ML20055E001

Forwards Revs 1 & 2 to Topical Rept 067, TMI-1 Cycle 8 Core Operating Limits Rept, Per Tech Spec 6.9.5.4

ML20055E001
Person / Time
Site:	Three Mile Island
Issue date:	07/02/1990
From:	Hukill H GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20055E002	List: ML20055E001
References
C311-90-2056, NUDOCS 9007100262
Download: ML20055E001 (2)

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h OPU Nuclear Corporation One Upper Pond Road N U C I M r- Parsippany, New Jersey 07054

, 201-316-7000 1 TELEX 136-482 Writer's Direct Dial Number.

July 2, 1990 C311-90-2056 Di 1

U.S. Nuclear Regulatory Commission 'I Attn: Document Control Desk Washington, D.C. 20555

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Gentlemen Three Mile Island Nuclear Generating Station, Unit 1.(THI-1)  !

Operating License No. DPR-50 Docket No. 50-289 10 CFR 50.46 Notification - Linear Heat Rate Limits 1 i'

This letter is to inform the NRC of recent B&W Nuclear Services Corporation (BWNSC) Loss of Coolant Accident (LOCA) evaluations as they- t relate to THI-1.

GPUN confirms the applicability.to THI-1 of the recent BWNSC analysis which resulted in a revised peak cladding temperature (PCT) of 2194F for the 6 ft. core elevation. BWNSC previously provided a detailed.

notification to NRC in BWNSC letter J. H. Taylor to Dr. T. E. Murley, JHT/90-43, dated March 19, 1990.

I The revised PCT-is within the acceptance criteria of 10 CFR 50.46.- j However, the revised PCT resulte in a change of greater than SOF from that f i -previously calculated, and is therefore considered significant in 2 accordance with 10 CFR 50.46(a)(3)(ii).

As stated in the above referenced BWNSC' letter, additional analysis is ongoing for the 4 ft. case to verify the existing LOCA Linear Heat Rate limits. GPUN will provide additional notification, as appropriate, i

-regarding the applicability of this analysis when the results are available. l

'The March 19, 1990 BWNSC letter referenced above concluded that the B&W >

177-FA Lowered-Loop plants would continue to operate without restriction

-with the previously established LOCA LHR limits. These included an h

allowable LHR of.16.5 kw/ft at the 6-foot level for BOC conditions (0-1000 MWD /MTU) and increases to less restrictive LHRs after 1000 MWD /MTU at the '

2, 4'and 6-foot levels. These LHR increases would normally occur at 45 i 9007100262 900702

=POR ADOCK 05000'89 2 P pdc 6{0 3'1'0'111-GPU Nuclear Corporation is a subsidiary of General Public Utilities Corporation

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• U. S. Nuclear R:gulatory Commission July-2, 1990

-Page 2 C311-90-2056-5 Effective Full Power Days at TMI-1 with concurrent changes to LOCA-based core operating limits setpoints (rod insertion and axial power imbalance limits) as allowed by the Cycle 8 Core Operating Limits Report, Rev. 0 (previously provided to NRC for information per Technical Specification 6.9.5.4).

Based on further evaluation concerning the supportability of the current LHR limits after 40 EFPD, BWNSC has recommended that the conservative BOC limits be maintained'beyond 40 EFPD for all core elevations until a recalculation of burnup-dependent LHRs is completed. GPUN concurs with the BWNSC recommendation for THI-1. Administrative changes were implemented to the Cycle 8 COLR and applicable plant procedures that maintain conservative BOC LOCA-based core operating limits beyond 40 EFPD.

Revisionn 1 and 2 to the TMI-1 Cycle 8 COLR are-attached in accordance with Technical Specification 6.9.5.4. Revision 2 was issued to correct limits after 100 EFPD (e.g. shutdown margin-rod insertion limits) omitted in Revision 1. THI-1 Cycle 8 reached 80 EFPD on June 12, 1990. It should be noted further that the BOC operating limits for THI-1 in the Cycle 8 COLR, and the DOC LOCA LHR setpoints in effect for Cycle 8, are based conservatively on an LHR of 16.1 kw/ft at the 6-foot level, even though the current analyses support 16.5 kw/ft, as discussed above.

Sincerely, _

H. D. Hunll Vice President & Director, THI-1 Attachment HDH/cjg ces. J. Stolz, USNRC R. Hernan, USNRC T. Martin, USNRC, Region I F. Young, USNRC, TMI-1 310111 l

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