ML20058D651
| ML20058D651 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/23/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058D640 | List: |
| References | |
| NUDOCS 9312030248 | |
| Download: ML20058D651 (4) | |
Text
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t UNITED STATES I'i*
E NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 20 % 5 0301 N..~...f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 176 AND 157 TO FACILITY OPERATING LICENSE N05. NPF-4 AND NPF-7 M GINIA ELECTRIC AND POWER COMPANY OLD DOMINION ELECTRIC COOPERATIVE i
NORTH ANNA POWER STATION. UNITS NO. 1 AND 60. 2 DOCKET NOS. 50-338 AND 50-339
1.0 INTRODUCTION
By letter dated November 10, 1993, as supplemented by letter dated November 16, 1993, Virginia Electric and Power Company (the licensee) requested emergency Technical Specification (TS) changes for the North Anna Power Station, Units No. I and No. 2 (NA-1&2). The proposed changes would eliminate the simulated reactor coolant pump (RCP) seal injection flow requirement of 48.3 gallons per minute (gpm) for cold leg flow injection balancing for the NA-l&2 TS 4.5.2.h.1.c.
The licensee found that the specific value of TS 4.5.2.h.l.c was too large and resulted in difficulty meeting TS 4.5.2.h.l.a. addressing required minimum high head safety injection (HHSI) delivered flow (2359 gpm), and TS 4.5.2.h.1.b, addressing HHSI runout flow (s660 gpm).
2.0 EVALUATION The NA-l&2 HHSI system licensing safety analyses require that at least 359 gpm be delivered to the reactor by each HHSI pump, excluding the flow rate of the highest injection flow line (of three lines). This is accomplished in the present NA-l&2 TS 4.5.2.h.l.a.
Surveillance requirements associated with this TS measure the actual in-plant flow balance in the HHSI lines, and do not take credit for seal injection flow which reaches the reactor in meeting safety analysis requirements.
The NA-l&2 HHSI pump design requires that the individual HHSI pump flow rate be maintained at or below 660 gpm. This is enforced in the present NA-l&2 TS 4.5.2.h.l.b.
Surveillance requirements for this T3 require that the value assumed for seal injection flow be consistent with that provided in TS 4.5.2.h.l.c.
The present North Anna TS 4.5.2.h.1.c requires that, for cold leg injection balancing, a value of greater than or equal to 48.3 gpm will be used for simulated seal injection flow during balancing.
9312030248 931123 PDR ADOCK 05000338 P
2 In its submittal of November 10, 1993, as clarified in a letter of November 16, 1993, the licensee indicated that, with deletion of TS 4.5.2.h.l.c, seal injection will continue to be accounted for in the surveillances associated with TS 4.5.2.h.l.a and TS 4.5.2.h.1.b, and that the value used will be consistent with the projected seal injection flow for accident conditions based on the actual in-plant setting.
The reference by surveillances associated with TS 4.5.2.h.l.a and TS 4.5.2.h.l.b to actual 4
plant settings makes TS 4.5.2.h.l.c unnecessary. We therefore find the proposed change to delete TS 4.5.2.h.1.c to be acceptable.
Finally, wordings of TS 4.5.2.h.l.a and TS 4.5.2.h.l.b are also changed in the proposed TS change to reflect deletion of TS 4.5.2.h.l.c.
The content of these TSs are not changed and, therefore, these clerical changes are acceptable.
3.0 EMERGENCY CIRCUMSTANCES 1
NRC regulations (10 CFR 50.91(a)(5)) require that whenever an emergency situation exists, a licensee must explain why this emergency situation occurred and why it could not avoid this situation, and the NRC will assess the licensee's reasons for failing to file an application sufficiently in advance of the event. An emergency situation exists when the NRC's failure to act in a timely way would result in derating or shutdown of a nuclear plant, or in prevention of either resumption of operation or of increase in power output up to the plant's licensed power level.
In such cases, the NRC may issue a license amendment involving no significant hazards consideration without prior notice and opportunity for a hearing or for public comment.
