ML18038A704
| ML18038A704 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/01/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17056A490 | List: |
| References | |
| NUDOCS 8912140335 | |
| Download: ML18038A704 (4) | |
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++*+4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
112 TO FACILITY OPERATING LICENSE NO.
DPR-63 NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION UNIT NO. I DOCKET NO. 50-220 INTRODUCTION By letter dated March 16, 1989, Niagara Mohawk Power Corporation (the licensee) submitted an application to amend the Nine Mile Point Unit No.
1 Technical Specifications to correct an error in Table 3.3.4 "Primary Containment Isolation Valves Lines Entering Free Space of the Containment."
The purpose of the change is to clarify that the containment spray isolation valves do not receive automatic initiation signals to open on reactor low-low water level and high drywell pressure.
This issue was also discussed in an earlier letter dated September 12, 1983.
The earlier letter provides additional background information and is consistent, in this regard, with the March 16, 1989 application.
DISCUSSION AND EVALUATION Table 3.3.4 provides Limiting Conditions for Operation (LCOs) for primary containment isolation valves in lines entering free space of the containment.
The current specifications indicate that the containment spray drywell and suppression chamber common supply valves receive an automatic initiation signal to open on reactor level low-low and high drywell pressure signals.
The proposed change corrects Table 3.3.4 to indicate that these valves do not receive automatic signals and that they are operated by remote manual action.
The error was discovered through review of piping and instrument drawings and electrical diagrams which indicate that the automatic signals are not present.
The licensee and the NRC staff have evaluated this discrepancy with respect to its potential safety consequence and have determined that there is no safety impact.
The subject valves are air/DC solenoid operated valves located in the primary and secondary loop of both trains of the containment spray system.
The four valves are open during normal operation as required by station operating procedures.
During an event which requires containment spray operation (isolated condition), the valves are also required to be open.
- Thus, these valves do not have to change position between their normal and isolated condition and no automatic opening signal is required.
The valves may be closed during surveillance
- testing, removal of water from the suppression pool, maintenance, or suppression pool cooling subject to the LCOs in the Technical Specifications.
During maintenance, the affected loop is tagged out and operability of the other loop (primary or secondary) is demonstrated immediately and daily thereafter.
Following surveillance
- testing,
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suppression pool water removal and suppression pool cooling, the governing procedures direct that the system be realigned with these valves left in the open position.
These procedures, in conjunction with the TS LCOs, also provide assurance that one or more of the remaining loops remain available for containment spray, if required.
Dur ing a design basis accident, only one of the containment spray loops is required to keep containment pressure and temperature within design limits.
The design basis of the containment spray system is maintained even considering a worst case single failure.
Therefore, the safety function of the containment spray system is not affected if one containment spray loop is in the test mode (valve closed) when containment spray is required.
Adequate administrative control exists to ensure that the valve is reopened following testing or maintenance.
Additionally, the containment spray loop in the test mode can be manually placed in operation from the control room.
In response to the licensee's request and based on the above, the staff finds the request acceptable and approves the correction of Table 3.3.4 to reflect the existing diagrams and system configuration which indicate that the containment spray drywell and suppression chamber common supply valves do not receive an automatic initation signal to open on reactor low-low water level and high drywell pressure.
ENVIRONMENTAL CONS IDERATION This amendment involves a change in the requirements with respect to installation or use of the facility components located within the restricted areas as defined in 10 CFR 20.
The staff has determined that this 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 this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Sec 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 this amendment.
CONCLUSION We have 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, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the pub1ic.
Dated:
December 1,
1989 PRINCIPAL CONTRIBUTOR:
D. Oudinot
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