PNO-IV-97-017, on 970324,Arkansas Nuclear One Initiated Loading of Third VSC-24 Canister for Storage of Spent Fuel at Plant Isfsi.Licensee Initiated Repair of Crack by Grinding Out Defective Area
| ML20137G452 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/31/1997 |
| From: | Everett V, Jim Melfi NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-IV-97-017, PNO-IV-97-17, NUDOCS 9704010398 | |
| Download: ML20137G452 (2) | |
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4 i March 31,1997 PfliLIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-97-017 t
l 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 Region IV staff in Arlington, Texas on this date.
i Facility Licensee Emeraency Classification Entergy Operations, Inc.
Notification of Unusual Event Arkansas Nuclear 2 Alert Russelville,A: kansas Site Area Emergency j
Dockets: 50-368 General Emergency X Not Applicable 4
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Subject:
WELD RELATED CRACK IDENTIFIED DURING LOADING OF THIRD SPENT j
CASK l
Arkansas Nuclear One (ANO) initiated loading on March 24,1997, of their third VSC-24 canister for the storage of spent fuel at the ANO independent Spent Fuel Storage Installation r
(ISFSI). On March 26,1997, ANO performed the root pass welding of the shield lid on the cask. During the dye penetrant testing of the weld, a crack was discovered in the canister wall approximately 1/8 inch above the weld. The crack initially appeared to be 3/4 inch in i
length. The licensee initiated repair of the crack by grinding out the defective area. During
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l grinding, the crack was found to exL td over 18 inches in length starting at the bottom of the j
weld.
The licensee secured the services of a metallergical analysis company and an independent welding consultant to determine the cause and corrective actions for the crack. The licensee's preliminary indication is that the crack resulted from a weld shrinkage stress related problem. When the shield lid root pass weld was performed, the shrinkage of the weld caused i-the weld and shield lid to pull away from the canister wall before the welding process was completed. The licensee has proposed a modification of their welding procedures such that
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segmented welding of the shield lid would be performed before initiating continuous welding j
of the root pass. The licensee believes this will reduce the weld shrinkage stresses on the canister wall.
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Repair of the crack was completed on the afternoon of March 28,1997. The repair was j
verified using dye penetrant testing. The remaining welding of the shield lid was completed.
The integrity of the final weld on the shield lid was verified using dye penetrate testing and helium leak testing.
The structurallid has been welded in place on the top of the cask and successfully passed the dye penetrant test. The cask is currently being vacuum dried in preparation for the vacuum leak test and the final helium leak test.
97040!O398 970331 PDR.Ia:E 2
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010051
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i The NRC will be conducting a special inspection at ANO to review this issue. There have i
been two other instances, one at ANO and one at Palisades, where welding difficulties were encountered while welding the shield lid of a VSC-24 cask. Region IV has notified OEDO, j
NMSS and OPA. The state of Arkansas has been notified. This information herein has been discussed with the licensee and is current as of noon (CST) March 31,1997.
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Contact:
Vincent Everett Jim Melfi 1
(817)860-8198 (501)968-3290 l
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