Civil Engineering Reference
In-Depth Information
Fig. 15.6
Basic representation of the discretization of a rotationally symmetric model as a section
of a spherical shell
the aircraft into the interior of the building when considering the impact of a fast
flying military aircraft according to the approach detailed in the RSK-LL (Phan-
tom). A small amount of spalling on the reverse side cannot be ruled out, however.
All enclosing walls of the safety-relevant constructions of the convoy complex are
designed for this eventuality and have walls that are either sufficiently thick or are
equipped with a redundant design with spatial partitioning. Thinner walls cannot
absorb the load according to the RSK-LL without significant local destruction or
can only absorb an impact with a lower impact speed than 215 m/s. The latter can be
assumed if there are structures in front of the wall that would decelerate the aircraft.
Assuming an increased amount of reinforcement, a wall thickness of at least
60 cm is necessary for the impact of a Starfighter, in the case of normal reinforce-
ment this increases to close to 80 cm. All facilities of a nuclear power plant with a
lower wall thickness only offer marginal or no constructive protection in the case of
an aircraft impact. Due to this the boiling water reactors of the series 69 that were
built in the 1970s are to be viewed critically, even after they were shut down in 2011
because radioactive inventory remains in these plants.
After the attacks on September 11, 2001 the computational models and load
approaches described in the previous chapter were used to determine whether a
large commercial aircraft, such as a Boeing 747 or an Airbus A320, could penetrate
the enclosure walls of the reactor building. These analyses were originally limited
to the reactor building of convoy facilities with a wall thickness of 1.80 m. Using
refined mathematical models it was shown that penetration could be prevent with a
high degree of confidence. In the impact zone the deformations of the wall can be
up to 50 cm, including intensive cracking but without rupture of the reinforcement.
These examinations were not carried out for every individual facility, but rather
generalized models were considered with reinforcement grades towards the lower
end of the scattering range presented at the beginning of this chapter. With respect
to the load-bearing capacity of the concrete it was taken into consideration that the
