoox sranon umr 1 animrmsAtlantic Energy Service Corporation l

1 i

i Facility Op'e. rating License. NPF-86i

Docket Noc50.443.

License' Amendment Request No/93-09J

? Condensate Storage Tank Enciosurei

. L Surveillance _ Frequencyi t

This License Amendment Request is submitted by North Atlantic Energy Service .

j Corporation pursuant to 10CFR50.90. The following information is enclosed in I

. support of this License Amendment Request:

j Section 1 -

Introduction and Description of Proposed Changes

. Section 11 -

Markup of Proposed Changes

. Section ill -

Retype of Proposed Changes

.Section IV -

Safety Evaluation of Proposed Changes

.Section V -

Determination of Significant Hazards for Proposed Changes 4

5

.Section VI -

Proposed Schedule for License Amendment issuance and i Effectiveness t

.i . Section Vil -

Environmental impact Assessment Sworn and Subscribed

' to before me this c2 / day of GMc ,1993 ,

i

+7W

// f^

W6. &ncm Ted C. Feigefibaum

' Notary Public Senior Vice President and Chief Nuclear Officer 9306290176 930618 PDR ADOCK 0500o443

P PDR

l .

i l

j I. - Introduction and Description of Proposed Chances A. Introduction The purpose of License Amendment Request 93 09 is to - y Tse changes to the Seabrook Station Technical Specifications to reduce the fre .uency of surveillances  !

which are required to verify the integrity of the Condensatt. Storage Tank (CST) l Enclosure. l 1

The Condensate Storage Tank (CST) provides a sufficient volume of water to ensure that the Reactor Coolant System (RCS) can be cooled to hot shutdown conditions following a design basis accident. The CST is verified OPERABLE as required by Technical Specification Surveillance Requirement 4.7.1.3 at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the contained water volume is equal to or greater than 212,000 gallons.

The CST is protected on its sides by a tornado missile proof concrete structure, the CST Enclosure, which is designed to ensure the availability of the water volume following the rupture of the CST by a tornado generated missile entering the top of .;

the CST. The CST Enclosure is verified OPERABLE as required by Technical Specification Surveillance Requirement 4.7.1.3 at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that integrity is maintained.

i The CST Enciosure integrity verification required by Surveillance Requirement 4.7.1.3 is performed each shift by an Auxiliary Operator. The Auxiliary Operator verifies the integrity of the CST Enclosure by observing the immediate concrete enclosure around the tank and the seals associated with the enclosure penetrations do not have work ongoing that may cause degradation. The CST Enclosure and its seals are passive

! devices that are not exercised during plant operations and which are not subject to i

transient or cyclical forces from the normal operation of the plant. The most likely l failure mode for the penetration seals is long term degradation due to aging. The 12 1

hour surveillance frequency would be appropriate for identifying an active condition ,

or parameter but is not appropriate for a condition that would take many years to develop.

l The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> frequency for performance of this surveillance is burdensome to the  !

operating crew in that it diverts an Auxiliary Operator for a short time each shift to perform an activity that does not provide substantial information related to the integrity of the Enclosure. The most likely activity to affect the integrity of the CST Enclosure is maintenance affecting the penetration seals. Maintenance activities on 1 the CST Enclosure seals would be performed in accordance with the Station work I control program and if it occurred in MODES 1,2 or 3 it would necessitate entry into the Action Statement of Technical Specification 3.7.1.3 for the Enclosure being inoperable. In all cases, the work control program would require the verification of the Enclosure integrity at the completion of the maintenance activity and prior to entry into MODE 3 when work is performed in MODES 4,5 or 6.

Therefore, LAR 93-09 proposes a revision to Surveillance Requirement 4.7.1.3 to verify that the CST Enclosure is OPERABLE at least once per 18 months by an j inspection to verify that CST Euclosure integrity is maintained. The proposed 18 '

month frequency for performance of the CST Enclosure inspection is consistent with the required frequency for the Containment Enclosure drawdown test (Surveillance l Requirement 4.6.5.1 d 4). The Containment Enclosure drawdown test is effectively verifying the leak-tightness of the Containment and the Containment Enclosure.

1 I

-)

I

The inspection of the CST Enclosure and seals will be similar to inspections performed on the containment prior to Type A testing as required by 10CFR50 4 Appendix J,Section V.A. The CST Enclosure and CST seal inspection procedure will involve a general inspection of the accessible surfaces to uncover any evidence of enclosure structural deterioration or seal degradation which may affect either the CST structural integrity or leak-tightness.

i The inspection of the CST Enclosure and seals will be performed by personnel from the Station Technical Support organization, the organization that performs similar inspections of the Containment and Containment Enclosure. The Technical Support -

personnel possess the requisite expertise and knowledge to detect potential degradation of the CST Enclosure. Therefore their inspection provides a superior ,

inspection to that performed by Auxiliary Operators.

B. Description of Proposed Changes The proposed Technical Specification change affects Technical Specification Surveillance Requirement 4.7.1.3 as discussed below:

Surveillance Recuirement 4.7.1.3 i

Technical Specification Surveillance Requirement currently requires that the CST and '

CST enclosure "be demonstrated OPERABLE at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying the contained water volume in the CST is within its limits and the CST enclosure '

integrity is maintained."

The proposed revision to Surveillance Requirement 4.7.1.3 will not affect the current requirement to verify the CST water volume at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The proposed revision to Surveillance Requirement 4.7.1.3 will split the current i surveillance requirement into two separate requirements. The first surveillance requirement will continue to verify that adequate CST volume exists. This new Surveillance Requirement,4.7.1,3a, will read as follows: '

"The CST shall be demonstrated OPERABLE at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying the contained water volume in the CST is within its limits."

The second surveillance requirement will affect the CST enclosure integrity verification frequency. Proposed Surveillance Requirement 4.7.1.3b will read as follows:

1 "The CST enclosure shall be demonstrated OPERABLE at least once per 18 months by an inspection to verify that CST enclosure integrity is maintained."

i 1

2

, , . - - . . , .