ML19332C536

LER 89-036-00:on 891017,reported That Various motor-operated Valves Energized Contrary to Plant Fire Hazard Analyses. Caused by Failure to Implement Design Documents.Valves Reanalyzed & Procedures revised.W/891116 Ltr

ML19332C536
Person / Time
Site:	River Bend
Issue date:	11/16/1989
From:	Booker J, England L GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-036, LER-89-36, RBG-31778, NUDOCS 8911280237
Download: ML19332C536 (6)

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GULF STATES UTILITIES COMPANY.  ;

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November 16, 1989 RBG- 31778 File Nos. G9.5,'G9.25.1.3 j U.S. Nuclear. Regulatory Commission.

Document Control Desk l

. Washington, D.C.- 20555 Gentlemen:

River Bend Station - Unit 1 Docket No. 50-458 Please find . enclosed- Licensee Event Report'No.89-036 for River Bend Station ~~. Unit 1.' This report is. being submitted pursuant to 10CFR50.73,.. L ,

5 Sincerely, Q/ put.t/ / '

L J.-E. Booker h Manager-River Bend Oversight River Bend Nuclear Group

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C/ch cct ~ U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite'1000 -

Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051<

St. Francisville, LA 70775 INPO Records Center 1100 circio 75 Parkway.

Atlanta,' GA 30339-3064 1

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Various System Motor Operated Velves Found Energized Contrary to Plant Fire Hazard Analyses Due to Failure to implement Deslon Documents

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operations initiated the required firewatches on the valves and j associated raceways, or the valves were de-energized. All valves have l been reanalyzed and procedures are being revised to require the valves l to be de-energized or provide justification to leave the valves

! energized. These actions ensure that a fire in any area in the plant would leave at least one method of safe shutdown unaffected.

Therefore, there was no significant impact on the health and safety of the public as a result of this event.

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0l 0 01 2 0F 0l5 j ten gggan wnn At 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on 10/17/89, with the reactor at full power in operational Condition 1, it was reported to the shift supervisor that various motor operated valves (MOVs) (*V*) in the plant were energized, contrary to the assumptions contained in the plant fire -

hazards analysis (FHA). These valves are listed in Tables 2 and 5 of design Specification 240.201, " Fire Analysis and Evaluation Criteria",

and are shown to be assumed to have power removed during plant operation. The list of valves affected consists of thirteen valves in the residual heat removal system (*BO*), three in the fuel pool cooling system (*DA*), one in the reactor core isolation cooling r

system (*BN*), two in the standby service water system (*KG*), and one in the main steam system (*TA*). -

Because these valves were not de-energized as assumed in the FHA, compliance with General Design Criteria 3 of Appendix A to 10CFR50 was not assured therefore, this event is being considered reportable under 10CFR50.73 (a) (2) (ii) (B) as a condition that is outside the design basis of the plant.

INVESTIGATION A detailed study of the FHA was prompted by the investigation of an ,

earlier condition involving improperly installed fire walls at the Division I remote shutdown panel (reference LER 88-009). Comparison of the FHA requirements to the valve lineups and station operating procedures (SOPS) noted that the valves listed as ' remove power' in the FHA were instead energized. The reasons why the FHA requirements were not reflected in procedures and operational practice is unknown.

A review of the USAR and the original design criteria, and conversations with the Architect / Engineer (AE) Stone and Webster Engineering Ccrporation, demonstrated why these valves were shown to be de-energized. Two of the valves, IE12*MOVF009 and 1B21*MOVF019 '

were considered potential LOCA pathways due to a fire in the main control room or in the remote shutdown panel.

In the case of the 1E12*MOVF009 valve, the concern is to prevent a fire-induced opening of the low pressure shutdown cooling residual heat removal (RHR) (*BO*) system to the reactor vessel at operating pressure. This high/ low pressure interface valve is identified in section 9.5 of the USAR. An enable switch (*IS*) on valve IE12*MOVF008, the outboard isolation valve (*ISV*), is used to protect the RHR system from spurious actuations generated in a fire in the main control room. This switch is located in the Division I remote shutdown room, along with the controls for IE12*MOVF009. A fire assumed to affect the remote shutdown room could potentially open both inboard and outboard valves, over pressurizing the RHR system with l vessel pressure. A review of the operating requirements for the l IE12*MOVF009 valve showed that plant operation in Operational Conditions 1, 2, and 3 with the valve de-energized is acceptable,

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0 l0 Ol8 0' 0h "EEEEEYFT1UEihe out board isolation valve for the main steam isolation valve (MSIV) (*IS*) drains. A postulated control room fire could cause this valve to open spuriously, along with valves 3D21*MOVF016 and IB21*MOVF085, dumping steam to the main condenser

(*CDU*). When this scenario is considered with a 3oss of offsite power, as required by the FHA, this steam may be vented to the atmosphere as main condenser vacuum is lost.

