ML20245C836
| ML20245C836 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/29/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20245C835 | List: |
| References | |
| NUDOCS 8711040040 | |
| Download: ML20245C836 (5) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMEN 0 MENT TO OPERATING LICENSE'DPR-35 BOSTON EDIS0N COMPANY PILGRIM NUCLEAR POWER STATION, UNIT 1 l
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DOCKET NO. 50-293 1.0' INTRODUCTION i.
By application dated May 22, 1987, BostonEdisonCompany(thelicensee) requested.
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an amendment to the technical specifications for Facility Operating License No.
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L DPR-35-for Pilgrim Nuclear Power Station, Unit 1.
The amendment reflects the-j L
following changes to the: functional description and trip setpoints for under-l l
l voltage instrumentation on" safety related buses:
a.
Periodic verification of one of two trip setpoints has.been k
deleted for startup transformer loss of voltage;
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Descriptions have been changed for the startup transformer loss l
I of voltage, startup transformer. degraded voltage, and 4160 volt buses A5 and A6 degraded voltage annunciation; and c.
The trip setting tolerances have been changed for degraded voltage annunciation and startup transformer loss of voltage.
2.0 EVALUATION I
I The Pilgrim technical specifications currently require that the startup trans-former loss of voltage relays must be calibrated once per operating cycle at two voltage points, i.e., 0 volts at 1.1 seconds time delay and 3094 volts with 18 seconds time delay. The proposed change deletes the requirement that these relays be calibrated at 3094 volts with 18 seconds time delay.
In justification I
of this change, the licensee indicated that in 1977 the NRC required additional 1
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- undervoltage devices be installed to provide improved degraded' voltage protection.
These. additional devices have been installed at Pilgrim, are calibrated once per
.j operating cycle, and provide a, higher and faster trip. level setting (3745 volts j
with 9.2 seconds time delay versus 3094 volts with 18 seconds time delay) for degraded voltage protection. With the installation of these additional under-voltage devices, the degraded voltage functional safety requirement for the startup transformer loss of voltage relays was made unnecessary and has,-thus, been removed by the proposed change to the Pilgrim technical specifications.
Based on the above, the staff agrees that calibration at 3094 volts with 18 seconds time delay was made unnecessary and concludes that its removal from the l
technical specifications provides clarification, is consistent with the NRC r
Standard Technical Specifications, and is acceptable.
i The licensee has also. proposed a revised functional description for undervoltage
.l instrument channels associated with startup transformer loss of voltage, start-up transformer degraded voltage, and buses AS and A6 degraded voltage annuncia-tion. The licensee, in justification, indicated that specific identification of i
components in the undervoltage instrument channels is provided in procedures.
Listing of relays but not timers in the functional description led to questions i
regarding testing of timers.
Specific reference to relays has, thus, been de-leted from the technical specification.
Periodic surveillance of relays has not changed and remains as part of procedure.
The staff agrees that specific refer-j ence to all components in the undervoltage instrument channels (i.e., relays, l
timers, cables, and potential transformers) should be included in test pro-cedures and need not be specifically referenced in the technical specifications.
I The staff concludes that the proposed revised functional descriptions provide clarification, are consistent with NRC Standard Technical Specifications, and l
are therefore, acceptable.
The remaining changes, described below, involve greater calibration tolerances for the time delay trip setting.
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'i For startup transformer loss of voltage, the time delay sett.ing has been changed.
from 0 volts with 1.1 seconds to 0 volts with 1.1 to 1.2' seconds time delay.
The licensee in justification indicated that the revised trip level setting in-cludes a 0.1 second tolerance and defines the acceptable accuracy required for l
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this electro-mechanical relay. The staff concludes that this increased calibra-tion tolerance of 0.1 second does not constitute a significant reduction in the,
margin of safety, is consistent with NRC standard technical specifications, and is, therefore, acceptable.
For emergency 4160 volt buses A5 and A6 degraded voltage annunciation, the tir,e delay setting has been changed from 9.2 0.0092 seconds to 9.2 t 0.5 seconds.
The licensee, in justification, indicated that the degraded voltage alarm timers t
are of the same type and accuracy as those used for safety related degraded voltage trip which have a 9.210.5 second time delay setting for trip. These timers provide a similar but non-safety related alarm actuation function. There-c
. fore, the trip and alarm instrument timers should have the same specification and tolerances. The existing degraded voltage alarm channel setting tolerance is 1
overly conservative and is, thus, being revised. Based on the.above, the staff agrees and finds the greater calibration tolerance acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The f
staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously published a proposed finding that the amendment involves no significant 0
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hazards' consideration and there h~as been no public connent on.such finding..
Accordingly, the amendment meets the el8qibility tyjterialfor cated6Pical///
.a exclusion set:forth in'10 CFR 151.22(c)p). Purs(Mt to 10 CFR 151.22(b), no environmental' impact statement or environmental' apsessment.need be prepared'in connectionwiththe.issuanceoftheamendment.,l//
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4.0 CONCLUSION
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'We have concluded, based'on the consideration discussed al%/e, that (11 there
-is reasonable assurance-that the health and safety of the public will not be
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. endangered by ~operatihn in the proposed manner, and (2) such act'$ities will be conducted in compliance with the Commission's regulations, and the issuance
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of this amendwent'will not be inimical to the. common defense and security or 4
to the health and safety.of the public.
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- Prigcip'al Contributor:
J. Knox.
Dated:
October 29, 1987
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