ML20113B191

License Amend Request 96-17 to License NPF-86,increasing Allowed Outage Time for Inoperable Svc Water Cooling Tower Loop Electrical Supply to Be Equivalent to Allowed Outage Time for Inoperable Svc Water Cooling Tower Loop

ML20113B191
Person / Time
Site:	Seabrook
Issue date:	06/20/1996
From:	Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20113B181	List: ML20113B178 ML20113B191 ML20113B203
References
NUDOCS 9606260238
Download: ML20113B191 (3)

Text

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1 This License Amendment Request is submitted by North Atlantic Energy Service Corporation pursuant to 10CFR50.90. The following information is enclosed in support of this License Amendment Request:

i e Section 1 - Introduction and Safety Evaluation for Proposed Changes i

e Section II - Markup of Proposed Changes l

. Section lli - Retype of Proposed Changes e Section IV - Detemilnation of Significant Hazards for Proposed Changes e Section V - Proposed Schedule for License Amendment issuance and Effectiveness l

. Section VI - Environmentallmpact Assessment Sworn and Subscribed  !

before me this l

1. 6 day of doxo/

.1996

! m esw/ M fe'd C. Feigenba Vica Pres J[ident and Chief Nuclear Officer

//[ VNotary Public Executive ,

l EGGY L MANNELt.O l l NOTARY PUBLIC 1

) It/ COMMIS$10N f.XPIRES SEP. 30, IM7

9606260238 960620 PDR 4

P ADOCK 05000443 PDR 4

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I. INTRODUCTION AND SAFETY ASSESSMENT FOR THE PROPOSED CHANGES A. Introduction Technical Specification 3.8.3.1, Onsite Power Distribution - Operating, requires in part that the Train B electrical bus be operable. This bus is comprised of 4160 y emergency bus E6, and 480 y emergency busses E61, E62, and E64. Technical Specification 3.8.3.1, Action a states "With one of the required trains of AC emergency busses not fully energized, reenergize the train within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />".

Unlike the other 480 v electrical busses, which supply electrical power to several different Train B safety related systems, Unit Substation (US) E-64 supplies electrical power to components which are only associated with the Train B service water cooling tower loop. The components which receive power from US-E64 are listed Table 1, US-E64 Loads. Technical Specification 3.7.4, Service Water System / Ultimate Heat Sink, Action b., allows one service water cooling tower loop to be inoperable for up to 7 days or be in at least Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />". Thus, it is apparent that the existing Action Requirement for US-E64 being inoperable is overly restrictive and inconsistent with the Action Requirement for one service water cooling tower loop being inoperable.

North Atlantic proposes to revise the Technical Specifications to change the action required for US-E64 being inoperable to be equivalent to the action required for one service water cooling tower loop being inoperable. Specifically, this would increase the allowed outage time for US-E64 to 7 days before further action is required. US-E64 is currently operable, however, it is beginning to exhibit signs of potential degradation as evidenced by increased noise level and unusual odors. North Atlantic plans to inspect the unit substation and perform corrective maintenance if required. The inspection and possible corrective maintenance cannot be performed within the current 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> allowed outage time.

Descriotion of Proposed Changes Technical Specification 3.8.3.1, Action a. [page 3/4 8-17] is revised by specifying that US-E64 can be inoperable for up to 7 days before further action is required. If US-E64 is not returned to operable status within the 7 days allowed outage time, then the plant is required to be in at least Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The proposed change is consistent with the Action required for one service water cooling tower loop being inoperable. The basis for the proposed change is that US-E64 only supplies power only to components associated with the Train B service water cooling tower loop and therefore the allowed outage time for US-E64 should be equivalent to the allowed outage time for the loads it powers.

B. Safety Assessment of the Proposed Changes If US-E64 is inoperable, there remains redundant, operable equipment within the same Train which is capable of supporting continued plant operation. The Seabrook Station Service Water System consists of two independent trains (Train A and Train B) each of which can operate with either a service water pump loop or a service water cooling tower pump loop. Each service water loop consists of a service water pump and the piping, valves and other components necessary to provide a flowpath for heat removal.

Each service water cooling tower loop consists of a service water cooling tower pump, and the necessary piping, valves and other components required to provide its flow path. The ultimate heat sink for the 1

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service water loop is the Atlantic Ocean whereas the ultimate heat sink for the service water cooling tower loop is a mechanical draft cooling tmver. The operability of the Service Water System ensures that sufficient cooling capacity is available for continued operation of safety related equipment during normal and accident conditions. Because US-E64 supplies electrical power only to components associated with service water cooling tower loop Train B, the inoperability of US-E64 does not affect any of the components associated with service water loop Train B nor does it affect any Train A components.

Thus, if US-E64 is inoperable the Train B service water loop remains operable and capable of providing cooling during normal and accident conditions in addition to the Train A service water and cooling tower .

service water loops.

l Technical Specification 3.8.3.2, Onsite Power Distribution - Shutdown, apparently recognizes that US- i E64 supplies electrical power to only Train B service water cooling tower loop components because it is explicitly excluded from the Limiting Condition for Operation. Technical Specification 3.8.3.2 is applicable in Modes 5 and 6, in these Modes there is no requirement for the Service Water System to be l operable. Thus it appears that for Modes 5 and 6, the Technical Specifications recognize that US-E64 supplies power to Train B service water cooling tower loop components only.

Based on the above, North Atlantic has concluded that the proposed revision to the Technical Specifications, to increase the allowed outage time for US-E64 to be equivalent with the allowed outage time for an inoperable service water cooling tower loop, makes no reduction in the capability of the Service Water System to perform its intended safety function.

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