PNO-V-87-022, on 870319,licensee Found Pressure Switch on Discharge Side of RHR Sys Pump B Isolated.Licensee Unisolated Switch & Restored Sys to Full Operability.Region V Followup Continuing

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PNO-V-87-022:on 870319,licensee Found Pressure Switch on Discharge Side of RHR Sys Pump B Isolated.Licensee Unisolated Switch & Restored Sys to Full Operability.Region V Followup Continuing
ML20205D496
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 03/20/1987
From: Dodds R, Johnson P
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-87-022, PNO-V-87-22, NUDOCS 8703300427
Download: ML20205D496 (1)


' PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-87-22 Date: 03/20/87 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public k int 2 rest significance. The information presented is as initially received without verification cr evaluation and is basically all that is known by Region V staff on this date.

FACILITY: Washington Public Power Supply System Emergency Classification WNP -2 Notification of Unusual Event Docket No. 50-397 Alert Richland, Washington Site Area Emergency General Emergency T Not Applicable

SUBJECT:

ECCS SYSTEM PARTIALLY DISABLED On March 19, 1987 at 2035 PST, with the reactor at 71% power in single loop recirculation flow, the licensee found a pressure switch on the discharge side of the "B" Residual Heat Removal (RHR) system pump isolated. This pressure switch provides an input signal to the "B" train Automatic Depressurization System (ADS) which indicates to ADS logic that the "B" RHR pump is running. This would permit the ADS valves to open and depressurize the reactor.

With the switch isolated, no pump running indication would have been available to the ADS system for the "B" RHR pump. The "B" ADS system also receives a permissive signal if the "C" RHR pump is running. If a valid initiation was required and the "C" RHR pump auto-started as required, then the "B" ADS system would have functioned normally. The licensee unisolated the pressure switch at 2100 PST and restored the system to full operabilii.y . Region V is continuing follow-up at this time, focusing on the circumstances l and events surrounding, and occuring subsequent to, the isolation.

This information is current as of 0930 PST, March 20', 1987.

CONTACT: P. Johnson R. Dodds FTS 463-3745 (509) 377-2627 DISTRIBUTION H St. MNBB Phillips N E/W Willste Air Rights 3: M Maii:

Chairman Zech ED0 NRR IE fiMSS ADM:DMB Com. Roberts PA OIA RES DOT:Trans Only Comm. Asselstine MPA AE0D Comm. Bernthal OGC I Com. Carr Regions:

SECY INP0J123 NSAC 312.7-ACRS Licensee: 3: 57 CA (Reactor Licensees REGION V: FORM 211 PDR Resident Inspectorf) .76 (Revised 3/14/83)

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