ML20043A741

LER 90-004-01:on 900212,discovered That Backwater Valve in Floor Drain Pipe in Emergency Feedwater Pump Room Missing. Caused by Inadequate Configuration Control.Backwater Pumps Installed & Will Be Included in Maint program.W/900517 Ltr

ML20043A741
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/17/1990
From:	Ewing E, Millar D ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2CAN059007, LER-90-004, NUDOCS 9005230067
Download: ML20043A741 (4)

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Arkansas Pomr & Ught Company .

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, Arkansas Nuclear One  ;

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Route-3, oox 137 G -

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. Russofivde. AFi 72801 4 - Tel 501064 3100 '

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May.17,L1990.

2CAN059007 b U. S. Nuclear . Regulatory Commission <

' Document. Control. Desk 4;

~ Mail" Station P1-137.

Washington, D..C.;20555. V y

SUBJECT:

Arkansas' Nuclear One --Unit 2 -

Docket No. 50-368 License'No. NPF-6.

i Li.censee Event' Report No. 50-368/90-004-01' '

Gentlemen:  !

In-accordance with 10CFR50.73(a)(2)(ii)(B) and 10CFR50.73(a)(2)(v),; attached .(

is-the, subject--report concerning a-missing backwater valve.in-a-floor drain  ;

which created a condition;that could have prevented the fulfillment:of1the-safety function of the. Emergency Feedwater System. .This reportiis being ,

supplemented to-be consistent with the schedule established in the-Arkansas'

Nuclear One Business Plan and scheduled' commensurate with other activities. d 1

Very truly yours,

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ar y C. Ewing General Manager, i 4 Technical Support L and Assessment

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ECE/DM/abw cc: Regional Administrator -

Region IV .

U. S. Nuclear Regulatory Commission  !

611 Ryan Plaza Drive, Suite 1000 .

Arlington, TX~ 76011' l

.INP0 Record Center L Suite 1500 1100 Circle 75 Parkway-c Atlanta, GA 30339-3064- .- -

t 75r2-9005230067 900517 An ENuh Company - L/

m, PDR ADOCK 05000368 , l - [- '

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I Form 1062.01A-NRC form 366 U.S. Nuclear Regulatory Commission i (9-83)- Approved OMB No. 3150-0104

' Expires

8/31/85 1- LICEN5EE- EVENT REP 0RT (L E R)

FACILITY NAME (1) Arkansas Nuclear One, Unit Two l DOCKET NUMBER (2) lPAGE (3) ['

l' 10151010101-31 61 8lIl0Fl013 l TITLE (4) Missing Backwater Valve in Floor Drain Created a Condition Which Could Have Prevented l the Fulfillment of the Safety function of the Emergency Feedwater System- --j l- 1 i EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) :i

1. I c 15equentiall , Revision l , . . l.. j Month Day Year Year i Number Number Month Day Year Facility Names Docket Number (s)- l t 0 510 0 01-  !

01 2 11 2 91 01 91 0' "I 01 01 41 --I 01 1 01 5 11 71 91 Of 0 5io 0 01 OPERA"ING iTHIS REPORT 15.5UBMITTED PUR5UANT O THE REQUIREMENTS OF 10 CFR 5:

1 l~ (Check one or more of the followina) (11)

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MODE C9) -

WeiER ,_,1 20.402(b) .

l_ 20.405(c) I l _l 73.71(b) ]

LEVEL ~ i 20.405(a)(1)(i) 1-~, 50.36(c)(1) l]l50.73(a)(2)(iv) l 50.73(a)(2)(v) I 73.71(c)

Other (Specify in .j 1

-(10) 11010 l 20.405(a)(1)(ii) 50.36(c)(2) ll,_,,l

_ l 50.73(a)(2)(vii)

,_,1 20.405(a)(1)(iii) Il"~l 50.73(a)(2)(1) 50.73(a)(2)(viii)(A) I l Abstract below and {

_ l 20.405(a)(1)(iv) .l~RI 50.73(a)(2)(ii).. l =in Text, NRC Form  :

1 20.405(a)(1)(v) I i 50.73(a)(2)(111) I _i l50.73(a)(2)(x) 50.73(a)(2)(viii)(B)! l 366A)- i LICENSEE CONTACT FOR THIS LER (12)

Name l Telephone Number l Area l ,

Dana Millar, Nuclear Safety and Licensing Specialist (Code l 510l1191614tal311l010 .

