ML20024E743

LER 83-025/01T-0:on 830811,during Underwater Camera Insp of Spent Fuel assemblies,15 Broken Fuel Assembly Holddown Springs Found.Cause Unknown.Investigation Continuing. W/830826 Ltr

ML20024E743
Person / Time
Site:	Millstone
Issue date:	08/26/1983
From:	Herbert R, Mroczka E, John Parillo NORTHEAST NUCLEAR ENERGY CO.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
LER-83-025-01T, LER-83-25-1T, MP-5332, NUDOCS 8309070009
Download: ML20024E743 (3)

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;;; l Underwater camera inspection of spent fuel assemblies identified 15 I

.i c is t Ibroken fuel assembly hold-down springs. In addition to the broken I

-i,jl springs, severe fretting was identified on the top nozzle 1

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SUPPLEMENT TO LER RO-50-366/83-25/01-T FACILITY-OPERATING LICENSE DPR-65 DOCKET NO. 50-336 During spent fuel inspection of Westinghouse manufactured fuel on August 11, 1983, severed. hold-down springs were discovered on the upper end fitting. Currently the entire core is in the spent fuel pool while work is being done on the thermal shield in Containment.

Examination of all'144 irradiated Westinghouse manufactured fuel-assemblies has shown 15 broken hold-down springs. Fifteen fuel assemblies each have one (1) broken spring.

Eight (8) of the broken springs were in once burned "G" fuel assemblies. Seven (7) of the broken springs were in twice burned "F" assemblies. Each of the springs exhibited a brittle type fracture.

In addition to the broken springs, the stainless steel top nozzle posts of Westinghouse fuel assemblies exhibited a varying degree of fretting due to interaction with the inconel springs. This fretting has been found in both assemblies with and without broken springs. Fuel assemblies with broken springs do not necessarily exhibit fretting. The fretting was severe on some top nozzle posts.

The 15 broken springs show a correlation with location in the reactor core. All posts with a broken spring were at some time up against the reactor core shroud. No correlation has been found with the top nozzle post fretting.

Examination of the 51 of 72 Batch "E" Combustion Engineering (three times burned manufactuggg) 33,000 discharge has shown fuel no assemblies broken springs and very little fretting.

'MT Some slight fretting is present on the center post but is has essentially no depth. The 21 "E" fuel assemblies not examined were all located only in the core interior and therefore were not examined.

There is no detectable correlation between the broken springs or fretted fuel assemblies with the fail fuel assemblies referenced in LER 83-19/3L-1.

Further information will be provided as it becomes available.

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OsNE00I5tsY,Nw.sv P O. BOX 270 m v., wi. -.i ue.av HARTFORD CONNECTICUT 06101 L w J  :".':;;llll'*:, 2,'L":: (203) 666-6911 August 26, 1983 Dr. Thomas E. Murley MP-5332

• Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue

, King of Prussia, Pennsylvania 19406

Reference:

Facility Operating License DPR-65 Docket No. 50-336 Reportable Occurrence RO-50-336/83-25/01-T

Dear Dr. Murley:

This letter forwards Licensce Event Report 83-25/01-T required to be submitted within fourteen days pursuant to the requirements of Millstone Unit 2 Appendix A Technical Specifications, Section 6.9.1.8.1, discovery of conditions not specifically considered in the Safety Analysis Report or iachnical Specifications that require remedial development action of an or unsafe corrective measures to prevent the existence or condition.

the report are enclosed. An additional three copies of Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY FOR: E. J. Mroczka ..

- Station Superintendent Millstone Nuclear Power Station f O BY: R. J. Herbert

., 5

- Station Services Superintendent i Millstone Nuclear Power Station EJM/JP:ejl i

Attachment:

LER RO-50-33 6/83-25/01-T '

cc: Director, D.C. (30) Office of Inspection and Enforcement Washington, . s Director,Washington, Control, Office of Management Information and Program D.C. (3)

U.S.

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Branch,Nuclear Washington,Regulatory Commission, c/o Document Management D.C. 20555 o

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