ML19325C568

LER 89-012-00:on 890912,reactor Vessel Level Instrumentation Sys Level Indicator Failed Monthly Channel Check & Declared Inoperable.Caused by Inadequate Training for Two Craft Personnel That Performed vlave.W/891012 Ltr

ML19325C568
Person / Time
Site:	Sequoyah
Issue date:	10/12/1989
From:	Bynum J, Hipp G TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-012-03, NUDOCS 8910170073
Download: ML19325C568 (5)

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TENNESSEE VALLEY--~ AUTHORITY

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E o ' October. 12,-1989. i s

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U.S. Nuclear. Regulatory Commission M ATTN:L Document Control Desk s

.. Washington, = D.C. - - 205 55 <

Gentlemen.

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TENNESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNIT 2 - DOCKET'NO.

R 50-3282- FACILITY OPERATING' LICENSE DPR LICENSEE EVENT REPORT.(LER) ,

150-328/89012: ,;

'The enclosed LER provides details of an event wherein-one train of reactor- ]

, vessel level instrumentation' system level indication was inoperable-for more

.than'seven days because an isolation valve was inadvertently left mispositioned during preventive maintenance.--This event is being reported in accordance with 10 CFR 50.73, paragraph a.2.i.

I Very truly yours, TENNESSEE VALLEY AUTHORITY j; ,

h J. R. Bynum, Vice President

• Nuclear Power Production Enclosure ce'(Enclosure):

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[ Regional Administration ,

U.S. Nuclear Regulatory Comission Office of Inspection and Enforcement Region II ,

.101'Marietta Street, Suite 2900 ,

Atlanta, Georgia 30323 l INPO Records Center i

l' Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia- 30339 s

! -NRC Resident Inspector Sequoyah Nuclear. Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 v- 8910170073 891012 'gp f

PDR ADOCK 05000328 5: PDC '

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An Equal Opportunity Employer

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-U.S. Nuclear l Regulatory. Commission' October 12,- 1989.

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.cc:' RIMS, MRLAN 72A-C-(Enclosure)

"" L M.: J. Burzynski, O&PS-4,: Sequoyah (2) (Enclosure)

D.:L. Conner, MBC 07-PTC:(Enclosure)  ;

(Attn: 'C.,T.~Benton)

- S. W.: Crowe, SB-1, < Sequoyah1 .i D. E.-Douthit, Watts Bar. . .

LW. H. Hannum, BR11N 77B-C'(Enclosure)-

N. C. Kazanas,-LP AN ASA-C F. D. Kelly, PMA-E, BrownsfFerry (Enclosure) -

RJ.:T..LaPoint,LO&PS-4. Sequoyah (Enclosure)

M. 0. Medford, LP.6N 38A-C M. J.LRay,'LP-SN 157B-0 (Enclosure)

P. G.~ Trudel,.DSC-E, Sequoyah 7

.C.-A. Vondra, P0B-2, Sequoyah (Enclosure)

(Attn: T. J.-Holloman)  !

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• ' FOMM 305 U.S. NUCLE A'A LE AVL ATORT COMMISS40N APPROVED OMB NO. 31604104 -

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ESTIMATED CURDEN 8'E3 RESPONSE TO COMPL Y ttffM THIS b

UCENSEE EVENT REPORT (LER) COuME#'Uo* fro'$*o'f"RD#EsYiUAYE tNE RICOEs AND REPORTS %4ANAOEMENT ORANCH IP4301. U S NUCLE AR T PAPERwo RE T I'ON J b 4 0 IC OF MANAGEMENT AND SUDGET.WA$HINGTON.DC 20603. -

DOCKET NUMSER GI PAGI G3 f ACILITY esAME III .

k Seouovah Nuclear Plant, Unit-2 o I6 10 l0l013 12 18 1 l0Fl013

''' One train of the reactor vessel . level instrumentation system level indication inoperabi t (l

l bteruse an isolation valve was inadvertently left mispositioned during preventive maintenanc e.

GVtNT VATE lll LER NUMBER (6) REPORT DATE 176 OTHER f ACILITIES INVOLVED 48) .

