ML19248D620
| ML19248D620 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 07/26/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19248D616 | List: |
| References | |
| TASK-07-03, TASK-09-06, TASK-9-6, TASK-RR NUDOCS 7908170101 | |
| Download: ML19248D620 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 28 TO FACILITY OPERATING LICENSE NO. DPR-6 CONSUMERS POWER COMPANY BIG ROCK POINT PLANT DOCKET N0. 50-155 INTRODUCTION By letter dated March 26, 1979, Consumers Power Company (CPC) (the licensee) proposed changes to the Technical Specifications for Big Rock Point Plant.
The amendment would (1) implement an NRC fire protection position related to Shutdown Cooling system isolation, (2) revise requirements on use and testing of the fire suppression water system, and (3) delete outdated Technical Speci-fications pertaining to Emergency Core Cooling Systems for core spray nozzles.
EVALUATION (1) Shutdown Cooling System Isolation By letter of November 20, 1978, we requested CPC to take measures which would assure that a fire would not cause inadvertent opening of the shutdown cooling system isolation valves when the reactor pressure exceeds the 300 psig design pressure of the shutdown cooling system.
Overpressurization c,f the shutdown cooling system could result in a breach in the system and a loss of primary coolant inventory. The isolation valves are interlocked to prevent opening when the reactor pressure exceeds 300 psig.
However, a postulated hot short during a fire could override the interlock and cause inadvertent valve opening.
CPC has proposed an administrative control change to require that the power breakers to these valves be open when reactor pressure is above 300 psig.
Open power breakers would prevent inadvertent actuation of the isolation valves from fire damage.
We have previously evaluated this revision to shutdown cooling system administrative control and on page 4-9 of the staff safety evalution report supporting Amendment No. 25 dated April 4, 1979, we stated that interrupting the power supply and changing the technical specifications provides adequate measures to assure that fires will not cause inadvertent opening of the isolation valves in the shutdown cooling lines.
The March 26, 1979 request, proposes a revised technical specification statement which would confom to the requirements and evaluation in Amendment No. 25 and is therefore acceptable from the viewpoint of fire protection.
The oower breakers which will be opened are 1ocated within containment. To actuate the shutdown cooling system, a 790817om person would have to be sent into containment to close the b eakers. The change, in effect, converts the shutdown cooling system frm a system that is capable of remote manual operation from the control rocm to a system requiring entry into containment to allow initiation.
The licensee has stated that use of the shutdown cooling system is not necessary in the event of a local fire in the vicinity of the breaker or in the event of an accident which makes containment uninhabitable.
Based on our prior reviews which accepted the shutdown cooling system as one not designed as an engineered safety feature, we agree with the licensee's statement.
Therefore, on the basis of previous evaluations we find the change acceptable.
(2) Core Soray System Ocerability Section ll.3.1.4. A of the Technical Specifications requires that the two core spray systems be operable whenever the plant is in a power operation condition and the original core spray be operable during the refueling operations.
The two core spray sysyms would use the fire water system as the initial source of core cooling water during a loss of cooling accident.
T% system is designed such that with the worst single failure (containment spray system isolation valve failed open), the available water supply from the fire protection system is equal to that required for emergency core cooling.
Water drawn from the fire suppression system during use or testing could reduce the water supply below that assumed in the design condition.
One Technical Specification, Section 11.4.5.3.2, requires a monthly test of the emergency diesel generator using the electric fire pump as a 1 cad.
This draws water fran the fire system.
In addition, the licensee draws water fran the fire system for flushing of fire hydrants, tests of fire hose stations and fire brigade training. Some of this testing and training is normally done when the reactor is operating.
CPC has requested that Section ll.3.1.4. A be revised to explicitly state that drawing water fran the fire suppression system during nomal use and testing is allowable.
Section ll.3.1.4.E states that if Section ll.3.1.4.A is not met, a nomal orderly shutdown shall be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
It is implicit in this requirement that if corrective action is taken so that Section ll.3.1.4. A is met within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, shutdown need not be initiated and technical specifications would not be violated.
However, the specifi-cation is not phrased as clearly as are specifications contained in Standard Technical Specifications for new plants.
In a telephone conversation on July 2,1979, a representative of CPC stated that no firefighting uses or testing would draw water fran the system for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Therefore, the fire system could be used as necessary without violating the existing technical specifications d' u
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or requiring reactor shutdown. Limited use of the fire protection system during operation was considered in previous reviews.
In addition an URC position on concurrent fires and non-fire related plant accidents has been established in Appendix A to Branch Technical Position APCSB 9.5-1 which was sent to CPC by letter dated September 30, 1976. Appendix A states that " Postulated fires or fire protection system failures need not be considered concurrent with other plant accidents or the most severe natural phenomena."
However, in the July 2,1979 and subsequent telephone conversations CPC stated that additional restrictions on use of the fire system were practical which would assure that the core spray system wou'd conform to design conditions a higher percentage of the tire than requirei by Technical Specification ll.3.1.4.E.
Based on experience, the total time that the fire suppression system would be used for purposes such as hydrant flushing, testing and training would be less than 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> per year.
(This does not include the 20 to 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> per year the suppression system was being tested with ficw passing through a relief valve which is designed to close if core spray were initiated during testing.)
In addition, all flushing, testing and training can be done with flows less than the flow which would be lest through an open containment spray isolation valve.
With restrictions on flow and on hours per year the fire suppression system is used for flushing, testing and training, a LOCA concurrent with a limited core spray
.e r supply is even more unlikely.
Based on the above considerations we conclude that the percentage of the time that water supply would be diverted during power operation by use and testing of the fire suppression system is insignificant and that the proposed technical specifications as specified provide additional assurance of core spray operability.
CPC has agreed to the modified specification.
(3) Deletion of Condensate System Recuirements Section ll.3.1.4.F, the last sentence of Section ll.4.1.4. A and the last paragraph of the bases portion of Section 11.3/4.1.4 viere added to the Technical Specifications by Amendment No.15 dated October 17, 1977.
These sections were related to an exemption from Paragraph I.D.1 of 10 CFR Part 50 Appendix K, which was only in effect to the reload shutdown which began in February 1979.
These technical specification sections added operability and surveillance requirements for the condensate system until such time as the spray effectiveness of the primary core spray nozzles had been proven.
By Sendment No. 26 dated April 10, 1979, we issued an evaluation which founu the core spray nozzles acceptable and added Sections to the Technical Specifications to assure adequate core spray. Therefore, the Sections of
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the Technical Specifications to be deleted are no longer pertinent and.their deletion is acceptable.
ENVIRON! ENTAL CONSIDERATIONS 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 a actior, which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR 5 51.5(d)(4) that an environmental impact statement or negative 'eclaration and environmental impact appraisal need not be pre;ared in c innection with the issuance of this amendment.
CONCLUSIONS We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a s:qnificant increase in the prcbability or consequences of accidents previou ly cor.sidered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) taere is reasonable assurance that the health and safety of the public will not te endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and tne issuance of this amendment will not be inimical to the common defense and security or :o the health and safety of the public.
Date: July 26,1979 1
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