Civil Engineering Reference
In-Depth Information
Large dry
containment
Hydrogen
monitor
RCS depressurization
valve
Igniter
Alternative containment
cooling
Containment water
injection
Drain line to
reactor cavity
Core debris
trap
Debris spreading
area
Liner plate covering
concrete
Reactor cavity
depth
Firewater injection
to reactor cavity
Fig. 3.16
Containment design and safety systems of US-APWR [
13
]
3.2.8.1 Reactor Scram
In a reactor scram, the absorber rods of the PWR are dropped into the reactor core
by gravity (Fig.
3.9
). The reactor goes subcritical and the reactor power drops to the
level of afterheat generation (Chap.
2
).
3.2.8.2 Emergency Power Supply
During normal reactor operation, the plant is connected to the public grid system. In
the case of a breakdown of the public grid, the plant is disconnected from the grid
and the output of the turbogenerator and the power generation of the reactor is
reduced to the level of the plant requirement. The plant generates its own supply in
isolated operation and is maintained operational. If also the isolated mode of
operation fails, only the safety systems will be supplied by emergency power.
Emergency power is supplied in a redundant layout by diesel generators,
gas/combustion turbines and battery systems. If the operation room is endangered
during an accident by fire, poisonous or radioactive gases or aerosols the plant can