MONTH OAV YEAR YEAR O

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20.40steH1Hvl to.f ateH2Hdel 90.73teH2Hal LICENSEE CONT ACT FOR THis LER (121 NAME TELEPHONE NUMBER ARE A CQOE j Csoffrey A. Hipp. Compliance Licensing Engineer 61115 81413l-l7l71616 COMPLETE ONE LINE 80R EACH COMPONENT F AILURE DESCRIBED IN TH18 REPORT list O' " AC- R POmiA E .

CAUSE SYSTEM COMPONENT "h'ONPR CAUSE SYSTEM COMPONENT p qpp m i I I I i 1 I I I i i ! I 'l I I I I I I I I I i l i l l 1 SUPPLEMENT AL REPORT EXPECTED H41 MONTH OAY YEAR

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-On September. 12, 1989, with Units 1 and 2 at 100 percent, 2,235 pounds per square inch I- gtuge, 578 degrees Fahrenheit, a Unit 2 reactor vessel level instrumentation system

! 1svel indicator failed a~ monthly channel check and was declared inoperable. A l' magnetically operated isolation valve for the level indicator was subsequently found

l. closed and was determined to have been closed since being inadvertently mispositioned while being exercised during preventive maintenance (PM) on August 15, 1989. After the isolation valve was opened and other isolation valves were verified to be fully open, i thi level indicator returned to a normal indication and was declared operable. The root cause of this event has been attributed to inadequate training for the two craft

.parsonnel who performed the PM in August. Additionally, the PM procedure should have included more detailed work instructions. As corrective action, the appropriate craft parsonnel have been trained, and the PM procedure has been revised to provide more datailed guidance.

shC Poem 384 (6491

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• • 't 4 J.z ' LICENSEE EVENT REPORT (LER) TEXT CONTINUATION - <*Rovao om No am-om l E EXPIR[$: $/31/SB =]

, FAC8LITV NAME (1) e DOCKET NWISER (H LER NUMSIR {Al - PAOf (3) vsaR -

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-S:quoyah Nuclear Plant,. Unit 2 3 9 _ _

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At' 0145'.on September 12, 1989, with Units 1 and 2-in Mode 1 at 100 percent power,  !

L .2;235 pounds per square inch gauge, 578 degrees Fahrenheit. Unit'2 Level 1 LIndicator'2-LI-68-370 was found to be in an upscale failure condition during performance i cf a monthly channel check. The level indicator is the Train B reactor vessel level l instrumentation system (RVLIS) wide-range postaccident monitor instrument (EIIS i i

C:de'IP). The level indicator was declared inoperable, and Limiting Condition for Opsration (LCO)'3.3.3.7 was entered as of 0145 on September 12, 1989. - Subsequently, while checking the transmitter and associated piping, one of the isolation valves for  ;

.tha Train B level indicators was found in the closed position, and several other Train A'  ;

and.B isolation-valves were found in a partially closed position.

Th3 isolation valves are Autoclave magnetically-operated valves that require a special magnetic-valve actuator to open or close them. The magnetic valve actuator is a partable device available only to Instrument Maintenance personnel and is not left on

.tha isolation valves-in the field. Because of the unique arrangement for changing the isolation valve position, it was suspected that the valves had been left in the

l. -incorrect position during the previous performance of the preventive maintenance (PM)

taak that exercises the valves (PM-1274). This PM is scheduled monthly and had been-

t. last performed on August 15, 1989. Interviews were conducted subsequent to this event

with the craft personnel who performe,1 the PM in August. These interviews established thnt the valves had likely been left mispositioned at that time as the result of a misconception about how far the magnetic actuator was supposed to be turned to move the <

valve and as a result of the craft personnel not being aware that the valve position could be' inadvertently changed if the actuator was not removed carefully.

With the isolation valves correctly repositioned, Level Indicator 2-LI-68-370 returned to.a normal indication and was subsequently declared operable. The LCO was exited at

-1518 on September 12, 1989.

