Westinghouse facility Hopkins

A Westinghouse factory south of Columbia manufactures fuel for nuclear power plants. The company told federal regulators that a drum of radioactive waste exploded around 2 a.m. Friday. High Flyer/Provided

A waste drum at a nuclear fuel factory near Columbia caught fire and exploded last week, according to a federal safety report. 

The workplace accident occurred at a Westinghouse facility in Hopkins, just off of Bluff Road. The plant makes pellets for nuclear power plants.

In a report filed with the Nuclear Regulatory Commission, Westinghouse said the drum exploded around 2 a.m. Friday after workers at the plant filled it with uranium-contaminated filters, rags, mops and some paper. The container held just over 70 grams of uranium, which is used in nuclear power plants to create a chain reaction that generates electricity.

Westinhouse said a chemical reaction caused the material to heat up, building pressure in the drum. The container blew off its lid, paper inside caught fire, and some of the contaminated material showered the surrounding area, according to the report.

A spokesman for the Nuclear Regulatory Commission said the fire essentially put itself out.

No workers at the plant were injured during the accident and testing confirmed that radiation levels didn't exceed federal safety limits, according to the company. Westinghouse employees also checked the other drums at the facility to ensure they wouldn't overheat and explode.

"Air samples taken within the area confirmed no impact to plant personnel, the public or the environment," Westinghouse spokeswoman Courtney Boone.

Boone said Westinghouse was studying what caused the drum to explode. The company plans to set new rules to keep the wrong materials from mixing, and it will let containers of nuclear material vent to keep pressure from building inside. The Hopkins plant isn't packaging waste in the meantime.

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NRC spokesman Joey Ledford said federal inspectors would address the explosion when they make a routine inspection later this month.

It's not the first time the factory has caught the attention of regulators. The NRC reported last year that uranium at the factory leaked out a small hole and into the ground, according to a story in The State newspaper.

Thad Moore contributed to this report.

Reach Andrew Brown at 843-708-1830 or follow him on Twitter @andy_ed_brown.