ML20096F648

Final Deficiency Rept,Item 105 Re Thermal Separation Criteria Violations in Steam Tunnel Electrical Equipment. Initially Reported in Nov 1983.Corrective Actions Taken & Drywell Inspected for Similar Deficiencies

ML20096F648
Person / Time
Site:	Fermi
Issue date:	08/21/1984
From:	Jens W DETROIT EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
105, EF2-69695, NUDOCS 8409100171
Download: ML20096F648 (3)

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= Wayne HJJens

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- Vice Prevdent :

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' Nuclear Operat;ons Fermi-2 6400 North Dexie H.ghroy Newpc1. PAchigan 48166 August'21, 1984 v

(313) ses41so EF2-69 69 5 -.

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'Mr. James G. Keppler Regional Administrator ~

Region III U.

S.' Nuclear. Regulatory Commission 799, Roosevelt Road

Glen Ellyn,. Illinois 60137

Dear Mr. Keppler:

References (1) Fermi 2 NRC Docket No. 50-341 (2)-Letter, D. A.. Wells to J.

G.

Keppler, December 5, 1983, EF2-66 482

Subject:

Final Report of 10CFR50.55(e) Item 105

" Thermal Separation Criteria Violations" This is Detroit Edison'.s final report of Item 105, " Thermal Separation Criteria Violations."

This item was originally reported-as a potential 10CFR50.55(e) deficiency in November, 1983.

Additional information has been provided in Reference (2).

Description of Deficiency Edison Specification 3071-33 requires a minimum separation of 12 inches for conduits and trays crossing a single insulated ~ process steam pipe.

Crossing multiple insulated-steam pipes or running parallel to a single insulated steam pipe is to be avoide'd whenever possible; however, if not avoidable a four foot separation is required.

Contrary to specification requirements, the required separation was not maintained in some cases.

Analysis of Safety Implications In situations where steam pipes are too close to electrical conduits and trays, high temperatures can result in the immediate vicinity of the cable.

These high temperatures can af fect the electrical characteristics of the cable and may result in premature aging of cable insulation.

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_ ?Mr.JJames G. Keppler AugustD21,J1984.

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.If;1ef tu uncorre'cted,' Lthis situation' could ~ result in f ailure

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offsafety.related cablei thereby reducing the: level of: ',

7 protection ~ provided by tthe safety systems.

The. potential 2 effects'of this deficiency are. mitigated.by redundancy,:

separation, Land proximity.criteriaidesigned into;the safety (

related. systems.'- '

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Corrective Action-Quality' Control initihlly identified thermalfseparation

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criteria: violations;in the main steam tunnel.

Edison Engineering ~Research',Depar'tment completed an.engi-neering study on heat transfer from steam pipes to

electrical conduits'and trays for specific applications where the specification'could not be met. -The study determined the relationship'between pipe' surface temperature,. pipe size and. radial = thermal effects at=various distances from the pipe. From this_ data,. acceptance criterial for. steam pipe and cable separation was established..

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. Quality Control inspected the steam tunnel electrical equipment and identified. instances of thermal separation criteria violations in-DDR E-12051.

Thermalsseparation was

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evaluated in accordance with the criteria and' corrective actions documented in the DDR Disposition.

Based on the results of the inspection of,the. main steam tunnel, Edison determined that the potential for similar' deficiencies existed in the Drywell.

Edison. initiated a walkdown'of the Drywell using'special procedure, Number J

7.39, " Inspection Requirements for' Drywell Thermal Separa-

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tion Between. Electrical Components and Hot Mechanical-Components."

Based on Edison Engineering Research Depart-ment criteria, c Edison Engineering-initiated DCN 10060 to specification 3071-33 to establish the inspection criteria to be.used in the.walkdown... The results of the~walkdown were documented in'DDR's 13079, 13080 and 13083.1

'All DDR's identified in this' report have been dispositioned and required modifications initiated.in accordance with the

~ Detroit Edison Quality Assurance ~ Program. -

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Mr. J ame s G. Keppler August 21, 1984-

.EF2-69695 Page 3 This is Detroit Edison's. final report on this-item.

If you have questions concerning this matter, please contact Mr. Lewis P.

Bregni, (313) 586-5083.

Sincerely,'

cc:

Mr. P. M. Byron Mr.

R.

C.

DeYoung Mr. R.~ C. Knop k