ML20042D314

LER 89-032-00:on 891210,as-left Type B & C Local Leak Rate Test Data Exceeded Tech Spec Limit of 488.452 Std Cubic Ft/H.Caused by Degradation of Telephone & Electrical Conduit Penetration Seal.Conduit Cut & capped.W/891229 Ltr

ML20042D314
Person / Time
Site:	Dresden
Issue date:	12/29/1989
From:	Eenigenburg E, Horbaczewski M COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
89-958, LER-89-032, LER-89-32, NUDOCS 9001080261
Download: ML20042D314 (4)

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%29, ' / 'N Commonweakh Edison [

[g ) Dresden Nuc^mr Power St; tion l

o 7 R/ Morris, R. # 1Illinois

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'. 'NM Telephone 815/942-2920 December 29, 1989 i 7

EDE LTR #89-958 j U.S. Nuclear Regulatory Commission *

. Document Control Desk I Washington, D.C. 20555  !

Licensee Event Report #89-032-0 Docket #050237 is being submitted as required by Technical Specification 6.6, NUREC 1022 and 10 CFR  !

50.73(a)(2)(1)(B).

g burg i E.D.Eey1 Station 1 ger  !

Dresden Nuclear Power Station ,

@ h EDE/jmt Enclosure ec: A. Bert Davis, Regional Administrator NRC Region III '

File /NRC File / Numerical 0743k

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S CK O$000237 PDC g;th I i i -

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[ o, ' LIEENSEE EVEN1 REPORI 1(ER)

!atility Name (I) Docket Number (2) _ Face _

Drtid.t:L!!aclear pgrer_ Station Unit 2 D_l5l0lD_.10j21317 1 db lffitle~(4) local Leak Rate lesting "As Found" Limit Exceeded Due to Excessive Leakage Frorn the Unit 2 Drywell P trinnet1_ Interlock

_[Y.trtt_Dile (5) LER Nygher (6) RepDIl_Q6te (7) OthtI_f8tilitiet Involved (B) ._

Nonth Day Year Year // Sequential /// Revision Month Day Year Facility Names _ Docket Numbert o ____

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1l2....]._10 8I9 Bl9 0 l 3 12 0 ll__1 12 2_.j 9 8l9 0 15 10 10 10 l 1 1_ I THl$ REPORT 15 $UBMITTED PUR$UANT TO THE REQUIREMENTS OF 10CFR  ;

g (Check one or more of the followinn) (111 l N -__

20.402(b) 20.405(c) __._ 50.73(a)(2)(lv) _ 73.7)(b) l POWER ___ 20.405(a)(1)(i) _._ 50.36(c)(1) ,_. 50.73(a)(2)(v) __ 73.71(c) '

LEVEL 20.405(a)(1)(ti) 50.36(c)(2) 50.73(a)(2)(vii) Othe r ( $pec i f y ,

!0 l0 (101 0 __ 20.405(a)(1)(iii) JL 50.73(a)(2)(i) _,_ 50.73(a)(2)(viii)(A) in Abstract l

////////////////////////// 20.405(a)(1)(tv) __. 50.73(a)(2)(ll) ,,_,_ 50.73(a)(2)(viii)(B) below and in

////////////////////////// 20.405(a)(1)(v) ._. 50.73(a)(2)(iii) _ 50.73(a)(2)(x) Text)

LICENSEE CONTACT FOR THIS LEP. (12)

Name TELEPHONE NUPSER AREA CODE i M. Herbaerewski . Technical Staf f GrQue leadtI_ . Ext. 2461 Bl115 914121 12191210_'

COMPLETE ONE LINE FOR EACH COMPON NT FAILURE DESCRIBED IN THIS REPORT (13)

CAU$E $YSTEM COMPONENT MANUFAC- REPORTABLE CAU$E $Y$ TEM COMPONENT MANUIAC- REPORTABLE TURER TO NPRDS TURER TO NPRDS {

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$UPPLEMENTAL REPORT EXPECTED (14) _ ,g E'pected Month ! Dav l Yead

