ML19319E078
| ML19319E078 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/24/1972 |
| From: | Davis E SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8003310588 | |
| Download: ML19319E078 (2) | |
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-SACRAMENTO MUNICIPAL UTILITY DISTRICI O 6201 S Street, Box 15830, Sacrainento, Califemia 95813; (916) 452 3211 October 24, 1972 4
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[Q g6,y. cA Mr. Angelo Giambusso i
o Deputy Director for Reactor Projects
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Dictorate of Licensing 5,3,
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U. S. Atomic Energy Commission g T-fi c@
QS 1ashington, D. C.
20545 Jh[$.VN -- db Rancho' Seco Nuclear Generating' Station, Unit No. 'l AEC Docket No. 50-312 Failure of Non-Category I Equipment ti
Dear Mr. Giambusso:
As requested in your letter of September 26, 1972, the District has reviewed the design of the Rancho Seco Nuclear Gencrating Station to
' determine the effect of f ailure of any non-category I (seismic) equipment j
on equipment
- required for safe shutdown of the facility or to limit the l
consequences of an accident.
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The results of this review indicate that the f ailure of non-category I (seismic) equipment would not result in flooding or the release of chemicals which would adversely affect category I equipment.
The potential for flooding by failure of the fire protection system was previously reviewed and is discussed in response 9A.36 to AEC request 9.37 and the design features provided to preclude flooding due to f ailure of the fire protection system are described.
The circulating cooling water system and the plant cooling water system each contain rubber expansion joints. The circulating water system piping is underground except for the portion in the condenser pit in the -
turbine building. The pit has a capacity of approximately 350,000 gallons.
Floor drains in the pit prevent water from reaching grade level due to moderate leakage. In the event of a large leak, the control room operator will receive a low 1cvel alarm on the intake structure before the level in the condenser pit reaches 5 feet below grade. This provides him with
- suff *cient time to' shutdown the circulating water pumps which are controlled in the control room. However, if no operator action is taken, and in the unlikely event that the pit does fill, all the water will drain to the west side of the turbine building and no safety related equipment will be affected.
This is because the west side of the pit is one foot below grade, and the
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area slope is away from safety related equipment.
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Mr. Angelo Giambusso October 24, 1972 N
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l Portions of the plant cooling water system which present a i
flooding potential are located in the outside area north of the reactor building. This area is covered with 6" of gravel and a catch basin with a _15" drain line is situated there. All safety related equipment in l
this area is set above grade by at least 4".
The downward slope from the catch basin is away from any safety related equipment. Thus, even in the unlikely event that the catch basin fills, the water would flow out of this area without ever rising to the level of safety related equipment.
In addition to the flooding question, the District has reviewed the effect of failure of the CO2 system on electrical and mechanical equip-ment. The design and location of the CO2 system relative to the equipment 4
being protected minimizes thermal shock.- Based on the District's prelimi-nary review of the effect of CO2 system failure, we have not found any electrical or mechanical equipment that would be unable to perform its safety related function as a result of failure or inadverent operation of the CO2 system. It should be noted that the Rancho Seco CO2 system is a category I (seismic) system. We will continue our review efforts in this area in more detail to confirm that no safety related equipment can be adversely'affected by the postulated failures.
S,6(relyyours, F,-
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E. K. Davis General Manager
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