PNO-V-87-032A, licensee Investigations Into Manner in Which Small Stones Introduced Into Hot Leg Side of Steam Generator 1 Determined That Stones Carried Into Generator During Erection of Work Platform.Tubes in Generators to Be Plugged

PNO-V-87-032A:licensee Investigations Into Manner in Which Small Stones Introduced Into Hot Leg Side of Steam Generator 1 Determined That Stones Carried Into Generator During Erection of Work Platform.Tubes in Generators to Be Plugged

ML20214J946
Person / Time
Site:	Palo Verde
Issue date:	04/29/1987
From:	Richards S, Zimmerman R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-87-032A, PNO-V-87-32A, NUDOCS 8705280261
Download: ML20214J946 (1)

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-87-32A Data: 04/29/87 This preliminary notification constitutes EARLY notice of POSSIBLE safety or public interest significance. The information presented is as initially received without v:rification or evaluation and is basically all that is known by Region V staff on this l date.

FACILITY: Arizona Nuclear Power Project Emergency Classification Palo Verde Unit 3 Notification of Unusual Event Docket No. 50-530 Alert Site Area Emergency General Emergency  ;

,T,_~Not Applicable

SUBJECT:

FOREIGN MATERIAL FOUND IN STEAM GENERATOR - PNO-V-87-32 UPDATE l

The licensee's investigation into the manner in which a number of small stones were introduced into the hot leg side of the No.1 Steam Generator determined that they were most likely carried into the generator unintentionally during erection of the work platform. The Itcensee's investigation included interviews with personnel involved, r: view of material accountability records and the development of a detailed chronology cf all work activities in the hot leg side of No. 1 Steam Generator. A temporary wooden  :

dam had been installed in the hot Icg of the No. 1 Steam Generator prior to errection of l the platform. Although the train of shutdown cooling which takes suction from the No. 1 St:am Generator hot leg had been run for approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> between the time the platform was erected and the discovery of the stones the licensee believes the probability that any foreign material was transported through the shutdown cooling system back into the reactor vessel is very small. A boroscopic examination down the hot leg side of the No.1 Steam Generator into the shutdown cooling suction line found na foreign objects to be present. Visual inspection of the cold leg side of the No. 1 Stram Generator and the cold and hot leg sides of the No. 2 Steam Generator revealed no foreign material. The platform erected in the hot leg side of the No. 1 Steam Generator was of different construction than the other platforms erected within the steam generators. This platform had been used previously in the licensee's steam generator mock up, was constructed of steel plating rather than wood, and had been stored for a time in an outside area.

The licensee is currently proceeding with the selected preventive tube plugging inTthe st:am generators. Approximately 60 tubes per generator are to be plugged. [

Unit 3 is currently in Mode 5 with initial criticality scheduled for July,1987. "

This information is current as of 1:50 TH (MST) April 29. 1987. T CONTACT: R. Zimmerman S. Richards r (602)386-5260 FTS 463-3853 g DISTRIBUTION l H St. NNBU Phillips V E/W W111ste Air Rights Mail Chairman Zech ED0 NRR IE NMSS ADMIDMB Comm. Carr PA OIA RES DOT Trans Only Cons. Bernthal MPA AE00 1 Com. Roberts ELD Com. Asselstine Regions:

SECY INP0 NSAC ACRS Liceiisect ~

CA (ReactorLicensees)~ REGION V: FORM 211 PDR Resident Inspector (Revised 3/14/83) g52g61070429 PNO-V-07-032A P Dft

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