ML17252B477

LER 76-059-00 for Dresden, Units 2 and 3 Re Review of Quad-Cities Unusual Event Letter Led to Discovery That Dresden'S Standby Gas Treatment System Deviated from Single Failure Criteria That Disabled the SBGT System

ML17252B477
Person / Time
Site:	Dresden, Quad Cities
Issue date:	09/15/1976
From:	Stephenson B Commonwealth Edison Co
To:	James Keppler NRC/RGN-III
References
BBS LTR 76-680 LER 76-059-00
Download: ML17252B477 (3)

Text

Commonweatadison Dresden Nuclear PSr Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 BBS Ltr. 1176-680 Mr. James G, Keppler, Regional Director Directorate of Re,gulatory Operations - Region III U, S, Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

REFERENCE:

Docket Number 50-237 Docket Number 50~249 Enclosed please find Reportable Occurrence report number 50-237/1976-59.

This report is being submitted to your office in accordance with the Dresden Nuclear Power Stat~on Technical S~ecifications, Section 6.6.B,.

ep son Statio.n .Superintendent Dresden Nuclear Power Station BBS :jo Enclosure cc: Director of Inspection ~ Enforc.ement Director of Management Information & P*rogram Control File/NRC

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CONTROL BLOCK:

LICENSEE NAME I

1

• r IJCENSEE EVENT REPORT 1* 1 1 1 6

. LICENSE NUMBER (PLEASE PAINT ALL REQUIRED INFORMATION)

LICENSE TYPE

• EVENT TYPE

@El 1.1 I"'- IDIR Is I d..I 10101-10101010101-1010 I l-4111111111 I 011 I 7 8 9 14 15 25 26 30 31 32 REPORT REPORT CATEGORY TYPE. SOURCE DOCKET NUMBER EVENT DATE REPORT DATE

@E)coN'T I I I lIJ lbJ 101s101~1012131?1 IOl'1 ID11171t. I 101q111517lbl 7 8 57 58 5!:) 60 61 68 69 74 75 80 EVENT DESCRIPTIOf\l

[Q:@J l1<£V1EW OF A QUAP-CIT/£S STATION UNUSUAL EV£NT LEITER LED TD THE 7 8 9 . 80 lo131 lt>1SGOVg&,Y =rum: DRE:SDEN's UNIT ')./3 SIJ}NR8Y G=AS IR~BTmW'[ SYSTEJ'Yl 1'E-j 7 8 9 . . . 80 lol4l lv1ArED £Rom IHE.StN(i.LE £81b.OB.E" c.~1TE~1A *.-T._i/s fOJ..-1...owt/'JG= DEScR.1PT10N I 7 8 .9 . 80

~ I : G:JVES 'THE S£QUNC£, OF EVE:N.TS. fi/JltCH _:CAN ,tJEAT> _TO A SING-LE FA/LURE-_ THAT I 7 8 9 .* - -- . 80 lol61 I. 1?15-AB&ES THE *SBG-T S'fSTEM._ _ (se:E:. ATrA_Cl-lED SH~1j I 7 8 9 PRIME 80 SYSTEM CAUSE COMPONENT COMPONENT COOE CODE COMPONENT CODE SUPPLIER MANUFACTURER VIOLATION 7

@0 IS ICI 8 9 10 lru 11 12 IXl>'-l><l><l~IXJ 17 IAJ 43 '

l:Z 44 I~ 1'119 I 47 lYJ 48 CAUSE DESCRIPTION lol0l I THIS DEVIRTION PRO!Yl JHE"; "SINGJ..E ~11... u12,;:" CRtWRJft was THI:: 'RESULT OF A DE:d 7 8 9 80

~ lnc1£Ncy 1N r1-1i;. 0R1G-1NBL L.OG.1c.. vts1G-N. 1mmEDtAT£ CORRe..cr1ve AC:floN' I 7 8 9 . 80 EE! WAS TO TAI<£ /NJ.E.T UT or= s£RY.ict IN 1fl£_~/:~Pf!N*. ,-

7 8 9 FACILITY METHOD OF SE:t AITl\GHEJ> SHEET 80 STATUS -  % POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EEJ8 t£J s 1a 101q171 #~ L2J 45 46 Nit 80 7 12 13 44 FORM OF ACTIVITY CONTENT rn 7 8 RELEASED lZJ 9

OF . RELEASE 10 11 AMOUNT DF ACTIVITY l______Jl/_'1_ 1 _~

44 45 LOCATION OF RELEASE 80 PERSONNEL EXPOSURES 1010101 ~

NUMBER DESCRIPTION

~ N/J 7 8 9 11 12 13 80 PERSONNEL INJURIES NUMBER DESCRIPTION

• EEJ lo 1010 I .____M_'ll_ _ _ _ _ _ _ _ _ _~--------~ 80 7 8 9 11 12 OFFSITE CONSEQUENCES

[ill] Nit 7 8 9 80 LOSS OR DAMAGE TO FACILITY TYPE

• DESCRIPTION

~. ~ 'It 7 8 9 10 80 PUBLICITY ffi?] Nit 7 8 9 80 ADDITIONAL FACTORS

~ NII 80 7 8 9 E1fil89 7 80 NAME: _ _ G-_._L_._1<_o_YY1_~_A;.___ _ _ _ _ _ _ _ .PHONE: EXT.. u~

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EVENT DESCRIPT~ON (Continued)

1. One of the two units produces a SBGT system auto-initiation signal, As the system logic is designed presently'. this aut.o-initiation signal closes the SBGT system inlet valve from the second unit~.

2, The initiation signal is removed, and the SBGT system is reset; however, the inlet valve from the other unit remains closed, 3, The operator does not recognize that the inlet valve has failed to open, and no corrective action is initiated, 4;* At this time, t~e second unit.produces aSBGT system auto-initiation signal, This signal closes the SBGT system inlet valve from the first .unit,

5.

• Both SBGT system inlet valves are now closed, and the SBGT system is disabled, Under these circumstances, therefore, a single failure could render the SBGT system inoperable, (50.;..237 /1976-59).

• cAUSED DESCRIPTION (ContinUE;d) position. *Since the reactor buildings for Hnits 2 and 3 are common, suction ca~ be taken from either unit for effec~ive reactor building atmosphere proc":ssing.

To prevent recurrence, a modif.ication request has been initiat~d for for-warding to the Station Nuclear Engineering D~pa.rtment, The resultant modification will includ*e, ~ .system: log.:l~_ r*evision to* preclude -the possibility of the described failure ~iJ.!!~~t~'1:::~~able.

• The SBGTS inlet valves for both unit*s will remain in tlie. open position until this* modification is. satisfactor~ly impleme?S.~,~/'.i; *>... .\ , *'~. *,. .\'-:* *~-  !  :-,:,, ,;-)'-<<

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