Enrichment Technologies, jointly owned by Areva and Urenco, said it had shut facilities in five countries after two workers died from their injuries in an accident at its Dutch plant last week.
The company, which supplies Urenco and Areva with machines for enriching uranium, stopped production on March 31 in the Netherlands, Germany, France, the United States and the United Kingdom, a spokeswoman said on Wednesday.
"We don't know when production will restart," she said without giving more details about the accident.
Dutch news agency ANP reported that the two employees became unconscious from a lack of oxygen while working in a furnace in Almelo. They were taken to hospital where they died.
The spokeswoman said the police and health and safety inspectors were investigating the accident.
"Safety is our main concern right now," she added.
Enrichment Technologies employs 2,000 people in the five countries where it operates, according to its website.
Urenco, the world's largest uranium enrichment company which is owned by the British and Dutch states and Germany's two top utilities, has a 50 percent stake in Enrichment Technologies, while French nuclear group Areva owns the other 50 percent.
(Reporting by Ivana Sekularac; and Thomas Escritt; Editing by Jane Baird and Helen Massy-Beresford)