Last month, rain leaked through the roof of a Savannah River Site nuclear processing facility, picked up radioactive contamination and then showed up in a so-called "clean area" on the facility's first floor, according to a final incident report filed Wednesday.
The leak and contamination was found Dec. 2, 2018, at H-Canyon, the nation's last up-and-running hardened nuclear chemical separations plant.
No injuries or exposures were mentioned in the report.
The contaminated water was removed from the clean area, a warning was posted and additional inspections of the facility were done, according to the incident report. No other contamination was discovered, according to the same information.
The rain made its way into H-Canyon through an "expansion joint" where previous leaks had been observed, according to the incident report. Joints between sections of the building run vertically from the roof to the first floor, according to the report.
"Over time, some of these joints have failed and rainwater migrates into the facility," the report reads.
A plan has been developed to repair the H-Canyon roof, according to the incident report.
H-Canyon – now operated by Savannah River Nuclear Solutions, the SRS management and operations contractor – was constructed around 1950 and began operations in 1955.
The Defense Nuclear Facilities Safety Board, an independent nuclear-safety watchdog, was notified of the leak and contamination on Dec. 3, 2018.
Inquiries made to the U.S. Department of Energy were not immediately returned.