Technology and Operation - Kernkraftwerk Gösgen

access for heavy goods vehicles. A direct connection
to the railway system facilitates the
transport of heavy loads to and from the site.
When positioning the various buildings and
plant facilities, care was taken to ensure a
functional and space-saving arrangement.
There is a clear spatial divide between the nuclear
and the conventional parts of the plant,
confining the radioactive systems to a welldefined,
specially controlled area. The easy
access to buildings, systems and components
is also an advantage for maintenance
work.
The compact arrangement of the buildings
ensures short pipe and cable connections
between the individual sections of the plant.
The cable ducts and piping for redundant
safety-relevant systems are always fed into
the buildings separately. The arrangement of
the turbine hall and the reactor building ensures
a short energy path from the reactor to
the transformers, which are located on the
eastern side of the turbine building. Electricity
is transferred from the transformers to the
380 kV switchyard via an overhead power
line.
Controlled area
The nuclear section of the plant comprises
the reactor building, the reactor auxiliary
building and the external spent fuel storage
building, completed in 2008, which together
form a closed controlled area. Access to this
controlled area is via a central guarded entrance.
The reactor’s spent fuel storage pool, together
with the plant components containing radioactivity
that are at reactor operating pressure,
are enclosed by a spherical steel shell.
This safety barrier (containment) protects the
Plant design and special technical features
environment against radiological impacts
from postulated severe incidents. It prevents
the uncontrolled release of radioactive material
to the outside.
The containment is in an off-centre position
inside the reactor building, which has an
outer shell in reinforced concrete. The containment,
together with the reactor building,
forms a twofold safety casing. The reactor
building protects the radioactive plant components
from external impacts; it is designed
to withstand earthquakes, shockwaves from
explosions and aircraft crashes.
The pressure-resistant containment with gastight
welds is embedded in a shell-shaped
foundation ring at the base but is otherwise
designed as a self-supporting structure.
When the containment was designed as a
fully pressurised structure, it was assumed
that a reactor coolant pipe could burst, with
the full water content of the reactor coolant
system and also one of the steam generators
evaporating. The steel shell is thus designed
to withstand an overpressure of 4.89 bar at
a temperature of 135°C for such a case.
Access to the containment is through a pressure-resistant
and gas-tight lock.
The reactor auxiliary building houses the processing
facilities for waste water, concentrates
and waste gases, the central air supply
and extraction system for the controlled area,
workshop facilities, laboratories for the analysis
of radioactive materials, decontamination
facilities and also storage for low and intermediate
radioactive waste. In June 2007,
after building work lasting 20 months, a
three-storey extension was completed, providing
an additional 8000 cubic metres for
workshops and storage. This extra space has
allowed the storage of materials to be optimised
and fire protection to be improved.
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