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,___llti_i t L.reldomni t te E X P EC l[Q._10DMi$ $10N QM E i -X .[_tf0 _ _.,' M e (15) l ll lg ,,1,,, j AB$ TRACT (Limit to 1400 spaces, i.e. approximately fif teen single-space typewritten 7tnes) (16) i On December 10. 1989, with Unit 2 at 0% power during a scheduled shutdowr, a Local Leak Rate Test (LLRT) was performed on the primary containment drywell personnel interlock ir accordance with Dresden Technical Staff Surveillance (DTS) 1600-14 After the required one hour test at 49 psig, a leak rate of 125 standard cubic feet per hour ($CFH) was calculated . Because inclusion of this result into the existing total containment "As Left" type 'B' and 'C' LLRT data exceeded the Technical $pecification 3.7.A.2.b.(2)(a) limit of 480.452 SCFH. an Unusual Event was declared at 0505 hours0.00584 days <br />0.14 hours <br />8.349868e-4 weeks <br />1.921525e-4 months <br />. Reactor water temperature was brought below 212'F. below which primary containment integrity is not required, by 0919 hours0.0106 days <br />0.255 hours <br />0.00152 weeks <br />3.496795e-4 months <br />. After an investigation, the source of the leakage was found to be an electrical and telephone conduit adjacent to the outer door. These penetrations were sealed, and on December 17. 1989 an LLRT was perfor1ned resulting in 0 $CFH leakage. The safety significance of this event is considered to be l

minimal due to the f act that the leakage was occurring f rom the outer door conduit and the integrity of l the inner door was unaffected. A previous f ailure of the inner door on Unit 3 is documented in LER 89-007-0. Docket 050249.

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's* 4* t(([M(( [y[NT REPORT (tER) TEXi CQH11NUATION Ff ridt ,

l FACILITY NAME (1) DOCLET NUMBCR 12)- . LER RVM_u) _.h t t-Year Sequential Revision g ((f fff

, El . Number RL _ Numbtf._

_Dresden Nuclear Power Station D I 5 1 0 1 0 1 0 12 13 17 8 l_9 -

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TEXT Energy Industry Identification System (E!!$) codes are identified in the text as (XX)-

1 PLANT Am $YSTEM IDENTIFICATION: J General Electric - Bolling Water Reactor - 2527 IWt rated core thermal power.

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~ Nuclear Tracking System (NT$) tracking code numbers are identified in the text as (XXX.XXX.XX.XXXXX).

EVENT IDENTIflCATION:

r L: cal teak Rate Testing "As Found" Limit Exceeded Due to Excessive Leakage From the Unit 2 Drywell Personnel Int:rlock ()M)

A. E02 1TIONS PRIOR TO EVENT:

Unit: 2 Event Date: December 10, 1989 Event Time: 050$

Reacter Mode: N Mode Name: $tartup Power Level: 0%

Reactor Coolant $ystem (RC$) Pressure: 341 psig i

B. QLKRJPTION OF EVENT:

On December 12, 1989, with Unit 2 at 0% power during a scheduled s Ltdown, Dresden Technical Surveillance (DTS) 1600-14, LLRT of Primary Containment Personnel Access Lock, was performed. The initial pressure for this test was 49.0 psig. Af ter the required one hour test, the pressure dropped te 46.2 psig resulting in a calculated leakage rate of 125 standard cubic feet per hour ($CFH). Because inclusion of this result into the existing total primary containment As lef t" type 'B' and 'C' LLRT data exceeded the Technics' 57ecification 3.7.A.2.b.(2)(a) limit of 488.452 $CfH an Unusual Event was declared at 050$ hours. Nesctor water temperature vas brought below 212'F, below which primary containment integrity is not required, by 0919 hours0.0106 days <br />0.255 hours <br />0.00152 weeks <br />3.496795e-4 months <br />.

