ML19325E826

LER 87-012-01:on 870918,while Performing Qos 1600-1, Vacuum Breaker 2-1601-33E Remained Open After Testing.Caused by Binding in Test Cylinder Portion of Vacuum Breaker. Nuclear Work Requests completed.W/891030 Ltr

ML19325E826
Person / Time
Site:	Quad Cities
Issue date:	10/30/1989
From:	Bax R, Cravens S COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
0371Z, 1077H, 371Z, LER-87-012-01, LER-87-12-1, RLB-89-245, NUDOCS 8911090092
Download: ML19325E826 (7)

Text

i 4.

Commomvealth Edison  :

osed Cites Nucleat Power Station l i  ;,

. O 32710 20s Avenue Norm Cordova. Illinos 61242 9740 -

TeWhone 30S'654 2241

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l; RLB-89-245 l

f October 30, 1989 l t

U.S. Nuclear Regulatory Commission l Document Control Desk  !

Washington, DC 20555  !

Reference:

Quad-Cities Nuclear Power Station

Docket Number 50-265. DPR-30, Unit Two  !

Enclosed please find Licensee Event Report (LER)87-012, Revision 01, for Quad-Cities Nuc1 car Power Station. This revision provides an update regarding  :

cause and corrective actions.  :

This report is submitted in accordance with the requirements of the Code l of Federal Regulations, Title 10,.Part 50.73(a)(2)(11), which requires the  !

reporting of any event or condition that resulted in the condition of the ,

nuclear power plant, including its principal safety barrier, being seriously  ;

degraded.  ;

Respectfully, f

'I COMMONWEALTH EDISON COMPANY OUAD-CITIES NUCLEAR POWER STATION  !

[N R. L. Bax  !

Station Manager RLB/MJB/e  !

Enclosure cc: R. Stols  !

R. Higgins INPO Records Center ,

NRC Region III j i

8911090092 891030  ;

~

PDR ADOCK 05000265 S PDC l l 1077H/03712 y i

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LICth5t[ (VENT REPORT (LER)

Facility name (1) Docket humber (2) _Paea f31 0UAD-CIT 1[1 buCLEAR PDWLR_ilA110lL_Qh!T TWO Dl1101O!0121611 1 of G i 6, I Undate on tomarettien thamber to Drywell Vacuum Bregler Failure to Cleig_pge to Tett Cylinder, Pindine

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!9 !0 (101 0 ,,,__ 20.405(a)(1)(111) so.73(aH2)(1) 50.73(a)(2)(viii)(A) in Abstract below l

////////////////////////// 20.405(a)(1)(iv) .2 50.73(aH2)(ti) ,_ 50.73(a)(2)(viii)(8) and in Text) l 50.73(a H 2)(iii)

///////////////////'/////// 20.405(a)(I Hv) ,_ ,_ 50.73(a H 2 H z )

LIC[hif E CONTACT FOR THis LER f121 l Name itLtPH0hLjig!$[R l AR(A CODE l tuvatte travant. Technical Staff Ennineer. Extention 2144 310 19 El 11 41 -l 21 fl 411_ '

COMPLETE Dht LINLf,1)R [ACH COM ON[!( FAILURE Df1CRI)[D lh TH11 REPORT f13)

CAuSE SYSTEM COMPONENT MANUFAC. R(PORTABLE CAust SYSTEM COMPONENT MANUFAC. R[ PORTABLE TURER T0 kPRDS_ TURER 70 hPRD1 x alF l VI flV All la 11 Y l I l l l l l l l 1 1 I l l 1 1 I I I I l SUPPLEMthTAL REPORT EXPECTED (141 Expected Month I Day I Yg&I submission lYet f1f vet. complete EXPECTED 10BM11110N DATE) X l ho *'("' I ll l1 A85 TRACT (Limit to 1400 spaces, i.e. approxim.tely fif teen single-space typewritten lines) (16)

On September 18, 1987, Quad Cities Unit Two was in the RUN mode at 90 percent of '

core thermal power. At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, while performing QOS 1600-1 (Suppression Chamber to Drywell Vacuum Breakers Monthly Exercise), the 2-1601-33E vacuum breaker remained open after testing. Efforts were directed at reclosing the vacuum breaker. At 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />, these efforts were successful. Because of the stuck open vacuum breaker, NRC notification had been completed at 1346 hours0.0156 days <br />0.374 hours <br />0.00223 weeks <br />5.12153e-4 months <br />. Position indication problems were also identified for vacuum breakers 2-1601-32A and 33A. Suppression enamber to l drywell differential pressure was reestablished at 1725 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.563625e-4 months <br />.

