ML17037C103
| ML17037C103 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 04/05/1972 |
| From: | Schneider F Niagara Mohawk Power Corp |
| To: | Skovholt D US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17037C103 (4) | |
Text
NIAGARA MOHAWK POWER CORPORATION NIAGARA~
MOHAWK 300 ERIE 8OUI EVARD WEST SYRACUSE; H.Y. IMOR
>pegulatoI'y April 5, 1972 FllS Cga Mr. Donald J. Skovholt Assistant Director for Reactor Operations Division of Reactor Licensing United States Atomic Energy Commission Washington, D. C.
20545
Dear Mr. Skovholt:
S
~l Re:
Provisional Operating License DPR-17 Docket No. 50-220 l<e were asked by the Commission to inspect the interior of the torus on Nine Mile Point Nuclear Station, Unit 81 during the April '2-May 13 poison-curtain removal outage to determine if any damage to the baffling had occurred due to discharge of steam from %he electromaticrelief Valves.
It may be necessary to remove all water from the torus to make an effec-tive inspection.
In the Technical Specifications for the Station, page 32, section 3.1.4 (e),
it states:-
"Ifboth core spray systems become inoperable',
the reactor'hall be in the cold shutdown condition within ten hours and no work shall be performed on the reactor or its connected systems which could result in lowering the reactor water level to more than seven feet-eleven inches below minimum normal level."
Ne desire to perform control rod drive maintenance during the time the torus water would be at a level below net minimum positive suction head, therefore, the core spray and containment spray systems would not perform as its intended design function.
However, in the unlikely event;that some malfunction occurred during the time the contxol rod drive is being removed and it could be possible for react drain through the opening, coverage of the fuel would be o
ollowing ways:
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Mr. Donald J. Skovholt April 5, 1972 1)
The drive would not be completely removed until water flow had stopped.
Should flow continue, it would be jacked back onto the flange and re-bolted.
2) 3)
A large inventory of water in the refueling cavity and equipment storage pit are available (400,000 gals.)
above the seven foot-eleven inch specification.
This would provide more than two hours time by most conservative calculation in which to plug the opening.
Core spray pumps may pump condensate from condensate storage tanks to the reactor vessel in the same manner as from the suction in the torus.
4)
Condensate from the condenser hot-well may be pumped to the reactor through the normal feed water chain.
5)
One or the other of 3 or 4 would always be available.
6)
Enough condensate would always be in storage to bring the level in the torus to specifications.
At this point, a self contained system is again established and the core spray pumps are again able to perform their intended function.
7) written procedures will be established to implement this tempor-ary condition.
In view of small probability of the problem arising and the high degree of protection afforded by the above, we request temporary relief from this con-dition for operation during the time the torus might be unwatered.
This plan has been reviewed by both the onsite and 'offsite safety committees who find no safety implications provided the plan is carried forth as described.
, Very truly yours, F. J. Schneider Vice President
- Operations FJS:pw
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