ML20024J188
| ML20024J188 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 09/29/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20024J187 | List: |
| References | |
| NUDOCS 9410110214 | |
| Download: ML20024J188 (3) | |
Text
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/pQ QtC UNITED STATES y-7 J.L/
E NUCLEAR REGULATORY COMMISSION 5
'E WASHINGTON, D.C. 20 2 5-0001 gv/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.154 AND 158 TO
_FfCILITY OPERATING LICENSE NOS. DPR-24 AND DPR-27 WISCONSIN ELECTRIC POWER COMPANY POINT BEACH NUCLEAR PLANT. UNIT NOS. 1 AND 2 DOCKET NOS. 50-266 AND 50-301
1.0 INTRODUCTION
By letter dated July 18, 1994, Wisconsin Electric Power Company, the licensee, proposed to modify the Point Beach Nuclear Plant (PBNP), Units 1 and 2, Technical Specifications (TSs) by adding an allowed outage time for one of the four connected station battery chargers and subsequent shutdown requirements.
Technical Specification 15.3.7.A.1.h requires a battery charger to be in operation to each of the four DC buses.
If this condition is not met, TSs state that the units be placed in the hot shutdown condition within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
The amendments add an allowed outage time of two hours to attempt to restore the inoperable battery charger to service or connect a spare battery charger to the affected DC bus.
2.0 BACKGROUND
The PBNP Final Safety Analysis Report (FSAR) contains the General Design Criteria (PBGDC) for the Auxiliary Electrical Systems.
Specifically, the 125V-DC system is covered in PBGDC-2, " Performance Standards," and PBGDC-39,
" Emergency Power." The PBGDC-2 specifies the design standards for systems and components essential for the prevention or mitigation of nuclear events which could cause undue risk to the public. The PBGDC-39 regt tres an emergency power source for engineered safety features and protect..; systems that is operable assuming a failure of a single active component.
The PBGDC-39 is met, in part, by the 125V-DC system.
The plant has four 125V-DC station batteries and four battery chargers with one swing battery and two swing battery chargers as back-ups.
The PBNP design allows for operation with one instrument bus out-of-service. Adequate redundancy for the loads 4
supplied by the instrument bus assures the initiation of proper protective actions, if a second instrument bus would fail.
Sufficient redundancy exists with an inoperable battery charger to meet the requirements of PBGDC-39, even i
if the entire instrument bus would become inoperable.
9410110214 940929 PDR ADOCK 05000266 P
. 3.0 EVALVATION The proposed amendment would add TS 15.3.7.B.1.j to the " Auxiliary Electrical Systems" requirements during power operation. The new section reads:
- j. One of the four connected battery chargers may be inoperable for a period not to exceed 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
If an operable battery I
charger is not connected to the affected DC distribution bus within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, the operating unit (s) shall be sequentially placed in hot shutdown within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> respectively, and placed in cold shutdown within the following 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
This issue was addressed in Regulatory Guide 1.93, " Availability of Electric l
Power Sources." The Regulatory Guide states, "If the available onsite DC supplies are one less than the LCO, power operation may continue for a period l
that should not exceed two hours.
If the affected DC supply is restored within these two hours, unrestricted operation may be resumed.
If not, the I
unit should be brought promptly to a controlled shutdown and to a cold shutdown state within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />." Also, according to Regulatory Guide 1.93, the regulatory positions for degraded levels should be incorporated in the Technical Specifications.
For PBNP, having one of the four connected battery chargers inoperable is essentially equivalent to having available onsite DC supplies one less than the LCO.
Therefore, the proposed change follows the regulatory guide.
The proposed changes are consistent with NUREG-1431, "WOG Improved Standard Technical Specifications," Revision 0.
In the improved Standard Technical Specifications (STS), the allowed outage time is two hours.
If operability is l
I not restored in the two hours, prepare the plant for "an orderly and safe unit shutdown." Also in the improved STS, the unit must be brought to at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to cold shutdown within the following 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
The proposed amendment is consistent with the improved STS with the exception of allowing the units to stagger the unit shutdowns by three hours.
(Having one of the connected battery chargers inoperable would affect both units, and if not restored to operability would require both units to shutdown.) The two different time limits to hot shutdown would allow plant operators to stagger major evolutions.
The staggered shutdown times help achieve the " orderly and safe unit shutdown" stated in the improved STS.
The proposed change would allow time to restore the inoperable battery charger to service, or to connect an operable battery charger, thereby possibly preventing unit (s) shutdown.
As stated in the NRC enforcement policy and modified in 58 FR 14309, the shutdown of the operating units could place them through unnecessary transients and increase the probability of initiating an event, which would challenge the engineered safety features of the reactor protection system.
Therefore, the two-hour allowed outage time is consistent with the NRC enforcement policy.
i
, The proposed amendments follow Regulatory Guide 1.93, and are consistent with the intent of the improved STS and the NRC enforcement policy. Therefore, the staff finds the changes acceptable.
The proposed changes to the basis of TS 15.3.7 are consistent with and support the above changes. Therefore, the staff finds them acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Wisconsin State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has i
determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent 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 (59 FR 42348). Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth ir,10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment i
need be prepared in connection with the issuance of this amendment.
l
6.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
G. Dentel Date: September 29, 1994 m
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