ML20117F869
| ML20117F869 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 08/30/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20117F867 | List: |
| References | |
| NUDOCS 9609040286 | |
| Download: ML20117F869 (5) | |
Text
4 Kr4 9
k UNITED STATES y
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3 NUCLEAR REGULATORY COMMISSION f.
WASHINGTON, D.C. 20066-4001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 48 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION. UNIT NO. 1 DOCKET NO. 50-443
1.0 INTRODUCTION
By application dated June 20, 1996, North Atlantic Energy Service Corporation (North Atlantic /the licensee) has proposed an amendment to the Appendix A Technical Specifications (TSs) for the Seabrook Station, Unit 1 (Seabrook)
Electrical Power Systems, Onsite Power Distribution. Currently, TS 3.8.3.1 Limiting Condition for Operation (LCO) requires, in part, two trains (Train A and Train B) of A.C. Emergency Busses to be energized.
TS 3.8.3.1, ACTION a.,
allows one of the required trains of A.C. emergency busses to be not fully energized for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
If the bus cannot be fully energized within that time, ACTION a. requires the unit to be in 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 in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
To be operable, the trains of the Emergency Busses are required to be fully energized as follows:
Train A:
q 1) 4160-volt Emergency Bus #E5, i
-2) 480-volt Emergency Bus #51, and
- 3) 480-volt Emergency Bus #52.
Train B:
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- 1) 4160-volt Emergency Bus #E6, 2)' 480-volt Emergency Bus #61,
- 3) 480-volt Emergency Bus #62, and
- 4) 480-volt Emergency Bus #E64.
The~ proposed amendment would modify TS 3.8.3.1, ACTION a., to increase from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 7 days the allowable time that Train B 480-volt Emergency Bus #E64 may be less. than fully energized. The allowable outage times for the remaining busses of Train B and all busses of Train A would not be changed by the proposed amendment. The proposed amendment would change ACTION a. to state:
With one of the required trains of A.C. emergency busses (except 480-a.
volt Emergency Bus #E64) not fully energized, reenergize the 9609040286 960830 PDR ADOCK 05000443 P
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train within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
1.
With 480-volt Emergency bus #E64 not fully energized, re-energize the bus within 7 days or be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
2.0 DISCUSSION North Atlantic has proposed to revise the Seabrook Station, Unit No. 1, Appendix A, Technical Specifications to change the action required for Bus
- E64 (including Unit Substation US-E64) being inoperable to be equivalent to the action required for one service water cooling tower loop being inoperable.
Specifically, this would increase the allowed outage time for Bus #E64 to 7 days before further action is required. North Atlantic has proposed this l
change at this time because US-E64 is exhibiting signs of degradation as l
evidenced by unusual odors and increased noise level. North Atlantic plans to q
l inspect US-E64 and perform necessary corrective maintenance.
North Atlantic asserts, however, that the inspection and possible corrective maintenance 4
cannot be performed within the current 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> allowed outage time.
North Atlantic's basis for the proposed change is that Bus #E64 only supplies power to components associated with the Train B service water cooling tower loop and therefore the allowed outage time for Bus #E64 should be equivalent l
to the allowed outage time for the loads it powers.
North Atlantic notes that unlike the other 480 y electrical busses, which supply electrical power to several different Train B safety-related systems, Bus #E64 supplies electrical power to components which are only associated with the Train B service water cooling tower loop. The components which i
receive power from Bus #E64 are listed Table 1.
North Atlantic notes, further' that Technical Specification 3.7.4, Service Water System / Ultimate Heat Sink, Action b.,
allows one service water cooling tower loop to be inoperable for up to 7 days. Thus, North Atlantic asserts that the existing Action requirement for Bus #E64 being inoperable is overly restrictive and inconsistent with the Action requirement for one service water cooling tower l
i loop being inoperable.
Technical Specification 3.8.3.2, Onsite Power Distribution - Shutdown,
_ recognizes that Bus #E64 supplies electrical power to only Train B service water cooling tower loop components because Bus #E64 is explicitly excluded from the Limiting Condition for Operation. Technical Specification 3.8.3.2 is applicable in Modes 5 and 6; in these Modes there is no requirement for the 4
Service Water System to be operable.
l 3.0 EVALUATION
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The Seabrook Service Water System consists of two independent trains, Train A and Train B.
Each train can accomplish its safety function with either a service water ocean loop or a service water cooling tower pump loop.
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' Each service water ocean loop consists of a service water pump and the piping, valves, and other components necessary to provide a flow path for heat removal.