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (:,3) ,

(Reportablel l- Reportable; Cause System Component Manufacturerl to NPRDS I- Cause System Component , Manufacturer. to NPRDS i l s 4 i l I i l i l i I 'l l I I l -1 I I l I l l -

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SUPPLEMENT REPORT EXPECIED (14) EXPECTED Month Day Year j ' SUBMISSION i' l~ lyes (Ifyes.completeExpectedSubmissionDate) lil No I DATE (15) l I i AB5 TRACT (Limit to 1400 spaces, i.e. , approximately fif teen single-space typewritten lines) (:,6)-

On February 12, 1990, while performing a review of the Equipment and Floor Drain ~ System (EFDS), it was . i identified that there was not a backwater valve located in the floor drain pipe in one of the Emergency .l Feedwater (EFW) pump rooms. Each of the two EFW pump. rooms is designed to be a watertight compartment  !

with normally closed watertight doors at the entrance of each room, watertight seals at each penetration .;

' irite and out of the room, and backwater valves 'in each drain pipe. Additionally, a float type level-  !

switch with audible and visible annunciation in the Control Room is installed in each room. The backwater valves are designed and installed to prevent crossflooding between the EFW pump rooms. With-.

the backwater valve missing in one room, the potential for crossflooding existed. Since Control Room i annunciation was available, it is reasonable to assume that an operator could be dispatched to the area and take appropriate actions if a high water level were detected. The safety significance is, therefore, l minimal. The details of the specific root cause of this event are' unknown, however, the ultimate root J cause was inadequate configuration control. As depicted on design drawings, the backwater valves were I installed in both pump rooms in 1975. It is not known specifically how the valves were removed, however, it is possible the valve was removed during a maintenance activity and not reinstalled. On February 15, 1990, backwater valves were installed in both EFW pump rooms.

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Form 1062.01B-NRC Form 366AL U.S. Nuclear Regulatory Commission

.(9 83) Approved OMB No. 3150-0104 LICENSEE EVENT REPORT (LER) TEXT CONilNUATION j FACILITY NAME (1) DOCKET NUMBDt (2) l LER NUMBER (6) l PAGE (3) ^I I 1, 5equential l . Revision)

Arkansas Nuclear One, Unit 2 l Year Number Number l 10151010101 31 61 819-l0 --

0l 01 4 --

01 Il01210F1013 TEXI (If more space is required, use additional NRC Form 366A's) (17)

A. Plant Status At the time of discovery of this condition, Arkansas Nuclear One, Unit Two (ANO-2) was operating at 100 percent power in Mode 1 (Power Operation), Reactor Coolant. System (RCS) (AB] temperature was approximately 580 degrees Fahrenheit and RCS pressure about 2250 psie.

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B. Event Description f

On February 12, 1990, while performing a review of the Equipment and Floor Drain Systems (EFDS),  !

It was identified that there was not a backwater valve located in the. floor drain pipe in one of i the Emergency Feedwater (EFW) (BA) pump rooms. The backwater valves.are designed to prevent .j crossflooding between the EFW pump rooms.

The EFW pumps, one motor driven (2P7B) and one turbine driven (2P7A),'are located in the auxiliary building at the 329 foot elevation. Each pump is housed in a watertight room with ] ;

normally closed watertight doors at the entrance of each room. Each penetration into and out of. -}

the room has a watertight seal to prevent crossflooding or. flooding from external sources. 1 Backwater valves are supposed to be installed in the floor drain lines from each of the EFW rooms '

to avoid crossflooding through the drain system. Additionally, a float type level switch with audible. j and visible annunciation in the Control Room is installed in each ETW pump room near the floor to 1 detect any gross water leakage. ~!

i At approximately 1815 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.906075e-4 months <br /> on February 12, 1990, the Operations staf f declared 2P7A-inoperable  ;

due to the missing backwater valve. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Technical' Specification Action Statement was i entered.

C. Safety Significance 'lI j

The EFW pump rooms are designed to be independent watertight compartments to prevent crossflooding and flooding from external sources. This design is based on: 1) high energy line breaks with outside passive the containment, 2) Non-Seismic Category I line breaks, and 3) design basis events failures.

