Civil Engineering Reference
In-Depth Information
While the economic losses arising, e.g., from major tanker accidents or oil
drilling platforms were estimated to run up to several billion dollars, the economic
consequences of the Chernobyl and Fukushima accidents are higher by about two
orders of magnitude. Besides the damage to health resulting from the radioactivity
to which workers and the population were exposed it is the contamination of land by
Cs-137 as well as the ban on food over prolonged periods of time which are a
problem very specific to the use of nuclear power [
1
-
4
].
In discussions about the risk of technical systems or especially by nuclear
energy the following argument is often stressed:
The large damage, caused by severe nuclear accidents, is associated with
extremely low probabilities of occurrence per year. Therefore the risk as the
product of damage times probability of occurrence is small.
Around 1989, Kessler-Hennies-Eibl (KHE) [
5
-
8
] raised the question whether
this risk argumentation and the associated findings of the risk studies had to be
accepted as unavoidable for future LWR safety concepts or whether they could be
improved upon.
European light water reactors are often located by large rivers passing through
densely populated regions with cities of more than 100,000 inhabitants and large
industrial plants. Cities of that size are impossible to evacuate fast enough in
Europe. Radioactive contamination of such cities and surrounding densely popu-
lated areas is beyond anybody's imagination.
From 1990 on, this thinking led to deeper research into the sequence and
consequences of severe core meltdown accidents in LWRs and to the proposal of
an extended safety concept in Europe.
10.2 Principles of the KHE Safety Concept
for Future LWRs
The safety concept for future LWRs as proposed by KHE at the Research Center
and Technical University of Karlsruhe, Germany, is based on these considerations
[
5
-
8
]:
- The major consequences of accidents as determined in WASH-1400 [
9
] and the
German Reactor Risk Study Phase A [
10
] assume that
a steam explosion also called fuel coolant interaction (FCI) after core melt-
down or
core melt-through under high primary pressure or
a major hydrogen detonation
damage the outer reactor containment such that a large leak will release
considerable amounts of airborne radioactivity (100 % radioactive noble
gases, 50-90 % of the radioiodine, Cs, and Tc), roughly within 1 h after
core melt down;
