ML20003H720
| ML20003H720 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 05/04/1981 |
| From: | Flynn J CINCINNATI GAS & ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NRC-212.79, NUDOCS 8105070322 | |
| Download: ML20003H720 (2) | |
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THE CINCINNATI GAS & ELECTRIC COMPANY Mb #
E c t NCIN N A?l O HIO -15 2 Cl
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May 4, 1981 Docket No. 50-358 e%%
06 Mr. Harold Denton, Director 788/g g
o Office on Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission b
Washington, D.C.
20555
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-RE:
WM. H.
ZIMMER NUCLEAR POWER STATION-U NRC 0212.79
Dear Mr. Denton:
Attached are two copies of an amended response to l
Question 212.79.
This question was sent to CG&E by the NRC on February 13, 1981.
This information will be incorporated into a May revision of the FSAR.
Very truly yours, THE CINCINNATI GAS & ELECTRIC COMPANY l
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By JAMES D. FLYNN JDF:gaj Attachment cc:
Service List Yy t (l 8105070 3 2 1
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ZIMMER RESPONSE TO QUESTION 212.79 212.79 Review Procedure 111.20 of SRP 6.3 requires that long term cooling capability following a LOCA should be adequate in the event of failure of any single active or passive component of the ECCS.
We require the applicant to discuss how leakage from the first isolation valve in an ECCS suction line from the suppression pool during post LOCA long term cooling will be contained. Our concern is a drainage of the suppression pool (heat sink) in view of the possible inaccessa-bility for repair of a leaking valve due to local contamination.
We have reviewed the above question and decermined three possible leakage scenarios.
They are:
(1) failure of the valve body and consequent leakage (2) leakage past the valve seat (3) leakage out of the valve via its packing In response to the above scenarios:
(1) Our valves are seismically designed and hydrostatically tested which insure valve body integrity.
(2) leakage past the seat would be contained in seismically designed piping and limited to the volume of pipe up to the next valve.
(3) Our valves are designed with a backseat to prevent leakage through the packing.
Further Information and Comment:
Even if the backseat feature mentioned in item (3) above should not function properly, it is reasonable to expect the leakage through the valve backseat and packing would not exceed 1 or 2 G.P.M.
Adding significant additional conservatism assume the leakage were as much as 5 G.P.M.
The total leakage would then be 25 G.P.M.
(5 G.P.M. x 5 valves).
The Zimmer Station has (4) Reactor Building Sump Pumps, each capable of 25 G.P.M.
for a 200 G.P.M. total.
These pumps would return any valve leakage to the condensate system via the radwaste treatment system.
CG&E believes this additional information resolves this matter.
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