The cause of the 2-1601-33E failure was determined to be due to binding in the test cylinder portion of the vacuum breaker. This is considered an isolated event and does not affect the operation necessary to mitigate the consequences of a loss of coolant accident. The position indication problems on 2-1601-32A and 33A should be l

corrected upon completion of modification M-4-1(2)-88-009 which is the result of the l Inspection and evaluation performed on Unit One's vacuum breakers. This report is submitted per 10 CFR 50.73(a)(2)(11).

1077H/03712

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PLANT AND SYSTEM IDENTIFICATION:  !

General Electric - Boiling Water Reactor - 2511 MWt rated core thermal power. Energy Industry Identification System (E!!S) codes are identified in the text as (XX).

EVENT IDENTIFICATION:- While testing suppression chamber to drywell vacuum breakers, ,

the 2-1601-33E stuck open for 50 minutes.

I A .~ CONDITIONS PRIOR TO EVENT:

Unit: Two Event Date: September 18, 1987 Event Time: 1300 Reactor Mode: 4 Mode Name: RUN Power Level: 90%

This report was initiated by Deviation Report 0-4-2-87-044.

l RUN Mode (4) - In this position the reactor system pressure is at or above 825 psig, l and the reactor protection system is energized, with APRM protection and RBM i interlocks in service (excluding the 15% high flux scram).

B. DESCRIPTION OF EVENT:

On September 18, 1987 Quad Cities Unit Two was in the RUN mode at 90 percent of I rated core thermal power. At 0207 hours0.0024 days <br />0.0575 hours <br />3.422619e-4 weeks <br />7.87635e-5 months <br />, 005 1600-1 (Suppression Chamber (NH) to Drywell (NH) Vacuum Breakers (BF, VACB) Monthly Exercise) was begun. The first vacuum breaker valve tested, 2-1601-32A, cycled open successfully but indicated a ,

dual position on both Olvisions I and II after the testing. Technical Specification l 3.7.A.4 b. states:

l "Any pressure-suppression chamber-drywell vacuum breaker may be non-fully closed as indicated by the position indication and alarm systems provided that drywell to

suppression chamber differential pressure decay rate is

demonstrated to be not greater than 25% of the differential l pressure decay rate for all vacuum breakers open the '

equivalent of 1/16 inch at all points along the seal surface of the disk."

As a result, the drywell/ suppression differential pressure (dp) was reestablished at 0250 hours0.00289 days <br />0.0694 hours <br />4.133598e-4 weeks <br />9.5125e-5 months <br /> and then QOS 1600-27 (Suppression Chamber to Drywell Pressure Separation I Test with >/=1.2 PSIO Established Between Drywell and Suppression Chamber (Orywell Inerted)) was satisfactorily completed. This test satisfied the requirements of the l above referenced specification.

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f N"r naam tillat ynit Two o11IoIeio 1 21 61 1 al7 . eI1 i2 . oI) ois er 011, ftKT At 0550 hours0.00637 days <br />0.153 hours <br />9.093915e-4 weeks <br />2.09275e-4 months <br />, electrical blocks (numbers 3954 and 3955) were installed to allow  !

resetting the vacuum breaker position annunciator alarms on the 902-3 panel in the  !

control room, and to clear the red "open" lights at the local control panel  !

