The following is a summary of information provided by the licensee via telephone:
On March 6, 2024, around 0600 CST, a technician found loose molybdenum (Mo-99) / technetium (Tc-99m) contamination inside a restricted area. Prior to the discovery, a production hot cell inside the restricted area had been deep cleaned as part of the regular maintenance program.
A thorough investigation of the area was conducted which revealed additional loose contamination on the lab floor. Surveys of surrounding areas did not reveal any spread of contamination outside of the restricted lab area.
Due to (1) the existing access controls, (2) personal protective equipment requirements for lab access, and (3) the absence of contamination identified by body scans of personnel exiting the lab; the licensee does not suspect any spread of contamination outside of the restricted area or personnel intake. Biological samples will be collected to confirm that no intake occurred.
The highest contamination level identified was 260 mrem/hr on contact and 2.3 mrem/hr at 1 foot. The contamination has been remediated to below licensee action levels. Overall, 2.4 mCi of
Mo-99 was identified outside of the production hot cell. The
10 CFR 20 Appendix B limit for
Mo-99 is 1 mCi. The licensee is investigating the root cause of this event.