ML17238A797

Quad-Cities Station Units 1 and 2 Anticipated Transient Without Scram (ATWS)

ML17238A797
Person / Time
Site:	Dresden, Quad Cities
Issue date:	04/03/1975
From:	Abel J Commonwealth Edison Co
To:	Anthony Giambusso Office of Nuclear Reactor Regulation
References
Download: ML17238A797 (2)

Text

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Commonwe. Edi so;~.

One Firs!* National Plaza, Chicago, llli:1oi::;

Address-FYep1y to: Pos-10ttice8ox-7Ef7 Chicago, Illinois 60690 i,.

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. Mr. Angelo Giambusso,, Director Division of Reactor. Licensing

• • .* u~s. Nuclear Regulatory commission Washington, D~C.

20555

Dear Mr. Giambusso:

.In response to, your letter dated October 19, 1973,

• .attached is a report which describes a study of the consequences of postulated A'rWS events.

This report entitled "Anticipated Transients With9ut Scram:

Study for Dresden 2, 3 and Quad-Cities*

1, 2 Nublear Power Stations"~ ~ED0-2084~, dated March 1975 is submitted in conformance with WASH-1270, Appendix A, Se.ct ion

.II.C.l.

As discussed iri previous letters to you dated December 10, 1973 and October 7, 1974, Commonwealth Edison Company considers a total failure to scra.."Tl in conjunction with a significant transient so unlikely that there is no significant risk associated with the ATWS event postulated_.

Further justification of this conclusion is contained' in the introduction of th~ attached report.

On the

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bas.is of these considerations, backfitting the plant modifications identified in the attached report is not recommended; because the modifications will not significantly improve-public health and safety.

The analyses performed in the attached report used a re~

lief valve capacity which is available from eight (8) Target-Rock combination s(1fety-relief valves.. It is planned to modify alJ.. Qr~ _1 four (4) units.to the configuration of eight (8) combination Si~~t relief valves during.the Fall 1975 and{~)'t-eling outages.

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• .Mr.. Angelo '(;iambus so

• Page. 2 April 3, 1975

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• :,,* : Presently, ail** four '(4) units are equipped with four * (4) electro..:..

• . inatic relief valves, one ( 1) combination safety-:-relief valve arid

• • eig&t (8) spring sa~ety valvei.

s{nc~ the results of the analyses

• for the 8-valve confitjuration will overestimate the consequences for.the present 13-valve configuration, the report is.conservatively applicable to the. present plant configurations.

one (1) signed original and 39 copies of ):his study are

.. subn{itt~d for your information.

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.. very t r.uiy yours' 4~:;1*//.*... *...

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J *. S. Abel.

Nuc.lear Lfcensing Administrator Boiling Water Reactors*

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