ML20066K876

Requests Temporary Waiver of Compliance in Meeting Tech Spec 4.6.1.6.1.b Re Removal of Containment Liner Weld Test Channels

ML20066K876
Person / Time
Site:	Beaver Valley
Issue date:	01/25/1991
From:	Sieber J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9102060149
Download: ML20066K876 (7)

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m.wo, con m2, m2n January.25,-1991 U.

S. Nuclear Regulatory Commission y

Attn:

Document control Desk i

Washington, DC-20555 i

Reference:

Beaver Valley Power Station, Unit-No.-1 4

Dock 6t No. 50-334, License No.- DPR-66 a

-Request for Temporary Waiver of Compliance Gentlemen:

The purpose of this letter is to request NRC approval of a i

request for a

temporary waiver of compliance in meeting the Beaver 1

Valley

-Unit No.-

1 Technical Specifications.

_-Specifically, o

surveillance requirement 4.6.1.6.1.b requires removal of containment liner weld test-channels if a.

testi channel vent 1 plug is found missing.

On January.22, 1991, we discovered missing vent plugs l'nLthe Unit j

No.

1 containment..

These-vent plugs cre. associated with_ test' channels on-the containment liner floor which11s under.approximately two feet of reinforced concrete.

Removal of: the test channels :is considered impractical for determining ;the-adequacy of'the liner-welds.

We are proposing an alternative'solutionLto testuchannel' removal.

l The inspections and tests performed on the_ liner weldsE(ie: Type A

Testing, sampling

.of!~ contents' of vent-lines / test channels) have provided assurance that.the missing vont plugc have_not resulted-in accelerated corrosion of-the: liner weld surface-areas.

Wesare developing a

plan of assessing corrosion _. rates applicable _tolthe-liner wolds.

The need for : reassessing _ corrosion rates was recognized during the Unit No.

2 second ' refueling outage when-an identical problem existed.

Resolution of the Unit No. 2 concern has-been 7

temporarily accomplished with an emergency Technical _ Specification Change.-

We propose a

similar interim < solution for-Unit:No. 1 and permanent solution' through' NRC~ approval-of our proposed Technical i

specification-Changes submitted on September 2 8,-_ 1 9 9 0.

l

'This request for

a. temporary. waiver of1 compliance'provides the basis-for asserting lthat the linor welds are' capable of performing their intended function without following the Technical Specification I

u surveillance requirement of removing the -test channels L:_ Additionally-compensatory actions are proposed and completed.. Tha have installed stainless steel vent plugs in each. missing plug location.

'This Jestablishes a

redundant pressure ' barrier' to the' containment liner welds.

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Temporary Waiver-of compliance,1 continued Pgge 2 An_ emergency ' Technical Specification. Change will be submitted by=

-February 8,

1991,

_to provide!.

an alternative surveillance requirement.

That proposed change;will; insert the-Standard' Technical Specification wording.and be1 consistent with Amendment No. 34 the-NRC has approved for Unit No.

2.

Unit No. 1 is scheduled to enter Mode 14 mn January 25, 1991.

NRC approval is required' before: thisJean be achieved.

The contents of4 i

this request have been-discussed with members of:the NRC staff during a

conference call on-January 124,.1991.

This.has also been reviewed by the station Onsite Safety Committee._

l I f.

you have-any questions regarding this submittal, please' call

{

me or members of my. staf f. -

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Sincerely,

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AD J ~. D.-Sieber-Vice President-

_ Nuclear Group cc:

Mr. J. Beall,.Sr. ResidentlInspector-Mr.

T.-T.

Martin, NRC Region I Administrator' Mr. A.

W. DeAgazio,_ Project Manager Mr.

R.

Saunders (VEPCO)-

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ENCLOSURE;

-Beaver-Vallev Pqggr Station - Unit No. 1 Evaluation Supporting a Temporary Waiver of Compliance-(RE:

Containment Liner We4d test Channel Vent Plugs) a 1.

Discuss the-requirements-for which a waiver--is requested:,

This waiver addresses-the Beaver-Valley 10 nit No. 1 Technical-Specification Limiting -Condition _of-Operation (LCO) 3'. 6.1. 6

" Containment-Structural Integrity".