On December 12, 1989, an inspection of the Unit 2 interlock doors was performed by a vendor representative, Mechanical Maintenance, and Technical Staff personnel. A second LLRT was then performed with personnel inside and outside of containment to determine the leakage path. Both doors were

! thoroughly checked f or signs of leakage with soap solution at this time. No leakage was found on the l- inner doort however, a small leak was discovered on an electrical condsit adjacent to the outer door.

l The test was terminated and Work Request 89203 was generated to seal the conduit adjacent to the outer i door. (The conduit contained telephone and lighting wiring for the airlock area.) On December 14, 1989, the telephone and lighting conduit f or the air lock space on the Unit 2 drywell personnel interlock was resealed by Electrical Maintenance. On December 15, 1989, a third LLRT was performed at l 48 psig. During the test, the junction box covers for the airlock telephone and lighting were removed i and significant air leakage was observed coming f rom the lighting conduit. The sealant injected into the conduit on December 14, 1989 had apparently not cured properly. The test was terminated after the l

1eakage was again calculated to be 125 $CFH. On December 16, 1989, the lighting and telephone conduits l , were cut and capped. On December 17, 1989, a final LLRT was performed at 49.3 psig. After the one hour test period, the pressure remained unchanged resulting in 0 SCFH leakage.

L l This report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B), which requires the reporting of )

any operation or condition prohibited by the plant's Technical Specifications.

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LJCER$LLOlENLRJf0RT f tER) TEXT CONTINUATION Fe ,

I, fACILITF NAMC i1) DOCKET IAIMDER (2) _tLR twt 1ELIL16) _, A_

,. Year // Sequential ///

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_ptgag[gg Ng124r 1 power Station 0 1 5 1 0 l 0 1 0 12 13 17 8l9 - 01312 - 0 10 0 13 tr l_,_- 1+

TLxi Energy Industry identification $ystem (E!!$) codes are identified in the text as (XX) t C. APPARENT CAUSE OF EVENT: j The root cause of the personnel interlock leakage was the degr/dation of the telephone and electrical conduit penetration sealant. This conclusion was confirmed t,y verification of 0 $CFH 1eakage af ter these conduit penetrations were cut and capped. A system history review indicates that this has not r been a recurring problem. ,

D. $AFETY ANALYS1$ OF EVENT:

As described in section B of this report, inspection and testing concluded that *.ne source of leakage was an electrical conduit adjacent to the outer door. The inner door was vertiled to be intact: this was verified by a measured leak rate of 0 SCFH upon completion of repairs to the conduit assembly.  ;

Therefore, this condition would not have resulted in leakage f rom the primary containment under design basis accident conditions. Consequently, the safety significance of this event was minimal.

E. (ORRECTIVE ACTIONS:

The electrical conduit was cut and capped, and the interlock LLRT was performed satisfactorily. The conduit will remain capped until this penetration can be reworked at the upcoming refuel outage (237-200-89-18801). Additionally, the Unit 3 primary containment drywell personnel interlock will be tested during its current refuel outage to verify that the lighting / telephone conduit is intact (237-200-89-18802). ,

F. PREVIOUS EVENTS:

A previous event involving the Dresden Unit 3 primary containment personnel interlock inner door is Insted below.

LER/ Docket Numbers lillt 89-7/050249 Local Leak Rate Test (LLRT) Failure Due to Improperly Seated Gasket During this event, the inner door gasket appeared to be leaking. An investigat1or.

revealed that the inner door seal esperienced a six inch longitudinal tear.

Corrective action taken was to replace the gasket, and to implement a periodic preventive maintenance replacement.

G. COMPONENT FAILURE DAT&:

The conduit seal configuration was f abricated in accordance with original construction design details.

An NPRDS data base search indicates this has not been a recurring problem.

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