ML20054D718
| ML20054D718 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 04/13/1982 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8204230311 | |
| Download: ML20054D718 (2) | |
Text
-/^N Commonwealth ECson
/
) one Fwst Nationti PIIza. ChicQo. Illinois.
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'O 7 Address Riply to: Post Ofhc3 Box 767
\\ y/ Chicago, Illinois 60690 April 13, 1982 m
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REcygyyy Mr. Harold R. Denton, Director 2
6' arm' Appg IbO2hZ r3 Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Amus pq Washington, DC 20555 g
Subject:
Zion Station Units 1 and 2 ATWS Modifications ( AMSAC)
Confirmatory Order Item C.4 NRC Docket Nos. 50-295/304 References (a):
H.R.
Denton let er to D.
L.
People s dated February 29, 1980.
(b):
E.D.
Swartz letter to H. R.
Denton dated November 10, 1981.
Dear Mr. Denton:
Included among the Reference (a) Confirmatory Order requirements for our Zion Station Units 1 and 2, was Item C.4 which required the submittal o f a schedule to implement the ATWS instru-ment modifications (AMSAC).
Reference (b) was provided to discuss the Commonwealth Edison Company difficulties in meeting our proposed implementation schedule for this Item C.4, due to the lack of NRC Staff guidance on and acceptance o f our proposed AMSAC design.
Additionally, Reference (b) discussed our submittal of the Zion Station Probabilistic Safety Study to the NRC.
Because this study clearly demonstrated that the NRC Staf f concerns which led to the imposition o f the " extraordinary interim measures" were unfounded, Commonwealth Edison had respectfully requested that all ongoing provisions of the Order be rescinced.
In view of the results o f the Zion study, it is our judgment that the installation o f any ATWS mitigation system will provide essentially zero reduction in the already low levels of risk associated with ATWS events.
Therefore, as discussed in Reference (b), any further NRC consideration o f an AMSAC installation on our Zion units in advance of the generic resolution o f the ATWS issue for all plants is wholly unjustifiable.
Ih 8204280 3 4.
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H. R. Denton April 13, 1982 In pursuit of our request to the NRC Staff for relief on the requirement for an advanced installation schedule associated with. Item C.4 A TWS instrument modifications, please be informed that j
the Zion Station Probabilistic Safety Stuoy did not take into account the installation o f AMSAC on -either unit. - The probabilities o f occurrence and consequences o f ATWS events were, determined solely on the basis of the existing plant systems as they are presently installed at Zion Station.
This has been discussed with Mr. David L. Wigginton.
4 Please address any further questions that you or your staf f l
may have regarding this issue to this office.
One -(l) signed original and thirty-nine (39) copies o f. this i
letter are provided for your use.
Very truly yours,
[.
]
E. Douglas Swartz Nuclear Licensing Administrator 1m cc:
J.
G. Keppler, Regional Adm - RIII Region III Inspecto r - Zion i
D. L.
Wigginton i
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