ML20235J025
| ML20235J025 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/15/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20235H987 | List: |
| References | |
| NUDOCS 8902240134 | |
| Download: ML20235J025 (3) | |
Text
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yanQ M'
'c UNITE C, STATES
!4,, I;i NUCLEAR REGULATORY COMMISSION
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,, E W ASHINGTON. D. C. 20555
%.".u-l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 94 TO FACILITY OPERATING LICENSE NO. DPR-6 CONSUMERS POWER COMPANY BIG ROCK POINT PLANT DOCKET NO. 50-155
1.0 INTRODUCTION
By letter dated December 22, 1986, Consumers Power Company (the licensee) requested amendment to the Technical Specifications (TSs) appended to Facility Operating License No. DPR-6 for the Big Rock Point Plant..The proposed amendment would revise the station battery surveillance test time from the present eight-hour requirement to two hours.
2.0 DISCUSSION The licensee stated in the December 22, 1986, letter that Section 11.4.5.3.A.1(h) of the current TSs, containing a requirement to demonstrate the capability of the station battery to supply all emergency loads for eight hours, resulted erroneously from Amendment 10 dated June 1976.
Further, there was no basis identified for the eight-hour design time interval in the licensee's amendment request or the NRC staff's Safety Evaluation (SE) for Amendment 10.
In contrast, the licensee also stated that the. initial station battery service test (conducted in August 1977) determined that the station battery had adequate capacity to supply and maintain in an operable status all the emergency loads during a loss of coolant accident (LOCA) coincident with loss of offsite power for 61 minutes, which was consistent with design requirements.
Additionally, during the review of the Systematic Evaluation Program (SEP)
Topic VIII-3. A, the acceptance criterion for the Big Rock Point Plant station battery service test was two hours.
To resolve the contradictions mentioned above and to meet the SEP Topic VIII-3.A criterion, the licensee has proposed the following two changes to the plant's Technical Specifications:
1.
In Specification 11.4.5.3.A.1(h), reduces the design time interval for the station battery from eight hours to two hours.
2.
In the last paragraph of the Bases on page 11-20, delete:
"The station battery has adequate capacity to carry normal loads plus an assumed failure (locked rotor current) of the de lube oil pump for 54 minutes l
without the battery charger and still provide sufficient power for equipment required to operate during a LOCA.
If steps are taken to reduce nonessential l
loads during a loss of offsite power (such as part of the emergency lights),
1 additional time (up to five hours) can be gained from the time of the loss of i
8902240134 890215 PDR ADOCK 05000153 P
l j
e 1
. the charger until the battery would no longer have sufficient power for equipment required to operate during a LOCA."
Substitute:
"The Station Battery has adequate capacity to supply and maintain in an operable status all of the emergency loads during a Loss of Coolant Accident (LOCA) plus an assumed Loss of AC Power for two hours."
3.0 EVALUATION l
As can be seen from proposed change 2., above, the proposed basis for the new two-hour battery capacity requirement is an assumed LOCA plus loss of all AC power for two hours.
To meet this new requirement, several loads (such as emergency lighting) have been removed form the station battery, and the original battery has been replaced by a larger one.
The new battery has been sized based on an assumed 121-minutes d-c load profile (submitted as Consumers Power Company, Nuclear Operations Department Engineering Analysis Work Sheet, EA-E-BRP-86-05A&B, and revised by the licensee's October 26, 1988, letter which included EA-SC 023-1) which includes valve actuations as a result of the assumed accident signals, miscellaneous breaker actuations due to load shedding, turbine lube oil pump and rod position M-G set running, miscellaneous alarms / indications, and breaker manipulations to return to off-site power during the 121st minute.
To determine the correct size for the station battery based on the assumed load profile, the licensee utilized the methodology contained in IEEE Standard 485-1978, "IEEE Recommended Practice for Sizing Large Lead Storage Batteries for Generating Stations and Substations." Continuous and momentary loads were included in the licensee's load profile development.
An aging factor of 125%
(corresponding to a battery replacement when its actual capacity drops to 80%
of its rated capacity as contained in the plant's battery Technical Specifications), a design margin of 10%, and a minimum allowable battery voltage of 105 volts (1.75 volts per cell) were used in the calculations.
The NRC staff has reviewed the battery sizing calculations and load profile submitted by the licensee.
Since the sizing methodology (IEEE Std. 485-1978) and the assumed two-hour scenario are consistent with current staff guidance and requirements, were find that the battery size is acceptable.
(It should be noted that this issue will be revisited during the NRC staff's plant-specific station black-out reviews.) Additionally, we find that the proposed changes to the plant's TSs are acceptable since they define and demonstrate the new two-hour scenario.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in a surveillance requirement.
We have 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 issued a proposed
finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
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5.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there l
is reasonable assurance that the health and safety of the public will not be I
endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: February 15, 1989 l
Principal Contributor:
F. Burrows I
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