2252-24 At 0825 hours0.00955 days <br />0.229 hours <br />0.00136 weeks <br />3.139125e-4 months <br />, testing resumed per QOS 1600-1. Vacuum breakers 2-1601-32B '

through F ope, rated satisfactorily but vacuum breaker 2-1601-33A, also indicated dual position on Division I.following the testing. At 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, the separation test  ;

(QOS 1600-27) was performed again successfully to satisfy Specification 3.7.A.4.b. '

referenced above and Specification 3.7.A.4.c. which states:

" reactor operation may continue provided that no more than one quarter of the number of pressure suppression i chamber-drywell vacuum breakers are determined to be  ;

inoperable provided that they are secured or known to be in '

the closed position."

Both the 2-1601-32A and 33A were known to be in the closed position because the separation tett was successfully performed. There are twelve suppression chamber-drywell vacuum breakers and only two were displaying indication problems.

At 1140 hours0.0132 days <br />0.317 hours <br />0.00188 weeks <br />4.3377e-4 months <br />, electrical blocks (numbers 3956 and 3957) were installed to reset the annunciator alarms on the 902-3 panel and to clear the red "open" light at the local control panel.

Subsequently, testing per 005 1600-1 resumed and at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, vacuum breaker 2-1601-33E stuck fully open when tested. /.ttempts were initiated immediately to reclose the vacuum breaker. These efforts included further manipulations of the l' vacuum breaker test pushbutton and isolation of the air supply to the vacuum breaker test solenold. '

At 1346 hours0.0156 days <br />0.374 hours <br />0.00223 weeks <br />5.12153e-4 months <br />, the NRC was notified via the Emargency Notification System (ENS) to satisfy the requirements of 10 CFR 50.72(b)(1)(11) because of the stuck open vacuum breaker. However, at 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />, as a result of the continuing efforts to close the 2-1601-33E vacuum breaker, the vacuum breaker was closed. Then the drywell-suppression chamber dp restoration was begun.

At-1630 hours it was apparent that the drywell-suppression chamber dp restoration  :

was not proceeding normally, so the nine vacuum breakers that were considered available were cycled again to ensure that they were all reseated. All but the 2-1601-32A, 33A and 33E were cycled. As a result, dp buildup was improved and at 1703 hours0.0197 days <br />0.473 hours <br />0.00282 weeks <br />6.479915e-4 months <br />, the dp of 1.2 psid required by Technical Specification 3.7.A.6.a. was '

established. This Specification states that:

" differential pressure between the drywell and suppression chamber shall be maintained at equal to or greater than 1.20 psid except this differential may be decreased to less than 1.20 PSID for a maximum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> during required operability testing of the HPCI system pump, the RCIC >

system pump, the drywell-pressure suppression chamber vacuum breakers, and reactor pressure relief valves.

l l 1077H/03712 l

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fixf If the Specifications of 3.7.A cannot be met, and the  ;

differential pressure cannot be restored within the  ;

subsequent six (6) hour period, an orderly shutdown shall i be initiated and the reactor shall be in a cold shutdown  !

condition in the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." l At 1725 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.563625e-4 months <br />, the separation test (005 1600-27) was completed satisfactorily. The  !

dp was lost at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> when the 2-1601-33E was tested and stuck open. By 1703 '

hours the dp was reestablished. As a result, only 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and 3 minutes of the six hours allowed by the Technical Specification were exhausted.  ;

C. APPARENT CAUSE OF EVENT:  ;

This report is submitted to comply with 10 CFR 50.73(a)(2)(11), which requires the reporting of any event or condition that resulted in the condition of the nuclear  !

power plant, including its principal safety barriers, being seriously degraded. j i

The apparent cause for the 2-1601-33E vacuum breaker initial failure to close was e due to binding of the test cylinder. Furthermore, vacuum breaker 2-1601-33A  !

position indication limit switches required adjustment. j D. SAFETY ANALYSIS OF EVENT:

The 2-1601-33E vacuum breaker is one of twelve vacuum breakers that are provided to ,

relieve noncondensables to the drywell from the suppression chamber. The capacity cf the vacuum breakers is designed to limit the dp between the drywell and  ;

suppression chamber to 0.5 psi to maintain the structural integrity of the i containment. The design flow can be achieved with 25 percent of the vacuum breakers  :

I closed without exceeding the 0.5 pst differential pressure limit.

