ML18029A894
| ML18029A894 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/19/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18029A893 | List: |
| References | |
| NUDOCS 8509300502 | |
| Download: ML18029A894 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
123 TO FACILITY OPERATING LICENSE NO.
DPR 33 AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO.
DPR-52 AMENDMENT NO.
94 TO FACILITY OPERATING LICENSE NO.
DPR-68 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2 AND 3 DOCKET NOS. 50-259, 50-260 AND 50-296 I. 0 INTRODUCTION By letter dated September 21, 1984, the Tennessee Valley Authority (the licensee or TVA) requested amendments to Facility Operating License Nos.
DPR-33, DPR-52 and DPR-68 for the Browns Ferry Nuclear Plant, Units I, 2 and 3.
By a letter dated June 6, 1985, the licensee revised the request, proposing a more extensive rewording of the affected Technical Specifications to better clarify the proposed new requirements.
The current Technical Specification Section 4. 1 contains a requirement that upon the failure of a reactor protection system (RPS) channel in the unsafe condition all RPS channels monitoring the same variable must be functionally tested.
This testing must be performed immediately before the trip system containing the failure is tripped.
The trip system may be in the untripped position for up to eight hours to perform the functional test.
The proposed revision is to delete the functional test requirement and replace it with a requirement to trip the channel containing the failure.
The amendments would revise Section 4. 1 and a footnote in Table
- 3. 1.A, of the Technical Specifications.
- 2. 0 EVALUATION The RPS is arranged as two separately powered independent trip systems.
Each trip system has three logics.
Two of the logics are used to produce automatic trip signals, and the remaining logic is used for a manual trip signal.
Each logic used for automatic trip receives input signals from at least one channel for each monitored parameter.
There are usually four channels provided to monitor each critical parameter, with one channel for each automatic trip system logic.
The outputs of the channel in a trip system are combined in a logic such that either channel trip will actuate its associated trip system.
The simultaneous tripping of both trip systems will produce a reactor scram.
The overall logic of the reactor trip system is termed "one-out-of-two taken twice."
Technical Specification Section
- 4. 1 presently contains a requirement that upon the failure of a RPS channel in the unsafe condition all RPS l
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channels monitoring the same variable must be functionally tested.
An unsafe failure means that the failure did not result in tripping the channel and thus, the trip system.
The testing must be performed immediately before the trip system containing the failure is tripped.
The current Technical Specifications allow leaving the trip system containing the unsafe failure in the untripped condition for up to eight hours in order to functionally test the other trip system.
This could possibly lead to a situation which could impair the ability of the RPS to respond correctly since the trip system containing the failure can be left as is for up to eight hours in order to test the other trip system.
To alleviate this situation, the licensee has proposed a revision to the Technical Specifications that deletes the functional test requirement and replaces it with a requirement to trip the channel containing the failure within one hour.
By tripping a failed channel in one hour as opposed to eight
- hours, the reliability of the RPS is increased, increasing the margin of safety.
Based on our review of the Browns Ferry FSAR including the Technical Specifications, the information submitted by the licensee, and the NUREG-0123, "Standard Technical Specifications for General Electric Boiling Water Reactors,"
the staff concludes that the proposed Technical Specification revision permits the operation of the facilities in a manner that is consistent with the licensing basis and the accident analysis.
Therefore, the licensee's proposed revision to the Technical Specification is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S 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 cumulative 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 considerations discussed above, that (I) 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 Comoission'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:
J.
Mauck Dated:
September 19, 1985
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