ML19254D221
| ML19254D221 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/11/1979 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910230140 | |
| Download: ML19254D221 (4) | |
Text
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.c, UNITED STATES
[' ' {#[ }j NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 5
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OCT 111379 MEMORANDUM FOR:
R. Reid, Chief, Operating Reactors Branch #4, D0R FROM:
G. Lainas, Chief, Plant Systens Branch, DDR
SUBJECT:
RANCHO SECO FIRE PROTECTION MODIFICATIONS Sy letters of August 31, and September 4,1979, Sacramento Municipal Utility District (SMJD) submitted certain details related to proposed modifications listed in our Fire Protection SER of February 23, 1978.
We have reviewed these details and find the proposed modifications acceptable.
Enclosed is a draft of a letter to be sent to SMUD in response to the above letters.
cu~
/G, Lainas, Chief
/ Plant Systems Branch Division of Operating Reactors
Enclosure:
As stated
Contact:
H. George X-27136 cc w/ enclosure:
D. Eisenhut D. Garner B. Grimes V. Benaroya W. Gammill E. Sylvester R. Ferguson D. Notley G. Lainas H. George
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7910230
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Mr. J.J. Mattimoe Assistant General and Chief Engineer Sacramento Municipal Utility District 6201 S Street P.O. Bo>.15830 Sacramento, CA 95813
Dear Mr. Mattimoe:
By letters dated August 31, and September 4,1979, you provided infomation relative to certain modifications identified in Section 3 of the Fire Protection Safety Evaluation Report (SER) for the Rancho Seco Nuclear Generating Station (see Amendment No. 19 of February 28,1978).
This information described +' means for implementing the above modifications, which are scheduled for implementation by the end of the 1970 refueling outage.
The above letters also described certain deviations you desired to make relative to these modifications.
This letter is to advise you
. of the staff's conclusions regarding the acceptability of the modifications, and the acceptability of the requested deviations.
Your letter of August 31, 1979, requested a deviation from the following previously approved modification for the west 480 volt switchgear room:
3.1.8(1)
Install a themal barrier around conduits containing L,annel B cables associated with: high pressure injection systems; auxiliary feedwater system, remote control for decay heat system valves; channels B, C and D control rod drive trip system circuits; and channels B and C safety features actuation.
1189 242 A similar descri9 tion of the proposed modification is contained in Section 5.3.6 of the SER.
The deviatic:. requested was to allow either rerouting of these cables or the protection as described above.
Your letter of September 4,1979, requested the same deviation for the previously approved modification for the east 480 volt switchgear room
( 3. '.11 (1 )).
We find the alternate approach provides equivalent or superior protection to the original proposed modification.
We conclude that there is reasonable assurance that the deviations you requested relative to the modification described in Sections 3.1.8(1) and 3.1.11(1) of the SER will allow the fire protection for these areas to continue to conform to the guidance set forth in Section 2 of the SER.
We, therefore, conclude that these deviations are acceptable.
Your letters of August 31, and September 4,1979 also described the designs 3 c u propose for implementing these modifications.
We find that:
(1) the proposed thermal barriers confom to a design that has been adequately tested to demonstrate its fire resistance, (2) the proposed rerouting of certain circuits out of the subject areas will assure that fires in these areas will not cause loss of these safe shutdown functions, and (3) the changes to Reactor Protection System routing will assure that a fire in these areas will not prevent a reactor trip. Based on the foregoing, we conclude that the designs you have proposed for implementing 1189 243
these modifications will provide the protection the staff intended in its preparation of the SER and, therefore, are acceptable.
Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors 1189 244