ENS 43344
ENS Event | |
|---|---|
23:47 Apr 4, 2007 | |
| Title | 30-Day Report Involving a Loss of Accountability of Less than 1 Gram Snm |
| Event Description | This is a non-emergency Event Notification made in accordance with 10 CFR 20.2201(a)(1)(ii) to inform the NRC of a loss of accountability of a very small amount (e.g., particle size) of special nuclear material (SNM). As part of preparations for an NRC inspection of Columbia's SNM Control and Accounting Program (April 16-19, 2007), documentation concerning the recovery of two pieces of a broken fuel rod was obtained. The documentation revealed existence of potential fuel particles estimated to be less than 1 gram in aggregate located in the spent fuel pool. The location of these particles cannot be positively identified at this time and is therefore being reported as missing SNM under 10 CFR 20.2201(a)(1)(ii).
The particles were created during a 1990 refueling outage while inspecting a leaking fuel bundle. To identify the leaking rod, the bundle was disassembled and rod-by-rod electronic sorting performed. Ultrasonic examination identified the leaking rod; however, during the inspection the rod bent and snapped while being guided through a fuel inspection funnel. A procedure was approved and successfully executed to recover the broken rod sections. Following the recovery, an inspection was performed with an underwater camera to determine if any fuel pellets had been released as part of the evolution. No fuel pellets were identified; however, a small dark particle of material surrounded by smaller black particles was observed in a stainless steel bucket which had been positioned under the broken fuel rod pieces. It is believed that the bucket containing the particles was suspended off the west wall of the spent fuel pool, north of the work table. The location of the particles within the bucket cannot be positively identified at this time. The contents of the bucket have been described by the individuals involved in the broken rod recovery as a small particle of material roughly the size of a fingernail clipping surrounded by a few black particles the size of ground pepper. An underwater survey indicated a radiation level of greater than 400 R on contact for the material. The total amount is believed to be considerably less than 10 percent of a single pellet's worth of material, or less than 1 gram. Energy Northwest is continuing to investigate this event. Based on the information gathered to date, the nature of the particles, and the existence of radiation monitoring, a high degree of confidence exist that the particles are located in the bottom of the spent fuel pool or in an otherwise radiologically controlled location such that the health and safety of the public would not be adversely affected. In addition, there is no evidence of theft or diversion. This notification satisfies the 30-day notification requirement of 10 CFR 20.2201(a)(1)(ii). A subsequent written report will be made in accordance with 10 CFR 20.2201(b). The NRC Resident and SNM Control and Accounting Inspectors have been informed of this issue. THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. This source is not amongst those sources or devices identified by the IAEA Code of Conduct for the Safety & Security of Radioactive Sources to be of concern from a radiological standpoint. Therefore is it being categorized as a less than Category 3 source |
| Where | |
|---|---|
Columbia Generating Station  Washington (NRC Region 4) | |
| Reporting | |
| 10 CFR 20.2201(a)(1)(ii) | |
| LER: | 05000397/LER-2007-002 |
| Time - Person (Reporting Time:+710.57 h29.607 days <br />4.23 weeks <br />0.973 months <br />) | |
| Opened: | Matt Hummer 14:21 May 4, 2007 |
| NRC Officer: | John Mackinnon |
| Last Updated: | May 4, 2007 |
| 43344 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (97 %) |
| After | Power Operation (97 %) |
WEEKMONTHYEARENS 433442007-04-04T23:47:0004 April 2007 23:47:00
[Table view]10 CFR 20.2201(a)(1)(ii) 30-Day Report Involving a Loss of Accountability of Less than 1 Gram Snm 2007-04-04T23:47:00 | |