ML20213E508
| ML20213E508 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 08/02/1983 |
| From: | Houston R Office of Nuclear Reactor Regulation |
| To: | Novak T Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0620, CON-WNP-620 NUDOCS 8308100422 | |
| Download: ML20213E508 (4) | |
Text
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.D,ccAeb I3 b SC - 3<j 7 gjG 2 1963 fiEriORANDU!! FOR:
Thomas M. Novak, Assistant Director for Licensing Division of Licensing FROM:
R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration SUdJECT:
TEClitiICAL SPECIFICATI0fiS FOR WNP-2 Plant f4a.me: Washington i;uclear, Unit 2 Docket No.: 50-397 Licensing Stage: OL DESIG:n ID ORIGIUAL Project Manager:
R. Auluck
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Review Branch:
ICS3 Certified 37 v
Review Status:
Incomplete
/
A i.:emorandum to the HRR Branch Chiefs from Cecil 0. Thoinas dated July 1, 19G3 requesteo a review of the technical specifications for Washington fluclear Unit 2.
From its review the Instrumentation and Control Systens Branch (ICSS) has found deficiencies in the metnod used to establish the protection systen trip setpoints and allowable values contained in the technical specifications.
Further, the Washington Puolic Power Supply Systen (the applicant) has been unable to demonstrata the acceptability of the aetnodology used to combine and account for instru:nent channel errors in establishing the trip setpoints and allowable values that appear in the proposed technical specifications.
Assuming that an operating license will be issued in September our plan of action to resolve these concerns is to: (1) request that the applicant correct known deficiencies in the technical specifica-tions trip setpoints and allowable values prior to OL 1:suance, and (2) condition the license to require a sucaittal which wiil include a discussion on the setpoint nethodology with justification for eacn assumption.
Accordingly, as Enclosure 1 we are providing a request for additional information and as Enclosure 2 we are providing a proposed license condition. We request that you forward the enclosures to the applicant as soon as possiole.
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ENCLOSURE 1 RE0 VEST FOR ADDITIONAL INFORMATION As proposed, the Washington Nuclear Unit 2 Technical Specifications con-tain trip setpoints and allowable values for the protection systems that were obtained by applying the NSSS Vendor's setpoint methodology.
For Washington Nuclear Unit 2 the trip setpoints are derived from the allowable values by taking into account sensor drift and trip unit drift.
The staff finds this methodology for establishing the trip setpoints and allowable values unacceptable.
The purpose of establishing allowable values in the technical specifications was to account for the drift of that portion of the instrument channel that is surveillance tested at 31 day intervals.
The allowable values included in tne Washington Nuclear Unit 2 Technical Speci-fications will permit excess channel electronics drift to be hidden by the allowan:e for sensor drift for those channels where the measurement of sen-sor drift is not included in the 31 day surveillance test.
Therefore, the staff requests that you provide revised technical specification allowable values for those channels assumed to operate in the transient and accident analyses that includes only the drift assumed to occur over a 31 day period for that portion of the channel tested every 31 days.
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ENCLOSURE 2 PROPOSED LICENSE CONDITION Within six months following the issuance of this operating license a detailed summary discussion shall be provided on the methods used to establish the trip setpoints and allowable values for the protection system channels assumed to operate in the transient and accident analy-ses.
This discussion shall include the following:
(1) the values assigned to each component of the combined channel error allowance (e.g., modeling uncertainties, analytical un-certainties, transient overshoot, response times, trip unit setting accuracy, sensor setting accuracy, test equipment accuracy, sensor drift, nominal and harsh environmental allowances, trip unit drift), the basis for these values, and the methods used to sum the individual errors.
Where zero is assumed for an error a justification that the error is negligible shall be provided.
(2) Confirmation that the setpoints selected for the initiation of protective actions ensure that the reactor core and reactor coolant system are prevented from exceeding the licensing safety limits for the transients and accidents analyzed, pr?O Ctrt