ML18026B185
| ML18026B185 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/15/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18026B184 | List: |
| References | |
| NUDOCS 8408280276 | |
| Download: ML18026B185 (2) | |
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t UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
110 TO FACILITY OPERATING LICENSE NO.
DPR 33 AMENDMENT NO.
103 TO FACILITY OPERATING LICENSE NO.
DPR-52 AMENDMENT NO.
76 TO FACILITY OPERATING LICENSE NO.
DPR-68 TENNESSEE VALLEY AUTHORITY BROMNS FERRY NUCLEAR PLANT, UNIT NOS.
1, 2 AND 3 DOCKET NOS.
50-259, 50-260 AND 50-296 1.0 Introduction By letter dated December 17 1982.(TS-182) the Tennessee
.Valley Authority (the licensee or TVR) requested amendments to 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 would change the Appendix A Technical Specifications (TS) to allow the main steam line high temperature isolation
'function to be made inoperable for periods up to four hours in order to permit continued plant operation during testing and maintenance activities which require isolation of reactor building ventilat'ion.
2.0 Evaluation Detection of postulated breaks in a main steam line is provided primarily by two diverse and redundant.sets of instruments
- main steam line flow and area temperature in.the steam line-tunnel.
For the latter, there are 16 temperature sensors grouped into four channels with four sensors in each.
The system is designed to detect very small breaks, (1Ã to 10Ã of rated steam flow - Final Safety Assessment Report (FSAR) 7.3.48).
The trip setting for the temperature sensors is set at 200'F - just slightly above normal area temperature in the tunnel with the plant air ventilation system operating.
A test of secondary containment automatically isolates the building, shutting off normal ventilation flows (to prevent a possible release of radioactivity to the environment).
Shutting off the normal ventilation flow quickly raises the ambient temperature in the steam tunnels, tripping the reactor.
Thus, it is not now possible to test secondary containment with the plant in operation.
The NRC has requested the licensee to develop a plan to test the entire secondary containment at one time when two or more of the units would be operating.
The test takes less than four hours to complete.
The proposed change to the Technical Specifications is to permit bypassing the isolation function of the temperature sensors for up to four hours to conduct the secondary containment test.
Other temperature sensors will still be available for measuring the temperature in the steam tunnel and reading out in the control room.
The TS change specifically requires that:
"During periods 8408280276 840815 PDR ADOCK 05000259 P
when normal ventilation is not available, such as during the performance of secondary containment leak rate tests, the control room indicators for the affected space temperatures shall be monitored for indications of small steam leaks.
In the event of rapid increases in temperature (indicative of0" steam line break),
the operator shall promptly close the main steam line isolation valves."
Since the temperature sensors are installed to detect small steam leaks, rapid, automatic action is not essential; manual operator action is acceptable for a limited period of time.
Based on the short (four-hour) inoperability interval for the main steam line high temperature isolation function, and the interim compensatory measures concerning monitoring of space temperatures by operators, we conclude that the change is acceptable.
3.0 Environmental Considerations The amendments invol've 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 Me 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
- 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:
R. Clark and W.
Long Oated:
August 15, 1984