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| Entered date | Event description | |
|---|---|---|
| ENS 41430 | 22 February 2005 17:25:00 | The following details were provided by the licensee via email after the telephonic notification: This is a non-emergency Event Notification in accordance with 10 CFR 20.2201(a)(1)(ii) to inform the NRC of missing special nuclear material (SNM) (up to approximately 0.15 grams of U235). The missing SNM consists of one complete and three partial in-core detectors. Since June 2004, Pacific Gas and Electric (PG&E) has been performing an investigation and search for three missing 18-inch rod segments at the Humboldt Bay Power Plant (HBPP) (reference NRC Event Notifications 40877 and 40963). The investigation also included a verification of the inventory of all SNM, including fuel and non-fuel SNM. As a result of the investigation, plant personnel identified HBPP records that indicate 54 in-core detectors should be in the spent fuel pool (SFP). In-core detectors were used inside in-core assemblies during plant operations to measure reactor power level. There were three in-core detectors contained inside each in-core assembly. The in-core assemblies were segmented for storage, and the in-core detectors from a total of 18 in-core assemblies (containing 54 in-core detectors) should be onsite. Each in-core detector is approximately 2-1/2 inches long. Depending on design, an in-core detector contains as much as 0.04 grams of U235, to slightly less than 0.002 grams of U235. PG&E personnel performed a search in the SFP for the in-core detectors from December 2004 through February 2005. On February 4, 2005, PG&E determined that not all 54 in-core detectors could be located and informed the NRC. PG&E is submitting this Event Notification in accordance with 10 CFR 20.2201(a)(1)(ii) that requires a telephonic report and an Event Notification to be made within 30 days from February 4, 2005. PG&E will be issuing a press release tomorrow that includes this issue. PG&E's search for in-core detectors is complete. PG&E has determined that 50 complete and three partial in-core detectors are in the SFP. Therefore, one complete and three partial in-core detectors are missing. The partial in-core detectors appear to have been cut when the in-core assemblies were cut to be shortened for SFP storage in the mid-1970s or mid-1980s. Most probable locations for the missing in-core detectors are licensed, monitored and restricted radiological control areas, therefore the public health and safety has not been adversely affected. PG&E will issue licensee event report (LER) 2005-001-00, 'Missing In-core Detectors,' dated February 22, 2005, to be submitted in accordance with 10 CFR 20.2201(b)(2)(ii) (Reference PG&E Letter HBL-05-002). Information pertaining to the missing in-core detectors is also included in the HBPP SNM Control and Accountability Project Interim Reports, to be submitted February 22, 2005 (Reference PG&E Letter HBL-05-001). NRC personnel at headquarters and in Region IV have been notified of the status of this issue. |
| ENS 40877 | 16 July 2004 14:04:00 | This is a non-emergency Event Notification made in accordance with 10 CFR 50.72(b)(2)(xi) to inform the NRC that a press release will be issued shortly informing the public of a nuclear material accountability discrepancy involving a portion of a spent fuel rod used at Pacific Gas and Electric's (PG&E) Humboldt Bay Power Plant (HBPP) Unit 3. HBPP Unit 3 has been shut down since 1976 and in SAFSTOR since 1988. In the process of reviewing records and verifying the contents of the spent fuel pool (SFP) in preparation for loading materials into dry cask storage, PG&E has identified a discrepancy in plant records that calls into question the location of three segments of a portion of a single spent fuel rod removed from assembly A-49 in 1968. Meeting records produced in 1968 indicate that the segments have been stored in the SFP since 1968. However, 1969 plant shipping records indicate that the entire A-49 assembly was included as part of a larger shipment of several spent fuel assemblies sent for offsite reprocessing in 1969. The 1969 shipping records make no mention that one rod had been removed from the A-49 assembly that was shipped. A more detailed review of records and a complete search of the SFP is underway to establish and verify the location of the three fuel rod segments. Since 2003, PG&E plant personnel have been conducting a complete review of plant records and cataloging the contents of the SFP in preparation for the planned decommissioning of the plant, including the transfer of spent fuel into an onsite Independent Spent Fuel Storage Installation. On June 23, 2004, plant personnel found Onsite Review Committee (OSRC) meeting minutes dated October 2, 1968, that described cutting one fuel rod from fuel assembly A-49 into three 18 inch segments that were placed into a small container (1 -1 /2 inch, schedule 40 pipe) in preparation for shipment to the Battelle Memorial Institute in Columbus, Ohio, for analysis. The meeting minutes further state that the shipment to Battelle was subsequently cancelled and the small container with the three 18-inch fuel rod segments was returned to the SFP, with the specific location in the SFP unidentified. The minutes also state that the remnants of the 84 inch long fuel rod from which the three 18-inch segments were cut were placed in the central storage container within the SFP. On June 25, 2004, after further research, PG&E found shipping records indicating that on August 6, 1969, the entire A-49 fuel assembly was shipped to Nuclear Fuel Services Inc. (NFS) in West Valley, New York, for reprocessing. No mention was made in the shipping record that a rod had been removed from the A-49 fuel assembly. This contradicts the OSRC meeting minutes that indicate one fuel rod from A-49 remains in the SFP. Further review of records did not resolve the discrepancy, so on June 28, 2004, PG&E verbally notified the Nuclear Regulatory Commission, Region IV office of the potential discrepancy in records and the uncertainty regarding the specific location of the fuel rod removed from A-49. On July 7, 2004, PG&E began a physical search of the central storage container in the SFP for the remnant portions of the A-49 rod, as well as the three 18-inch segments. On July 9-11, 2004, PG&E identified what appears to be the remnant portions of the A-49 rod in the central storage container in the SFP as specified in the 1968 OSRC meeting minutes. However, the three 18-inch segments were not found in the central storage container. PG&E is continuing with a thorough search of the remaining storage containers in the SFP as well as other possible areas in the SFP where the three fuel rod segments may be located. The search is a painstaking process performed under tight procedural guidance that could take at least several weeks to complete. NRC inspectors have been onsite during the week of July 12 and are fully aware of the status of these inspections. In addition, PG&E is continuing its review of plant records as well as interviewing plant personnel who were onsite during the 1968-1969 period to find further evidence that may expedite location of the three fuel rod segments. This notification also satisfies the 30-day notification requirement of 10 CFR 20.2201(a)(1)(ii). If ongoing searches fail to confirm the location of the material, a subsequent written report will be made in accordance with 10 CFR 20.2201(b). |