ENS 42661
ENS Event | |
|---|---|
19:25 May 26, 2006 | |
| Title | Potential Loss of Licensed Nuclear Material |
| Event Description | In Event Notifications 42597and 42599 on May 22, and 23, 2006, respectively, as updated on May 26, 2006 Pilgrim Nuclear Power Station notified the NRC that during ongoing activities to remove non-fuel material from the Pilgrim Spent Fuel Pool it had been identified that nine (9) irradiated neutron detectors containing very small quantities (less than 0.003 grams each) of special nuclear material were not in their expected locations. Per the inventory sheets, the neutron detectors were expected to be enclosed in "dry tubes" in the Spent Fuel Pool. Processing of the "dry tubes" identified that the neutron detectors are not in their expected locations.
Subsequent investigation has determined that an error in the records was introduced in 1996 when the current base inventory sheets were developed. During the 1996 inventory, the assumption was made that these nine (9) "dry tubes" contained neutron detectors. The investigation has determined that the detectors, although moved to the spent fuel pool, were removed from the "dry tubes" prior to the "dry tubes" removal from the reactor vessel in 1987. This affected the validity of the 1996 base inventory. A written report will be submitted consistent with 10 CFR 20.2201(b). The licensee notified the NRC Resident Inspector.
Worst case isotope totals for the 9 detectors combined would be the following (all other isotopes would be an order of magnitude or more lower): U 235 - 5.382E-08 Curies, Pu 239 - 2.376E-07 Curies, Pu-238 - 3.510E-08 Curies, Pu 241 - 4.572E-08 Curies The licensee notified the NRC Resident Inspector. Notified R1DO (Perry) and NRR EO (MJ Ross-Lee). 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 | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 20.2201(a)(1)(ii) | |
| Time - Person (Reporting Time:+665.42 h27.726 days <br />3.961 weeks <br />0.911 months <br />) | |
| Opened: | Michael Mcdonnell 12:50 Jun 23, 2006 |
| NRC Officer: | Jeff Rotton |
| Last Updated: | Jun 26, 2006 |
| 42661 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Pilgrim with 10 CFR 20.2201(a)(1)(ii) | |
WEEKMONTHYEARENS 568152022-07-06T04:00:0006 July 2022 04:00:00
[Table view]10 CFR 20.2201(a)(1)(ii) Lost Sealed Sources ENS 426612006-05-26T19:25:00026 May 2006 19:25:00 10 CFR 20.2201(a)(1)(ii) Potential Loss of Licensed Nuclear Material 2022-07-06T04:00:00 | |