The remaining _ valves were listed as ' power removed' by the A/E because i the divisional separation of the raceway was never verified to meet 10CFR50 Appendix R standards. As a result of this event, GSU has l_

identified all affected cabling, including associated circuits, and has evaluated their separation and fire area locations. This

cvaluation shows that all valves listed have adequate Appendix R separation. This analysis considers the effect of a fire anywhere in the plant, with the requisite loss of offsite power.

The three spent fuel pool cooling (SFC) (*DA*) valves require administrative control as a fire may effect either the inboard or outboard division, possibly causing a loss of fuel pool cooling to the containment fuel pools. This situation could only occur during refueling, and assuming worst case conditions, 1.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> is required to heat the pool to the upper limit of 150 degrees F. This is more than adequate time to manually reposition the valves if required.

A review of previously submitted LERs by River Bend Station revealed six previous LERs related to design requirements not being reflected in plant operating procedures. LERs86-066 and 87-026 identified fire doors which were not listed on the appropriate surveillance test procedures (STPs), LER 88-030 identified a secondary containment-door which was not listed on the appropriate STP, LER 89-003 identified a breaker which was not listed on the appropriate STP. Additionally, LER 86-059 identified that a design modification to the low pressure coolant injection line that changed the location of the piping high point vents was not reflected in tha appropriate STP and LER 87-030

• identified that the appropriate area temperatures were not being monitore? in the reactor plant component cooling areas as required by the Technical Specifications. However, none of these events were related to ensuring that the assumptions of the FHA were properly reflected in the plant operating procedures.

CORRECTIVE ACTION Engineering identified two possible methods to satisfy the requirements of the analysis and the plant Technical Specifications (TS). One method was to de-energize the MOVs an assumed in the FHA.

The second method was to treat the valves and the associated i electrical raceways as having missing installed fire barriers, and to take the action prescribed in TS 3/4.7.7, instituting a roving firewatch in the affected areas. The latter method was adopted and

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" UIe TeqT IrI U 17eYaYe$ s were initiated. Two valves, lE12*MOVF009 and IB21*MOVF019 were in areas not accessible to firewatch personnel and were therefore de-energized. The choice of methods considered the effect on Operations personnel due to a number of de-energized valves,

[ including the effect due to lit annunciators, and the additional requirement to enter the auxiliary building to de-energize the valves.

Operations will change the valve lineups to show valve IE12*MOVF009 de-energized until reactor pressure is reduced below 135 psig reactor pressure, which is the systeu pressure for shutdown cooling piping.

Valve IB21*MOVF019 is required for startup and is used in some operational trannients. Therefore, the status of this valve was changed to closed and de-energized. However, administrative controls will be implemented to allow station personac1 while at local motor control centers to open the valve when needed. This will enable positive control of this pathway in the event of a control room fire.

The valves are currently tagged out. Revision of the valve lineup and procedural changes will be completed by 1/15/90. The three SFC valves require administrative control under worst case conditions to be aligned to supply cooling to the upper pools within 1.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> to limit the upper pool temperature to 150 degrees F. This caution will be added to the pre-fire strategy for the area in the fuel and reactor buildings containing these valves. A change document will be initiated to revise Table 2 and 5 of the FHA. This document change will also be completed by 1/15/90.

SAFETY ASSESSMENT As identified in the investigation, the majority of the valves and cabling were found to have sufficient separation to enable re-energizing. In the cases of SPC, e fire could potentially cause either division to close while the plant was in a refueling cycle and fuel pool cooling to the upper containment pools would be required.

The closure of these valves would be noted with any gradual rise of

• pool temperature. Assuming a fire did affect these valves, upon detection of increasing pool temperature, valve positions could be determined and repositioned if necessary. Alternate methods exist to provide water to the upper pools (water from fire protection system

(*Kp*) for instance). Therefore, pool temperatures would not be expected to exceed design levels, i.e. operator actions would prevent any overheating in the upper pool.

For all valves except IE12*MOVF009 and IB21*MOVF019, analysis demonstrates that a fire in any area would leave at least one method of aafe shutdown unaffected. The safety consequences of a fire potentially affecting valves 1E12*MOVF009 or IB21*MOVF019 is more complex. The analysis of these valves will follow in a revision to this LER to be submitted by 1/31/90.

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• Ex7e7t T r"ITIE Yw U Ei'Oes listed above, engineering evaluation shows all valves listed have adequate Appendix R separation and/or can be  ;

administratively controlled. No fires have occurred in these areas.

There was no significant impact on the health and safety of the public  !

as a result of this event.

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

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