W3P90-1314, Requests NRC Concurrence That Design/Controls/Testing to Minimize Potential for Common Header Blockage Acceptable Per 900510 Meeting.Tap Alternatives for Shutdown Cooling Level Indication Sys Discussed

Requests NRC Concurrence That Design/Controls/Testing to Minimize Potential for Common Header Blockage Acceptable Per 900510 Meeting.Tap Alternatives for Shutdown Cooling Level Indication Sys Discussed

ML20055C604
Person / Time
Site:	Waterford
Issue date:	05/21/1990
From:	Burski R LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
W3P90-1314, NUDOCS 9005290029
Download: ML20055C604 (2)

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L Inter-Office Correspondence W3P90-1314-

3. :A4.05 QA May.21, 1990 U.S. - Nuclear Regulatory Conaiission ATTN Document Control Desk Washington, D.C. 205'55

Subject:

Waterford.SES Unit 3

-Docket No.53-382 '

- Waterford'3 SDC Level Indication System Taps 4

Gentlemen 1This letter is written in follow-up to the May 10, 1990 meeting between the NRC'and Lp6L. As presented during the meeting, Waterferd 3 has evaluated tap alternatives for the new SDC level indication jstem, the Reactor Coolant Shutdown Level Measurement System (RCSLllS). - This system is scheduled to be installed during the March 1991 refueling

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outage. 'The' selected tap alternative' involves using the same: piping header on Hot Leg 1 that is used'by~ the existir.g level measurement system, the Refueling Water Level Indication System (RWLIS).

' Although both systems will use the same piping header with separate conacetion points, we have concluded that design and test'ing measures

.' minimize the potential for blockage.

The significant design. aspects of the system which minimize blockage o pocential are tha. large (two inch) diameter of the reactor coolant l'

. system drain line, which is used as the common header for the respective E ~~1evel monitoring systems,..and the vertical orientation of the line where it connects with - the' two 1cvel systees .

'Sevsral testing measures will be used to ensure no blockage of the

' common connection header. Pre-operational testing, which.will occur each time before the systems are brought into service, wili involve A

backfilling of the systems and then making level / alignment comparisons with the known' reactor coolant system (RCS) level. Acceptance criteria i'

wil'1 be included as part of the test (e.g. leve', response time).

During extended operation at constant reduced inventory level, additional Ltesting'will be conducted. To ensure the least impact on safety, the appropriate operating procedure will allow the operators some flexibility in choosing.a testing method. For instance, operators may choose to vary RCS. level and observe RCSLMS response or insert water at the RCSLMS test connection and observe the' response. We expect to identify other methods which,1following evaluation, may be included in procedures. Regardless of- the testing method employed, confirmation that common blockage does

nat exist willLoccur at least every'72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. [l)

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(Finally,TWaterfordL3_ procedures require a. dedicated re' actor: operator- .j

% 'on station 'tol continuously monitor. RCS level land temperature. . We-Q !anticipatel thatlthisioperator wil1 quickly.recognizeLblockage.'during

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? drain ldo'wn/up as, well .as recognizi any anomaly while, at part-l'oop; operation.  :

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,:As.; discussed?in'the.Mayr10, 1990 meeting and for: the; reasons indicatedi Labove,.; we; requ.est . written NRC. concurrence that' the deiign/ controls / testing ;

L minimite. potential' fo'rl common header blockage and are' acceptable under LCL.88-17. -

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% .lBecause-ofkthe'engineeringdesignandprocurement. lead. time'requiredto support!the. Marchi1991: refueling outage implementation, 'a response to this-i

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llettersisrequestedbyjJune 15, 1990.

' . ;Very trulylyours,:

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3 .. . p.-.A m ', R.F. Burski-h RFB/RWP/dc

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lR.D.5 Martin-W E.L.'Blake:-

1 iW.M.LStevenson?

.NRC Resident Inspectors Office

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