ML19275A276
| ML19275A276 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 09/28/1979 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Miller W NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| NUDOCS 7910030445 | |
| Download: ML19275A276 (1) | |
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't S M U D SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452 3211 September 28, 1979 U.
S. Nuclear Regulatory Commission ATTN:
William O. Miller, Chief License Fee Management Branch Office of Administration Washington, D. C.
20555
Dear Mr. Miller:
Please refer to the attached copy of our letter addressed to Mr. Robert W.
Reid dated September 4,
- 1979, wherein the District requests that approval be given to changes in paragraph 3.1.11(1) and to the design criteria to implement the change to the Fire Protection Safety Evaluation Report attached to License Amendment No. 19 dated February 23, 1978.
We are enclosing our check in the amount of $4,000 in payment of the fee required for NRC's review of the above mentioned letter.
The enclosed license fee is paid under protest since a lawsuit is on file in the United States Court of Appeal for the 5th Circuit (Mississippi Power & Light Co.,
et al. vs.
United States Nuclear Regulatory Commission, et al. Civ. No.
78-1565) to obtain review of the validity of tbose rules.
Sincerely, MdW John J. Mattimoe Assistant General Manager and Chief Engineer Encl.
cc:
Mr. Robert W.
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Feptenber 4, 1979 Director of Nuclear React 6r Regulation Attention:
Mr. Rebert 'J.
Reid, Chief Ooeratinq Reactors, Branch No. 4 U. S. Nuclear Rcoulatory Comission Washington, D. C. 20555 l
l Docket Un. % -31 2 Rancho Seco Nuclear Generatinq Station, ' nit No.1
Dear Mr. Reid:
Paraoraph 3.1.11(1) of the Fire Protection Safety Evaluation Report attached to License Anendment No. 19, dated February 28, 1978 i
8 describes the followinq modification for the east 480 switchgear room:
" Install themal barriers over all channals A, C, and D conduits containing cables required for safe shutdown."
The District requests that the paragraoh be rewritten to state the following:
" Reroute or install a themal barrier over all channel A, C, and 0 conduits containing cables whose failure could prevent a safe shutdown and/or cooldewn.
This chance is necessary to allow the District the ootion of either rerouting or installing fire barriers on all channel A, C and D conduits containing cables, required for safe shutdcwn and cooldcwn. The existing paragraph does not give the District the option of rercuting.
Licensing kendrrent tio.19 reauested that design details en the proposed modification in paragraph 3.1.11(1) be submitted to the NRC to assure that the desian is acceptable.
The design details based on the NRC cccepting the District's proposed rewording of the paragraph, are listed below.
esign Details for Inolecentino paranraoh 3.1.11(1) r The design criteria is to ensure that no function or indication required for saft shutdown and cooldown is lost or made inoperative for a design basis fire in the east 480 volt switchgear room.
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Mr. Reid September 4, 1979 The east 480 volt switchgear room is a channel "B" room, and a design basis fire in this room will cause the loss of B channel functions.
Therefore the modifications are designed to protect channel A C and D circuits which are required for safe chutdown and cooldown. This will be accomplished by the following methods:
1.
Insulating channel A conduits that are routed through the room that contains circuits required for safe sh'.'tdown and cooldown. The conduits will be insulated with two inches of fiberfrax hot board manufactured by Carrorundun Company. The insulation will be Jacketed with.016 inch stainless steel sheets held in place with stainless steel bands.
A description of the qualifying test perfomed on this insulation system is in the District's Fire Stop Test Report, test set-up one, conduit insulation fire test two. This test report was submitted to the NRC on March 1, 1978.
2.
Routing required circuits out of the east 480 volt switchgear room through other fire areas. When this is done, a fire hazard analysis will be performed for all the areas that the circuit is routed through to ensure a safe shutdown and cooldown is still possible with a design basis fire in the area with the new circuit.
3.
Reroute the control drive trip circuits that interconnect the Reactor Protection System and control rod drive system in separate conduits. These ciicuits fail safe, i.e.
cause a reactor trip on an open, short on ground. However, they were routed in conduits with other circuits and a failure mode existed where the trip circuits could interact with other circuits in the conduit and fail in a non-safe direction. Rerouting the circuit in a separate conduit corrects this problem.
The proposed modification in wording to paragraph 3.1.11(1) and the criteria used to implement the modification ensure that a design basis fire in East 480 volt switchgear room will not prevent safe shutdown and cooldown.
To complete the modification described in paragraph 3.1.11(1) by the end of the 1979-1980 refueling as required by Table 3.1 of the Safety Evaluation Report attached to Amendment No.19, the District requests NRC coments and/or approval on the change in paragraph 3.1.11(1) and the design criteria to implement this change by October 15, 1979.
Sincerely yours, John J. Mattimoe Assistant General Manager and Chief Engineer RFlhdd d 109334[