ML20247C747
| ML20247C747 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/07/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247C740 | List: |
| References | |
| NUDOCS 8909140095 | |
| Download: ML20247C747 (3) | |
Text
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' SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 4,
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RELATED TO AMENDMENT NOS.123 ' AND ' 107 TO
.e, FACILITY OPERATING LICENSE' N05. NPF-4 AND NPF-7 VIRGINIA ELECTRIC AND POWER ~ COMPANY
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OLD DOMINION ELECTRIC COOPERATIVE
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NORTH ANNA POWER STATION, UNITS NO.1 AND NO. 2 DOCKET NOS. 50-338 AND 50-339 INTRODUCTION By letter dated July 12, 1989, as supplemented July 26, 1989,'the Virginia-Electric and' Power Company '(the' 11censee) proposed a. change to-the Technical S
ifications (TS) for the North Anna Power Station, Units No. l'and No. 2
~(pecNA-1&2). The proposed changes would revise the NA-1&2 TS 3/4 3.2.1 and the TS
' definition of slave relay testing and clarify the testing requirements for selected Engineered Safeguards Features (ESF) slave relays. The proposed ~
changes ~ would also add a requirement to test the selected ESF system slave relays = on a quarterly test frequency.
This change is consistent with the
-latest revision of the. Westinghouse TS. A minor revision was also made to the
- notation for manual initiation to re:nove the redundant listing for. testing all circuitry other than the manual switch every other 31 days.
The requirement to test the manual initiation switch at refueling and all other circuitry every other 31 days' remains unchanged.
These criteria were esteolished following an extensive evaluation by the iicensee cf the captidlity of NA-la? to perform online testing of slave relays.
l The evaluation referenced the material sAmitted to the NRC dated May 8,1989, and (1s0 included a technical dr.sesavnt and failure analysis of the installed hardware that would be used for testing and relays.
In addition, the system i
ef fects, operational impact, and safety significance of testir,g these relays i
were evaluated.
Based on the results of this evaluation, the licensee determined L
thai, the additional assurance of equipnent operability provided by testing all L
t% relsys online woeld be negated by the adverse consequences such that the D
Wera11 margin of safety would be reduced.
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The testing of some slave relays online would require significant plant manipu-lations, abnormal configurations, and remove from service various equipment for the duration of the relay test.
By imposing off-normal plant manipulations and configurations, there exists some increased probability of human error or component malfunction which may lead to more significant events.
In addition, the time to complete this type of testing is expected to take several 8-hour shifts, if not more.
For example, the testing of one relay would take over 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to perform.
If an actual demand was required during this time, some equipment would not be available to perform its intended safety function.
The
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safety implications of this are significant when considering that a single failure on the opposite train could result in a total loss of an ESF safety function. This could also lead to a more safety significant event and could cause the NA-1&2 design basis and accident analysis to be exceeded.
Finally, the licensee concluded that the additional risk in testing all the slave relays online is not justified by the failure analysis, operational impact, and safety significance since there presently exists adequate design features, sufficient, safe, and proven testing methods, and administrative i
controls to assure proper equipment operation.
DISCUSSION The subject amendment addresses only the change regarding the licensee's request for testing selected ESF protection system slave relays on a quarterly test frequency.
Other changes requested in the licensee's July 12, 1989 submittal, as supplemented July 26, 1989, will be addressed at a later date.
The present NA-1&2 TS 3/4 3.2.1 requires that on-line testing of ESF slave relays be conducted on a monthly basis by inclusion in the Channel Functional Test. The licensee would revise the NA-1&2 TS 3/4 3.2.1 to specify that on-line testing of selected ESF relays be revised fron monthly to quarterly.
The staff finds the selected relays to be tested on a quarterly basit to be acceptable at this time.
In addition, reasontble assarance is previhd that the relays will function as recuired when changing the testing intervai from monthly to querterly.
If any ESF equiptaent fails to actuate cue to a malfunction or failure of a slave relay or its contacts, adequate tenting, da.;igr, and adainhtrathe controls exist to ensure that the equipment can operate when required.
The majority of all ESF equipnent (pumps, valves, etc.) is tested at least quarterly by the NA-1&2 TS and the NA-1&2 Inservice Inspection Program.
Those components that cannot be tested at power are tested during' shutdown.
These tests verify equipmert operability as well as the operability of the manual actuation circuitry. The manual actuation circuitry was designed such that a failure of the slave or auxiliary relay contacts will not prevent the equipment from being manually actuated.
Therefore, if a relay or contact fails, manual operation is still available.
Immediate Actions described in the Emergency Operating Procedures ensure that all equipment actuates by requiring a manual actuation for equipment which may not automatically operate.
Major equipment is verified immediately while verification of all equipment takes approximately 5 minutes to perform.
Therefore, the reliability of ESF equipment to perform its safety function remains high and is acceptable.
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EVALUATION The proposed change for testing on a quarterly basis is in accordance with NUREG-0452, Revision 4, Standard Technical Specifications for Westinghouse Pressurized Watt.r Reactors and NRC Regulatory Guide 1.22, " Periodic Testing of Protection System Actuation System." Also, a recent Westinghouse study:
" Evaluation of Surveillance Frequencies and Out of Service Times for the Engineered Safety Features Actuation System," (WCAP-10271-P-A, Supplement 2, Revision 1) which supports quarterly testing of slave relays includes an NRC
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Safety Evaluation Report which endorses the quarterly test frequency for ESF slave relay testing.
Finally, the changing of the test frequency from monthly to a quarterly basis is consistent with the NRC Policy issued October 26, 1988 (Secy 88-304), " Staff Actions To Reduce Testing at Power" wherein the stated objective is to reduce or eliminate testing at power for equipment where acceptable reliability can be achieved without testing.
Based on all of the above, the staff finds quarterly testing of NA-1&2 selected ESF slave relays to be acceptable.
ENVIRONMENTAL CONSIDERATION These amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to surveillance requirements. The staff has determined that the amend-ments involve 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 amendments involve no significant hazards consideration and there has been no public comment on such finding.
Accordingly, the amendments meet the eligibility criteria for cate Pursuant to 10 CFR 651.22(gorical exclusion set forth in 10 CFR SS1422(c)(9).b), no envimn ment need be prepared fr, connection with the isruance of the amendments.
CONCt.USION We have concluded, bv.ed on the considerations discussed above, that (1) there is reasonable asstrance tnat thu health and safety ot the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in ecmpliance with the Commission's regulations, and the issuance of the amendments will not be inimical to the cormon defense and security or to the health and safety of the public.
Date: September 7, 1989 Principal Contributor:
Leon Engle O