PNO-I-89-056, on 890710,reactor Vessel Lower Head Cracks from Guide Tubes E-7 & G-6 Discovered.Tubes Substantially Damaged by Flow of Molten Fuel.Investigation & Cleanup Started

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PNO-I-89-056:on 890710,reactor Vessel Lower Head Cracks from Guide Tubes E-7 & G-6 Discovered.Tubes Substantially Damaged by Flow of Molten Fuel.Investigation & Cleanup Started
ML20246H590
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 07/10/1989
From: Cowgill C, Young F
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-89-056, PNO-I-89-56, NUDOCS 8907170146
Download: ML20246H590 (1)


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DCS No: 50320890710 j,,o Date: July 10, 1989 PRECIMI' NARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-89-56 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The C mation is as initially received without verification or evaluation, and is bas' y all that is known by the Region I staff on this date.

Facility: Licensee Emergency Classification:

GPU Nuclear Corporation Notification of Unusual Event Three Mile Island, Unit 2 Alert Docket Number 50-320 Site Area Emergency General Emergency X Not Applicable

Subject:

DISCOVERY OF REACTOR VESSEL LOWER HEAD CRACKS The licensee recently completed defueling a major portion of the lower head region.

Visual examination of several incore guide tubes revealed lower head cracks that propagated from two of the guide tube to vessel welds. The two guide tubes, E-7 and G-6, were substantially damaged by the flow of molten fuel during the accident. At present, approximately 1" of the original 12" tubes remains. The crack at location E-7 is the more visible and is approximately 4-5 inches long and approximately 1/4" to 1/2" wide. Crack depth is unknown at this time. The licensee is presently investigating  !

methods of determining the actual size of these cracks, along with additional cleanup of the area. The resident inspectors are following the licensee's investigation.

The Commonwealth of Pennsylvania has been informed.

Media interest is expected. This PN is issued for information only and is current as of 1:00 p.m., July 10, 1989.

CONTACT: F. Young C. Cowgill b% i (717) 948-1167 (215) 337-5128 ,$ c,r DISTRIBUTION:

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