ML20137V237
| ML20137V237 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/18/1985 |
| From: | Fee W, Opeka J, Opela J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| FO816A, SD-85, NUDOCS 8510030426 | |
| Download: ML20137V237 (2) | |
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(203)665 500 September 18,1985 Docket No. 50-42 3 F0316A Dr. Thomas E. Murley Regional Administrator U.S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406
References:
(1) laspection & Enforcement Notice 85-45.
(2)
J. F. Opeka letter to T. E. Murley, F0809A, dated July 26, 1985.
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e):
Seismic Interaction Between the Flux Manoing System and Seal Table (SD-85)
In a June 26,1985 telephone conversation between your Mr. H. F. VanKessel and our Mr. P. J. Quinlan, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the design of Millstone Unit N o.
3 in accordance with 10CFR 50.55(e).
The significant deficiency involves the potential seismic interaction of the flux mapping sys tem with the seal table / bottom mounted instrumentation, Reference (1).
This condition was under evaluation by both Stone & Webster Engineering Corporation and Westinghouse, as noted in Reference (2) and the evaluation is now complete.
The equipment was reviewed to ensure that the flux mapping equipment would not become a gravity missile during a seismic event and interact with the seal table pressure boundary.
The support for the equipment was seismically analyzed by Stone & Webster Engineering Corporation during the original design phase. The support is designed such.that the flux mapping equipment could not become a gravity missile.
However, an evaluation of the installation indicates that the equipment anchorage is not sufficient to limit the displacement of the tt,bing connecting the flux mapping equipment to the seal table. Although f ailure of the reactor 8510030426 850918 PDR ADOCK 05000423 j
16 g S
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.. coolant system pressure boundary is unlikely, the reaction at the tubing to seal table interface due to the equipment displacement is extremely dif ficult to analytically predict. Therefore, supports will be added to the equipment to ensure that the relative displacement between the flux mapping equipment and seal table will be limited to acceptable levels.
If this deficiency had remained undetected, unacceptable consequences may have resulted during a seismic event (small break LOCA). Therefore this is considered to be a significant deficiency in the design of Millstone Unit No. 3 in accordance with 10CFR50.35(e).
As such, we consider this to be our final report for SD-85. This final report is being submitted on September IS rather than September 12, as discussed with your Mr. D. Lipinski. We trust that the above information satisf actorily responds to your concerns.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY J. F.Weka f
Senior Vice President h
o By: W. F. Fee Executive Vice President
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