05000254/LER-1980-007-03, /03L-0:on 800308,while Performing Control Room Insp & Panel Check,B Main Steam Line Radiation Monitor Found Reading Low.Caused by Logarithmic Radiation Monitor Chassis Electronically Drifting Out of Calibr.Chassis Recalibr

/03L-0:on 800308,while Performing Control Room Insp & Panel Check,B Main Steam Line Radiation Monitor Found Reading Low.Caused by Logarithmic Radiation Monitor Chassis Electronically Drifting Out of Calibr.Chassis Recalibr

ML19305D735
Person / Time
Site:	Quad Cities
Issue date:	03/25/1980
From:	Wykoff D COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19305D732	List: 05000254/LER-1980-007, Forwards LER 80-007/03L-0 05000254/LER-1980-007-03, /03L-0:on 800308,while Performing Control Room Insp & Panel Check,B Main Steam Line Radiation Monitor Found Reading Low.Caused by Logarithmic Radiation Monitor Chassis Electronically Drifting Out of Calibr.Chassis Recalibr
References
LER-80-007-03L-02, LER-80-7-3L-2, NUDOCS 8004150467
Download: ML19305D735 (2)

LER-1980-007, /03L-0:on 800308,while Performing Control Room Insp & Panel Check,B Main Steam Line Radiation Monitor Found Reading Low.Caused by Logarithmic Radiation Monitor Chassis Electronically Drifting Out of Calibr.Chassis Recalibr

Event date:
Report date:
2541980007R03 - NRC Website

text

__

NRC FORM 386 U. S. NUCLEAR REGULATORY COMMISSION

.wm LICENSEE EVENT REPORT.

CONTROL BLOCK: l l

l l

l l

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

f' T'l l l I L l a l ^ l o 11 J@15 01 01 01 -l01 0101-1010101@ 41111li11l@l I

l@

7 8 9 LICENSEE CODE 14 UCENSE NUM8ER 25 28 UCENSE TYPE JO 57 CAT 58 COwr ITTil Ou% L_t_J@l0 i s 1010 10 12 is l4 l@l 013 I O I 8 I 8 i 01@l 01312 l s I 810 l@

7 8

60 61 DOCKET NUMB ER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h ml While performing the Normal Control Poom inspection and Shift Turnover Panel Check.

I i

gl procedure QOS 005-2, the B main steam line radiation monitor was found to be reading l

l

~

io ;4; l low. An instrument problem resulting in a lower than normal reading could cause the Bl i

o 3 l system to trip at a radiation level greater than those established by Technical I

g o is l l Specification 3 1.

The reJandant A, C, and D main steam line monitors were operating i

~

~

fB T-I l normally and would have provided the required high radiation level setpoint trip l

functions.

l lO la l I 7

8 9 80 0E OE SU C E COMPONENT CODE SUSCodE SU E

O 9 ll lB l@

@ ll lN l S lT lR lU l@ jJ@ U @

7 8

9 to 11 12 13 18 9

20 SEQUENTIAL OCCURRENCE REPORT REVISION LE R/RO EVENT YEAR REPORT NO.

CODE TYPE N O.

@,REgg l288l0l g

l 0l0l 7l y

l0 l3 l [Lj l-l

]

j 22 23 24 26 27 28 29 30,

31 32 f

N AC ON O

NT ME HOURS 22 SS I FOR B.

SU Lt MANUFA RER l Elgl34Zlg Jg W@

l0l0l0l0l lYl@

]g lN l@

lG l0 l8 l0 l 33 35 36 37 40 -

41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i l 0 l l The B logarithmic radiation monitor chassis electronically drif ted out of l

gl calibration, lhe instrument chassis was recalibrated and functionally tested I

ii l 2 I l satisfactorily.

l l l

11131 I l

Lt l.,4 ] I l

7 8 9 80 STA

% POWER OTHER STATUS 01 O Y

DISCOVERY DESCRIPTION

(_E_l @ l 0 l 9 1 6 l @ l NA l

lAl@l Operational Event I!

t 5 A TIVITY CO TENT l

RELEASE @D OP RELEASE [Z_j@l AMOUNT OF ACTIVITY LOCATION OF RELEASE

(,,_Z_j NA I

l NA l

1 6 PERSONNEL EXPOS ES NUM8ER TYPE

DESCRIPTION

I0l0l0l@lZl@l NA l

i 7 PERSONNE L INJU IES NUMBER DETCRIPTION 10l0l0l@l NA l

i a 7

8 9 11 12 80 LOSS OF OR DAMAGE TO FACILITY TYPE

DESCRIPTION

]- W@l NA l

7 8 9 10 80 g,,.h"'l'2 ISSUEJ8l E CRIPTION D

LN NA q o pa y e: n l

lllllllllllll; 2 O 7

8 9 10 68 69 80 T.

3M6-2241 en.1% {

NAME OF PREPARER PHONE:

l.

LER NUMBER:

LER/R0 80-07/03L-0 i

11.

LICENSEE NAME: Comnonweal th Edison Company Quad-Cities Nuclear Power Station Ill.

FACILITY NAME: Unit One IV.

DOCKET NUMBER: 050-254 V.

EVENT DESCRIPTION

On March 8, 1980, while performing Procedure QOS 005-2, Normal Control Room inspection and Shif t Turnover Panel Check, the Unit One B main steam line radiation monitor was found to be reading low. The B main steam line radiation monitor. was reading about 50 millirem per hour while the A, C and D main steam line radiation monitors were reading about 100 millirem per hour. The low reading on the B main steam line radiation monitor was determined to be the result of the B logarithmic radiation monitor chassis being out of calibration. This would cause the B system to trip at a radiation level greater than or equal to seven times the background radiation level (Technical Specification 3.1, Table 3 1-3).

VI.

PROBABLE CONSEQUENCES OF THE OCCURRENCE:

The safety implications of this event are minimal. The A, C 7 and D main steam line radiation monitoring systems were operational and would have provided the required trips on a high radiation level.

Vll.

CAUSE

The cause of this occurrence was equipment failure. The B logarithmic radiation monitor chassis electronically drif ted out of cailbration. The logarithmic radlaiton monitor chassis is a General Electric model 194X629G7 monitor, with a range of zero to one million millirem per hour.

l Vill.

CORRECTIVE ACTION

An instrument mechanic was immediately called to recalibrate the B logarithmic radiation monitor chassis. Thc instrument mechanic calibrated and functionally tested the B logarithmic radiation monitor chassis in accordance with procedure QlS 31-1, Main Steam Line Radiation-Log Rad Monitor Chassis - S.T.

31A. No further corrective actions were deemed necessary-to prevent recurrence.

Surveillance procedure QOS 005-2 verified that the other logarithmic radiation monitor chassis were acceptable.

d

}