Abstract
Fuel Debris (FD) extracted from Fukushima Daiichi Nuclear Power Station (1F) reactors is expected to contain unsealed high level radioactive materials. Its handling from transportation to safe storage will pose several challenges in terms of safety and process feasibility. This paper focuses of how Orano’s experience and best practices in the design, operations, and maintenance of facilities handling high level radioactive waste (HLW) such as La Hague Reprocessing Plant can be leveraged to benefit TEPCO in the FD handling process on 1F.
Three main design requirements of HLW handling facilities are expected to apply to future FD handling facilities or equipment on 1F. The first requirement is to ensure the safety of the public and the workers operating these facilities (protection against ionizing radiation, containment of radioactive materials, management of radiolysis hydrogen generation, subcriticality and evacuation of thermal power). Then, high level radioactive FD will have to be handled in remotely operated confined spaces in which contamination management is a key point to ensure safe and reliable longterm operations. Finally, the installation of relevant analysis equipment is required to collect data on FD properties.
The following technologies and practices used by Orano for decades in its reprocessing facilities to transport, process, store and characterize radioactive materials, could be implemented on 1F to comply with the above requirements.
The PADIRAC shielded cask and airtight DPTE container is one example of a qualified, reliable, and simple solution used by Orano for moving safely small quantities of HLW while maintaining confinement during product transfer between the container and a containment structure.
Shielded and airtight hot cell which can be operated and maintained remotely is also one of the main contributors for safe handling of radioactive materials. Various solutions are used to ensure reliable management of contamination in handling of HLW, such as dynamic confinement using ventilation, contamination monitoring, container air-tight docking and the use of high-performance filters to ensure both hydrogen release and confinement of radioactive particles.
Finally, Orano has decades of experience and expertise in the operation of analysis equipment to quantify and characterize radioactive materials such as gamma/neutron dose rate measurement, gamma-ray spectrometry, gas chromatography for hydrogen measurement, and Active Neutron Interrogation, a non-destructive measurement of fissile matter in waste containers which will most certainly be required for the quantification of fissile materials in FD extracted from 1F reactors.
