The reactor vessel is surrounded by a thick steel-and-concrete primary containment vessel, equipped with a water reservoir designed to suppress overheating of the vessel.
With the primary containment vessel of reactor 1 still too full of steam, the radical decision was made to flood it with sea water to absorb the heat.
Chernobyl's reactor lacked a containment facility, unlike the Fukushima plant, whose GE-made containment vessels have withstood both an earthquake, tsunami, and thus far, a partial meltdown.
By contrast, reactors have strong containment vessels that stand a better chance of bottling up radiation from a meltdown of the fuel in the reactor core.
Lab5 apparatus: black tank as reactor vessel, pipes with valves to simulate breaks in the reactor vessel, red tank as simulated containment vessel.
There was also a fire at No. 4, on the right and that there was a real danger that the reactor's containment vessel had been damaged.
Pressure was stable inside the reactors of the Daini plant but rising in the containment vessels, a spokesman said.
The nuclear core in many newer reactors, including the ones in Japan, is enclosed by a steel containment vessel.
The features of double-walled cylindrical explosion containment vessels closed with flat heads are presented.
Numerical simulation on dynamic response of the cylindrical explosion containment vessel with an elliptical cover
The features of double walled cylindrical explosion containment vessels closed with flat heads are presented.
That means cooling water is not getting to the reactor core, causing a build up of steam inside the containment vessel.
Water in the core began to boil off, raising the temperature and pressure inside the massive steel containment vessel.
Radioactive steam will still bubble up to the top of the water in the containment vessel, but will be harder to vent as the systems for doing so in an orderly manner are now underwater.
That in turn sits within a larger steel structure, the primary containment vessel.
At unit three the plant managers decided to flood only the pressure vessel hanging in the neck of the containment vessel, not the whole of primary containment.
