ML17252B467

LER 76-048-00 for Dresden 2 Regarding Discovery of APRM Channel #5 Indication Had Dropped from 54% Power to 31%

ML17252B467
Person / Time
Site:	Dresden
Issue date:	07/28/1976
From:	Stephenson B Commonwealth Edison Co
To:	James Keppler NRC/RGN-III
References
BBS Ltr. #564-76 LER 76-048-00
Download: ML17252B467 (3)

Text

Commonwealth rson Dresden Nuclear Power Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 BBS Ltr. #564-76 July 28, 1976 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations - Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Enclosed please find Reportable.Occurrence report number 50-237/1976-48.

This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B.

~,,.,_,

~i. Step~nson .

Station Superintendent Dresden Nuclear Power Station .

BBS:jo Enclosure cc: Director of Inspection & Enforcement Director of Management Information & Program Control File/NRC

~ENSEE EVENT REPORT e l

CONTROL BLOCK: ....._..___.._I~'-'-* _._l___.1--'I [PLEASE PRINT ALL REQUIRED lrJFORMATIOr.J)

J 1 6 LICENSEE LICENSE -EVENT NAMF.* LICENSE NUMBER TYPE TYPE

@E] II IL ID l:R IS ll I 10101-10101010101-10101 l-4 I I I I Il I I I 1°131 7 8 9 14 15 25 26 30 31 32 REPORT. REPORT CATEGORY TYPE. SOURCE DOCKET NUMBER . EVENT DATE REPORT DATE

@TI] CONI I I I 7 .8 57 . 58 U::J 59 lbJ 60 101s101~101213171 61 68 Io I l, I 3 Io 17 IG I 69 74 10171~1~

75 17 IG80I EVENT DESCRIPTION

(£Ifil !DURING $TEADY-S'TJ11"£ OP£RfrnoN, TuE UNIT OPER.IITOR. NqncE:DTHATAPR/Yl CHANNEJ... -:#5 INDIC.ATION HADJ 7 8 9 . . 80

@Ifil !DROPPED F"ROl'Y\ 51.f~o POWER To 31 ~o. AN *oD-3 PROG-RAM (H£Af 'SAJ..ANC.£ c.At..CULkf/o,:.i) WAS I 7 8 9 . . ' .80 lo1418 91Ru1'1, WH1cH V£R1F1£P THE 1ND1cAT£.D POWER DRoe ON C.HANtJE& # 5. THE 'PROG-RArn 1(£SULTS Ai.So I 7 . . 80 lolsl I 1ND1CATED nyrr IHE AVERAGE GAIN AWV~mEf\ff FAC!OR.. (AGAE) foR. l.HANr.J£L # <o HAD DR1 FTE'D To l.OLf'i I 7 8 9 . . ..* .. * . 80 lfilfil I( PROCEDURAL 1-IMIT: 1.01). IN COMPJ...1A.N(£ WITH "TECH SPECS~ THf: "'8 ' REACTOR P~OTEC.TION S'(STErY) 1 I

7 8 9 PRME . (S££ ATrACHEP SHEET) 80 SYSTEM CAUSE COMPONENT COMPONENT CODE CODE COMPONENT COOE SUPPUER MANUFACTURER VIOLATION 7

@EJIIIAI 8 9 10 LEJ 11 IZIZIZIZIZIZI 12 17

~

43 IZl'flqlql 44 47 lt{j 48 CAUSE DESCRIPTION *

.1£1@ 1-n-tE: HIGH AG-AF VALUE ON APRM CHANNEL* b WAS Ail~tBIJTED TO INSTR.OM£NT DRIET.CUArlAIEd 7 8 9 . 80 7

~

8 9 I# k IJAS fROMPILY R£Ai>.rusrED 'TO THE PROPER VALUE. THE HIGH FR.£QUNCY OF APRl'Y] AGAF.

. 80 r

IT@! l1N'SPECTIO.N$ (oNCt ?ER SHIIT) IS CONSIDER.ED ADEQUAIE To T'REV£tJT VARIATIONS OF ANY SAF'e:Ty , .

7 8 9 . (_ ~t:E AiTACJ.l£1) SHE:£r\q0

• FACILITY METHOD OF . I STATUS  % POWER

• OTHER STATUS DISCOVERY ' DISCOVERY DESCRIPTION EE]..

7 8

~

9 10151412I. 13I 10 NA 44 IAJ 45 46 NA 80 FORM OF ACTNITY CONTENT rn 7 8 RELEASED gj 9

OF RELEASE

~

. 10 11 AMOUNT OF ACTNITY I......'---...1...,;N.._A_ ______,

44 LOCATION OF RELEASE PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION

~ 1010101 LlJ Nf!t 7 8 9 11 12. 13 80

• PERS"ONNEL INJURIES NUMBER DESCRIPTION

[El IOIOlol ~~~N_A~~--.,~~~~~~~---~~..,.-~~~~~

7 8 9 11 12 80 OFFSITE CONSEQUENCES filfil 7 8 9

'.Ii 80 LOSS OR DAMAGE TO FACILITY TYPE DESCRIPTION

(!E} lZJ NA 80 7 8 9 10 PUBLICITY

[ill]

7 8 9 80 ADDITIONAL FACTORS

~ 80 7 8 9

[iliJ 80 .

7 89 NAME: _ _ s-r_A_N_.J""--=E,_R""'"'z=----------- PHONE: gx.r. -J../:t /

EVENT DESCRIPTION (Continued) channel was immediately tripped manually, resulting in a half scram. The APRM channel #6 gain was adjusted to within 2% as required, Indication on APRM channel

1. 5 suddenly returned to normal when the "page" on panel 902-37 was opened by .,

troubleshooting instrument maintenance personnel. The "B" safety system trip was reset, and a work request was initiated for investigation of the intermittent indication problem on channel #5. This is not a repetitive occurrence.

(50-237/1976-48)

CAUSE DESCRIPTION (Continued) consequence.

Exan;dnation of the APRM channel //5 indication circuitry revealed a broken lead on DC amplifier connection P-l-l-J32. The failure was apparently caused by a poorly soldered connection made at the time of the initial system installation. Connection P-l-l-J32 was repaired, and the remaining soldered connections on the DC amplifier were inspected and found to be satisfactory. All soldered APRM amplifier connections on Units 2 and 3 were subsequently exami~ed, and all were satisfactory.