Each service water cooling tower loop consists of a service water cooling tower pump, and the necessary piping, valves and other components required to provide its flow path. The ultimate heat sink for the service water ocean loop is the Atlantic Ocean; the ultimate heat sink for the service water cooling tower loop is a mechanical draft cooling tower.
l Bus #E64 supplies electrical power to components associated with service water i
cooling tower loop Train B only, the inoperability of Bus #E64, including US-E64, does not affect any of the components associated with Train B service water ocean loop nor does it affect any Train A components. Thus, even if Bus
- E64 is inoperable, the Train B service water ocean loop remains operable and capable of providing cooling during normal and accident conditions in addition to the Train A service water ocean and service water cooling tower loops.
Maintaining the operability of Train A and Train B emergency and vital busses ensures that the emergency safety features redundancy incorporated into the design is not defeated, and a single failure within any system or within the electrical power distribution subsystems will not prevent safe shutdown of the reacto.'.
Since Bus #E64 serves only the Train B service water cooling tower loop, and since the allowed outage time is 7 days for the Train B service water cooling tower loop (TS 3.7.4), North Atlantic's proposed change to tiie action requirement would have no effect upon redundancy and single-failure issues, i.e., the result would be the same whether Bus #E64 or the service water cooling tower loop were inoperable. Thus, the proposed change to l
increase the allowed outage time for Bus #E64 to be equivalent with the allowed outage time for an inoperable service water cooling tower loop would make no reduction in the availability of the Service Water System to perform its intended safety function beyond that which is already permitted by the technical specifications.
Furthermore, the capability of the Service Water System to perform its function would not be affected.
The staff has reviewed North Atlantic's proposed change to TS 3.8.3.1, Action a., to increase from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 7 days the allowable time that 480-volt Emergency Bus #E64 may be less than fully energized. The staff concludes that because the proposed change would not have any effect upon redundancy and single failure issues, and would not reduce the Service Water System
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availability beyond that now permitted, the proposed change is acceptable,
3.0 STATE CONSULTATION
4 In accordance with the Commission's regulations, the New Hampshire and Massachusetts State officials were notified of the. proposed issuance of the amendment. The State officials had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC 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 issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (61 FR 33142). Accordingly, the 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 the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the i
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 the amendment will not be inimical to the common 1
defense and security or to the health and safety of the public, i
ATTACHMENT:
Table 1 1
Principal Contributor: Albert W. De Agazio Date: August 30, 1996 i
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i TABLE 1 480V UNIT SUBSTATION 1-EDE-US-64 LOADS 9
2 US-E64 4
SERVICE WATER COOLING TOWER FAN 1-SW-FN-51B 4
SERVICE WATER COOLING TOWER FAN 2-SW-FN-518 460V MCC-E641 MOTOR CONTROL CENTER 1-EDE-MCC-641 LOADS MCC-E641 i
SW SYSTEM PROCESS HEAT TRACING DISTR. PNL. HT-CP-429 COOLING TOWER SW PUMP 110B TEST / BYPASS VLV. SW-V26 COOLING TOWER SW PUMP 110B DISCHARGE VLV. SW-V25 J
COOLING TOWER FAN 51B GEAR REDUCER IMMERSION HEATER SW-H-678 COOLING TOWER FAN 2-51B GEAR REDUCER IMMERSION HEATER 2-SW-H-678 j
COOLING TOWER SPRAY BYPASS RECIRC VLV SW-V140 COOLING TOWER SW PUMP 110B TEST RECIRC VLV SW-V27 COOLING TOWER SWGR RM TRAIN B SUPPLY FAN SWA-FN-63 4
COOLING TOWER SWGR RM TRAIN B EXHAUST FAN SWA-FN-70 COOLING TOWER SWGR RM TRAIN B HEATER SWA-UH-114 COOLING TOWER SWGR RM TRAIN B HEATER SWA-UH-115 480-120/240V XFMR FOR 12 CIRCUIT DISTR. PNL.
l HT-CP-429 I
COOLING TOWER PUMP DISCHARGE NORMAL SYSTEM HEATER HT-H-301A 3,
COOLING TOWER PUMP DISCHARGE BACKUP SYSTEM HEATER HT-H-301B COOLING TOWER SPRAY BYPASS HEADER NORMAL SYSTEM HEATER HT-H-302A COOLING TOWER SPRAY BYPASS HEADER BACKUP SYSTEM HEATER HT-H-302B EDE-MCC-641 i
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MOTOR HEATERS:
1-SW-V140-HTR 1-SW-V26-HTR 1-SW-V25-HTR 1-SW-V27-HTR 1-SWA-FN-63-HTR 1-SWA-FN-70-HTR 1-SW-FN-51B-HTR 2-SW-FN-518-HTR SPACE HEATERS:
1-EDE-US-64-HTR 1-EDE-MCC-641-HTR shunt trip coil for heat tracing panel (ht-cp-429)
NOTE: Allloads are Train B only r