26.08.2015   Rudiger Meiswinkel, Julian Meyer, Jurgen Schnell

Dismantling phases

The process of decommissioning a nuclear power plant until when it is deregistered under the Atomic Energy Act, including the rundown phase in direct dismantling, takes around 12 years.

We will now describe the individual phases of the process, taking the Stade nuclear power plant (KKS) as our example (Figure 4.24).

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Fig. 4.24 Stade, dismantling timetable [32]

Dismantling phases, using KKS as example:

Phase 1:

— Take down various systems inside and outside control area

— Put different buildings to different uses

— Set up dismantling infrastructure

Phase 2:

— Remove main coolant lines and pumps

— Remove boiler and other large components

— Remove other contaminated system components

Phase 3:

— Make preparations to remove and pack activated building sections and components

— Remove and treat reactor pressure vessel fittings

— Remove reactor pressure vessel

— Remove bioshield

Phase 4:

— Remove remaining system components within control area

— Decontaminate and clear standing structures

— Withdraw from decontaminated areas in stages and seal against recontamination

— Clear site

— Release complete site from Atomic Energy Act monitoring

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Fig. 4.25 Removing bioshield using reinforced concrete blocks previously obtained by using wire

saws using HOCHTIEF LAP 60 heavy load anchor as retrofitted load attachment point

4.5.1 Individual structural measures involved in dismantling

We list some individual building services below which those involved in dismantling

will normally have to carry out [35]:

— Reconstruction measures: fit extra shields, create openings, close openings, take fire precautions

— Strengthen building components to take increased loads due to temporary interim conditions, for example

— Create routes for transport logistics within control area while removing contami­nated and activated system components and logistics work retrofitting lifting gear, including creating access roads required

— Removing contaminated concrete structures: establishing depth and extent of contamination levels, cutting off and removing contaminated building surfaces and packing in transport containers

— Removing activated concrete structures (bioshield)

— Measures to prevent building work problems: making safe against falling loads

— Setting up temporary buildings for treating and storing radioactive waste, clearance measurement of system components released completely and unconditionally if classified accordingly

— General service functions such as scaffolding or client providing site electricity supply