In the event of a Loss of Coolant Accident (LOCA) with the suppression chamber to '

drywell vacuum breakers stuck opeil, some of the steam created by the LOCA would flow from the drywell to the suppression chamber atmosphere through the vacuum breaker, I resulting in incomplete condensation of the steam during the blowdown. This would  :

raise the suppression chamber pressure above the pressure as analyzed with all vacuum breakers closed. Two design features assist with resolution of this  ;

equipment problem: >

1077H/0371Z l

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1. The high velocity steam passing through the valve would tend to close the valve, 7

2. Steam which would be passed through the unclosed valve could be condensed  ;

through the use of the Suppression Pool Spray subsystem of the Residual Heat Removal (BO) system. j Station management discussed the problem with this vacuum breaker and concluded that based on the indications observed while trying to reclose the valve, it was apparent '

i' that the problem was with the air operator portion of the valve. Each time the l vacuum breaker test button was operated (given an open signal) from the local control panel, it took longer to have the green " closed" indication go out. Since 7 the air operator is for test purposes only and does not perform any function when -

the valve operates as a vacuum breaker, it wat agreed that the 2-1601-33E would i still perform as required during a LOCA.  ;

As a precautionary measure, this vacuum breaker was declared inoperable (but only I for testing) per 005 1600-02 (Suppression Chamber-Drywell Vacuum Brenkers Inoperable).

Because the 2-1601-32A showed dual indication in both 01 vision I and Il position indicating and alarm systems, it was declared inoperable per 005 1600-2. The safety significance of this condition was minimal because this vacuum breaker and the 2-1601-33A were still capable of performing their function during a LOCA. Vacuum breaker position indication is to provide indication that valve opening exceeds the ,

equivalent of 1/16 inch at all joints along the seal surface of the disk. (T.S.

3.7.A.4.a.3) Closure integrity of all valvis is assured by satisfactory completion of the separation test (005 1600-27). The vacuum breakers were tested every 15 days in accordance with Technical Specification 3.7.A.4.d which states:

"if failure occurs in one of the two-position alarm systems I for one or more vacuum breakers, reactor operation may r continue provided that a differential pressure decay rate  !

test is initiated immediately and performed every 15 days thereafter untti the failure is corrected."

l l The testing was performed satisfactorily on 10/02/87, 10/17/87, and ,

11/01/87.

l l l E. CORRECTIVE ACTION:

Nuclear Work Requests 060285, Q60288, and 060289 were completed and the testing was ,

satisfactorily completed by November 5, 1987. Vacuum breakers 2-1601-32A and 33E  ;

test cylinder lever arm and valve disc arm were adjusted. Additionally, the 2-1601-33E test cylinder was rebuilt. Vacuum breakers 2-1601-32A and 33A position  !

l indication limit switches were adjusted.

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[ y etttat unit Tuo e i t i e i e IJLL11 AL.1 al ? - ei1 12 . oI1 016 J L J1L fist h The problem that caused the 2-1601-33E to stick open is considered an isolated event. The dual indicaticas present on vacuum breakers 2-1601-32A and 33A is considered to be primarily indication problems. Correction of the indication problem will be accomplished under modification M-4-1(2)-88-009. The modification t;lil provide a more reliable method of position indication by placing the CLOSED position indication switches at the bottom of each vacuum breaker body. Completion of the modification is being tracked with Nuclear Tracking System (NTS) 2652008800101 for Unit Two and 2542008800503 for Unit One. This modification is the result of the inspection and evaluation performed on Unit One Luring its last refuel and maintenance outage.

f. PREVIOUS EVENTS Licensee Event Report (LER) 0eserIDtion 265/87-004 2-1601-33A failed to close due to dimpled bushing and/or corroded solenold.

Reportable Occurrence Descriotton 265/82-22/03L 2-1601-33A Stainless steel packing and stuffing box bushing bound to the shaft caused failure to close.

265/82-06/03L 2-1601-32C counterweight mispositioned.

G. COMPONENT FAILURE DATA:

The vacuum breakers are 18 inch swing-check valves manufactured by Atwood and Morrill Company, Incorporated. The air test cylinder is manufactured by Atwood and Morrill, model number 20781-F.

1077H/03712