ML20237C369
| ML20237C369 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 08/17/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20237C366 | List: |
| References | |
| NUDOCS 9808210118 | |
| Download: ML20237C369 (3) | |
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- '+,*****,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.127 TO FACILITY OPERATING LICENSE NO. NPF-30 UNION ELECTRIC COMPANY cat t AWAY PLANT. UNIT 1 DOCKET NO. 50-483
1.0 INTRODUCTION
By letter dated March 9,1998, as supplemented by letter dated July 8,1998, Union Electric Company (UE), requested changes to the Technical Specifications (Appendix A to Facility Operating License No. NPF-30) for the Callaway Plant, Unit 1. The proposed changes would revise Technical Specification Surveillance Requirement 3/4.5.2b.1 and its associated Bases to add clarification in regard to venting the emergency core cooling system (ECCS) pump casings and accessible discharge piping high points.
The July 8,1998, supplemental letter provided additional clarifying information and did not change the staff's original no significant hazards consideration determination or expand the scope of the original Federal Register notice published on May 6,1998 (63 FR 25118).
2.0 EVALUATION Technical Specification Surveillance Requirement 3/4.5.2b.1 requires verification that the ECCS piping is full of water at least once per 31 days by venting the ECCS pump casings, i.e., the safety injection (SI) pump, residual heat removal (RHR) pump and centrifugal charging pump (CCP) casings and accessible discharge piping high points. The associated Bases section states that this surveillance requirement ensures the pumps remain water filled and gas binding or water hammer in ECCS piping will not occur. The proposed changa to vent only the safety injection and residual heat removal pump casings is being requested since the CCP casings do not require venting and do not have installed casing vents.
The ECCS is designed to supply core cooling and negative reactivity to ensure the reactor is cooled and shut down following a postulated accident. The ECCS pumps include the high head safety injection pumps, or CCPs, the intermediate head safety injection pumps, or Si pumps, and the low head safety injection pumps, or RHR pumps. The Si and RHR pumps are designed with installed pump casing vents.
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The CCPs are eleven stage, multi-diffuser type pumps manufactured by Pacific Pumps with no l
installed pump casingvent. The CCPs are designed with top-mounted suction and discharge l.
nozzles. This design allows noncondensible gases in the pump to escape through the nozzles 9808210118 980817 PDR ADOCK 05000483 P
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and be effectively vented at a location on the discharge piping. The licensee has concluded, after consultation with the pump manufacturer, that the mechanical effects of starting the pumps with small quantities of gas will be insignificant.
In order to verify the CD pump casings are properly vented, the licensee has utilized flushing connections off of th side of discharge CCP piping. During the last quarter of 1997 the licensea installed new vent assemblies to the high point of the CCP discharge piping above the "A" and "B" CCP discharge nozzles. The licensee has concluded that venting at these new locations ensures the CCP casings will be completely vented from discharge piping high points and the venting will assure that no gas is left in the discharge line or pump. Only the pump discharge side of oiping is vented since the suction side piping to the CCPs is vented back to the normally running Normal Charging Pump. The license also verified that there are no l
relative high points in the pump suction and, as a result, gas will not form in the suction piping and become trapped.
The staff has reviewed the information provided by the licensee and the licensee conclusion that (1) the CCPs do not require casing vents and the mechanical effects of starting the pump with small amounts of gas are insignificant, (2) the installation and use of new discharge vents assure there is no gas in the pump or discharge piping, and (3) the suction piping of the CCPs contain no loop seals, and gas will not form and be trapped in the suction piping. Based on its j
review, the staff finds the amendment acceptable. As a result, the staff concludes the changes j
to Technical Specification 3/4.5.2b.1 and its associated Bases in regard to venting the emergency core cooling system (ECCS) pump casings and accessible discharge piping high points will make the TS surveillance requirements consistent with the design of the ECCS system, and that the TS surveillance, as modified, will provide continued confidence that unacceptable accumulation of gases will not occur in the ECCS.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Missouri State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 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 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 (63 FR 25118). 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 stat 6 ment or environmental assessment need be prepared in connection with the issuance of the amendment.
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5.0 CONCLUSION
The Commission has cencluded, 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 cornpliance 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: Mel Gray i
Date: August 17, 1998 I
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