ML17331A296
| ML17331A296 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/26/1993 |
| From: | Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:0398Y, AEP:NRC:398Y, NUDOCS 9305030341 | |
| Download: ML17331A296 (5) | |
Text
ACCELERATED DOCUMENT DISTRIBUTION SYSTEM REGULAT INFORMATION DISTRIBUTIO1YSTEM (RIDE)
ACCESSION NBR'.9305030341 DOC.DATE: 93/04/26 NOTARIZED: NO DOCKET FACIL:5Q.-315 Donald C.
Cook Nuclear Power Plant, Unit 1, Indiana M
05000315 50-316 Donald C.
Cook Nuclear Power Plant, Unit 2, Indiana M
05000316 AUTH.NAME AUTHOR AFFILIATION FITZPATRICK,E.
Indiana Michigan Power Co. (formerly Indiana
& Michigan Ele RECIP.NAME RECIPIENT AFFILIATION MURLEY,T.E.
Document Control Branch (Document Control Desk)
I
SUBJECT:
Suppls 920515 ltr re status of mod of commitment re control room habitability,per GDC 19.Damper need no longer be maintained closed.TS changes s supporting analyses associated w/control room habitability will be submitted.
DISTRIBUTION CODE: A003D COPIES RECEIVED:LTR i ENCL 0 SIZE:
TITLE: OR/Licensing Submittal:
Suppl 1 to NUREG-0737(Generic Ltr 82-33)
NOTES:
D RECIPIENT ID CODE/NAME PD3-1 LA DEANFW INTERNAL: NR /JVR HHFBll EXILE 01 EXTERNAL: NRC PDR COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD3-1 PD OC/LFMB RES/DSIR/EIB NSIC COPIES LTTR ENCL D
D D
NOTE TO ALL"RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 10 ENCL
American Electric P~
Service Corporation~
1 Riverside Plaza Columbus, OH 43215 414 223 1000 SlNMICQN KI.MTQIC IrWM AEP:NRC:0398Y Donald C. Cook Nuclear Plant Units 1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
DPR-58 and DPR-74 MODIFICATION OF COMMITMENT REGARDING CONTROL ROOM HABITABILITY U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Attn:
T. E. Murley April 26, 1993
Dear Dr. Murley:
In our letter AEP:NRC:0398W, dated May 15, 1992, we provided the NRC with information on measures we have implemented at the Donald C.
Cook Nuclear Plant in order to bring the control room ventilation systems more in compliance with the NRC's interpretation of the dose limits of 10 CFR 50 Appendix A General Design Criteria (GDC) 19.
This letter provides an updated status regarding those measures.
In AEP:NRC:0398W, we committed to maintaining the (non-redundant) normal intake isolation damper in a closed position, and to limit allowable air intake rates such that the whole body and thyroid doses would be within the Standard Review Plan criteria of 5 and 30 rem, respectively.
(These measures would result in a corresponding skin dose of approximately 32 rem, which was within 7% of the 30 rem Standard Review Plan limit.)
Maintaining the normal intake isolation damper closed eliminated the need to account for the possible failure of this damper, and thus reduced the calculated dosee Although the control zoom remained habitable from an environmental perspective with the normal intake isolation damper closed, this was not a desirable long term solution since it does limit the amount of fresh air that enters the control room during normal operations.
In order to reduce the calculated doses and therefore demonstrate compliance with the Standard Review Plan dose criteria without relying on maintaining the normal intake isolation damper closed, we obtained the services of a meteorological consulting firm to provide a plant specific determination of the atmospheric dispersion term (Chi/Q) that is used in the analytical model.
The plant specific evaluation resiilted in a ninety fifthpercentile Chi/Q of
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Dr. T. E. Murley AEP:NRC:0398Y 7.85E-4 sec/m3, versus the previous value of 2.41E-3 sec/m3 which had been derived using the generic methodology referenced in the Standard Review Plan.
Since calculated doses are directly proportional to Chi/Q, the newly calculated doses are only one third of the previous.
The consultant's report is available for audit at the AEPSC offices in Columbus, OH and at the Cook Nuclear Plant.
The reduction in dose enables us to accommodate a failure of the non-redundant normal intake isolation damper to close while still demonstrating compliance with the Standard Review Plan dose limits
- dose, provided appropriate limits on air intake are applied.
(In accordance with the guidance of Section 6.4 of the Standard Review
- Plan, the damper is assumed to be closed manually two hours after the accident.)
Therefore, this damper need no longer be maintained closed.
Limits will be applied to air intake rates such that the Standard Review Plan dose limits for whole body, thyroid, and skin doses are met.
It is our intent to submit proposed technical specification changes (and the supporting analyses) associated with control room habitability.
This will be the subject of separate correspondence.
Sincerely, ee~~q E. E. Fitz atrick Vice President dr cc:
A. A. Blind Bridgman J.
R. Padgett G. Charnoff A. B. Davis Region III NRC Resident Inspector Bridgman NFEM Section Chief
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