ML19350B041
| ML19350B041 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/06/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19350B039 | List: |
| References | |
| TAC-43083, TAC-43202, TAC-43282, NUDOCS 8103190235 | |
| Download: ML19350B041 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COM2AISSION
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nAsMNGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENOMENT N0. 23 TO FACILITY OPERAT'HG LICENSE N0. NPF-5 GFORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MUNICIPAL ELECTRIC AUTHORITY OF GEORGIA CITY OF DALTON, GEORGIA EDWIN I. HATCH NUCLEAR PLANT, UNIT N0. 2 DOCKET NO. 50-366
1.0 INTRODUCTION
By letter dated October 15, 1980, as supplemented by letter dated Novecher 11, 1980, Georgia Power Company (licensee). requested changes to the Technical Speci-fications (TSs) for Hatch Nuclear Plant, Unit No. 2.
The requested changes would reflect the addition of a power monitoring system for the Reactor Protec-tion System (RPS) power supply as required by the Hatch 2 license (para. 2.C.(3)(e)).
The license requires the licensee to install, prior to startup following the first scheduled refueling outage, a Class IE system capable of de-energiGg the RPS power supply when its output voltage exceeds or falls below limits within which
. tha equipment being powered from the power supply has been designed and quali-fied to operate continuously and without degradation.
2.0 BACKGROUND
During the operating license review for Hatch 2, the NRC staff raised a concern about the capability of the Class IE RPS to operate after suffering sustained, abromal voltage or frequency conditions from a non-Class IE power supply.
'anormal voltage or frequency conditions could be produced as a result of one of the following causes: combinations of undetected single failures, or multiple failures caused by external phenomena such as a seismic event.
The concern for the power supply integrity is generic to all Boiling Water Reactor (BWR) 3's, 4's, and 5's and all BWR 6's that have not elected to use the.
solid state RPS design. We have therefore pursued a generic resolution, one that could be applied to both operating plants and plants in the licensing review process. Accordingly, tne General Electric Company (GE) proposed a design, in conceptual' form, for resolution of this concern (Reference 4). The proposed modifications consist of the addition of two Class IE " protective packages" in serier.hetween each M-G -Set and its respective RPS bus' and the addition of two similar packages in series in the alternate. power source circuit to the RPS buses.
' Each protective package would include a breaker and associated overvoltage, under-voltage and underfrequency relaying. Each protective package would meet the testa 5ility reqwrements for Class IE equipment.
With the protective packages installed, any abnomal outpat type failure (randon
- undetectable or seismically caused) in either of the two M-G sets (or the alter-nate supply) would result in a trip of one or b'ith of the two Cless IE protec-
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. q tiye packages installed between each zwer supply and its respective RPS bus, thus producing a half scram on that ciannel and retaining full scram capability in the other channel. Thus, fully redundant Class IE protection is provided, bringing the overall RPS system design into full confomance with General Desi Criteria 2 and 21 (including IEEE-279, IEEE-379, and the Standard Review Plan We reviewed the proposed design and concluded that the proposed modification was conceptually sound and acceptable, and should be implemented in conformance with the applicable criteria for Class IE systems (Ref. 5).
3.0 REQUIREMENTS The NRC requires that the components of the RPS not be exposed to unacceptable electric power conditions, i.e., sustained abnomal voltage or frequency condi-tions which could damage the RPS. This involves providing means to detect any overvoltage, undervoltage, or underfrequency condition that is outside the design limits of the RPS equipment and to disconnect the RPS from such abnomal elec-tric power conditions before damage to the RPS could occur. The equipment which performs this function must satisfy the single failure criterion and be seis-mically qualified.
4.0 DESIGN DESCRIPTION The licensee has proposed to install an electric power monitoring system on each of the three sources of power for the RPS.
The monitoring system logic is identical to the one approved by the NR: staff for Hatch Unit No.1, 5.0 EVALUATION The proposed changes to the TSs include the same relays setpoints as applied to the relays on Unit 1.
The values are~found to adequately protect the RPS from harmful -electric power conditions. The RPS monitoring logic is similar to that for Unit 1 and established to provide automatic protection-to the RPS considering a single component failure.
Since the Unit 1 and Unit 2 RPS monitoring systems are based on the same design, the Unit 2 system is also seismically qualified as Category 1 in conformance with IEEE 344-1975 and each of its channels is physically. and electrically inde-pendent of rny other channel.
The licensee propos'ed TSs-that would require functional testing and calibration at a frequency of once-per-cycle. This is a relaxation from that previously approved by the NRC staff. We discussed this aspect of the licensee's request and stated that we would consider such a frequency if the licensee would pro-vide data on the performance of the power monitoring system installed on Hatch
- 1. to justify a relaxation.
Pending the receipt of such data, we suggested, and the licensee agreed that-the amendment should conform the Hatch 2 TSs-to those currently approved for Hatch 1.
In view of the above, we find the TSs, as amended by the NRC staff, to be acceptable.
< During our review of the licensee's request, we identified an omission 'n the TSs as originally issued on June 13, 1978.
The omission relates to the Limiting Conditions for Operation for the AC inverter 2R444003 which is associated with the Low Pressure Cbolant Irjection System (LPCI).
This inverter need only be operable if the LPCI is operable. We suggested to the licensee that this specification should be clarified to reflect this requirement He agreed.
6.0 ENVIRONMENTAL CONSIDERATION
S We have determined that the amendment does not authorize a change in effluent types'or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement, or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of this amendment.
7.0 CONCLUSION
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We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does 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, and (3) 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.
8.0 REFERENCES
l 1.
Amendment No. 70 to Hatch Nuclear Plant Unit 1, Docket No. 50-321, l
dated August 14, 1979.
2.
Georgia Power (W. A. Widner) letter to NRC, dated October 15, 1980.
I 3.
Georgia Power (W. A. Widner) letter to NRC, dated November 11, 1980.
4.
GE letter (G. G. Sherwood) to NRC, dated October 31, 1978.
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5.
Memo from F. Rosa to J. Stolz, T. Ippolito and G. Lainas, dated l
February 12, 1979.
1 Dated:
Pbrch 6, 1981 L
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