ML20216C798
| ML20216C798 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/09/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20216C791 | List: |
| References | |
| NUDOCS 9804150042 | |
| Download: ML20216C798 (3) | |
Text
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WASHINGTON, D.C. 20666 0001
$9.....,o SbFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 5 6 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION UNIT NO.1 DOCKET NO. 50-443
1.0 INTRODUCTION
Py application dated September 26,1997, as supplemented by letter dated March 12,1998, North Atlantic Energy Service Corporation (the licensee) proposed an amendment to the Appendix A
' Technical Specifications (TSs) for the Seabrook Station, Unit 1 (Seabrook). The existing TS 3/4.7.6,
" Control Room Emergency Makeup Air and Filtration Subsystem," requires that each subsystem of control room emergency makeup air and filtration system include an operable emergency makeup air and filtration unit and an operable air conditioning unit. The proposed amendment would separate the TS 3/4.7.6 limiting condition for operation (LCO) and surveillance requirements (SR) for the control room emergency makeup air and filtration subsystem (CREMAFS) and the control room air conditioning subsystem (CRACS) based on system function. Additionally, the proposed amendment would increase the allowed outage time (AOT) for the CRACS from 7 days to 30 days. The supplementalletter provides clarifying information within the scope of the original application and did not change the staff's initial proposed no significant hazards determination.
2.0 DISCUSSION The control room heating, ventilation, and air conditioning (HVAC) system includes, among other subsystems for normal and emergency conditions, the CRACS and the CREMAFS. The CREMAFS is required to remove particulate and gaseous radioactivity from the control room atmosphere following an event which involves core damage and subsequent release of radioactive material. The CRACS is required for control room habitability and for maintaining the appropriate environment for equipment in the area. The HVAC system for the control room is classified as a safety related system and is supplied from Train A and Train B emergency buses that are backed by the respective emergency diesel generators.
LCO 3.7.6 requires two independent CREMAFS io ou operable in all operational modes. SR 4.7.6.a requires verification that the control room is mrdntained below the limiting equipment qualification temperature in the control room area. Thus, the current TS 3/4.7.6 is considered to include the combined functions of emergency makeup air and filtration and the control room air conditioning.
North Atlantic asserts correctly that as currently written, LCO 3.7.6 could require a plant shutdown due to unrelated failures in opposite trains of the air conditioning and makeup air and filtration subsystems.
In such a scenario, one train of air conditioning and one train of makeup air and filtration could be 9804150042 980409 PDR ADOCK 05000443 l
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2-provided in ead subsystem. However, shutdown would be required per TS 3.0.3 because neither train would have both subsystems operable. Additionally, the current LCO Allowed Outage Time (AOT) of
- seven days restricts the ability of Seabrook Station to perform scheduled preventive maintenance and normally occurring corrective maintenance. This restriction could result in the shutdown of the unit due to the loss of both air conditioning units.
3.0 EVALUATION The existing TS 3/4.7.6 combines the LCO and SR for the CREMAFS and CRACS, treating them as a combined subsystem. The proposed amendment would establish separate LCO and SRs for each subsystem based on system function. The requirements for the CREMAFS would be contained in LCO 3.7.6.1 and SR 4.7.6.1. The requirements for the CRACS would be contained in LCO 3.7.6.2 and SR 4.7.6.2.
The proposed amendment does not alter any of the LCO or SRs requirements applicable to the CREMAFS established in the existing TSs.
SR 4.7.6.a establishes the existing testing requirements for the GRACS. The proposed amendment
. would remove SR 4.7.6.a and establish a new SR 4.7.6.2 for the testing of the CRACS. The existing SR 4.7.6.a requires that at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> the CRACS shall be demonstrated operable by verifying that the control room is maintained below the limiting equipment qualification temperature in the control room area. The proposed amendment would eliminate this requirement and in its place establish a new SR 4.7.6.2 to require that each CRACS shall be demonstrated operable each quarter by verifying the ability to maintain temperature in the control room area below the limiting equipment qualification temperature for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The 24-hour surveillance run would represent typical load variations based on the normal daily fluctuations in outdoor temperature. SR 4.710 requires that the control room temperature be verified less than 75 F every 12-hours. The actions specified in LCO 3.7.10, should the temperature exceed the limit, are more restrictive than the actions contained in the existing LCO 3.7.6. Therefore, it is determined that the 12-hour temperature verification per SR 4.7.6.a is redundant and unnecessary.
The proposed amendment would also increase the AOT for the CRACS from 7 days to 30 days.
Controlling the temperature in the control room is achieved primarily by the CRACS. The system is conservatively sized to handle the worst heat load condition postulated based on normal conditions, accident conditions, and conservative meteorology. Temperature changes in the control room are gradual even under degraded conditions. Time is available to find attemate sources to cool the control room. If altemate cooling methods are not effective, the plant can be shu=down from the Remote Safe
' Shutdown Panel. A 30-day AOT is reasonable for a system whose full capability may not be required at certain times of the year for any postulated design basis accident, whose complete failure will not have an immediate, irreversible impact, and whose function can possibly be restored or mitigated by plant staff actions. The proposed surveillance requirement for the CRACS would reqtire that each.
subsystem be demonstrated operable on a quarterly basis by verifying the systems e,ooling capability to maintain the control room environment below the equipment temperature limit for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The separation of the TS requirements for CREMAFS and CRACS based on system function is consistent with NUREG-1431, " Standard Technical Specifications Westinghouse Plants," Revision 1.
The AOT of 30 days for the CRACS is also consistent with NUREG-1431. The surveillance
. requirements proposed by the licensee differ from those listed in NUREG-1431, but are acceptable.
The NUREG-1431 surveillance requirements require testing every 18 months, and the licensee has proposed a quarterly test schedule.
In consideration of the foregoing, the changes are acceptable.
4.0 STATE CONSULTATION
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.
5.0 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 and changes a surveillance requirement.
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,-
rnd there has been no public comment on such finding (62 FR 54874). 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.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the
_ proposed manner, (2) such activities will be condea.:in compliance with the Commission's regulations, and (3) the issuance of the amendment wG not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Craig W. Smith Date:A p ri l.9, 1998 t
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