ENS 42893
ENS Event | |
|---|---|
04:00 Jan 2, 2003 | |
| Title | Part 21 Notification - Voids in Plate Steel |
| Event Description | Facility Reporting: Oconee Nuclear Station, Duke Power Company
Basic component: 3/4 in thick, 32 sq ft (4 ft by 8 ft) A36 steel plate manufactured in accordance with ASTM/ASME Section II; manufactured by CORUS; supplied by CONSOLIDATED POWER SUPPLY Purchase Order ON 46703, Heat number A2WT; Duke QC receipt inspection on 9/25/2001. 192 sq-ft of plate was ordered on this Purchase Order, of this, 128 square feet of plate had the applicable heat number Nature of the defect or failure to comply and the safety hazard: During fabrication of hangers for use during a modification, pieces were cut from a sheet of 3/4 inch steel plate for use as hanger support base plates. Personnel noted that a base plate contained a lamination, resulting in the hanger strut being welded to only a thin layer of material. The piece was examined by engineering and a Ultrasonic Test examination of the remainder of the original 4 foot by 8 foot sheet found that the lamination area was approximately 15 inches by 36 inches and approximately 1/32 to 3/32 inches deep. This area was cut out and discarded and the remainder of the sheet was considered acceptable for use. The issue was entered into the Duke corrective action program and an evaluation for Part 21 reportability was initiated. The Part 21 evaluation concluded that, if the deflective material had been used for hangers as initially intended, the hangers may have failed during a design basis transient or accident due to failure of the thin lamination layer. Duke hanger designs are typically conservative such that failure of a single hanger will not result in the failure of the supported system/component, but within the rules for evaluation of a Part 21 defect, it must be assumed that this defective material may have resulted in a significant safety hazard and therefore must be reported under Part 21. The material known to be defective was not actually installed; therefore, this event is not reportable under 10 CFR 50.72 or 50.73. At this time Duke has no information to determine if this defect could extend to other material of the same heat or same manufacturer. Duke has no information on other possible customers. Duke did use the remaining sheets from the same purchase order in various applications, and is creating corrective actions to inspect the material with the same heat number for additional lamination areas: However due to the fact that no similar deficiencies were observed during fabrication and installation of the components made from this material or in use of similar materials, Duke considers this an isolated instance and does not consider this to be a current operability issue. Additional details will be provided in the required 30 day report. A sheet (4'x8') of this heat of plate steel was shipped to Catawba. Catawba has been notified and will investigate their use. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+33032.58 h1,376.358 days <br />196.622 weeks <br />45.248 months <br />) | |
| Opened: | Randall Todd 11:35 Oct 9, 2006 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Oct 9, 2006 |
| 42893 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Oconee with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 469552011-06-07T15:52:0007 June 2011 15:52:00
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