PNO-V-86-020, on 850418,Unit 2 Reactor Was Brought to Criticality Following Dilution of Rcs.Estimated Critical B Was 1015 Ppm W/Group 5 Control Rod Bank 75 Inches Withdrawn. Resident Inspector Witness Approach to Initial Criticality

PNO-V-86-020:on 850418,Unit 2 Reactor Was Brought to Criticality Following Dilution of Rcs.Estimated Critical B Was 1015 Ppm W/Group 5 Control Rod Bank 75 Inches Withdrawn. Resident Inspector Witness Approach to Initial Criticality

ML20212E964
Person / Time
Site:	Palo Verde
Issue date:	04/21/1986
From:	Miller L, Zimmerman R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-86-020, PNO-V-86-20, NUDOCS 9711040123
Download: ML20212E964 (1)

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,h , PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO V-86-20 Date: 4/21/86 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by Region V staff on this date.

FACILITY: Arizona Nuclear Power Projec)UELic 00COMIH1 Fold 1 Emergency Classification Palo Verde Unit 2 Notification of Unusual Event .

Docket No. 50-529 Alert

.g yR 22 NO Sg Site Area Emergency General Emergency Not Applicable  :

itHE PL30EillD

SUBJECT:

INITIAL CR!TICALITY On April 18,1985at1445PMMST,t$eUnit2reactorwasbroughttocriticalityfollowing I

. dilution of the reactor coolant system. Estimated critical boron concentration was ,

1015 ppm with Group 5 control red bank 75 inchec withdrawn. Actual critical boron '

concentration was 1022 ppm with Group 5 control rod bank 50 inches withdrawn. This is within 0.2 percent of estimated critical conditions. The resident inspectors witnessed the-approach to initial criticality.

Low power physics testing is expected to be completed by April 23rd. The resident inspectors sonitored control room activities over the weekend.

O CONTACT: L. Miller R. Zimmerman, Sr., Resident inspector FTS 463-3869 (602)386-5260 DISTRIBUTION H St. MNBB _Phillips E/W Willste Air Rights Mail:

Chairman Pallidino EDO NRR ~ IE NMSS ADM:0MB Comm. Zech PA O!A RES DOT:Trans Only Comm. Bernthal MPA AE00 Comm. Roberts ELD Comm. Asselstine Regions:  !" s SECY INPO NSAC gi ACRS Licensee:

CA (Reactor Licensees) REGION V: FORM 211 ,Uk PDR Resident Inspector,__ (Revised 3/14/83) .}\

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9711040123 860421 SECY, g,cor'ds. 3 Historian',

PDR ISE PNO-V-86-020 PDR

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