ML20054L123
| ML20054L123 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 07/01/1982 |
| From: | Garrity J Maine Yankee |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| JHG-82-122, MN-82-127, NUDOCS 8207070170 | |
| Download: ML20054L123 (3) | |
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July 1, 1982 MN-82-127 JHG-82-122 United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention: Office of Nuclear Reactor Regulation Division of Licensing Operatirg Reactors Branch #3 Mr. Robert A. Clark, Chief
References:
(a) License No. ORP-36 (Docket No. 50-309)
Subject:
Fire Protection - RCP Oil Collection System Exemption Request
Dear Sir:
Maine Yankee Atomic Power Company requests an exemption from the requirements of Section III.0 of Appendix R to 10 CFR Part 50.Section III.0 identifies the requirements for design, engineering, and installation of a Ieactor coolant pump oil collection system to ensure that a lube oil system failure will not lead to fire during normal or design basis accident conditions.
This exemption is justified for the following reasons:
a.
Containment Building Loop Area Layout There are three loop areas within the reactor containment building, each of similar equipment and volume.
Each loop contains a steam generator, a reactor coolant pump, 2 loop stop valves, other associated valves and piping, and instrumentation taps.
The loop areas are surrounded by massive concrete walls, floors, and ceilings.
Each loop contains a small rectangular opening for gaining entrance into the loops.
In the event of a loop fire, components are widely separated and redundant functions will not likely be involved due to the localized and limited sources of combustibles within the containment building. Considering the large volume of each loop aIea and the small quantity of lube oil contained in each RCP motor (approx.140 gallons), a fire would likely be of limited duration and propagation outside a loop area is not expected. Construction of small curbs would contain and preclude any spread of fire.
8207070170 820701 PDR ADOCK 05000309 p
M AINE YANKEE ATOMIC POWER COMPANY
=
United States Nuclear Regulatory Commission July 1, 1982 Attention: Mr. Robert A. Clark Page two b.
Lube Oil Fire Detection / Suppression There are two sensing elements of the smoke detection system in each loop, which will alarm in the control room in the* event of a fire caused by a lube oil system failure.
In addition, other means are available to the plant operator for fire detection, such as high RCP bearing temperatures, abnormal oil reservoir levels, and increasing pump vibration readings. Fire stopression equipment is located outside each loop area (dry chemical type extinguishers), with two firewater hose stations also available at different containment locations. Fire suppression equipment could be utilized during normal conditions.
However, during off normal events, fire suppression equipment may or may not be available depending on the accessibility of the loop area.
It is understood that it is not the intent to have fire suppression capabilities during a design basis LOCA, as containment environmental conditions would virtually preclude a fire occurrence.
The present detection / suppression systems are considered adequate, since fire effects do not adversely impact on safe shutdown, therefore elaborate fire systems are not justifiable.
c.
Safe Shutdown Capability Emergency power supplies and motor control centers would not be affected by a loop fire, as these are all housed outside the containment building. Reactor coolant system interfacing valves would not change position due to fire effects, as energizing control centers are located outside the loop areas.
In the event of a loop fire, all or numerous electrical connections and cable may fail however RCS parameters could still be monitored from the other Ewo unaffected loops.
In addition, secondary plant pressure could also be used for determining primary plant temperature.
Primary system makeup and decay heat removal would remain available due to the numerous redundant systems.
The two unaffected loops would provide primary plant cooldown through normal means using forced or natural circulation via the steam generators or any of the emergency safety systems.
The ability to reach and maintain a safe shutdown condition is not compromised by the occurrence of a fire in the loop area. Adequate fire detection means presently exist.
It is expected that a fire will be contained within the concrete loop barriers, with the two unaffected loops providing means for a primary plant cooldown.
We are continuing to verify the above justification information.
If this verification process uncovers needed additions or corrections, they will be supplied in a timely manner.
MAINE YANKEE ATOMIC POWER COMPANY United States Nuclear Regulatory Commission July 1, 1982 Attention: Mr. Robert A. Clark, Chief Page 3 We trust this information is satisfactory. However, should you have any questions please do not hesitate to contact us.
Very truly yours, MAINE YANKEE ATOMIC POWER COMPANY
/dA
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John H. Garrity, Senior Director, Nuclear Engineering and Licensing JHG:pjp