Radioactive Waste Management and Transport Safety Division

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The Radioactive Waste Management and Transport Safety Division conducts investigation, testing and research for securing the safety of radioactive waste treatment and disposal, radioactive material transport, interim storage of spent nuclear fuel, reprocessing facilities and fuel fabrication facilities, and for improving safety regulations.

1.Safety for Decommissioning, Radioactive Waste Disposal and Others

(1) Decommissioning

The Division reviews, compiles and accumulates knowledge contributing to the review of decommissioning plan such as safety evaluation methods for decommissioning of nuclear installations. The Division also improves the confirmation methodology of the completion of decommissioning of nuclear installations and the confirmation method of decommissioning waste.

(2) Clearance

Waste materials from nuclear installations include "materials that need not be dealt with as radioactive waste" for its extremely low radioactive concentrations whose influence on human health is negligible. A clearance system whereby such materials can be recycled or disposed of be in place. The Division also reviews the examination standards for measurement and evaluation which ensure that the radioactive concentrations of materials are below the clearance levels. It also reviews confirmation procedures that an approved measuring method has been implemented. (Fig. 1)

(3) Confirmation of Radioactive Waste Disposal

1) Disposal of Low level radioactive waste
For waste packages subject to the on-going near-surface pit disposal, the Division conducts technical evaluation of characteristics of the waste and the review and improvement of the current confirmation methods. The Division also studies the characteristics and other attributes of wastes subject to the near-surface trench disposal and intermediate depth disposal, expected to be launched in the future, and improves those confirmation procedures. (Fig. 2)

2) Returned waste
The Division also studies requirements for receiving radioactive waste in Japan, which will be returned from overseas in the near future.

Fig.1 Clearance measurment apparatus, Fig.2 Disposal methods for radioactive waste

2. Safety of Radioactive Waste Disposal Facility

For disposal facilities of the low level radioactive waste under consideration in Japan, the Division is improving safety evaluation methods and approaches for verifying whether or not the long-term safety of disposal facilities complies with the standards.
For geological disposal of high level radioactive waste, the Division is conducting the survey and analysis to develop (1) the criteria to evaluate the appropriateness of the site investigation result which is used to select a final repository by an implementing body and (2) the standards to review the safety of construction of a burial facility. (Figs. 3 and 4)

Fig.3 Cross-section of a disposal cavern, Fig4. concept of geological disposal

3. Safety of Spent Fuel Storage Facilities and Transport

Fig.5 Cask drop test from a height of 9 metersThe Division studies safety of storage and transport of dual purpose casks (used for transport to and storage in spent fuel storage facilities). In addition to those safety studies, the Division collects and analyzes the relevant information, evaluates the standards established by the scientific and industry associations and develops the codes and the standards. (Fig. 5) The Division also studies safety verification procedures for waste management facilities.
Furthermore, in order to ensure the safety of land and sea transport of nuclear fuel materials, the Division reviews and studies the IAEA regulations and collects information, evaluates safety and improves standards pertaining to domestic transport.

4. Safety of Reprocessing and Fuel Fabrication Facilities

The Division conducts safety analysis and assessment, safety research and preparation for regulatory safety standards for reprocessing, and fuel fabrication facilities.
These efforts include various activities, i.e. analyses and assessments of radiation shielding, criticality, abnormal events etc.; studies on fire protection; and corrosion and thermal fatigue of the materials used in reprocessing facilities.
Furthermore, the procedures of probabilistic safety analysis are developed to apply risk information to safety regulations.