Since there was not a backwater valve in the drain line of the.2P7A EFW pump room, there was no assurance that crossflooding could be prevented if any of the above conditions occurred. A float type level switch with audible and visible annunciation in the i Control Room is installed in each EFW pump room. Therefore, it is reasonable to assume if a i

flooding condition were to occur in either or both rooms it would be detected and appropriate  ;

actions by the Operations staff could be taken to mitigate the consequences of the flooding. .

Additionally, each pump is mounted on a raised section of flooring which provides added protection to the pumps in the event of flooding. With the reliance of operator actions, the safety- .]

l significance is considered minimal. i l

l' O. Root Cause i

The details of the specific root cause of this event are unknown, however, the ultimate cause was l i

I. Inadequate configuration control. The backwater valves were installed in the floor drain piping.

of both EFW pump rooms in 1975 (as depicted on design drawings). An initial review of design  ;

changes did not identify any additional modifications to the EFW room backwater valves. .Apparently i the valve in the 2P7A room was previously removed and not reinstalled.~

E. Reportability 4 i

This event is reportable pursuant to 10CFR50.73(a)(2)(ti)(B), as a condition which resulted in tbe plant being in a condition that is outside the design basis of the plant. The event is also }

i reportable pursuant to 10CFR50.73(a)(2)(v), as a condition that alono could have. prevented the fulfillment of the safety function of the EFW system which is needed to shut down the reactor and ,

l' maintain it in a safe shutdown condition. 1 n

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Form 1062.01B NRC Form 366A U.S. Nuclear Regulatory Commission (9-83) Approved OMB No. 3150-0104 Expires: 8/31/85 '7 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION.

FACILITY NAME (1) l DOCKET. NUMBER (2) l LER NUMBER (6) PAGE (3) l l . j 1 Sequential). [ Revision Arkansas Nuclear One, Unit 2 l l Year Number Number 10151010101 31 61 81 9) 0 -- 0l 01 4 --

01 IfOl310F1013- .!

TEXT (If more space is required, use additional NRC Form 366A's) (17)  ;

F. Corrective Action On February 15, 1990, backwater valves were installed.in both EFW pump rooms. The repairs ensure that crossflooding of the EFW pump rooms will-nct occur throur,h the drain line piping.

A review of the EFDS was on going when the discrepancy in the EFW pump room was identified. While . -

performing the review of the EFDS it was identified that the rooms housing the B and C High Pressure Safety Injection (HPSI) (BJ) pumps were connected with a common drain line. A backwater valve was' located in the drain line of each room and an engineering evaluation of the design basis for the system in the rooms was performed. The design basis requirements were. satisfied for the EFDS -in the HPSI rooms. No additional discrepancies were identified while performing the review of the EFDS. The EFDS~

for ANO-1 was not reviewed due to the different design requirements for the EFDS.

The backwater valves, which were not previously assigned an equipment number, will have equipment I' numbers-assigned by July 1,'1990. The backwater v.alves will be incorporated into the SIMS data base for future reference and control. Additionally, when a maintenance job order is issued'an impact >

statement (i.e., a statement clarifying the effect of maintenance on the equipment to this and related systems) is now required.. Also, a memorandum was issued to maintenance personnel:in August,1989.to emphasize the responsibilities nf maintenance personnel regarding configuration control. Directions were given to stop work and contact a maintenance engineer whenever a condition was~ encountered during work which potentially impacted the design of the plant. -The maintenance engineer is to evaluate the condition and determine'if a change to the configuration of the plant is~ involved. The evaluation performed by maintenance engineering is to be documented in writing and maintained as part of the job order package. Training was provided on the contents of the memorandum in November'1989. A maintenance engineering administrative procedure has been issued which contains the responsibi1} ties of the maintenance engineers. As a result, the improvements provide additional assurance that a backwater valve would not be inadvertently removed and not reinstalled.

The backwater valves will be included in a preventative. maintenance (PM) program. This will ensure '

that the valves are periodically inspected and maintained in an operable condition. The PH program is-being evaluated and the appropriate procedures will be revised to include the backwater valves by October 31, 1990, to be consistent with the ANO Business Plan.

G. Additional Information There are no previously reported events identifying missing backwater valves.

l' Energy Industry Identification System (E!IS) codes are identified in the text as [XX).

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