05000416/LER-1983-187, Updated LER 83-187/03X-1:on 831122,maint Technicians Filling Ref Leg Caused Spike on Reactor Vessel Level Transmitters, Resulting in Div 1 Automatic Actuations.Caused by Personnel error.W/840326 Ltr

Updated LER 83-187/03X-1:on 831122,maint Technicians Filling Ref Leg Caused Spike on Reactor Vessel Level Transmitters, Resulting in Div 1 Automatic Actuations.Caused by Personnel error.W/840326 Ltr

ML20087N850
Person / Time
Site:	Grand Gulf
Issue date:	03/26/1984
From:	Byrd R, Dale L MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
AECM-84-0176, AECM-84-176, LER-83-187-03X, LER-83-187-3X, NUDOCS 8404050084
Download: ML20087N850 (5)

LER-2083-187, Updated LER 83-187/03X-1:on 831122,maint Technicians Filling Ref Leg Caused Spike on Reactor Vessel Level Transmitters, Resulting in Div 1 Automatic Actuations.Caused by Personnel error.W/840326 Ltr

Event date:
Report date:
4162083187R00 - NRC Website

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Update Report - Previous Re ort Due 12/28/83 LIC NSEE EVENT REPORT Attachment to AECM-84/0176

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EVENT DESCRIPTION AND PROSAsLE CONSEQUE8eCES h J3TTl 10n November 22. 1983 while in Cold Bhutdown. maintenance technicians I rami l filling a reactor vessel level transmitter reference leg caused a spike _j g lthat resulted in Div. I automatic actuations includina en injection by 1 3 Ithe Low Pressure Core Spray pump and an isolation of Shutdown Cooling.__]

oe IThe injection lasted for approximately 1 minute and 4o seconds. Shutdownl 0 7 l Cooling was restored within_one hour as required by T.S.3.4.9.2. This is!

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g ] (The cause was personnel error. The Reference Leg Check Procedure was notl g-] lbeing used. The procedure is being revised to provide more auidance. Thel responsible supervisor was reprimanded. I&C technicians were instructed l g [to use the procedure when filling reference legs associated with vessel 1 g g ginstrumentation. l T . . .

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- Supplementary Information to

. LER 83-187/03 X-1 f

Mississippi Power'& Light l Company.

Grand Gulf Nuclear Station'- Unit 1-

. .LDocket No. 50-416 .

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Technical Specification Involved: 3.4.9.2 1 Reported Under Technical Specification: 6.9.1.13.b Event Narrative LAt.2324 on November 22,;1983, maintenance technicians filling a reference leg

. caused a1 spike on. reactor vesseldlevel transmitters. 1Riis resulted in_several Division'I automatic actuations including an injection by the Low Pressure

' Core-Spray pump. The plant was in Cold Shutdown at the time of the event.

iThe LPCS~ injection lasted for 1 minute'40 seconds and raised the vessel level ifrom 58 inches to-104 inches on the' Upset Range level recorder

. Reactor

coolant temperature was.approximately 121*F.

t Other automatic actuations were:

~

.o Division I Diesel Generator start o Division I LSS initiated for.a LOCA 3 o . Auxiliary Building 10utboard isolations

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Lo _ Standby-Gas Treatment-started-

.  ; o ' Control Room Fresh Air Unit started o RWCU isolated o '_ Shutdown: Cooling; Loop "A" isolated

.t l,, to :LPCI "A" pump attempted;to start-twice but tripped each time due to,

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.its! suppression-pool s'uction valve being closed for Shutdown Cooling

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ioperation'.

Computer pri_ntouts reviewed folloEing the event indicated that RPS bus "A" 6 -

experienced some voltage transients._-Power supplies for APRMs A C, E, and G

' tripped off atithe'same time the' manual scram relay computer point indicated a

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strip at- 2327:47 hours. 'The-manual scram relay trip. reset 0.5 seconds later Jand tripped.again at 2327:54 hours. It reset approximately 7 seconds later.

Operators verified that RPS bus "A" was energized by. the motor generator set.

7

?A; subsequent investigation revealed the shields on computer cables were not

, connected which would have contributed to erroneous indications on the computer. 'These shields are'now-being connected. Design' Change 83/3552 was

complsted March 16, 1984',' which removed the neutron monitor power supply'

? ground:from the chassis ground and connected it to a signal common bus to iprevent ground loops which could result in spurious trips.

~

'TheTeause of.the ESF actuations was due to personnel error in filling the

. reference. legs.- The Reference Leg Check Procedure (07-S-13-23) was not used ifor thisfactivity.--Technicians were< working 1under a work authorization to

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investigatefand correct!a' mismatch in the narrow-range level indicators.

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AECM-84/0176

" -Page 3 of 3 LTransmitter C34-LT-NOO4A was found to have a milliamp output higher than expected. Historically,.this has indicated that the reference leg needed filling, therefore, the technicians were instructed by.their supervisor to

' fill the reference leg. When the fill-supply valve was opened, a pressure

. spike was placed on several level transmitters sharing the common reference leg resulting in a reactor half scram signal and ESF initiations.

~

The ' generically written Reference Leg Check procedure is being revised to 9 provide guidance in filling reference legs associated with vessel

" instrumentation. The Maintenance Assistant Plant Manager issued a memo to the

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-I&C Supervisors ~ emphasizing the importance of using the procedure when filling reference-Llegs associated with vessel instrumentation. The maintenance supervisor was reprimanded. This is submitted as a final report.

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P MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi J ACKSON, MISSISSIPPI 39205 P. O. B OX 164 0,0 0 9 n\B.

March 26, 1984

$4 Nkb

• NUCLEAR PRODUCTION DEPARTMENT U.S. Nuclear Regulatory Commission Region II 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Regional Administrator

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-13 File: 0260/L-835.0 Update Report - Spike on Reactor Vessel Level Transmitters Results in Division I Automatic Actuations LER 83-187/03 X-1 AECM-84/0176 This letter submits an update to a previous report submitted on December 22, 1983. The event for which the report was submitted occurred on November 22, 1983, when maintenance technicians filling a reference leg caused a spike on reactor vessel level transmitters. This resulted in several Division I nutomatic actuations including an injection by the Low Pressure Core Spray pump and an isolation of Shutdewn Cooling. The plant was in Cold Shutdown at the time of the event. Shutdown Cooling was restored within one hour as required by Technical Specification 3.4.9.2. This was reported pursuant to Technical Specification 6.9.1.13.b.

Our investigation into the cause of the event is complete. Corrective actions to prevent recurrence are complete or are in the process of being completed. This is a final report. Attached is LER 83-187/03 X-1 with Supplementary Information.

Yours truly, y -

L. F. Dale 6 Manager of Nuclear Services EBS/SHH:rg Attachment cc: See next page (apy3gyfoy W2L Member Middle South Utilities System

. # AECM-84/0176 3

MISS12CIPPI POWER Q LI2HT COMPANY cc: f Mr. J. B. Richard (w/a)

Mr. R.- B. McGehee .(w/o)

Mr. T. B. Conner (w/o)

Mr. G. B. Taylor (w/o)

Mr. Richard C. DeYoung, Director (w/a)'

Office of Inspection & Enforcement

.U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Document ~ Control Desk (w/a)

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 f