The accident released a small amount of radioactive steam into the air.

The blast unintentionally vented radioactive steam while the press watched.

The worst accident occurred on Sept. 23, 1965, when he was hit with radioactive steam while cleaning a vent.

It is designed to trap radioactive steam and gases in the event of a nuclear accident.

Pressure valves released the gas, together with radioactive steam, whenever the pressure grew too great.

The second reactor at the Ignalina nuclear power station has been closed down after a leak of radioactive steam.

Government officials today reported an incident at an atomic power plant near Frankfurt last year in which radioactive steam was released into the atmosphere.

They said the radioactive steam was confined to the building and did not escape.

They'd have turned it into a ring system, or a cloud of radioactive steam.

Terms like "radioactive steam" and "containment vessel" appear frequently without sufficient definition.