ML20070D604

Forwards SER for Return to Svc After Repair of Steam Generators.Final Plans for Steam Generator & RCS Cleanup & Results of post-repair Testing Will Be Addressed at Later Date.Affidavit Encl.Rept Withheld (Ref 10CFR2.790)

ML20070D604
Person / Time
Site:	Crane
Issue date:	12/10/1982
From:	Phyllis Clark GENERAL PUBLIC UTILITIES CORP.
To:	Eisenhut D Office of Nuclear Reactor Regulation
Shared Package
ML19268D514	List: ML20070D604 ML20070D618
References
5211-82-284, NUDOCS 8212150110
Download: ML20070D604 (2)

Text

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MNUC MF GPU Nuclear Corporation 100 lnterpace Parkway Parsippany. New Jersey 07054 l

201 263-6500 i

TELEX 136-482 l

Writer's Direct Dial Number:

Eccember 10, 1982 5211-82-284 l

l l

Office of Nuclaer Reactor Regulation i

Attn:

D. G. Eisenhut f

Division of Licensing U. S. Nuclear Regulatory Commission Wanhington, DC 20555

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

Operating License No. DPR-50 Docket No. 50-289 TMI-l OTSGs Enclosed is our Safety Evaluation for the return of TMI-l to service after repair of the steam generators. Final plans for steam generator and reactor coolant system cleanup and results of post-repair testing will be addressed later.

Present plans provide for a separate safety evaluation to be made of the effects of chemical cleaning prior to proceeding with the process.

The results of post-repair testing will be available on site.

The safety evaluation enclosed reflects internal GPU evaluation, and preliminary comments, questions and concerns raised by the independent Third Party Review (TPR) group. Further meetings with the TPR are to be held in the j

l future.

GPUN will address any further issues identified by the TPR and will

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keep you informed regarding the group's concerns.

The SER covers the testing and analysis which shaped our conclusions, and the comprehensive precritical and posteritical test program planned to confirm them.

The proposed startup program begins with testing and hydrostatic tests, followed by a period of hot precritical operation during which the steam i

generators will be subjected to both routine conditions and test transients selected to place proof loads on the tubes. Following return to service of i

the plant, an inservice insnection program is planned for the steam generator

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tubes to monitor for any unanticipated defect growth or initiation.

Finally, I

long term laboratory corrosion test program, leading operation by several a

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months, is also underway to simulate the planned future operational environment for the OTSG.

I Our work has brought us to the following conclusions:

1.

We have suf ficient understanding of the failure mechanism to assure safe operation and have taker steps to prevent its recurrence or reinitiation.

2.

Our inspection techniques have been adequate to find and characterize relevant damage in these steam generators and the remainder of the reactor coolant system.

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8212150110 821210 PDR ADOCK 05000289 P

PDR oon is a subsidiary of the General Pubhc Ut hties Corporation

Mr. D. G. Eietnhut 5211-82-284 3.

Our kinetic expansion repair technique is adequate to remove from service all significant defects above 8" above the lower face of the upper tube sheet. The repair creates a new tube-to-tubesheet joint below this point which meets the licensing basis of the original joint, and removes the degraded portions of tubing from the primary system pressure boundary.

4.

The number and distribution of tubes plugged is such that the performance of the steam generator remain within the licensed basis during normal, transient, and accident conditions.

5.

All tubing remaining in service has been examined and found to have no defects of a size which would propagate to failure due to normal operational vibration or loading, or to transient or accident loads.

6.

Neither the performance of the kinetic expansion and plugging repairs, nor the operation of the repaired aceam generators will have a detrimental effect on the remainder of the plant or on the environment.

These items have in turn led us to conclude that when the repairs are completed the steam generator will once again be operable as part of the primary pressure boundary within the licensed basis.

1 Further, the repaired steam generator will not have introduced the possibility of an unanalyzed accident or increased the probability of an analyzed accident.

We are aware of your desire to examine our work in this area, and will l

continue to supply you with updated information as it becomes available.

Our future work is proceeding with targets as follows:

i Early January complete kinetic expansion l

Mid-February complete post-repair cleanup Late February complete tube end milling Early March complete plugging Mid-March complete cold testing

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Late March complete RCS H202 cleaning Late April complete hot, precritical testing Please note that the enclosed document contains information which is considered proprietary.

We request that it be protected from public disclosure in accordance with 10 CFR 2.790.

l If you have any questions or need any further information, please contact us.

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Sinreircly, b

P. R. Clark Executive Vice President PRC:MJG: dis Enclosure

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