ML18029A194
| ML18029A194 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/19/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18029A193 | List: |
| References | |
| NUDOCS 8410260196 | |
| Download: ML18029A194 (4) | |
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+~*y4 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
112 TO FACILITY OPERATING LICENSE NO. DPR-33 AMENDMENT NO.
106 TO FACILITY OPERATING LICENSE NO.
DPR-52 AMENDMENT NO.
- 80. TO FACILITY OPERATING LICENSE NO.
DPR-68 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNIT NOS. 1, 2 AND 3 DOCKET NOS. 50-259, 50-260 AND 50-296 1.0 Introduction By letter dated Febraury 22, 1984 (TS 196), the Tennessee Valley Authority (the licensee or TVA) requested amendments for Facility Operating License Nos.
DPR-33, DPR-52 and DPR-68 for the Browns Ferry Nuclear Plant, Units 1, 2 and 3.
The proposed amendments and revised Technical Specifications would change the reactor water level setpoint for Group 1 isolation from 470 inches above vessel zero to 378 inches above vessel zero.
2.0 Evaluation Boiling water reactors (BWRs) are equipped with safety/relief valves.(SRVs) to provide overpressure protection to the reactor coolant pressure boundary and also for automatic depressurization in the case of small-break loss of coolant accidents (LOCAs) with concurrent failure of the high-pressure coolant injection systems.
The operating history of these valves has been relatively'poor.
Malfunctions include failures of valves to open on demand and failures to close after either a proper or a spurious opening.
Failures to close result in small LOCAs, which can produce unnecessary thermal transients on the reactor vessel and internal components, unnecessary hydrodynamic loadings on the containment pressure-suppression
-chamber and internal components, and potential increases in the release of radioactivity to the environs; they can also increase challenges to the emergency core cooling systems.
In order to reduce the probability of occurrence of an SRV malfunction, NUREG-0737 (TMI Action Plan)
Item II.K.3.16 required licensees to conduct a
feasibility study for reducing SRV challenges.
By letter dated March 31, 1981 the BWR Owners'roup submitted the results of the study.
One of the recommendations was to lower the reactor pressure vessel water level isolation setpoint for main steam isolation valve (MSIV) closure from Level 2 to Level 1.
In the event of a pressurization transient, this design modification would maintain the main condenser available for a longer time, allow more energy to be released to the main condenser, and result in a sl'ower repressurization rate.
The result would be to reduce isolations and 8410260196 840919'DR ADOCK 05000259 P
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SRV challenges and provide some benefit toward reduction of SRV subsequent actuations; Our Safety Evaluation, letter from D. Vassallo to H. Parris dated April 3,
- 1984, concluded that this modification is acceptable for Browns Ferry.
That Safety Evaluation is incorporated herein and for the reasons set forth in that Safety Evaluation, we find that the proposed change in reactor water level setpoint for group 1 isolation is acceptable.
3.0 Environmental Considerations The amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The 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 cumulat'ive occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding.
Accordingly, the amendments meet 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 with the issuance of the amendments.
4.0 Conclusion We have concluded, based on the considera'tions 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 these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
K. Desai Dated:
September 19, 19S4
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