05000255/LER-2001-001
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This report provides the content required by 10 CFR 20.2201(b)(i) through (vi), as well as the pertinent information required by 10 CFR 50.73(b).
Description of Licensed Material Involved The missing source was a charcoal cartridge of solid form, approximately 2.25 inches in diameter and 1.0 inch thick. This "BG-300" cartridge source was used for efficiency calibration of the gamma spectroscopy system. The BG-300 charcoal cartridge had a mixture of the following nine isotopes, with the activities for each decay corrected to July 1, 2000:
Isotope Activity (microcurie) Am-241 0.154 Cd-109 0.693 Co-57 0.007 Ce-139 0.002 Hg-203 0.000003 Sn-113 0.0015 Cs-137 0.057 Y-88 0.002 Co-60 0.0759 Total 0.992 Description of Circumstances Under Which Loss Occurred/Cause of the Event On February 8, 2001, at approximately 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> with the plant at 100% power, during performance of the semi-annual radioactive source inventory, radioactive source SRS 56299-66, a BG-300 charcoal cartridge, could not be found. This source was present during the last source inventory, completed in August 2000. The source was a mixed gamma source used for efficiency calibration of the gamma spectroscopy system. The source was stored inside the Radiologically Controlled Area (in the grey lab source locker) and was a licensed source because it contained greater than 0.001 microcurie of Americium-241.
A search was immediately made for the missing source. Source storage areas, source use areas, and disposal release pathways were searched. Chemistry Technicians, staff, and anyone else who may have had reason to use this source, were questioned to determine if anyone knew the location of this source. The source was not found.
The physical appearance and container label on the BG-300 charcoal cartridge source, SRS-56299- 66, was very similar to the labeling of radiochemistry cross check samples prepared for Palisades by Analytics, Inc. on May 20, 2000. The cross check samples were prepared in BG-300 charcoal cartridges identical to the BG-300 charcoal cartridge used for SRS-56299-66. The BG-300 charcoal cartridge cross check samples and the BG-300 source SRS-56299-66 were both stored inside the Radiologically Controlled Area (in the grey lab source locker) from the end of May until approximately the middle of August 2000. The written results for the BG-300 cross check samples were sent by Analytics to Palisades, on July 17, 2000. Sometime after July 17, 2000 the radiochemistry cross check samples in the BG-300 charcoal cartridges should have been discarded. One cross check sample was found in the source locker during the search for the missing licensed source. The presence of the BG-300 cross check sample in the source locker, when it should have been discarded, suggests that the BG-300 SRS-56299-66 source was discarded by mistake. This is likely because both the source and cross check sample were in identical containers and were similarly labeled. The source, SRS-56299-66, would have been discarded in a yellow trash bag (radioactive material for disposal). This waste has been shipped to a licensed vendor for incineration. The addition of the BG-300 charcoal source to the radioactive waste shipment did not change the shipping classification (LSA 2). The vendor was contacted and asked to look for this source in the sorting process. However, the vendor reported that the radioactive waste from the period in question had already been sorted and disposal completed.
Probable Disposition of Licensed Material The source, SRS-56299-66, was most probably discarded in a yellow trash bag (radioactive material for disposal). This waste was shipped to a licensed vendor for disposal.
Exposure of Individuals to Radiation/Safety Consequences There were no safety consequences with respect to plant operation. There were no known exposures to individuals associated with the loss of this source. The total curie content of the source decay, corrected to July 1, 2000, was 0.992 microcurie. The most significant risk from this source would come from ingestion. Unknowingly ingesting this source would be impossible because of its size and shape. The charcoal cartridge was approximately 2.25 inches in diameter and 1.0 inches thick. To put the risk in perspective, typical home smoke detectors contain a one microcurie Americium-241 source.
Actions Taken to Recover Material Upon discovery, a search was immediately made for the missing source. Source storage areas, source use areas, and disposal release pathways were searched. Chemistry Technicians, staff, and other persons who may have had reason to use this source, were questioned to determine if anyone knew the location of this source. The source was not found. The vendor to which Palisades ships radioactive waste for disposal was contacted and asked to look for this source in waste from the period in question. However, the vendor reported that the radioactive waste from the period in question had already been sorted and disposal completed.
Measures to Ensure Against Recurrence/Corrective Actions Investigation determined the causes for this event were (1) Inadequate program guidance for radioactive sources and cross check samples resulted in poor physical controls; and (2) The failure to use effective self-checking techniques resulted in a licensed source being mistakenly discarded.
On February 14, 2001, Chemistry and Radiological Services (C&RS) management issued a memo to C&RS Department staff stating there will be no further radioactive sources or radioactive cross checks disposed of until Health Physics Procedure, HP-6.25, "Radioactive Source Control" is revised and training on the revision completed. This was also communicated to C&RS staff personnel verbally. Health Physics procedure HP-6.25, "Radioactive Source Control" will be revised by May 31, 2001 to strengthen administrative controls over the disposal of radioactive sources.
Anticipated changes include:
a. Require that the removal of radioactive sources for disposal be done only by the Radiological Material Supervisor.
b. Require documentation be developed recording the source identification, disposal method, and individual performing disposal, for sources that are discarded. This document will be retained.
c. Require that radiochemistry cross check samples be included in the source inventory and be considered and handled the in the same manner as radioactive sources.
Previous Occurrences
There are no known previous occurrences of this type of event at the Palisades Plant.