Light Water Reactor Design Against External Events - The Risks of Nuclear Energy Technology - page 161

Crashes of large commercial airliners were described and treated theoretically in
[ 42 - 45 ]. After thorough analyses, Eibl SMP Engineering Consultants, Karlsruhe
[ 46 ], found that the impact of a Boeing 747 jumbo jet at an approach velocity of
175 m/s hitting a convoy-type PWR with 180 cm of concrete of the outer concrete
shell could give rise to cracks in the concrete containment of convoy-type PWR
plants. However, kerosene would not penetrate (no fire). This finding applies to the
180 cm thick concrete containment of the Neckarwestheim-II nuclear power plant
but can be transferred to all German convoy-type PWR, pre-convoy PWR, and
Gundremmingen B + C, each with outer steel-reinforced concrete containments of
180 cm thickness. The European Pressurized Water Reactor, EPR, has a total wall
thickness of the inner and outer containment of 2.6 m (Fig. 7.13 ).
7.3 Chemical Explosions
Chemical explosion hazards can arise in transports of explosible materials by
barges on rivers and ocean-going vessels or nearby railway lines and roads. In
Germany, nuclear power plants must be designed against a given pressure wave
resulting from such hazards. In this pressure wave, the pressure is supposed to rise
to 0.045 MPa (0.45 bar) overpressure within 0.1 s and then drop to 0.03 MPa
(0.3 bar) within 2 s and remain at that level for another 1 s (Fig. 7.14 )[ 10 ].
The buildings adjacent to the reactor building should be arranged in such a way
that any focusing arrangements and structures promoting turbulences are avoided.
All these requirements are met in all pre-convoy PWR, convoy-type PWR, and
the Gundremmingen B and C BWR [ 25 ].
Toxic gases which could enter the ventilation system can be detected. The
ventilation system can be shut off against the entry of toxic gases.
7.4 Flooding
In German nuclear power plants, the risk of flooding by a maximum-level flood
must be taken into account on the basis of scientific findings about maximum floods
for the past 10,000 years [ 10 , 47 ]. Flooding by tsunamis must be considered for
nuclear power plants located at the coasts of zones endangered by seismic events
[ 20 , 48 ]. Table 7.4 shows a list of historically documented tsunamis initiated by
earthquakes along Japanese coasts.
Table 7.4 shows that very high tsunami waves can be produced even by
earthquakes of relatively low magnitudes (Richter scale).