ML20217E036

Forwards Rev 0 to Topical Rept TR-121, TMI-1 Control Room Habitability for Max Hypothetical Accident for Review & Approval by 980630 to Support Planned TS Change Requests Addressing TMI-1 NRC Insp Open Items

ML20217E036
Person / Time
Site:	Three Mile Island
Issue date:	03/24/1998
From:	Rone A GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20217E040	List: E000-98-012, Forwards Rev 0 to Topical Rept TR-121, TMI-1 Control Room Habitability for Max Hypothetical Accident for Review & Approval by 980630 to Support Planned TS Change Requests Addressing TMI-1 NRC Insp Open Items ML20217E081 ML20217E117 ML20217E166 ML20217E197
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-3.D.3.4, TASK-TM 1920-98-20145, E-98-12, E000-98-012, NUDOCS 9803300365
Download: ML20217E036 (2)

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GPU Nuclear,Inc.

l g One Upper Pond Road Parsippany, NJ 070541095 NUCLEAR

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March 24,1998 I 1920-98-20145 E000-98-012 l

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U.S. Nuclear Regulatory Commission

~ Attention: Document Control Desk

-Washington,DC 20555 y

i Gentlemenf

Subject:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 \

Control Room Ilabitability Evaluation In response to the NRC letter to GPU Nuclear, dated September 24,1997 (6710-97-3439),GPU Nuclear is submitting the enclosed Topical Report TR-121,"TMI-l Control Room Habitability for Maximum Ilypothetical Accident". This Topical Report provides an analysis of control room operator thyroid dose, as well as reanalysis of control room operator whole body and skin dose consequences,resulting from postulated design basis accidents.

TMI-l control room habitability (NUREG-0737, Item III.D.3.4) was previously reviewed and approved by NRC Supplemental Safety Evaluation Report dated August 14,1986. TMI-1 was required to address only the whole body and skin doses since consideration of thyroid dose from iodine releases was deferred until completion of the NRC source term reevaluation effort. This source term reevaluation effort is still ongoing. As a result, GPU Nuclear was requested by NRC in the above-referencedletter to provide an analysis of the control room operator thyroid dose based on the existing TID-14844 accident source term releases.

.-9803300365 DR 980324 ADOCK 05000289 i

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/ page 2 of 2 I The enclosed TMI-l control room habitability evaluation incorporates updated analytical methodologies and assumptions as described in TR-121. The results of this evaluation continue to satisfy the intent of GDC-19 and NUREG-0737, Item III.D.3.4, for control room habitability based on the conservatism contained in the TID-14844 source terms assumed and the performance of the control building ventilation (CBVS) system and control building envelope (CBE). Periodic inspection of CBVS dampers and CBE door seals will be performed to maintain their integrity.

Periodic testing of CBVS flow rates and area pressures will be performed to verify the ability to maintain positive pressures and preclude negative pressures. Additionally,it is noted that breathing apparatus and potassium iodide will continue to be available to the control room operator which would further reduce the calculated dose results.

The TID-14844 accident source term assumptions are acknowledged to be inherently conservative and our expectation is that reanalysis using the new revised accident source terms, currently approved only for use in new plants, would result in a significant reduction in the calculated control room dose values contained in the attached TR-121.

GPU Nuclear requests NRC review and approval of the enclosed TMI-l control room habitability evaluation by June 30,1998 in order to support planned Technical Specification Change Requests addressing TMI-l NRC inspection open items. GPU Nuclear is available to respond to any NRC review questions or clarifications.

If additional information is required, please contact Mr. David J. Distel, Nuclear Safety &

Licensing,at (973) 316-7955.

Sincerely, i

/?lR A. H. Rone Vice President and Director, Engineering

/DJD cc: Administrator, Region I TMI-l Senior Project Manager TMI Senior ResidentInspector Encl. 1. GPU Nuclear Topical Report TR-121, Rev. O, "TMI-l Control Room Habitability for Maximumilypothetical Accident"

2. GPU Nuclear Calculation C-1101-826-E540-020,Rev. O, " Atmospheric Transport X/Q's Using Arcon 96 Code - Control Room llabitability", March 1998

3. GPU NuclearCalculationC-1101-826 E540-022,Rev. O,"EstimateofX/Q Values for TMI-l Control Building Ventilation System Exhaust", March 1998

4. GPU Nuclear Calculation C-1101-826-E540-025, Rev. O,"X/Q @ TM1 Ventilation System Exhaust", March 1998

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