ML17252B531

LER 78-041/03L-0 for Dresden, Units 2 and 3 Re While Testing the Diesel Generator to Allow Monthly Inspection of Redundant Diesel the Thermal Overload for the Diesel Cooling Water Pump Tripped

ML17252B531
Person / Time
Site:	Dresden
Issue date:	07/26/1978
From:	Stephenson B Commonwealth Edison Co
To:	James Keppler NRC/RGN-III
References
BBS LTR 78-1100 LER 78-041/03L-0
Download: ML17252B531 (3)

Text

Commonwe Edison Dresden Nuclear er Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920

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July 26, 1978 **-: :t:.,.._

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Directorate of Regulatory Operations -*Region III

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\) i U, S; . Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 Reportable Occur.uience Report 117g..

.041/03L-O, Docket .11050-237 is hereby submitted to your office in accordance with*Dresden Nuclear Power Station Technical Specification 6,6,B,2, (b), conditio_ns leadi:flg *to operation in a degraded mode permitted by a limiting condition for operation or p~ant shutdown required by a )_iiniting condition for operation,

• 1:;;;:_B,B. Stephenson*

,--Station Sup~rintende:nt Dresden Nuclear Power Station BBS/deb Enclosure cc: Director of Inspection*& Enforcement Director of Management Information & Program Control File/NRC

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• LICENSEE EVENT REPORT . * . *

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6 0 (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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• 7 8 9 LICENSEE CODE 14 15 . LICENSE NUMBER 25 26 LICENSE TYPE JO 57 CAT 58 CON'T filD 7 8

~~~~ LJJ© I oI 60 61 5 I oI o I o I 2 I DOCKET NUMBER 3 I 1 68 101 69 o I 6 I 3 I oI EVENT DATE 1 I s '(!)I o ! 1 I 2 I 6 I

.. 75 . REPORT DATE 1 I s 10 BO EVENT DESCRIPTION AND PROBABLE CONSEQUENCES@

(PJ2] I While test:!:..g the 2/3 diesel generator to allow monthly inspection of redundant dieselb the th~rmal overload for the ?./3 diesel cooling water pump tripped. This event had

~ minimal safety s1.gnificance because both. the Unit 2 and Unit 3 redundant diesels were available. Previous pump trips as reported 'in 50-249-76-13, 50-249-77-29, and 50-249-1 77-38.

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I [J))] I High amperage of cooling water pump tripped.overload for breaker. Pump was replaced I

! o::::IIJ I but inspection revealed no problem with. removed pump. Overload trip then dis*covered i o:::IIJ I set too close to pump running current, Heat loads requiring excessive pump service

[JJ]J I have been reduced, ITTIJ8 7 9 80 FACILITY tJQ\ METHOD OF ~

STATUS  % POWER OTHER STATUS ~ DISCOVERY DISCOVERY DESCRIPTION ~

E!:fil L!J@ I OI 910 l@I Unit 2 @ 85% PWRI L!J@L-l_O.!..pe_r_a_t_io_n_a_l_E_v_e_n_;_t_ _ _ _ _ _ _ ____.

a 9 10 12 n 44 45 46 80 ACTIVITY CONTENT (.;;:'\

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NUMBER TYPE DESCRIPTION

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NUMBER DESCRIPTION6

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__:.;.:.:.._ _ _~------------------------'80 LOSS OF OR DAMAGE TO FACILITY 143' TYPE DESCRIPTION v::.::J DJ2J ~@)....___________________N_A__,_________________~-------~-~

B 9 10 so PUBLICITY ~ NRC USE ON ISSUEDQ DESCRIPTION~ *

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0 NAME OF PREPARER _ _ _J_.,._E_,___D_o_y._l_e_*__________ PHONE:--=.2.;:..6;:;..5_ _ _ _ _ _ _ __ .,.

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ATTACHMENT TO LICENSEE EVENT REPORT 78-041-03L-0 COMMONWEALTH EDISON. COMPANY (CWE)

DRESDEN UNIT 2 (ILDRS2)

DOCKET 1150-237 While testing the 2/3 diesel generator to allow the redundant diesel generator to be taken out of service for it's monthly maintenance inspection, the thermal overload for the 2/3 diesel generator cooling water pump tripped. The diesel generator control switch was innnediately put in the off position. The thermal trips were then reset and the breaker contacts picked up allowing the diesel cooling water pump to start. At this time, a normal run of the 2/3 diesel generator was made starting at 0221 and ending at 0329. The diesel generator cooling water pump operated normally during the surveillance run. This event had minimal safety significance _

... because both the Unit 2 and Unit 3 -- redundant dies~ls w-ere - ~--- _:- __ - _, _________ .

available. Trips of the breakers have occurrec:Cpreviously for other reasons

---_-a~ -reported--in LER'-s S0--249:..:76~13,- So.:..:~l+-9~-77-29, and 50-249..;.77-38.

The pump was replaced. An inspection of the pump ~hich was removed revealed only normal wear, and no cause for the pump trip could be discovered, Further review of records indicated that the removed pump had always run at an amperage slightly in excess of -its nameplate rating- and ccrn::..

-~s_equentiy, very close to the breaker thermal trip setting. The pump was ----- -

a unique design, and had been installed last November--usfn:g*-*,in--approved -

-~-1llodi*ricatici!l __ ~hen no other pumps of the original design could be obtained.

_The original canned rotor pumps typically ran at a point on their head

-* *-curve* -considerably-befo_w__t uli. name-PTate .amp-erage:---As- -a-resul t--there ~~s-.

--- -~ _s~bs-ta~tial. marg:i.n ...i:o--the-~Eile-rna"i -overicl"a<l-trip point--base<l--on- -nanie.pla.te rating. The newly installed pump is of the same design as the ()r:iginaJ.

--~------p-ump-~ --a:ria.-*sufric"ie-nt-*iiiargiri- to-- the*- breal<er tlie-rmaf "trip-ha_s_ heeri res tared.

-- ---*Aiso~---as-rurther--Eorr-ective* acflo-nto -ellmlriate-unnecessary--u"iiie of .these - .

• • • -pumps, a cross de modification to the.service water system has'been completed.

to allow the HPCI and LPCI ECCS room coolers to use service water instead of water from the diesel cooling water pumps during normal plant operating conditions.