ML20203A528
| ML20203A528 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/11/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20203A512 | List: |
| References | |
| NUDOCS 9802240052 | |
| Download: ML20203A528 (3) | |
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y UNITED STATES s
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.c. 30eeH001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. > < TO FACILITY OPERATING LICENSE NO. DPR 66 DUQUESNE LIGHT COMPANY OHIO EDISON COMPANY PENNSYLVANIA POWER COMPANY BEAVER val i FY POWER STATION. UNIT NO.1 DQCKET NO. 50-334
1.0 INTRODUCTION
L By letter dated November 4,1997, the Duquesne Light Company (the licensee) submitted a request for changes to the Beaver Val:ey Power Station, Unit No.1 (BVPS-1) Technical Specifications (TSs). The requested change would revise item 6.a.2, "4.16kV Emergency Bus (Start Diesel)," of Table 3.3-4 of TS 3.3.2.1. The proposed change would rtduce the trip setpoint for starting the emergency diesel generators on emergency bus undervoltage from a inp setpoint of greater than or equal to 83 percent with a 12-cycle delay time % a setpoint of greater than or equal to 75 percent of nominal bus voltage with a time delay ct less than 0.g seconds including auxiliary relay times. The proposed change would also reduce the allowable value from greater
- than or equal to 81 percent of nominal bus voltage to greater than or equal to 74 percent of nominal bus voltage with a time delay of less than 0.g seconds n cluding auxiliary relay times.
The purpose of these changes is to eliminate unnecessary diesel generator starts.
i 2.0 EVALUATION -
Diesel generators are the standby onsite ac power sources at BVPS-1. During certain postulated abnormal events (e.g., a loss of offsite power), the diesel generators must start and provide sufficient ac power to permit the functioning of structures, systems, and components which
- assure the core is cooled, and containment integrity and other vital functions are maintained.
The safety function of the diesel generators is to start and supply sufficient ac power to the structures, systems, and components important to safety in time to assure that specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded.
To start the diesel generators at BVPS-1 during a postulated loss of offsite power event, the licensee has installed loss of power relays which start the diesel generators when voltage on the 4.16 kV emergency busses dips below a preset value. The function of the loss of power (start diesel) relays is an anticipatory function, and these relays are in addition to the degrnded grid voltage protection relays. A second set of loss of power relays, the loss of power (trip feed) relays, is used at BVPS-1 to trip the 4.16 kV emergency bus feed breakers to allow the diesel generators to connect to the 4.16 kV emergency busses.
i 9002240052 900211 PDR ADOCK 05000334 F
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4 2-Because the licensee has been experiencing unnecessary anticipatory starts of the diesel generators during reactor coolant pump starts and occasionally during fast bus transfers, the licensee has proposed to change the trip setpoint and allowable value of the loss of power (start diesel) relays. The present trip setpoint value of the loss of power (start diesel) relays is too high to allow operators to start large motors at BVPS 1 without causing unnacessary diesel generator starts. To correct this problem, the licensee has proposed to change the trip setpoint value of the relays from 283% (12 cycles) to 275% of nominal bus voltage with a <0.g second time delay that includes auxiuary relay times. 'The licensee has also proposed to change the allowable value of the relays from 281% of the nominal bus voltage to 274% of nominal bus voltage with a
<0.g second time delay that includes auxiliary relay times. These new values proposed by the licensee for the loss of power (start diesel) relays are acceptable.
f The revised relay trip setpoint value and allowable value proposed by the licensee are acceptable because: (1) these new values will not adversely affect any equipment needed to mitigate a postulated abnormal event; and (2) the proposed lower relay idp st. point value will prevent future unnecessary starts of the diesel generators. Eliminating unnecessary starts of the diesel generator eliminates unnecessary wear of the diesel generators. Equipment connected to the.
4.16 kV emergency busses will not be affected by the proposed relay trip setpoint change because the licensee uses a second set of loss of power relays to trip the emergency bus feed breakers.
3.0
SUMMARY
The NRC staff has reviewed the licensee's proposed changes for compliance with regulatory requirements and determined them to be acceptable. The revised relay trip setpoint value and allowable value proposed by the licensee are acceptable because: (1) these new values will not-adversely affect any equipment needed to mitigate a postulated abnormal event; and (2) the proposed lower relay trip setpoint value will prevent future unnecessary starts of the diesel generators.
4.0 - STATE CONSULTATION in accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the resthcted area as defined in 10 CFR Part 20 and changes surveillance requirements.- The NRC staff has determined that the amendment involves no signi'icant 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 (62 FR 63976). 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 statement or environmental assessment need be prepared in connection i
with the issuance of the amendment.
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6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be enda7gered by operation in the proposed manner, (2) such activities will be conducted in compliance 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.
PrincipalContributor: V, Beaston Date: February 11, 1998