ML17193A489
| ML17193A489 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/30/1980 |
| From: | Abel J COMMONWEALTH EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17193A490 | List: |
| References | |
| TASK-03-12, TASK-3-12, TASK-RR IEB-79-01B, IEB-79-1B, NUDOCS 8011040197 | |
| Download: ML17193A489 (3) | |
Text
nwealth Edison ational Plaza. Chicago. Illinois Addres, eply to: Post Office Box 767 Chicago, Illinois 60690 October 30, 1980
- Mr. Darrell G. Eisenhut, Director Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Dresden Station Unit 2 Response to NRC Order Concerning Environmental Qualification of Class IE Electrical Equipment NRC Docket Nos. 50-237 References ( a) :
D. G. Eisenhut letter to J. s. Abel dated September 19, 1980
( b) :
J. G. Keppler letter to c. Reed dated January 16, 1980
( c) :
J. G. Keppler letter to c. Reed dated September 30, 1980
Dear Mr. Eisenhut:
Reference (a) transmitted a Revised Order for Modification of License requiring Commonwealth Edison Company to submit certain environmental qualification of electrical equipment information by November 1, 1980.
Enclosed for your review is the three (3) volume Bechtel Power Corporation Final Report for Dresden Unit 2, entitled "Environmental Qualification of Electrical Equipment" (dated November 1, 1980).
In response to a particular SEP requirement of the order for Dresden Unit 2, Commonwealth Edison has elected to supply an analysis of the drywell pressure and temperature versus time for a small steam line break.
The resultant curves are included in the above report.
Supplemental information concerning this analysis will be supplied under separate cover by Nov~mber 1, 1980.
This information, in conjunction with the enclosed report, fully and completely responds to the staff's Revised Order.
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References (b) and (c) transmitted IE Bulletin 79-0lB and Supplement No. 2 to IE Bulletin 79-018 respectively.
Although these documents are not explicitly referenced by the Dresden Unit 2 Revised Orders, Commonwealth Edison assumes that Supplement No. 2 to IE Bulletin 79-0lB will be used by the Staff to measure the adequacy Aool s
1 /'fo
Mr. D. G. Eisenhut, Director October 30, 1980 Page 2 of our responses.
In that regard, we have provided information concerning position indication limit switches as indicated below:
(1)
Valve Position Indicators Supplement No. 2 to IE Bulletin 79-0lB, Question/Answer 5 states that "valve position indicators", among other items, should be qualified to function in the relevant accident environment.
This submittal addresses all safety related limit switches which have a control function.
None of the limit switches excluded from this report perform a safety related function, i.e., the switches do not activate or block any action designed to mitigate the consequences of an accident.
Supplement No. 2 to IE Bulletin 79-0lB made significant changes in previous staff directions in the following area:
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(2)
One Hour Plus Requirement Supplement No. 2 Question/Answer No. 12 states that equipment designed to perform its safety funciion within a short time into an event must be qualified for a period at least l hour in excess of the time assumed in the accident analysis.
The staff had previously indicated that it would be acceptable to environmentally qualify equipment that performs its safety function within a short time after an accident begins for the period of time it can reasonably be expected to be requiredll.
. This may be substantially less than l hour, for example, in the case of an isolation valve.
This submittal addresses all equipment from the standpoint of performing its safety function within the time frame the equipment is required to function.
We believe this approach to be technically justifiable.
Di~cussed in the August 27, 1980 Bethesda, Md. meeting attended among others by P. DiBenedetto, J. Lombardo, C. Crane and E.
McKenna for the NRC, and N. Smith and H. Stolt for Commonwealth Edison and in the July 28, 29, and 30 Dresden Station meeting attended among others by J. Lombardo and C. Crane for the NRC and R. Mirochna and N. Smith of Commonwealth Edison.
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Mr. O. G. Eisenhut, Director October 30, 1980 Page 3 In addition, this submittal may not be in explicit agreement with NRC Staff guidance in the following respect:
(3)
Radiation Source Terms The radiation source terms to be used in environmental qualification of electrical equipment are contained in NUREG-0578 and NUREG-0588 as referenced by IE Bulletin No. 79-018.
These documents require noble gases, halogens, and particulates to be released instantaneously.
The enclosed Environmental Qualification submittal has assumed noble gases are instantaneously released, with halogens and particulates released instantaneously after a time delay of ten minutes.
This is conservative relative to time dependent core release mec~anisms discussed in WASH-1400.
In the case of small break LOCA~s, Commonwealth Edison has determined HPCI to be a qualified system up to the point in an accident scenario where it is no longer needed.
At this point, the harsh radiation environment is assumed to exist (large break LOCA source term).
Although this requires the use of methods not explicitly contained in NUREG-0578 and NUREG-0588, we believe this approach to be technically sound.
- this office.
If you have any questions in this regard, please contact One (1) signed original and thirty-nine (39) copies of this response are provided for your use.
Ver.y truzyy yo rs,
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/'.,/,:/ J": S. Abel.
// Director of Nuclear Licensing cc:
Director, Division of Reactor Operations Inspection NRC RIII Inspector - Dresden w/o att.
1980 Notary Public 7789A