ML19261A658
| ML19261A658 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 01/19/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19261A657 | List: |
| References | |
| NUDOCS 7902060004 | |
| Download: ML19261A658 (3) | |
Text
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UNITED STATES y1 NUCLEAR REGULATORY COMMISslCN g(Mj j
.I WASHINGTON, D. C. 20555
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,y SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTIt.G AMENDMENT N0.18 TO FACILITY LICENSE NO. DPR-71 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO. 1 DOCKET N0. 50-325 INTRODUCTION During the end of Cycle 1 refueling outage for Brunswick Steam Electric Plant Unit 1, Carolina Power & Light Company (the licensee) had proposed Technical Specification changes to the low reactor vessel water level instrumentation. These changes are necessary to provide a means for per-forming specific maintenance and modification work to the reactor systems during this refueling outage.
In order that this work may be performed, the vessel low water level must be lowered below the Level #1 and Level
- 2 vessel low water level set points. Since shutdown cooling as a means of level control and water chemistry control must be maintained during this maintenance certain isolation actuation instrumentation must be temporarily modified. These modifications will alter the isolation actuation of valve groups 2, 3, 6 and 8.
Reactor vessel water chemistry control and shutdown cooling will still be maintained using the normal systems installed for this purpose.
Vessel water level will be controllad by feeding with the control rod drive system and bleeding with the reactor water cleanup system. The vessel water level will be monitored using specially installed instrumen-taticn.
SUMMARY
The major effect of these changes is that the RHR shutdown cooling system isolation valves and the cleanup system isolation valves will not close automaticelly at the normal level set points. Closure of these valves must now rely on operator actuation. To determine the need to actuate closure the operator will rely on special instrumentation that is designed and installed such that the water level can be monitored through a range of + or - 15 inches about the desired level.
Alarms and level indicators are provided on the refueling floor and in the control room. The control room monitoring and alarm function will use a normally installed reactor water level recorder and annunciator which will alarm if the water level deviates from the desired level by + or -
5 inches.
790206000'
. If the water level drops to -10 inches, the operator shall take action to isolate (close) the shutdown cooling system suction valves to prevent further loss of inventory and provide additional makeup as necessary.
In addition, if the temporary reactor vessel water level monitoring and alarm system fails (becomes inoperable) the operator will take corrective action as specified in the temporary Technical Specifications.
Normal vessel level control will use water from the control rod drive system feeding the vessel with the cleanup system letting down excess inventory. A backup source of makeup water from clean demineralized water system will be available for use if necessary. The control rod drive system and the clean demineralized water system are adequate to provide normal level control and makeup for small leaks. For larger leaks and LOCA's for which these systems are not cdequate, a level decrease (to L3) will automatically initiate LPCI to maintain vessel inventory. Since LPCI is required to be operable in accordance with T.S. 3.5.3.2, the ECCS availability has not been changed for this special test exception. The significant change is manual closure of the shutdown cooling suction isolation valves.
In the unlikely case of certain LOCA's greater initial loss of inventory than with automatic closure could result. However, with either manual or automatic closure, any rapid, level decrease is by design limited to 1/3 core height. For long term cooling, the systems available for maintaining adequate cooling are not affected by this change. Therefore, no new safety concerns exist and we find the proposed change acceptable for the current refueling outage at BSEP Unit 1.
Environmental Consideration We have determined that this amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in cny significant environmental impact. Having made this determination, we have further concluded that this 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, negative declaration, or environmental impact appraisal need not be prep 6 red in connection with the issuance of this amendment.
Conclusion We have concluoed. based on the considerations discussed above, that:
(1) because this 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 amend-ment 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.
Dated:
January 19, 1979