ML20148C790
| ML20148C790 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 01/12/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20148C766 | List: |
| References | |
| NUDOCS 8801250259 | |
| Download: ML20148C790 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.14 TO FACILITY OPERATING LICENSE NO NPF-43 DETROIT EDISON COMPANY WOLVERINE POWER SUPPLY COOPERATIVE, INCORPORATED FERMI-2 DOCKET NO. 50-341
- 1. 0 INTRODUCTION AND BACKGROUND By letter dated January 6, 1988, Detroit Edison Company (the licensee) proposed revisions to Table 3.4.3.2-2 of the Fermi-2 Technical Specifications (TSc) to correct alarm setpoints for the reactor coolant system (RCS) interface valves leakage pressure monitors (LPMs).
The RCS interface valve LPMs are designed to alarm on increasing pressure on the low pressure side of the high/ low pressure interface to provide indication to the plant operators in the control room of abnormal RCS interface leakage.
Should abnormal interface valve leakage occur, the low pressure portion of the system in which the leakage is occurring would begin to increase in pressure due to the leakage from the RCS.
The pressure would increase to the setpoint for the system relief valve installed on the low pressure piping.
The relief valve would lift to relieve the pressure buildup once that setpoint is reached.
In the course of upgrading Instrumentation and Control (I&C) system surveillance procedures, under a program instituted by the licensee to verify the accuracy of those procedures in reflecting and implementing surveillances required by the Fermi-2 TSs, the licensee determined that the LPM alarm setpoints specified in Table 3.4.3.2-2 of the TSs were nonconservatively high, such that LPM alarm actuations to alert plant operators of increasing pressure on the low side of the high/ low pressure interface valves would not 1
be timely.
In the case of the Residual Heat Removal-Low Pressure Coolant Injection (RHR-LPCI) system and the RHR Shutdown Cooling System, LPM alarm setpoints specified in Table 3.4.3.2-2 of the TSs are such that the LPM alarms may not occur prior to system relief valve actuation.
Accordingly, by letter NRC-88-0001 dated January 6,1988, the licensee proposed an emergency TS change to reset the alarm setpoints for the RCS interface valve LPMs.
Since emergency TS action was needed by the licensee for plant restart, and since the revised setpoint values would provide more conservative and timely indication of RCS leakage, the licensee was granted a temporary waiver of compliance until January 12, 1988, while the NRC completed processing the emergency TS amendment.
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- 2. 0 EVALUATION As stated in the licensee's proposed TS change, the LPM alarm setpoints in Table 3.4.3.2-2 of the TSs are currently listed as nominal values with a specific tolerance.
Since completion of the LPM function depends solely upon the alarm setpoint being less that the lowest pressure relief valve setpoint, the licensee proposes to specify LPM alarm setpoints only as an upper limit to allow flexibility in the system design, while also ensuring that the LPMs alarm before system pressure reaches the relief valve lift setpoint.
The existing LPM alarm setpoint for the RHR-LPCI system is 482 1 12 psig.
The relief valve lift pressure value on the RHR-LPCI low pressure piping is set at 464 1 14 psig.
The proposed upper limit for the RHR-LPCI would be 5 449 psig to ensure the LPM alarms prior to relief valve actuation which is based on the lowest relief valve lift pressure being 450 psig.
Similarly, the existing RHR Shutdown Cooling System LPM alarm setpoint is 138 3 psig, and the corresponding relief valve lift pressure is set at 140 1 4.2 psig.
The proposed upper limit for the RHR Shutdown Cooling System LPM alarm would be 5 135 psig, which is based on the lowest relief valve lift pressure being 135.8 psig.
For the remaining interface valves in Table 3.4.3.2-2, the existing LPM alarm setpoints were also found to be below the corresponding relief valve lift pressure setpoint.
