ML20011E755

Requests Temporary Relief from Tech Spec 4.7.A.2.b.1.d, Limiting Condition for Operation.

ML20011E755
Person / Time
Site:	Pilgrim
Issue date:	02/09/1990
From:	Highfill K BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-22, NUDOCS 9002220386
Download: ML20011E755 (4)

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. 'i Pilgrim Nuclear Power Station f Rocky Hill Road ,

Plymouth, Massachutetts 02360  ;

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l i l Italph G. Bird Senior Vice President - Nuclear February 9, 1990 BECo Ltr #90-22  ;

U.S. Nuclear Regulatory Commission Attn: . Document Control Desk H Washington, D.C. 20555 i l  :

H Docket No. 50-293 License No. DPR-35 ,

Subject:

REQUEST FOR RELIEF FROM TECHNICAL SPECIFICATION 4.7.A.2.b.1.d LIMITING CONDITION FOR OPERATION  ;

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Dear. Sir:

Boston Edison Company hereby reluests a temporary relief from the requirements .

of Pilgrim Nuclear Power Station Technical Specification 4.7.A.2.b.1.d until  ;

the mid-cycle outage scheduled to begin on March 9, 1990. Plant operation subsecuent to the granting of this request would not create a significant hazarc'to the public health and safety and is justified on technical merit. ,

'He have also concluded that a request for an emergency change to the Pilgrim "

Technical Specifications would not be appropriate in this case r.ince the nature of the requested relief is temporary and non-recurring.

Bitkaround l Technical Specification 3/4.7.A.2.b.l.d requires that the operability of the ,

reactor coolant system instrument line flow check valves be verified once per operating cycle. During the October, 1989 outage, excess flow check valves 2-CK125 A&B had their test aborted because sufficient actuation flow was unattainable due to the instrument line configuration. i The inability to verify operability conflid s with Technical Specification 3/4.7.A.2.b.l.d because the surveillance interval and its 25% " grace period" .

expired for these two valves, f Justification ,

.Tiie excess flow ~ check . valves serve two purposes: that of a passive component of the pressure boundary, similar to a spool piece; and that of an active component in reducing coolant flow in the event an instrument line sustains a

, catastrophic break 1.e. a " double guillotiirc break.

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. . Page 2 Boston Edison Company . Docket No. 50-293 l Pilgrim Nuclear Power Station License No. DPR-35 i

i Its passive " spool piece" role is not specifically a part of Technical  !

Specifications because the failure of the check valve internals in the open  ;

position does not affect the process instrument associated with it. Failure  !

of the valve internals in the closed position will be detected by a response  !

time differential between process instruments downstream of the failed valve and similar redundant process instruments associated with open valves.

The excess flow check valve's active function is to reduce flow into secondary f containment if there is a line break downstream of the valve. The FSAR safety analysis of a potential instrument line break is'provided in Section *

< 5.2.3.5.3. This section describes the instrument line containment boundary as -

an upstream orifice located inside primary containment and a downstream instrument flow check valve located outside primary containment. As stated in >

the FSAR:

"The combination of orifice and excess flowcheck [ sic] valve will reduce leakage to as low a value as practicable in the unlikely event of line failure."  ;

The subsequent analysis of instrument line failure is based on a guillotine line failure of the instrument line unstream of the excess flow-check valve. .

This failure results in a leak of 20 gpm to the secondary containment; the l flow' limitation being strictly due to the upstream flow orifice. This leak rate is "well within the capability of the Reactor Coolant Makeup System" and, therefore, does not present a safety hazard to the reactor core. This flow does not endanger the integrity of the Reactor Building as there "would not be any significant pressure rise due to the relatively high Reactor Building ventilation exhaust rates" and "the operation of one standby gas treatment filter train will prevent Reactor Building pressure from exceeding its design value." Finally a leak rate of 20 gpm results in a site boundary exposure "which .is substantially below the guidelines of 10CFR100."

The flow reduction contribution of the excess flow check valve is not a contributor to the instrument line break analysis. In addition, the-active function of the excess flow check valves, to reduce flow in the. event of a -

line break downstream of the check valve, is not required to protect the core or.the health and safety of the public. In effect, the safety function of the

- excess flow check valves is reduced to maintaining a pressure boundary and an <

open flow path to the associated instruments.

The surveillance requirement given in Technical Specification 3/4.7.A.2.b.1.d addresses only the active function of the check valves to reduce leakage "to as low a value as practicable" and this function is not required to meet the design of the plant. This is the only function that has.not been " verified" for valves 2-CK125 A&B within the prescribed surveillance interval. Noting that the flow orifices and valves are new and not subjected to a fluid flow environment other than that required for surveillance testing it is reasonable to assume that these orifices and valves have not eroded or degraded in any way which could result in an increase of their critical / limiting flows. Also, all other excess flow check valves which were tested during the October mini-outage passed their test.

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Page 3 Boston Edison Company Docket No. 50-293 Pilgrim Nuclear. Power. Station License No. DPR-35 Comnensatory Measures Until the excess flow check valves (2-CK125 A&B) are replaced during the March 9, 1990 mid-cycle outage, the following additional compensatory actions are being taken:

• Control access to the vicinity of the lines from the check valves tn the instrument racks.

• Control work and maintenance in the area of lines from check valves to instrument racks.

• A standing ~ Radiation Hork Permit will be prepared to allow operations personnel to isolate root valves if required by a line break

' downstream of.the check valve.

• Operations personnel will conduct tours each watch to inspect the '

affected lines for leakage.

Given the evidence of the ability of the orifice and check valve combination

, to meet the safety requirements described in the FSAR, and the compensatory measures discussed above, we believe there is no adverse impact to the public health and safety by continued operation until the scheduled outage.

Continued operation is the better~ course of action than subjecting the plant to an unnecessary shutdown.

Please do not hesitate to contact me if you have questions or comments

- regarding this request.

A' u K. L. Highft1F, Acting Senior Vice President - Nuclear l

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Page 4 l c Boston Edison Company Docket No. 50-293 _;

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Pilgrim Nuclear Power Station License No. DPR-35

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i cc: Mr. Hilliam Russell, Regional Administrator l U.S. Nuclear Regulatory Comission 475 AllenCale Road  :

King of Prussia, PA 19406  :

Mr. William Kane, Director  !

Division of Reactor Projects U.S. Nuclear Regulatory Comission 475 Allendale Road ,

King of Prussia, PA 19406  ;

I Hr. Jon Johnson, Branch Chief Division of Reactor Projects  ;

U.S. Nuclear Regulatory Comission l 475 Allendale Road j King of Prussia, PA 19406 Mr. Richard Hessman, Project Director [

Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation '

Mail Stop: 1401 -

U. S. Nuclear Regulatory Comission One White Flint North ,

11555 Rockville Pike Rockville, MD 02852 Mr. M. Fairtile, Project Manager Division of Reactor Projects - I/II -

L Office of Nuclear Reactor Regulation i:

Mail Stop: 1401 l

? U. S. Nuclear Regulatory Comission One White Flint North io 11555 Rockville Pike-1 Rockville, MD 02852 ,

Senior liRC Resident Inspector - Pilgrim Nuclear Power Station l l:

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