The LCO' defines: containment' y

structural integrity being satisfied through _ compliance. with j

surveillance requirement 4.6.1.6.1.

This surveillanceLin part

.i states that if a

containment liner test channel vent plug is j

found

removed, the corrective -action is tot remove theitest n

channel and apply a protective coating to the liner in-that_ area.

9 On January 22, 1991, while performing a' tour of1 containment,-we observed = missing vont plugs from vent lines which were connected 1

to test channels installed on the floor'of the liner.- Thisiliner is carbon steel and the floor of the liner 11s covered-with reinforced concrete of a nominal two'footithickness.1 To comply with LCO.

'3.6.1.6 it would be necessary-to remove a significantL portion of the containment ' basement-floor, remove' the test

channels, coat the liner welds and-return,the floor to its normal arrangement This is -considered an--unacceptable solution for demonstrating the containment structural integrity. ; Resolution of the structural integrit'.

is_necessarygbefore-Unit:No. 1 can y

enter Mede 4

which is-scheduled ~_to ' occur ; Friday afternoon, January 25, 1991.,

We request permission to operate withLan alternative solution to, the corrective-action specified in surveillance requirement 4.6.l.6.1.b.

This action consists of. installing 1stainlessusteel vent plugs in all missing locations.. The request would'remainJin H

effect for the length

-of. time _ required to-process an emergency Technical Specification.

Change _-

to revise-- the surveillance-requirement in a

manner s'imilar:to that approved byLtheLNRC for R

Unit No.

2 in-Technical ' Specification Amendment No. 34.;

Thati amendment approved an alternate surveillance:

requirement' consistent with the:

Standard-Technical.SpecificationL for-demonstratinc containment structural integrity.

2.

Discuss the circumstances surrounding the situation-including the need for prompt action, and why the situation could'notLhave-been avoided:-

'q Surveillance

. requirement 4.6.1.6.1L is_ normally' performed in support of ' conducting Type A -containment leakage ratentests.

When preparing to perform-this -test' on Unit No. 2 during the second refueling

outage,

-it--was determined that_the inspections j

conducted in support of-the-surveillance requirement-did_not include the vent plugs _ located on. the-containment-basement floor.

This resulted in requesting-.an_ emergency.Techn~1 cal Specification Change on-October 9,

1990.

As a result of'that experience, we intended to perform ~aLsimilar inspection'for Unit No.

1 -during the upcoming. eighth' refueling outage,. scheduled to begin in, April 1991.

t

Enclosure,_ continued Tamporary' Waiver of1 Compliance Page 2

-i Unit No.

I was operating at-the> time:the' Unit No.=2 inspection was performed..

It; was-unclear.as to1whether the floor test channel vent plugs had. been verifieds to exist =in1 Unit'No.il

(

during previous _ inspections = inl supportsof TypeDA tests..

There-was-no recollection of-this. verification 7and-procedures do.not specifically -callE_out--verifying -vent plugs. associated with the:

j test -channels. located in the' floor._ LTechnical. Specification Surveillance - 4. 6.1~. 6 ; b ' infers' inspections.. of Jthe;. containment:

liner cylindrical-_ walls'in that<if a vent _plugLis found missing, i

the test channel"is to be removed.

The test channels are visible-on the liner walls and their existence is' obvious.- ESurvel-11ance j'

requirement 4.6.1.6.1.c addresses-inspections of"the_ containment

dome, As a -result o f.

the -Unit' No.

2' inspection during-theisecond-f refueling outage,. We:were: concerned that we had not-verified the j

existence of.the. Vent plugs'on=the floor test channel' vents and 3

were preparing to inspect this= area during.the nextiUnitiMo. 1 L

refueling outage.

~

j On January-21,

-1991, ' Unit No. 1 prepared.to shutdown;due:tonan unrelated problem.

During-this-shutdown,Jcontainment entries-were -made since the: plant wasfbeing cooledcto' Mode Suconditions and containment' was being~ returned to atmospheric! conditions.

