Decommissioning and dismantling
Decommissioning and Dismantling
There is no nuclear safety regime designed specifically for decommissioning and dismantling, so therefore the existing regulations for the construction and operation of nuclear power plants are applied by analogy. The Federal Ministry for the Environment issued the "Decommissioning Guideline" as an aid for this process.
Decommissioning and dismantling licenses are required by law for the demolition of a nuclear power plant. Since the dismantling measures cannot be entirely pre-planned in detail, basically the dismantling permits define the scope of the dismantling activities and regulate the procedure for project control during the dismantling phase. In contrast to plants in power operation mode, the condition of a plant undergoing dismantlement changes continuously. Problems in the execution of dismantling operations are often only detectable or comprehensible when viewed on site. This situation requires the reinforced presence of the supervisory body and the called-in experts in the plant.
Nuclear installations in the process of being dismantled or in safe enclosure
In Baden-Württemberg, the following nuclear power plants and the testing and research facilities on the site of the former Karlsruhe Research Centre (now Karlsruhe Institute of Technology KIT) have been shut down and are in the process of being dismantled or are in safe enclosure. Specifically, these are:
- Nuclear power plant Obrigheim (KWO)
- Karlsruhe Reprocessing Plant (WAK)
A reprocessing plant established for experimental purposes that was operated from 1971 to 1990. Dismantling should be completed by 2023.
- Compact Sodium-Cooled Nuclear Reactor Facility (KNK)
A fast breeder reactor with a thermal capacity of 58 MW and an electrical output of 20 MW. The plant was permanently shut down in 1991. Dismantling started in 1993 and should be completed by 2021.
- Multi-Purpose Research Reactor (MZFR)
A heavy-water-cooled and moderated pressurized water reactor with a thermal capacity of 200 MW and an electrical output of 57 MW. The MZFR was first commissioned in 1965, and served primarily for the testing of nuclear components and materials as well as for the testing of the operation of a commercial heavy-water-cooled and -moderated nuclear power plant. Following permanent shut down in 1984, dismantling began in 1987 and should be completed by 2019.
- Research Reactor 2 (FR 2)
A heavy-water moderated reactor, which began operation in 1963 as a source of neutrons for research purposes and for the production of radionuclides. It was permanently shut down on December 21st, 1981, and then was converted to the present state of "safe enclosure." The safe enclosure is limited to the reactor building with the reactor block.
- Research facilities that are no longer required (e.g. hot cells)
The dismantling of the Karlsruhe plants is carried out by the Karlsruhe Rückbau- und Entsorgungs-GmbH (WAK GmbH), which was established especially for this purpose. This company also operates the Central Decontamination Department (HDB) for the conditioning and interim storage of low and intermediate level radioactive waste.
- The nuclear power plants GKN I (Neckarwestheim) and KKP 1 (Philippsburg) have been shut down and are in post-shutdown operation. Applications for the issue of decommissioning licenses have been submitted for both nuclear power plants.
The supervision by the Ministry of the Environment during dismantlement is usually done in two stages:
- In the first stage, the detailed planning documents will be checked before the commencement of dismantlement activities. For example, it checks whether the outlined work conforms to the approved scope of dismantling and whether the safe removal of residue is ensured in order to prevent contamination. Compliance with the rules of occupational health and safety is also verified.
- In the second stage, the implementation of these measures is checked. Operator reports on the beginning and conclusion of activities are evaluated and, in particular, the accrued radiation exposure of personnel is monitored. Furthermore, the documentation is checked upon completion of work steps, and incidents that occur during the dismantlement work, and planned changes to the system status are examined and evaluated.
These activities are supplemented by on-site inspections, often in the attendance of expert consultants. The focus here is on inspecting the condition of the plant and the trouble areas at the construction sites. Additional supervisory control visits take place as warranted.
External companies are also hired for the dismantlement work. Naturally, the screening of their staff is also one of the tasks of the Nuclear Supervision division of the Ministry of Environment. Another essential element of supervision is the scrutiny of the business organization and the defining of the interfaces of responsibilities.
The validation of the quality of radiation protection, occupational health and safety, and fire protection is yet another supervisory task. The protection of employees and the general public must be organized in such a way that it has a strong position in the company and that sufficient qualified personnel is always available. In terms of radiation protection, for instance, supervision focuses on minimizing the radiation exposure through the appropriate planning of the individual dismantling activities, and through compliance with the regulations for personal radiation protection in general.
In order to ensure that no radioactive material is released into the environment as a result of a dismantling activity, the safety measures taken by the operator are also subjected to periodic critical examination.