ML17174A109

LER 79-054/03L-0:on 791004,portion of Drywell Ventilating Line 2-1605-10 Declared Inoperable Due to Degraded Pipe Supports.Caused by Insufficient Thread Engagement & Missing Nuts,Causing Hanger Supports to Become Loose.Nuts Replaced

ML17174A109
Person / Time
Site:	Dresden
Issue date:	10/29/1979
From:	Badran S COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17174A110	List: ML17174A109 ML19250B998
References
LER-79-054-03L, LER-79-54-3L, NUDOCS 7911060388
Download: ML17174A109 (2)

Text

Commone1th Edison Dresden Nuclear Power Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 October 26, 1979 BBS Ltr //79-862 James G. Keppler, Regional Director Directo~ate.of Regulatory Operations - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, 60137 Reportable Occurrence Report #79-54/031 Docket #050-237 .

. is hereby submitted to your office in accordance. with Dresden Nuclear Power Station Technical Specification 6.6.B.Z':::Cb) conditions leading. to operation in a degraded mode permitted by a limiting condition for operation or plant shutdown re-quired by a limiting condition for operatio~.

Dresden ~uclear Power Station BBS:lcg Enclosure cc: *Director of Inspection & Enforcement Director of Management Information & Program Control File/NRC

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NRC FORM. U.S. NUCLEAR REGULATOHY COMMISSIUN (7-771~-JI,...

LICENSEE EVENT REPORT CONTROL BLOCK: .__-.L.._ _.___._l_~l _ _.___.IG) .. ;*. (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 6

[il2J II IL ID IR Is I 2 101 0 I 0 I _;_I 0 I 0 j..-~()**"1 0 I 0 I - I 0 I 0101 4 I l I 1 I i I i 101 I 10 7 B 9 LICENSEE CODE 14 15 LICENSE NUMBER 25 26 LICENSE TYPE :JO 57 CAT 5B .

CON'T CITD ~~~~~~ I r:u-1© Io I s Io I0-10 12 I 3 I 1 101 i I oI oI 4I 1 I 9 I© I 11 o I ~ I 9 I 1 I 9 IG) 7 B 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE BO EVENT DESCRIPTION AND PROBABLE CONSEQUENCES@ . .

~ I* During normal operation, a portion of the drywell ventilating line 2-1605-10 was

[£TIJ declared inoperable as a result of degraded pipe hanger supports found during EIID I.E. Bulletin 19-74 inspections. To ensure primary containment integrity was

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maintained during repairs, drywell and torus vent line isolation valves were kept IIITJ in closed position. Therefore, the safety significance was minimal. This is the

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first failure of its kind which required the system to be inoperable.

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IT:ill 7 B 9 BO SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE 7

~B 18 ID I@ L!J@ ~@) I s I u I p I 0 I R I T 9 10 11 12 13 18 1B

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19 20 SEQUENTIAL OCCUR REN CE REPORT REVISION Q LE R/RO LVENT YEAR REPORT NO. CODE TYPE NO.

~ REPORT NUMBER I I I 7 9 I o Is I 4 I I ,..,..I Io I 3 I ~ L=.l ~

21 22 23 24 26 27 2B 29 30 31 32 ACTION FUTURE EFFECT SHUTDOWN ~ ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

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33 ~ 34 . 35 36 37 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS @

DJ)) I Due to vibration after construction, the piping hanger supports were found to have ITIJ] I bolts with insufficient-thread engagement and. missing nuts, causing the hanger supports to become loose. Missing nuts were replaced and lock nuts were utilized rJ:II] I to prevent reoccurrence. Proper thread engagement of remaining bolts was verified.

ITEl 7 B 9 BO FACILITY STATUS  % POWER OTHER STATUS .@ METHOD OF DISCOVERY DISCOVERY DESCRIPTION @

DI] ~@ Io I 9 I 2 l@_I__N_/A_ _ __ I L£J@I Hanger Inspection

• 7 B 9 10 12 1'3 44 45 46 BO ACTIVITY CONTENT ~

RELEASED OF RELEASE AMOUNT OF ACTiVITY LOCATION OF RELEASE @

~ LLl@ W@ I. . . _N'-/A_ _ _ _ _ __.I N/A 7 B 9 10 11 44 45 BO PERSONNEL EXPOSURES t::";;..

NUMBER ~TYPE DESCRIPTION~

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7 B 9 11 12 13 BO PERSONNEL INJURIES ~

NUMBER DESCRIPTION~

~ 10 I 01 01@.___ _N/_A_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _~

7 B 9 11 12 BO LOSS OF OR DAMAGE TO FACILITY t;:jJ\

TYPE DESCRIPTION ~

[Q2) ~@ N/A 1 B 9 ~10--------~-------,--------------------------------B~O PUBLICITY ~ S ISSUED~ DESCRIPTION~ NRC U E ONLY o ITI2] ~~.___ _._ ___;N~/~A--------------~ I I I I I I I I I I I I I~

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Shafic Badran PHONE: _ _ 2_6_5_/_42_1_______ o:

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