ML20083J098
| ML20083J098 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/30/1983 |
| From: | Counsil W, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| F0337B, F337B, SD-34, NUDOCS 8401160174 | |
| Download: ML20083J098 (2) | |
Text
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.o tl0ptwagY eduCLEAR EedEAGVCOhr488 December 30,1983 Docket No. 50-423 F0337B Dr. Thomas E. Murley Regional Administrator Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
References:
(1)
W. G. Counsil letter to 3. M. Allan, Dod<et No. 50-423, dated April 8,1983.
(2)
W. G. Counsil letter to T. E. Murley, Docket No. 50-423, dated July 7,1983.
(3)
W. G. Counsil letter to T. E. Murley, Docket No. 50-423, dated August 24,1983.
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Design and Construction:
Interference and Possible Binding of ITT Grinnell Mechanical Snubbers (SD-34)
In Reference (1), Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the construction of Mills:nne Unit No. 3 as required by 10CFR50.55(e). The potential deficiency involves interference and poss;i le binding of mechanical snubber hardware manufactured by ITT Grinnell prior to April 1980.
Reference (2) provided written confirmation of a June 30, 1983 telephone conversation between our Mrs. P. C. Bandzes and your Mr. T. Elsasser requesting an extension of the due date for providing the necessary follow-up information.
Reference (3) provided you with an interim report on this matter.
This represents NNECO's final report concerning this issue.
Our architect-engineer, Stone & Webster Engineering Corporation, has identified a total of 233 snubber installations which have the potential hardware interference. This has been determined through interface with ITT Grinnell regarding a specific model of snubber hardware and the time si 'abrication.
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' Stone x& Webster Field Quality Control personnel will check.for hardware interference using the vendor approved inspection procedure. The hardv'cre -
inspection will be an additional attribute in the snubber preservice inspection
- program which has already been established. ' Any hardware which has an interference will either be replaced or modified as required.
Concerning the safety question, ITT Grinnell has performed extensive testing on
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what it defines as the worst case hardware interferences. The results indicate that although the drag force during snubber movement may increase, the snubber will not bind durir.g thermal transients and will in fact perform its safety i:
function during dynamic loading. Therefore, NNECO concludes that even if the potential hareware interferencc went undetected, the increased drag force is.
Insignificant and the condition does not present a safety concern. However,it is NNECO's intent to take corrective action if any interference is identified during
- the preservice inspection.
This letter constitutes our final report closing out all items related to SD-34.
We trust that the above information satisfactorily responds to your concerns.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY LO. b.
W. G. Counsil Senior Vice President By: C. F. Sears Vice President Nuclear and Environmental Engineering cc:' Mr. R. C. DeYoung, Director Division of Inspection and Enforcement
- U. S. Nuclear Regulatory Commission Phillips Building-7920 Norfolk Avenue Bethesda, MD 20014
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