The reactor
Once fission has started inside the reactor, water is heated to boiling point.
The reactor plant is of the boiling water reactor (BWR) type. Here, water is the reactor coolant and moderator. During nuclear fission, the water is heated and converted into steam inside the reactor vessel. In the upper part there are steam separators and moisture separators, which separate water droplets from the steam. The pressure inside the reactor vessel is about 7 MPa (MegaPascal). The reactor vessel at Oskarshamn 3 weighs 760 tons and consists of thick steel. In the core, the uranium fuel is placed in fuel rods. The heat generation in the fuel is regulated partly by maneuvering the control rods inside the reactor vessel, which contain a neutron-absorbing material, and partly by controlling the amount of water circulating through the core.
The reactor containment wall, consisting of a thick concrete cylinder, is cast using advanced slipform and prestressing techniques. A steel plate is embedded in the cylinder wall as a sealing element.