The proposed equivalent upper limits for those system LPM alarms would be changed as follows:
SYSTEM EXISTING LPM SYSTEM PRESSURE PROPOSED UPPER ALARM SETPOINT RELIEF VALVE LIMIT VALUE (PSIG)
(PSIG)
(PSIG)
Core Spray 440 1 12 500 1 15 5 452 HPCI 70 1
10013 5 71 RCIC 7011 100 1 3 5 71 We nave reviewed the changes proposed by the licensee and agree that the specification of an upper limit LPH alarm setpoint in lieu of nominal values plus tolerance in TS Table 3.4.3.2-2 is preferable and will better ensure that the LPM alarms precede relief valve actuations as was intended in the design for RCS leakage monitoring.
Therefore, we find the proposed TS changes to be acceptable.
The TS Bases Section 3/4.4.3.2 (page B 3/4 4-2) has been expanded tu describe the purpose and intent of the LPM design by incorporating a new paragraph using the wording contained in the "Background / Discussion" section of the attachment to the licensee's January 6,1988, in lieu of the new sentence suggested by the licensee.
This change is agreeable to the licensee.
3.0 EMERGENCY CIRCUMSTANCES
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In its January 6, 1988 letter, the licensee requested that this amendment be treated as an emergency because insufficient time exists for the Commission's usual 30-day notice without extending the current outage.
With incorrect LPM alarm setpoints, these LPMs are not properly operable.
4 TS 3.0.4 requires that the LPMs must be operable to permit plant startup.
In accordance with 10 CFR 50.91(a)(5), the licensee has explained that it could not have avoided this emergency situation because the LPH alarm setpoint errors were not discovered until recently during the licensee's I&C validation program instituted to assure that surveillance procedures are consistent with the plant design and that they correctly implement TS requirements.
The Commission has determined that emergency circumstances exist in that swift action is necessary to avoid a delay in startup not related to safety.
In connection with a request indicating an emergency, the Commission expects its licensees to apply for license amendments in a timely fashion.
- However, with this consideration in mind, it has been determined that a circumstance has arisen where the licensee and the Commission must act quickly, and the licensee has made a good effort to make a timely application.
4.0 FINAL NO SIGNIFICANT 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 considerations 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 an accident previously evaluated; or (3)
Involve a significant reduction in a margin of safety.
The Commission has determined that the proposed TS change:
(1) does not involve a significant increase in the probability or consequences of an accident previously evaluated as the correction of the LPM alarm setpoints will only ensure that the LPMs provide warning to plant operators of high/ low interface valve leakage as intended by the RCS design; (2) does not create the possibility of a new or different kind of accident from any accident previously evaluated since the LPMs are passive indications and thus the change does not add any new equipment, does not affect the operation of any of the systems involved, or alter any of the design assumptions previously evaluated; and (3) does not involve a significant reduction in a margin of 1
safety since, as stated in (1) and (2), the change will result in the specification of more conservative LPM alarm setpoints which will ensure more timely indication of RCS leakages, thereby enhancing the margin of safety.
Therefore, based on these considerations and the three criteria given above, the Commission has made a final determination that the amendment request involves no significent hazards consideration.
5.0 STATE CONSULTATION
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In accordance with the Commission's regulations, efforts were made to contact the Michigan representative.
The state representative was contacted and had no comments.
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- 6. 0 ENVIRONMENTAL CONSIDERATION This amendment infolves changes to requirements with respect to the installation or use of facility compc.ients located within the restricted area as defined in 10 CFR Part 20.
We have determined that the amendment involves no significant increase in the amounts, and no significant change in +5e 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 consideration finding with respect to this amendment.
Accordingly, this amendment meets the eligibility criteria for categorics1 exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental 6ssessment need be prepared in connection with the issuance of this amendment.
- 7. 0 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 mann r, and (2) such activities will be conducted in compliance with the Commission's regula-tions 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.
P. incipal Contributor:
Kenneth Dempsey, NRR John J. Stefan., NRR Dated: January 12, 1988
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