ML20032E497
| ML20032E497 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 11/17/1981 |
| From: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8111200618 | |
| Download: ML20032E497 (3) | |
Text
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O THE CINCINNATI GAS & ELECTRIC COMPANY di J
CINCINN ATI. OHIO 45201 E. A. BO RG M AN N stNice vu:t PatsIDENT Docket No. 50-358 November 17, 1981 Mr. Harold Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 RE: WM. H. ZIMMER NUCLEAR POWER STATION -
UNIT 1 - CONTAINMENT LEAKAGE TESTING
Dear Mr. Denton:
The attachment to this letter discusses The Cincinnati Gas
& Electric Company's position and response to Section 1.8, Summary of Outstanding Issues in the Second Supplement to the Zimmer Safety Evaluation Report (NUREG-0528). The outstanding issue of containment leakage testing is further discussed in Subsection 6.2.6 of SSER-2.
The attached material will be documented in a subsequent FSAR Revision.
Very truly yours, THE CINCINNATI GAS & ELECTRIC COMPANY ff n~
By E. A. BORGMANN EAB: dew Enclosure cc:
John H. Frye III M. Stanley Livingston y
s Frank F. Hooper ff Troy B. Conner, Jr.
, p'r p 9,
James P. Fenstermaker g g#
l Steven G. Smith w
t NOV.
William J. Moran
,6 u.s = I 9 193; u J. Robert Newlin
^
w Samuel H. Porter
\\-x a w n %ot V James D. Flynn
'NQ' W. F. Christianson g
James H. Feldman, Jr.
N John D. Woliver Mary Reder David K. Martin Andrew B. Dennison 8l 0
George E. Pattison bl l 8111200618 811117' 05000 58 gDRADOCK
~ _. - _
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Docket No. 50-358 November 17, 1981 Zimmer's SER Supplement 2, dated October,1981, Subsection 6.2.6 requires that CG&E demonstrate a 30 day water seal on our ECCS injection lines following the loss of a diesel.
Furthermore, if we cannot demon:trate this 30 day water seal then we will have to air test these valves.
We are very concerned that the Staff is focusing on water sealing to the exclusion of other methods for retaining gaseous fission products inside containment.
Another method of retaining the fission products is to have a " closed" system outboard of the isolation valve. This philosophy is that, even if the isolation valve leaks, the leakage is contained and not released to the environment.
A closed system was the alternative criteria evaluated in-the original Zimmer SER to determine that our systems were acceptable from a containment integrity point of view. We remain totally convinced that this logic still applies regardless of whether jockey pump fails as before or whether both jockey and main pumps are lost due to diesel failure.
In fact, we believe that the closed system concept is much better than the water seal concept for the diesel failure scenario. This is because the diesel failure could conceivably happen at a time during the i
accident (i.e., after the isolation valve is open). Having a leak tight l
l valve in this case would do no good, the valve-would be open. With the a
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" closed" system concept as at Zimmer, whether the valve is leak tight or open makes no difference since the effluent is contained in either case.
l CG&E does not feel, given the NRC's criteria, that we can demonstrate a 30 day water seal.
It would appear that we are therefore required to l
perform an air test of the valves in question.
But to perform this air test would require the addition of extra containment isolation valves. These l
l I
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. additional valves are necessary to gain a testable boundary and proper test pressure orientation. To add these valves would mean the expenditure of large sums of money and large schedule delays due to procurement, installation, and testing. All this with no safety gain and not necessary for the reasons discussed above.
There is no improvement in safety associated with the additional valves needed to air test, they are manual valves and would not be accessible during an accident, plus a leak rate established up to 18 months prior might not still be valid. There may even be a net negative impact on safety if these valves were somehow closed when they should have been open, preventing ECCS injection.
In sunnary, CG&E believes that the high cost of complying with the staff's position and the potential negative safety impact does not justify this equipment. We feel confident, that our closed system approach properly addresses this subject. lle, therefore, feel that the Zimmer design is acceptable and this issue should be closed out in our SER.
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