ML20043F472

LER 90-021-00:on 900509,RWCU Sys Differential Flow High Trip Instrumentation Inoperable for Period Greater than Allowed by Tech Spec.Caused by Misinterpretation of Tech Spec 3/4.3.2,Table 3.3.2.-1.4.Personnel retrained.W/900608 Ltr

ML20043F472
Person / Time
Site:	River Bend
Issue date:	06/08/1990
From:	England L, Odell W GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-021, LER-90-21, RBG-32976, NUDOCS 9006150048
Download: ML20043F472 (4)

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e GULF STATES UTILITIES COMPANY filVER SL60 ST A fiON POST OFFict 60) 220 - St FRANCISylti t LOUiSiAN A 70f'PJ AREA CODE 604 03$ 60S4 3468%1 June 8 , 1990 RBG- 32976 File Nos. G9.5, G9.25.1.3 U.S. Nuclear Regulatory Ccanission Document Control Desk Washington,' D.C. 20555 Gentlemen:

River Bend Station - Unit 1 Docket No. 50-458 Please find enclosed Licensee Event Report No.90-021 for River Bend Station - Unit 1. This report is being subnitted pursuant to 10CFR50.73.

Sincerely i

dW. H. Odell Manager-Oversight River Bend Nuclear Group

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0l5 0 l9 90 9 l0 0 l2 l1 0l0 0l6 0l8 9l 0 0151010101II OPE R ATING THl$ REPORT 18 SueMITTIO PUR$UANT TO THE RLQUIREMENTS OS to CFR { (Cnece one e, mee et rae feue..asi His Moot si 1 a mai to sum s0mHHi 13 nmi PowgR M 406dald Hal 60 36NH1) to 1St.H2 Hel 73 ?Hel to 1 l0 10 =0 40s=HiHai *0 maHei so rsieHan ai ofwaa u.we a meen 20 40steIU Hdd to 73 tall 2H4 to 73 tall 2HvileHAl J66A w mnH., .On.iuH., .O n.in n..n. ,

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$v99!ssiON vis (n pas como<ere ExetCTIO Sugw$$t0N DA TE) NO l l l 19tT R ACT (L eur to 100 speces # e , speroswisee y twwen seas <e soece typewertwo west (16i on 05/09/90 with the reactor at 100 percent power (Operational Condition 1), during a routine LCO review, the night shift Control Operating Foreman (COP) discovered that the channel "A" reactor water cleanup (RWCU) system differential flow high trip instruments and the channel "A" reactor water cleanup differential timer were in an inoperable condition for a period of time greater than allowed by the action statement of Technical Specification (TS) 3.3.2. This was identified during the performance of an 18 month channel calibration Surveillance Test Procedure (STP-207-4215). This report is submitted pursuant to 10CFR50. 73 (a) (2) (i) (B) to document the non-compliance with the action statement. The root cause of this . event was a misinterpretation of TS 3/4.3.2, table 3.3.2-1.4. Corrective action will' consist of training for all operation crews to summarize the event and review TS applications by June 30, 1990.

l The leakage monitoring system provides two redundant divisions of isolation instrumentation. In this case, only one division was

( removed from service, leaving the redundant system available to L

. provide isolation capability. In the event of a system leak requiring isolation, the remaining division would have isolated as designed.

Therefore, this event did not have an adverse impact on the safe operation of River Bend Station or the health and safety of the public.

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d0 0 12 0F 0h saw ., . a aoco, mem REPORTED CONDITION On 05/09/90 with the reactor at 100 percent power (Operational Condition 1), during a routine LCO review, the night shift _ Control Operating Foreman discovered that the channel "A" reactor water cleanup system (*CE*) differential flow high trip instruments (*FT*)

IE31*N075A, N076A, N077A and the channel "A" reactor water cleanup differential timer (*TMR*) 1E31*R615A were in an inoperable condition for a period of time greater than allowed by the action statement of Technical Specification 3.3.2. This was identified during the performance of an 18 month channel calibration Surveillance Test Procedure (STP-207-4215). This report is submitted pursuant to 10CFR50. 73 (a) (2) (1) (B) to document the non-compliance with the action statement.

INVESTIGATION At 0842 hours0.00975 days <br />0.234 hours <br />0.00139 weeks <br />3.20381e-4 months <br /> on 05/09/90, with the reactor at 100 percent power (Operational Condition 1) STP-207-4215 "RWCU Differential Flow and Differential Flow Timer", was presented to the COF for work release.

