ML17056A861
| ML17056A861 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/24/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17056A860 | List: |
| References | |
| NUDOCS 9006040063 | |
| Download: ML17056A861 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR R'EACTOR REGULATION RELATED TO AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO. DPR-63 NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION UNIT NO.
1 DOCKET NO. 50-220 INTRODUCTION The Niagara Mohawk Power Corporation (NMPC) submitted an application dated March 27, 1990 to amend the Technical Specifications (TS) for the Nine Mile Point Nuclear Station, Unit 1 (NMP-1).
The change would revise TS Table 3.3.4, "Primary Containment Isolation Valves Entering Free Space of the Containment,"
to reflect that the normal position of the isolation valves in the drywell and suppression chamber oxygen sampling line is "open".
The licensee states that the prior listing of these isolation valves as normally closed was an administrative error in the TS.
EVALUATION As discussed in Section VII of the FSAR, the hydrogen-oxygen sampling systems continuously monitor the hydrogen and oxygen concentrations within the drywell and suppression chamber.
- A continuous indication of concentrations is provided in the control room.
As stated in the TS and its BASES the oxygen concentration is determined at least once per week to ensure that TS 3.3.1 on allowable concentration is met.
As stated in the application, the hydrogen-oxygen sampling systems are an integral part of the containment atmospheric dilution (CAD) system.
The CAD system, in conjunction with the containment inerting system is designed to prevent a combustible hydrogen-oxygen concentration from accumulating in the primary containment atmosphere immediately following or during a loss-of-coolant accident.
Therefore, as discussed
- above, the hydrogen-oxygen sampling system is utilized during normal operation to ensure compliance with the TS limits and in response to potential accident conditions.
In the event of conditions indicative of a loss-of-coolant accident (LOCA)
(high drywell pressure or low-low reactor vessel water level) the isolation valves wi 11 be automatically actuated to close.
The valves can be reopened to permit monitoring of the containment during LOCA conditions.
The operating characteristics of the system are such that an initial startup period would be required to initiate and to stabilize the system for the monitoring of oxygen concentrations if the system were normally maintained inoperable with the isolation valves closed.
Therefore, to facilitate a more practical surveillance monitoring to meet the weekly TS surveillance requirement and to provide continuous indication in the control room, the system remains continuously operable while the plant is in operation with its isolation valve open to permit sampling of the containment atmosphere.
9006040063 9005 PDR ADOCK 05000220 I DC
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The staff has reviewed the licensee's application and on the basis discussed above finds the change in the normal valve position from "open" to "closed" to be acceptable.
ENVIRONMENTAL CONSIDERATION This amendment involves a change in a requirement with respect to the 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 public.
Dated:
Nzy 24, 1990 P RINGIPAL -CONTRIBUTOR:
Robert E. Martin
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