ML20235A247
| ML20235A247 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/31/1987 |
| From: | Standerfer F GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 4410-87-L-0192, 4410-87-L-192, NUDOCS 8801120168 | |
| Download: ML20235A247 (3) | |
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Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84-2386 Writer's Direct Dial Nurnber:
(717) 948-8461 December 31, 1987 4410-87-L-0192/0331P US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 f
Dear Sirs:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 Handling of Core Bore Equipment Above the Defueling Work Platform The purpose of this letter is to request NRC approval to modify the lift height limit for installation of the core bore machine on the Defueling Work Platform.
The Core Stratification Sample Acquisition Safety Evaluation Report (SER),
Revision 4 submitted via GPU Nuclear letter 4410-86-L-0101 dated June 11, 1986, evaluated the postulated drop of a load of 5000 lbs. onto the work platform. Based on this evaluation, the lift neight limit for the 5000 lbs.
load was set at elevation 339'-0".
The load was postulated to impact the interface platform that is mounted on top of the work platform. The interface platfonn would then transmit the impact load to the work platform main load bearing beams.
However, due to the incorporation of an underwater tool changer, an 18" high spacer platform will be installed between the work platform and the interface platform (see attached sketch). Note, the footprint for the spacer platform is identical to the interface platform. Thus, the lift height limit must be raised 18" to the 340'-6" elevation to facilitate installation and removal of the core bore machine.
The travel distance that the load will fall to the interface platform for a postulated drop remains the same as previously analyzed. Therefore, the impact energy of 409,000 in-lbs. that the falling object would develop if dropped remains the same as previously analyzed. The impact energy of 559,000 in-lbs. transmitted to the portion of the work platform along the load path over to the interface platform is also still within the allowable limit of 780,000 in-lbs. previously analyzed for the Core Stratification Sample Acquisition SER, 8801120168NNI251
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, 1987 4410-87-L-0192 The installation and removal procedure for the drill rig and underwater support structure will specify the shortest load path to further reduce the potential consequences of a postulated load drop.
Based on the above discussion, GPU Nuclear believes that the proposed increased lift height limit does not increase the probability or consequence of an accident previously evaluated, create an accident of a different type than previously evaluated, or reduce the margin of safety of any Technical Specification. In addition, this activity does not require a change to the plant's Technical Specifications.
Per the requirements of 10 CFR 170, an application fee of $150.00 is enclosed.
Sincerely,
/
Y-F. R. Standerfer Director, THI-2 CJD/eml Enclosed: GPU Nuclear Corp. Check No. 009111 cc: Regional Administrator, Region 1 - W. T. Russell Director, TMI-2 Cleanup Project Directorate - Dr. W. D. Travers
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