10 test engineer was ' assigned

.to 1 perform specific-containment

' integrity 1 checks.

Whi-le in containment and being knowledgeable inspection during. 2-ventiplug concern and the_ Unit'No.-11 planned!

of the-Unit No.

cthe--next : refueling! outage-the test-engineer i

decided to perform a

limitedEsurvey;andedeterminedia numberoof vent-plugs-were missing.

It is our belief the test channels are(in1 good condition-(Ref-.

Item

-4).

We intend to implement a1compensatoryLaction:to1further q

enhance containment integrity.

. Additionally, we ;intendi:to develop a plan.to assessJ1ong term corrosion 1affects ontthe liner.

i welds.

.This is-intended

-to, support. the proposed Technical J

-Specifications which were submittedson.-September 28',jl990.

The schedule-for.' returning _to power.-operation-includesLentering j

Mode 4

on Triday, January-2 5,-

1991-. Land: Mode 11 operation'is-3 anticipated to occu t-earlyl Sunday : morning.

.Any delay _ in' returning-to power operation.beyond Monday,- January;28, 1991, has L

the potential-to. push: back the. start -date fori-the: eighth refueling. outage.

This in'turnfmay; affect our-projected restart-4 date of June 14, 1991.

This~ restart 1 schedule-has beeniselected to provide _ additional capacity to support the; projected summer peak. loads.

The above' forms.the' basis for=the-need for prompt l-action.

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s Enclosure, continued.

I T4mporary' Waiver. of Compliance' i

Page 3-

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3.

Discuss compensatory actions (if any):-

l We will replace the missing vent plugs:withistainless st' eel plugs 1

prior to entering _ operational Mode 4._ LThis action will-provide a-redundant. barrier-to -the containment liner fwelds-and further; ensure that the-containment will. continue to provide.afleak-tight _

barrier against 'the uncontrolled' release _of_ radioactive materialf 1

to the environment.

j i

4.

Provide a

preliminary-evaluation of'the safety. significance 1and!

-potential consequences of the proposed' request L i

The inspection of the: containment floor: test channel vent; plugs-resulted-in-identifying missing' -carbon' steel! venttplugs.

l These are categorized.as follows:.

15 missing plugs located on.the containment floor.

12 missing plugs located on vent lines attached: to containment columns 1at a'

2 foot' ' distance above the t

containment floor.

1 11' vent plugs failed when disturbed for inspection-purposes; For each floor location, an effort was made to. collect afsample q

of -the contents- (if any) _ of the_ test channel.

Invall.but two

'l cases samples of dirt,_ sand,1and other-. materials.wereEcollected-by forcing a capillary tube into_the; vent.line..~In.some cases it is believed the 'capillarygtube was'extendedEfullyJintolthe test channel and.no-moisture was: collected-(it is believedLthesefwere d

dry).

The samples will be sent;out1forlanalysis and theiresults will be available-in approximately1twoMweeksi; ~

l The sampling of the remaining-two vent lines;also resulted-in I

i several-drops of moisture 1being collected.. Those two vent' lines were part of. the sampleL of ;11 which-had vent l plugs disturbed-

'j during-the inspection.

An' effort: was.-Lmade to analyze these-t L'

samples.

The quantity was. insufficient tofprovide1 conclusive results.

The 191 of the samplesLwas' neutral, however,2 dilution may have.made'the results inconclusive'.

j The 12 vent lines located on columns could..not beisampled due.to U

configuration.

A 90*

.fftting is. located _at the vent opening which -does not permit-insertion of a sampling tool..

However, since these -lines-are selevated= above the floor it is unlikely-l corrosive materials couldeget intofthe test channels.-

.j From the above sampling, there isLno-indication!that:a corrosive i

~

environment-exists

-within Lthe testLJchannels: lbeyond-that originally assumed.

Additionally,_since'each floor vent line is either totally or partially-plugged with-dirt thereL is. no d

Opportunity for reoxygenation of the test: channel in a sufficient i

manner-to promote -accelerated corrosion..

The Unit No-24 vent line inspection also resulted in identifying dirt.-and-debris!1' eft-M over from the construction of the containment.-

It is believed d

the same. can be said for the Unit 1No.El test channel vent lines d.

coming from theifloor.

