PNO-V-87-053, on 870723,high Radiation Alarm Automatically Diverted Liquid Radwaste Flow to Storage Tank.Licensee Determining Root Cause.Chemical Drain Tank Properly Recirculated & Sampled Prior to Discharge Per Procedure

PNO-V-87-053:on 870723,high Radiation Alarm Automatically Diverted Liquid Radwaste Flow to Storage Tank.Licensee Determining Root Cause.Chemical Drain Tank Properly Recirculated & Sampled Prior to Discharge Per Procedure

ML20236D486
Person / Time
Site:	Diablo Canyon
Issue date:	07/24/1987
From:	Mendonca M, Narbut P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-87-053, PNO-V-87-53, NUDOCS 8707300473
Download: ML20236D486 (1)

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g PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V 53Date July 24, 1987 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or ,

public interest significance. The information presented is as initially received l without verification or evaluation and is basically all that is known by Region V staff ,

on this date.  !

FACILITY: PACIFIC GAS & ELECTRIC COMPANY Emergency Classification DIABLO CANYON UNIT 1 ~

X Notification of Unusual Event i' DOCKET NO. 50-275 Alert SAN LUIS OBISP0 COUNTY, CA Site Area Emergency i General Emergency l Not Applicable i

SUBJECT:

HIGH RADIATION ALARM DURING LIQUID RAD WASTE DISCHARGE

'On July 23,1987, at 2:45 pm PDT, during a planned discharge from the Chemical Drain Tank, a high radiation alarm automatically diverted the liquid radwaste flow to ,

a storage tank ~. The licensee is determining root cause, but initial indications 6re that a resin exchange procedure in progress prior to the event was the source of the high radiation.

The Chemical Drain Tank had been properly recirculated and sampled prior to dischar9a .

in accordance with procedure. Likewise, the involved common piping had been properly t flushed after the resin exchange.

The licensee suspects that some high activity waste may have been trapped in a branch 1 conn:ction and was freed during the Chemical Tank discharge. The licensee does not  !

believe a high activity discharge to the environment occurred due to the relative 4 locations of the radiation monitor and diversion valve in the discharge path.

Post event sampling has shown the liquid in the discharge path to be of acceptable

c. concentrations for discharge.

This information is current as of 0830 PDT 7/24/87.

CONTACT: M. Mendonca, RV P. Narbut FTS 463-3720 805-595-2354  !

DISTRIBUTION H St. MNBB Phillips E/W Willste Air Rights Mail:

Chairmln Zech EDO NRR IE NMSS ADMiDMB 4 Comm. Roberts PA DiA RES D0T:Trans Only Comm. Asselstine MPA AE0D l Comm. Bernthal OGC Comm. Carr Reg ir.ns :

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/g o ACRS Licensee: 31u CA . (ReactorLicensees) REGION V: FORM 211 i PDR ResidentInspector<0!9[ 1 Headquarters Opera H ons Center 2 bc (Revised 3/14/83) 8707300473 870724 i PDR I&E PNO-V-87-053 PDR Il E_ N p'l l TEM l,

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