Research Topic
"Pursuit of safety, nonproliferation and nuclear security"

Key wards：Nonproliferation, Nuclear Terrolism, Non-destructive assay, Utilization of nuclear waste, Nuclear material dispersion in environment, Numerical analysis


Nuclear reactor design for utilization of "Nuclear waste" as fuel
Long life radioactive material with high radioactivity for long term remains in the spent fuel as "nuclear waste" but it is indeed available as excellent fuel partitioning and recycling carefully. Advanced nuclear reactor design for minimization of nuclear waste and sustanable nuclear energy utilization.
Conceptual desing of advanced fast reactor
The figure shows a concept of nuclear material accountancy methodology for fuel debris in a container using gamma ray.The fuel debris have to be measure and managed in the view of safeguards because it is containing nuclear material such as uranium and plutonium. However the nuclear material accountancy is challenging issue without knowledge on nuclear material composition and situation inside of the fuel debris container.

Robust nuclear system against natural disasters, nuclear terrolisms and nuclear proliferations
Nuclear disaster can be occured by not only the natural disasters and human error, but also malicious attack of terrorists. Theft of nuclear material and use it for nuclear explosive devices manufacturing is also one of significant threats in nuclear field. We are studing the ncuelar system to prevent and mitigate the significant consequence.
High temperature gas cooled reactors
The mult coated fuel particle are shown in the figure, which is a fuel type used in the high temperature gas cooled reactor, a generation four reactor. It is a very small particle coated nuclear fuel such as uranium and plutonium oxides with 3 to 4 layers made from carbide ceramics with less than 1mm in diameter. 3S features synergies is expected because high thermal resistance, mechanical strength and chemical innertness can keep fission products inside.

Simulation of radioactive material dispersion
The figure shows the radioactive material dispersion in Japan from the Fukushima Daichi Nuclear Power Plant at the accident on March, 2011 silulated with World SPEEDY system. The simulation result give us useful knowledge to make evaluation plans and to minimized the consequence at the accident happen (Prof. Han).

Impact analysis using AUTODYN
The figure shows results using AUTODYN, a impact simulation software. The phenomena of transformation and destruction of concrete walls in the nuclear power plants by explosion can be simulated. The simulation code is available to evaluate nuclear safety ans security in nuclear systems.

Science of nonproliferation
-Persuit of technologyies-Application to decomission of Fukushima Daiichi Nuclear Power Plant
We are studying nondestructiven assay measuring uranium and plutonium mass in the fuel debris for rapid and safe decommission of the Fukushima Daiichi Nuclear Power Plant unit 1,2 and 3. This simple measurement equipment will be useful for criticality safety and safeguards at the fuel transportation and contribute to the smooth decomissioning.
Development of safeguards techniques of discharged fuel debris
The figure shows a concept of nuclear material accountancy methodology for fuel debris in a container using gamma ray.The fuel debris have to be measure and managed in the view of safeguards because it is containing nuclear material such as uranium and plutonium. However the nuclear material accountancy is challenging issue without knowledge on nuclear material composition and situation inside of the fuel debris container.

Space nuclear system standing future space development
We study super long lifetime and small nuclear reactor systems serving energy without fuel replacement for long term over 10 years in the isolated space such as the space station and space ships.
Core design for space nuclear reactor