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7 Enclosure,---- continued

' Temporary Waiver of: Compliance page : 4 The test channels-are-believed ~ to-be in good. condition on1the basis of a

lack of conclusive;information'to prove otherwise.

Preliminary assessments have'resulted-in-the? conclusion-that the liner welds -are still-capable-of. performing = their intended function.

The compensatory actions'further' enhance the ability' of the-liner ~. -to properly; function' through :the addition of a redundant barrier (ie: -carbon steel-test channel'p stainless steel

-vent tube and new stainless steel-vent plugs).-

f The proposed request' would allow. the~ liner Ltest channels"to remain in place.-

LThe. l'ong term -Technical Specification corrective-action. is to remove the: surveillance requirementLwhich directs' removal ' o f, the test channel.

This will beifurther:

discussed in. support Lof the : permanent. change : submitted on:

September 28, 1990..

Additionally, we successfully completed a.

Type. A test in-the~. fall.of 1989.during the Unit:No.;1-seventh refueling outage.

This test provides added assurance that the l'iner is capable of performing its function.

On this basis: 1)- successful-Type A test,. -2) redundant -barrier, 3) no evidence of ac :alerated corrosion - we characterize this ni request as not' increasing-ithe potential consequences. of.any postulated-accident.

5.

Discuss justification for the' duration 1of the(request:

This Temporary ' Waiver.of' Compliance Lneeds to' remain in effect until an Emergency Technical Specification'Changeican;be approved by the NRC.

The proposed Emergency,1 Technical Specification Change will allow an alternative.to.the present surveillance requirement which does not contain specific details-on 'the required actions pertaining - to' test channels.. In' addition, e fcotnote. will lua -added which limits the duration:for whichLthe alternate-surveillance is applicable.

The test channels whl'ch we found to haveLmissing:-vent? plugs <are located _under approximately Ltwo~= feet of reinforced) concrete.

1 This-factormakes complying with the: surveillance. requirement of.

removing the test channel an extreme hardship.-.Therefore,:the "g

requested -duration.of this Temporary = Waiver-supportssthe planned

-restart!'without meeting the current surveillance requirement 4.6.1.6.1 until-a Technical Specification Change.can be approved by the NRC.

We will submit an Emergency Technical Specification-Change Request by February 8,

1991, i

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Enclosure, continued Temporary Walver of compliance f

1 LPage 5 i,

6.

Provide a

basis for :the conclusion -that the; request 1does:not y

involve-a significant hazards consideration:-

t There

' a ro. no indications from 'our current 'evaluationi that l

significant corrosion of the. containment : liner: welds fhas-

[

occurred.

To further ensure ' that the containment :-wi.ll: continue:

to provide a leak-tight barrier against1the uncontrolled: release-of radioactive ~ material to-the. environment,,we havelinstalled

~

stainless steel plugs -in place.of the missing vent plugs incthe containment liner test' channels.

.This^will provide an additional barrier to-ensurectheuleak-tightness 1of.the containment redundant vessel ~.

1 Wo-have taken steps 7through! sampling.and re-installing missing vent plugs to will continue ~to provide a11eak-tight barrier, ensure that the-containment steel? liner-Therefore, -based on the 'above,-this requestidoes not?involvera-4 significant hazards' consideration.

7.

The-basis 1for irreversible environmental: consequences:.the -conclusion thatothe request.do The -requested change'does'not' involve. irreversible environmental-consequences based on theHoonclusion that the liner weldsfare not degraded; There are no indications from1the current sampling of.

the test channels thatHsignificant degradation of.the containment:

I liner-welds-has occurred.-

In; addition, aLredundant barrier in the form of a plugged test l channel has been established:to, ensure that the : leak-tightness of the containmenttvessel will; continue-to be ' maintained.

The;abilityLto provide a leak-tight barrier against the uncontrolled-release of radioactive' material ~to the environment remains unchanged.

- There f ore,- -. based on-he above,'

this -

change' does not consequences.

involve irreversible. environmental 1

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