Cause of Event

, Ths root cause of this event has been attributed to inadequate training for the two craft personnel who performed PM-1274 it August 1989. These personnel had a basic

knowledge about how to read the position indicator on the magnetic actuator but were -

otherwise unfamiliar with how it worked. Other craft personnel who have received instruction about how the magnetic actuator works have been performing the PM for osveral-years-without incident. Additionally, the detailed work instructions in PM-1274 should have included more detailed guidance about how to install and remove the magnetic L atetuator and how to open and close the valve. The PM did not contain sufficient precaution statements and did not require training prior to performing the PM. The daficiencies in this PM are believed to be an isolated instance resulting from the

, unique operating characteristics of the magnetic actuator. The RVLIS isolation valves l'

are the only application of Autoclave magnetically-operated valves at SQN.

i Ancysis of Event This event is being reported in accordance with 10 CFR 50.73, paragraph a.2.1, as an opsration prohibited by technical specifications in that the number of operable RVLIS chnnnels was less than the required number of channels for a period of time greater than seven days, i.e., from August 15, 1989, until September 12, 1989.

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' NRC FOR48 364A

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N 8 SAC f orm ageA u UA NUCLEJ.R EE%ULAfDRY CoMMleSION i'i * ** LICENSEE EVENT REPORT (LER) TEXT CONTINUATION: mRovEo oMe wo. 3moio4  :

EXPIRES; $"$1l15 F ACILITY NAMt (16 DOCKET NUM8ER (21 LtR NUM8ER ISI PA06 (31 VEAR II Ab t f (E ,

S;qiioyah Nuclear Plant Unit ;

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Analysis of Event (Continued)

The RVLIS is part of the instrumentation installed at SQN in response to NUREG-0737,

" Clarification of TMI Action Plan Requirements," Item II.F.2, " Instrumentation for ,

Detection of Inadequate Core Cooling." The function of the RVLIS is to measure reactor vissel level or relative void content of the circulating primary coolant system fluid following s postulated severe accident, such as a loss of coolant accident, to aid in the detection of an approach to core uncovery. The RVLIS utilizes two redundant sets of three differential pressure (D/P) cells. These cells measure the pressure drop from the bottom of the reactor vessel to the top of the vessel and from the hot legs to the top

.of the vessel. This D/P measur.ing system utilizes three D/P cells to cover different flow behaviors vith and without reactor coolant pump operation.

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Essential information is displayed in the main control room in a form directly usable by the operators.

The RVLIS is intended to be used in conjunction with the incore thermocouples and other incore and excore instrumentation to detect the approach of an inadequate core cooling (ICC) condition. The potential consequence of not detecting the approach of an ICC ccndition could be severe core damage, such as the core damage that occurred during the i Three Mile Island, Unit 2, accident in 1979. However, the RVLIS is a redundant,

! two-train system, and only one train was inoperable during this event. In addition, the incore thermocouples and other incore and excore instrumentation to be used to detect l

the approach of an ICC condition were unaffected by this event. Therefore, because of the redundant RVLIS channel and the other means for detecting the approach of an ICC

• l condition, it is concluded that this event did not result in any increased risk to the h2alth and safety of plant personnel or the general public.

l L Corrective Actions As immediate corrective action, the isolation valves on both trains of the RVLIS were E

checked and repositioned as necessary to the fully open position. ,s corrective action A

to prevent recurrence, the appropriate craft personnel have received training on the l proper' method of exercising the Autoclave valve and precautions about how to ensure the L valve is left in the proper position. In addition, the detailed work instructions in i

PM-1274 have been revised to include adequate instructions and precautions-to guide a i trained craftsman through the required process of installing the magnetic actuator, sxercising the valve, and removing the actuator. Signoffs have been placed in the PM procedure to show that the craftsman has received training on the use of the Autoclave magnetic actuator and has had an opportunity to use the magnetic actuator on a test valve in the shop prior to performing the PM in the field. Independent verification of

-the as-left valve position has also been incorporated into the revised PM procedure.

Additional Information No previous events could be identified that reported an inoperable RVLIS channel as the result of mispositioned isolation valves.

Commitments None.

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