Also, in such cases, the regulations require that the NRC be particularly sensitive to environmental considerations. Our discussion of why this proposed change meets the conditions necessary for emergency consideration is provided below.
F At 09:30 hours and again at 14:45 hours on November 8, 1993, NA-2 entered an action statement to be in hot standby within six hours as required by TS 3.0.3.
The licensee determined that TS 3.5.2, which requires two operable HHSI pumps, could not be met. The HHSI pumps were determined to be inoperable
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because the total pump flow rate required by TS 4.5.2.h.l.b may not have been met. As noted above, the limitation on seal injection flow specified by TS 4.5.2.h.l.c contributed to this determination by the licensee.
On November 8,1993, the NRC verbally granted an enforcement discretion to eliminate the simulated reactor coolant pump seal injection flow requirement of 248.3 gpm in the NA-2 TS 4.5.2.h.l.c and to allow the licensee a 24-hour period to readjust seal injection flows in order to return the total pump flow rate to within TS limits.
The licensee's letter dated November 9, 1993 documented the requested enforcement discretion. By letter dated November 10, 1993, the NRC provided written documentation of the verbal approval granted on November 8,1993, and requested the licensee to submit an emergency TS change by November 12, 1993. Consistent with NRC policy on enforcement discretion, the licensee submitted an emergency TS change to permanently implement the
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3 change initially supported through NRC's exercise of enforcement discretion on November 8, 1993.
Therefore, the staff concludes that failure to act in these circumstances could be reasonably expected to result in an unnecessary shutdown of NA-2 and, therefore, the request meets the criteria in 10 CFR 50.91(a)(5) for an emergency situation.
4.0 Final No Sianificant Hazards Consideration Determination The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the amendment would not:
(1)
Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2)
Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3)
Involve a significant reduction in a margin of safety.
The license proposed that the requested TS changes did not involve a significant hazards consideration, stating as follows:
Continued operation of North Anna Power Station in accordance with the proposed Technical Specification changes will not:
1.
Involve an increase in the probability or consequences of an accident or malfunction previously evaluated. The proposed Technical Specification changes continue to require that with one HHSI pump running, the sum of the flows through the two lowest flow branch lines shall be 2359 gpm and the total HHSI pump flow rate shall be s660 gpm. These requirements ensure the correct flow balance alignment and flow rates required to meet the safety analysis.
Likewise, the consequences of the accidents or malfunctions previously evaluated will not increase as a result of the proposed Technical Specification changes. The system performance will remain bounded by the existing safety analysis for all postulated accident conditions.
2.
Create the possibility of a new or different kind of accident or malfunction from any previously evaluated. The proposed Technical Specification changes will not affect the capability of the HHSI System to perform its intended function. The propcsed Technical Specification changes are bounded by the existing safety analysis and do not involve operation of plant equipment in a different l
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4 manner from which it was designed to operate.
Since a new failure mode is not created, a new or different type of accident or malfunction is not created.
3.
Involve a reduction in a margin of safety. The system performance will remain bounded by the existing safety analysis at the specified flow rates, therefore, safety margins are not. reduced.
Based on its evaluation of the above, the staff concurs with the licensee's analysis and, therefore, concludes that these amendments meet the criteria, and do not involve a significant hazards consideration.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Virginia State official was notified of the proposed issuance of the amendment. The State official had no comment.
6.0 ENVIRONMENTAL CONSIDERATION
These amendments change the surveillance requirements. The NRC staff has determined that the amendments involve 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 made a final _no significant hazards finding with respect to these amendments. Accordingly, these amendments meet.the eligibilitf 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 these amendments.
7.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) the amendments do not (a) significantly increase the probability or consequences of an accident previously evaluated, (b) increase the possibility of a new or different kind of accident from any previously evaluated or (c) significantly reduce a safety margin and, therefore, the amendments do not involve a significant hazards consideration; (2) there is reasonable assurance that the health and safety of the public will not be. endangered by operation in the proposed manner; (3) such activities will be conducted in compliance with the Commission's regulations; and (4) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
F. Orr L. Engle Date: November 23, 1993