DEFENSE NUCLEAR FACILITIES SAFETY BOARD

March 1, 2024

TO: Timothy J. Dwyer, Technical Director

FROM: Frank Harshman and Clinton Jones, Resident Inspectors

SUBJECT: Oak Ridge Activity Report for Week Ending March 1, 2024

Building 9212: CNS operators were preparing to weigh material contained in birdcages 

received from Building 9204-2E. Upon opening a birdcage, the operators noted excessive 

amounts of plastic from the oversized bags used for contamination control. The birdcage was 

one of 16 received from Building 9204-2E and the others also appeared to have excessive 

amounts of plastic. The operators entered the CNS procedure for an abnormal condition 

involving fissile material and established a nuclear criticality safety (NCS) administratively 

controlled boundary. The operators notified the shift manager (SM) and a NCS engineer for 

further guidance. The NCS engineer, operators, and shift manager entered the administratively 

controlled boundary to inspect the birdcages, determining four of the 16 birdcages had excessive 

amounts of plastic. The SM rescinded the administrative boundary for the 12 other birdcages 

and released them from additional NCS controls. The SM marked the remaining four as 

containing excessive plastic, posted NCS administrative controls, and placed them into secured 

NCS approved storage. The four birdcages will remain in NCS approved storage until ready for 

processing and the administrative controls will be rescinded upon removing the items from the 

excessive plastic. Birdcages being loaded in Building 9204-2E with excessive plastic is a repeat 

occurrence that was previously identified as part of an extent of condition review due to previous

birdcage loading issues (see 11/4/2022 report).

Building 9215: Upon completion of a depleted uranium casting, three supervisors that were 

observing the operation discovered radioactive contamination in their hair while using the handheld friskers at the boundary control station. Radiological control technicians successfully 

decontaminated the supervisors. As a precaution, the RCTs performed nasal swabs on the 

supervisors to determine if they had a potential for internal contamination. The results of the 

nasal swabs were negative. Although the contamination levels were less than required for CNS 

to file an occurrence report, this is the second time in three months that personnel have been

contaminated on their heads while performing this process (see 12/1/2023 report). CNS 

performed an event investigation this week for the latest event, which the resident inspector 

attended. As a result of the personnel contamination and the spread of loose surface 

contamination in the immediate area of the furnace, CNS established new airborne 

contamination boundaries around the process area as a precaution while a new baseline is 

established. CNS is revising the radiological work permit to require the use of full hood 

respiratory protection while lowering a casting stack into a cooling can. CNS is continuing to 

evaluate the equipment and the process to determine if there is a potential for buildup of 

contamination in the cooling cans or vacuum purge system that may need periodic cleanout.

Building 9204-2E: During a disassembly and inspection of a unit in one of the positive pressure 

gloveboxes, personnel discovered a hole in one of the gloves. CNS conservatively closed the 

area while industrial hygiene performed smears of the area around the glovebox and the walking

path to the exit. No personnel were contaminated, and CNS found no detectible activity on the 

smears taken. During the event investigation, CNS discovered that there were several gloves in 

the glovebox that had been previously taped up due to suspected holes.