ML20249C642
| ML20249C642 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/24/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20249C641 | List: |
| References | |
| NUDOCS 9806300473 | |
| Download: ML20249C642 (2) | |
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a necy p
4 UNITED STATES y
j NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 20665 4 001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i
RELATED TO AMENDMENT N058 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION. UNIT NO.1 DOCKET NO. 50-443 i
1.0 INTRODUCTION
By letter dated March 2,1998, as supplemented by letter dated April 21,1998, North Atlantic Energy Service Corporation (the licensee) submitted a request for a change to the Seabrook Station Technical Specifications (TSs). The requested change would revise TS 4.5.2.b.1 for the emergency core cooling system (ECCS) subsystems to delete the requirement to vent the operating chemical volume and control system (CVCS) centrifugal charging pump (CCP) casing.
The supplemental letter provioed clarifying information within the scope of the original application and did not change the staff's initial proposed no significant hazards determination.
2.0 BACKGROUND
TS 4.5.2 describes the surveillance requirements necessary to demonstrate the operability of each ECCS subsystem. TS 4.5.2.b.1 requires, in part, that the ECCS piping be verified full of water each 31 days by venting the ECCS pump casings. In the ECCS mode of operation the CCPs receive an putomatic start signal and deliver flow to the reactor coolant system (RCS) at the prevailing RCS pressure. In licensee event report (LER) 98-001-00, the licensee reported that its previous practice of not venting the operating CCP was not in literal compliance with TS 4.5.2.b.1. The licensee has since revised its surveillance procedures to require venting of the operating CCP by aligning the CCP's minimum flow recirculation valve to the top of the volume control tank (VCT). Though this is the high point in the system, this method of venting the operating CCP does not allow visual confirmation of the presence of air or gas in the fluid stream. Therefore, the proposed change would eliminate the requirement to vent the operating CCP.
3.0 EVALUATION The CCPs are described in the Seabrook Station updated final safety analysis report (UFSAR) as being high-head pumps of a multi-stage diffuser design with a barrel-type casing and vertical suction and discharge nozzles. The licensee stated in its submittal that the CCPs have no installed pump casing vents and that the design of the pump with top mounted suction and discharge nozzles make it unlikely that gasses of any significance would accumulate inside the pump casing while the pump is operating or when it is secured. Any gasses that may be introduced into the pump would not accumulate in the pump casing, but would be carried with the fluid flowinto the system. The licensee stated that opening a vent valve on piping under the dynamic conditions present on an operating CCP is ineffective for venting gasses due to the high 9806300473 990624 PDR ADOCK 05000443 P
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2-system operating pressure and flow rate. In addition, venting of piping under high system pressures poses a risk to personnel safety. The licensee has concluded that routine venting of the operating CCi' is unnecessary for verifying ECCS subsystem operability. Further, the licensee does not believe swapping the operating CCP every 31 days solely for the purpose of statically venting the CCP is justified based on the additional startup and shutdown cycles that would be imposed on the system.
The NRC staff has reviewed the licensee's submittal and the conclusions it has reached about eliminating the requirement for venting the operating CCP. The staff finds that the requirement is not necessary to ensure the quality of the ECCS system, facility operation within safety limits or to meet limiting conditions for operation. Therefore, the change is 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 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 Comm,ssion has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (63 FR 17225). 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 conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Craig W. Smith Date: June 24 :1998 f