PNO-III-88-020, on 880310,sample Results from Unit 1 Sump Indicated Small Amount of Reactor Coolant Leakage Showing Measurements of Less than 0.1 Gpm.Visual Insp Revealed Misting in Reactor Head.Region III Monitoring Situation

PNO-III-88-020:on 880310,sample Results from Unit 1 Sump Indicated Small Amount of Reactor Coolant Leakage Showing Measurements of Less than 0.1 Gpm.Visual Insp Revealed Misting in Reactor Head.Region III Monitoring Situation

ML20148H243
Person / Time
Site:	Prairie Island
Issue date:	03/11/1988
From:	Farber M, Jackiw N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-88-020, PNO-III-88-20, NUDOCS 8803290359
Download: ML20148H243 (1)

PRELIMINARYNOTIFICATIONOFFVENTORUNUSUALOCCURRENCE--PNO-III-88-20DateMarch 11, 1988 h rf 3 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.

Facility: Northern States Power Licensee Emergency Classification:

Prairie Island Unit 1 Notification of an Unusual Event Welch, MN 55089 Alert Site Area Emergency Docket No. 50-282 General Emergency

,X Not Applicable i

Subject:

SHUTDOWN TO REPAIR MINOR LEAK On March 10, 1988, while operating at 80 percent power, sample results from the Unit I sump indicated that a small amount of reactor coolant was leaking. Inventory measurements showed the leakage to be less than 0.1 gallon per minute. The Technical Specification limit for unidentified reactor coolant leakage is 1.0 gallons per minute.

Visual inspection inside containment revealed misting in the area of the reactor head. A later inspection determined that the leak was in a seal weld on an instrument column in the reactor head.

The licensee began a controlled shutdown with cooldows, completed at 3:22 a.m. (CST),

March 11. Preparation for seal weld repairs is in progress. The plant is expected to be shut down for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Region III (Chicago) and the resident inspectors are monitoring the situation.

The State of Minnesota will be notified.

Region III was notified of this event at 11 a.m. (CST), March 10, 1988. This information is current as of 10 a.m. (CST), March 11, 1988.

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CONTACT: M. Farber .. ac iw FTS 388-5774 /FTS 8-5697 1

I DISTRIBUTION:

H. St. NMBB Phillips E/W WFN 1 Chairman Zech XEDU NRR DTA N Com. Roberts ARM 01 Comm. Bernthal E00 AirRights Mail To:

Comm. Carr PA SLITP F 4 0 DCS (Original)

Comm. Rogers OGC DOT (Trans.Only)

SECY OGC-H FAX T0: Nicholson Lane Regions CA INPO Si9&- RES Region I GPA NSAC SIMI* Region II ACRS Licensee SiO Region IV PDR Resident Inspector Region V O \

HOS. OnaraHa- Officer 3:M 8803290359 880311 Region III g6g Rev November 1987 N-I!T88-020DCD