Nuclear Power Plant Maintenance BusinessDecommissioning

What is decomissioning?

Decommissioning is the dismantling, demolition, and removal of a nuclear power facility that has been shut down permanently due to ageing.
The separation, stabilization, and disposal of radioactive materials is carried out while taking care not to allow radioactive materials or radiation to leak outside of nuclear facilities, thereby preventing waste and excessive exposure to radiation.
In Japan, nuclear power facilities are phased out over a comparatively long time span, ranging from 24 to 40 years.
At a nuclear power plant, after the spent nuclear fuel is removed from the nuclear reactor, while we wait for the attenuation of the sections that have high radiation dose equivalent rates due to the activation of the nuclear reactor and from radioactive materials, we go from Stage 1, the dismantling and removal of equipment and machinery from non-radiation controlled areas, to Stage 2, the dismantling and removal of plant and equipment around the reactor, Stage 3, the dismantling and removal of the reactor itself, and then Stage 4, the demolition of the buildings and the greening of the site.
Because decommissioning is a long-term project, it is necessary to maintain and manage equipment and machinery to prevent the leakage of radiation or radioactive materials. For that reason it is important to carefully plan the order of the dismantling and removal of equipment and machinery and the transition to the use of temporary facilities.
In addition, all materials that contain any radioactive materials are either buried or recycled according to the type of radioactive materials and their quantities, so it is important to know in advance the types, quantities, and properties of radioactive materials in each part of the facility, as well as to plan and secure the treatment methods for stabilization and the necessary plant and equipment, and disposal sites.

At ATOX, we perform a range of tasks involved in decommissioning, such as the measurement and recording, dismantling and removal, decontamination, sorting and waste volume reduction of the various buildings and plant and equipment at nuclear power facilities, nuclear fuel factories and other estalishments handling radioactive materials. In addition, we develop many kinds of machinery and apparatus necessary for this work, and also work to improve work safety and quality, reduce exposure, improve work efficiency, and reduce costs.