Assessment of Risk Studies and Severe Nuclear Accidents - The Risks of Nuclear Energy Technology - page 228

10.8 Flooding of the Reactor Cavity Outside of the Reactor
Pressure Vessel
For all presently operating LWRs it must be investigated whether flooding of the
reactor pressure vessel is feasible as an accident management measure. This is
extremely important for the case that accident progression cannot be stopped and
core cooling is endangered.
If the above described severe accident management measures are success-
fully applied, the safety concept of presently already operating LWRs can
approach to a certain extent the safety concept of new reactor designs
described in Chap. 3 . It is important that these severe accident management
measures are well planned in advance and trained by the operational staff.
10.9 Mobile Rescue Teams
For the case of a severe accident in an LWR plant mobile rescue teams must be
available which can reach the plant in short time. They must be able to provide:
- mobile radiation measurement and decontamination equipment,
- remotely controlled dredging machines or cranes,
- mobile robotic machines with radiation instruments and tools to enter the
internal rooms of the containment,
- mobile emergency power generators.
10.10 Concluding Remarks
Almost all safety concepts and licensing requirements for the operation of present
LWRs in the world are still based on the probabilistic approach described in
Chaps. 5 and 6 .
The new research results described in Sect. 10.3 show that the deterministic
approach, e.g. applied for EPR and SWR-1,000 (KERENA), is feasible in parallel
to the application of the probabilistic approach (for optimizing the internal plant
systems). Future LWRs can be built such that their containment can withstand large
scale steam explosions and hydrogen detonations. High pressure core melt through
the bottom part of the reactor pressure vessel or core melt through the concrete
basement of the containment can be avoided by design. Leakages into the annulus
between inner and outer containment as well as leakages after steam generator tube
failures followed by stuck open steam relief valves can be avoided by proper
design.