Following this, the COF reviewed the STP for applicable technical specifications. When Technical Specification 3.3.2 was reviewed, a misinterpretation of the required minimum operable channels was made.

It was assumed that the requirement for one operable channel was met by maintaining "B" channel operable while "A" was removed from service as indicated in the Surveillance Test Procedure steps 5.1, 6.5, and 7.1. However, TS 3/4.3.2, table 3.3.2-1.4 a and b require a minimum of one operable channel per trip system and channels "A" and "B" each constitute a separate trip system. . Thus, the TS requires that "A" and "B" each have a minimum of one channel operable, necause there is only one instrument por trip system in this case, and channel "A" was l inoperable, TS 3.3.2, table 3.3.2-1, action 27 applies. Action 27 l requires the closure of the affected system isolation valves within I hour and declaring the affected system inoperable.

Due to the TS misinterpretation a tracking limiting condition for operation (LCO) was issued. Review by the Shift Supervisor failed to recognize the error in the COF's interpretation. This misinterpretation was the root cause of the event which led to channel "A" being rendered inoperable.

The TS misinterpretation resulted in work beginning on the "A" reactor water cleanup system differential flow high instruments (*FT*) and differential flow high timer (*TMR*). This placed the "A" channel in an inoperable condition from 0842 hours0.00975 days <br />0.234 hours <br />0.00139 weeks <br />3.20381e-4 months <br /> 05/09/90, until 1311 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.988355e-4 months <br /> 05/09/90 at which time work was temporarily suspended.

At 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> 05/09/90, the calibration was restarted and continued until 1945 hours0.0225 days <br />0.54 hours <br />0.00322 weeks <br />7.400725e-4 months <br /> 05/09/90 when the night shift COP discovered the violation and stopped work in order to comply with action 27 of TS table 3.3.2-1.

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ol 0 ol3 or o l3 von n . anc w an4vnn At 2014 hours0.0233 days <br />0.559 hours <br />0.00333 weeks <br />7.66327e-4 months <br /> on 05/09/90 the reactor water cleanup system was secured i and the Division I isolation valves 1G33*MOVF004, F054, F039 were closed to isolate the system. (IG33*MOVF034 was already closed.)

This placed the unit in compliance with TS 3.3.2. The "A" channel instruments were restored to operable condition at 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> 05/09/90 thus exiting the LCO, and the reactor water cleanup system was returned to service at 2330 hours0.027 days <br />0.647 hours <br />0.00385 weeks <br />8.86565e-4 months <br /> 05/09/90.  :

A review of previously submitted LERs has identified three events which are similar. LER 85-025 describes an event in which reactor water conductivity recorders (*CR*) were taken out of, service.

Technical Specifications require conductivity measurements to be taken every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the plant is in cold shutdown with the recorders inoperative. This requirement was overlooked by plant personnel.

Corrective actions included improving the shift turnover procedure to put more emphasis on chemistry status, and revising the LCO tracking system. LER 88-013 described a failure to initiate the annulus mixing and- standby gas treatment (SGTS) (*BH*) systems due to a misinterpretation of TS 3.3.2. Action 29 of this TS requires that annulus mixing and at least one train of the SGTS be initiated within one hour when an annulus exhaust radiation monitor (*IL*) is rendered inoperable. Additional training was provided to plant personnel on the interpretation of Technical Specifications. LER 88-028 described an event identical to LER 88-013. In this case, corrective actions included review of LERs88-028 and 88-013 for the responsible party and enhancing the station test procedures to clarify the requirements ,

for annulus mixing and SGTS operation when the annulus exhaust radiation monitors are taken out of service.

CORRECTIVE ACTION Training on this event will be completed by June 30, 1990 for all operation crews to summarize the event and provide a review of Technical Specification applications.

SAFETY ASSESSMENT The leakage monitoring system provides two redundant divisions of

. isolation instrumentation. In this case, only one division was removed from service, leaving the redundant system available to provide isolation capability. In the event of a system leak requiring isolation, the remaining division would have isolated as designe6.

-Therefore, this event did not have an adverse impact on the safe operation of River Bend Station or the health and safety of the public.

NOTE: Energy Industry Identification System Codes are identified in the text as (*XX*).

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