Civil Engineering Reference
In-Depth Information
available in redundant and diverse ways for the action of the safety/relief
valves [
101
].
10.6.2.1 Securing the Emergency Electrical Power Supply for BWRs
In BWRs, in addition to the options described above for PWRs, there is the
possibility to use the steam generated by the afterheat in the core in order to drive
small steam turbines combined with water pumps or generators. The water can be
taken from the condensation chamber or other water supplies. This option repre-
sents a diverse and redundant possibility to the diesel generators, or combustion
turbines etc. Cooling the control rod guide tubes by applying additional diverse
emergency power and diverse coolant water supply appears to be promising [
76
].
10.6.2.2 Securing the Feedwater Supply in BWRs
In case of complete failure of the feedwater supply in BWRs, water can be taken
from deep wells located on the site of the plant or it can be supplied by mobile
pumps from water sources like a lake, river or the ocean. The power supply of these
pumps must be secured as described above.
Similar possibilities can be used for the cooling of the pressure suppression
chamber.
10.6.2.3 Overpressure in the Inner Containment of BWRs
In case of rising pressure in the nitrogen inerted inner containment of BWRs the
hydrogen can be consumed by catalytic hydrogen recombiners and steam can be
10.7 Emergency Control Rooms
German LWR plants, e.g. are equipped with a special emergency control room,
sheltered against external events and poisonous or radioactive gases. The emer-
gency control room is equipped with the critical instrumentation and control
mechanisms to control the plant during the course of a severe accident. It is
important that independent emergency power supply is available for critical instru-
mentation and control mechanisms in the emergency control room.
