Technology and Operation - Kernkraftwerk Gösgen

gency and residual heat removal systems,
from the 6-kilovolt and 380-volt emergency
distribution systems. A 2940-kilowatt diesel
generator unit is assigned to each train. This
starts up automatically if the main bus voltage
in the associated train falls below 80 %
for 2 seconds. Once the diesel start-up time
of a maximum of 15 seconds has elapsed, the
reactor protection system then sequentially
reconnects the key safety-related consumer
groups. Each of the four diesel generator sets
can independently cover the electricity requirements
of the associated safety system
line for several hours.
Instrumentation and control systems, such as
the reactor protection system, which need
to operate without interruption during the
diesel start-up phase too, are supplied in duplicate
via diode-decoupled, battery-based
48-volt or 220-volt direct-current bus bars.
For particularly important components, which
must be able to implement rapid isolation
and shutdown measures at any time, there
are four non-interrupted, secure 380-volt networks
fed by battery-based rotary converters.
For the extremely unlikely case of more than
two safety system lines failing at once, there
are an additional two special emergency systems
ready to come into operation. Their
diesel generators start up automatically and
are self-supporting with electricity and
coolant for 10 hours.
Great importance is attached to the electrical
and spatial separation of the four trains. It
must be ensured that no interaction occurs in
the event of electrical malfunctions or a fire.
The cable routing for the different lines is
also kept strictly separate, with the trains insulated
against each other from the emergency
diesel generator units, via the
switchgear, right through to the electrical
Station service power supply
consumers. The redundancy concept with 6
trains, 4 of which are emergency power networks
and 2 emergency standby networks
with a total of 6 diesel generators, has been
consistently implemented in the building
structure, with the switchgear building split
into four parts. This strict spatial separation
is clearly evident when looking at the emergency
diesel generator buildings and the special
emergency building. These are separate
from the switchgear building and more than
60 metres away from each other. This then
also makes allowance for the consequences
of a hypothetical aircraft crash.
The service power network described above,
which has 35 transformers, supplies the energy
for approximately 1400 motors and 950
electric valves.
Electricity feed into the switchyard.
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