05000457/LER-1990-009
| ML20055D632 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 07/02/1990 |
| From: | Querio R, Stroh D COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BW-90-0670, BW-90-670, LER-90-009-04, LER-90-9-4, NUDOCS 9007090208 | |
| Download: ML20055D632 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| 4572090009R00 - NRC Website | |
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Commonweshh Edison
/ Braidwood Nucl :r Po:cr St: tion i
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%) Route #1. Box 64
/ Braceville, Illinois 60407 I
Telephone 81$/458-2801 i p I . i' , l June 29,1990 BW/90-0670 ; i l i l
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U. S. Nuclear Regulatory Commission I Document Control Desk j Washington, D.C. 20555 1 l
Dear Str:
l L The enclosed Licensee Event Report from Braldwood Generating , t Station is being transmitted to you in accordance with the requirements of 1 10CFR50.73(a)(2)(ll) which requires a 30-day written report. 1 This report is number 90-009-00: Docket No. 50-457. < l Very truly yours, ] [
. R. E. Querto 1 Station Manager l Braldwood Nuclear Station REQ /JDW/sjs ;
l (7126z). i
Enclosure:
Licensee Event Report No. 90-009-00 j i ! cc: NRC Region III Administrator NRC Resident Inspector [ INPO Record Center - Ceco Distribution List 1 i u
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AD$1RACT (Limit to 1400 spaces, i.e. approelmately fif teen single-space typewritten lines) (16) At 0030 on June 4,1990, with unit 2 in mode 4, during a routtre ins;mtion of the 2A tiann Steaminne Inistion - Valve (H$ly) It was identified that the pressures for the actl e anti standh accumu1Mors were 3&QO ps' d and 4600 psig tespectively. This was below the 4800 psig required ler operability. The M!!vs are not renun- u to be crerable in mode 4 At Approximately 0910 it was identified that the tause of the low accur...nor pressore was th) "N" four way hydraullt valve. The N velve had an tolernal lost which allowed hydra 9)(c fluid to Le perted to the reservoir. An evaluation was conducted to determint, tow the valve ucu?d have pertWed in its as feund
.tondition. It was tontivded that the valve would have been Intspeble of closure trae tha ;.:tive -accumulator.
There was adequate hydraulic fluid and pressure in the standby accumulator to ens ere 0% of atrote travel in the closed direction but it covid not be assured that 100% clovvre would be echiend. At44tienally, with the hydraulic leak on the N valve the air driven hydraulic pg distharge vould have been directed back to the reservoir instead of assisting with the final $t. of valvo r.losure. Ibe cause of the event was comsonent
-follure. The four way valve and the hydraulic oli fllter for the TA fl$1V were replar.e!, Slnre replaceme.it, the 2 A H$IV has performed satisf actorily. previous correct lvt octions are not appitcable.
1 3042m(06/27/90)2
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' I Unitt Braldwood 21 tvent Date! June 4. 1990; [ vent ilme: 0030 4 - Hot $hutdown; Rx powert 0%;
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zMode RC$ (AB) Temperature / pressuret 330 DtGRits f / 350 psig ; Dhdiptionoftvent: I J ' Th;re were no systems or components innperable at the beginning of the event which contributed to the ;
. Severity of the event.
At 0030 on June 4.1990 during a routine inspection of the 2A Main Steamilne Isolation Valve (MSIV) ($B) it was identified that the pressures for the active and standby accumulators were 3400 pilg and 4600 psig t respectively. This was below the 4000 psig required for operability. The MSIVs are not required to be j
;perable in mode 4. The valve was classified as degraded equipment as a means for tracking and restoring to i i
op; table prior to entry into a mode where operability was required. Trouble shooting activities were immediately initiated. -: At approntmately 0910 it was identified that the cause of the low accumulator pressure was the *N" four way hydraullt valve. The N valve had an internal leak which allowed hydraulic fluid to be ported to the !
! r servoir. The System Test Engineer (Sit) was requested to evaluate how the valve would have performed in this as found condition. Based on the results of this evaluation it was concluded that the valve would have m toen incapable of closure from the active accumulatot which Indicated 3400 psig. The $ft concluded that
'th;re was adequate hydraullt fluid and pressure in the standby accumulator to ensure 95% of stroke travel in
- the cloe,ed direction, but it could not be assured that 100% closure would be achieved. Additionally, with
-the hydraulic leak on.the N valve the air driven hydraulic pump discharge would have been directed back to th) reservoir Instead of assisting with the final 5% of valve closure. .j < this event was conservatively classified as an event found while the reactor was shut down, that, had it been found while the reactos. was in operation, would have resulted in the Nuclear power plant, including its , . principal saf ety barrlers, being seriously degraded. The appropriate NRC notification via the CNS phone system was made at 1150 pursuant to 10CrR50.72(b)(2HI).
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,i This eventt is being reported pursuant to 10Cf R50.73(a)(2)(li) - any event or condition that resulted in the j
tondition of the nuclear power plant. including its principal safety barriers, being seriously degraded. C. = C:use of tvent 1he root cause of this event was component failure. The defective four way valve wns removed and placed on a tist stand. During test operations leakage was evident and traced to poor sealing tetween the metal spool piece and it's mating thlmble. This was a metal to metal seal with a ground finish. Any small imperfection ,' sr dirt buildup on the faces would cause leakage. The hydraullt fluid was analyred and Indicated a very low particulate count. This would tend to indicate that the event was isolated. L 30422(06/27/90)3
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p . F A(it t f Y NAME (1) 00(s.[1 NUMBER (2) _.1LR.EWl0LILifd - _ _f' age _.t3L_ Year /// Sequential fj
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i fff ul _ Neber //,f _'Nabet u ; ltaldwied_2 QJ 51 0 10In._L L M 1 9IO - 0-.Lo-l9 - .OIO a Or 013 [lftXT Energy industry Identification $ystem (L!!$) codes are identified in the text as (XX) 8 [ L t - 4 D. Safety Analysis: , f p s This event had no effect on the safety of the plant or the public. The H$!V was not required.to be operable 'n ll [p mod') 4. The M$1Vs for the three remaining steamilnes were operable and evallable had isolation been required, Und0t the worst case of this event occurring with a Unit at power and an actu61 HSIV isolation being required
,4 ~ there would still be no effect. The analyses of the postulated accidents which require steamline isolation assuae ! , the failure of ore H!!V to close, the conclusions of the analyses' indicates that for all cases the integrity of f, structures and components required to mitlpate this accident will be maintained, no Departure from Hucleate B2414ng will occur, and that any potential rad .. logical consequences would be within the guidelines of 10 Cf R , 100. This is enveloped in section 1$ of the Updated final Safety Analysis Report.
L t, CCrrective Actions: The four way valve was replaced. The hydraulic oil filter for the 2A M$1V was also replaced. $1nce replacement of ti.e filter and the valve, the hydraulic system of the 2 A HSIV has performed satisfactorily.
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'F1 previous Occurrences:
There was a previous occurrences of an inoperable HSIV due to a failed four way solenold valve, n LERJE - DYRJiot 1111e
'$0-4$6/ 88-024 20-1-08-25$ Inoperable H$1V dt.e to failure of H1 Four Way Solenoid valve.
The corrective actions were implemented addressing both root and contributing causes. previous corrective actions s, iare not appilcable to this event.
- G. Component failure Date:
MeDufAclurJtL. MQEtMlli.WLt- !i[o. Fati.Rg2
' Anchor Darling Valve Co. Four Way Hydraulle valve W19595
-(Teledyne Republic). (23304-7001-2852)
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