Jan.5th, 2016, Japanese media reported that Japan will return the 331KGS plutonium, which is used for nuclear research previously provided by the United States  in March this year. The provided time of these plutonium can be dated back to World War II. Plutonium is a sensitive nuclear material that used to make the nuclear weapons. Fukushima, the town of Japan, had occurred a serious nuclear accident on March 28, 2011, subsequently caused serious radiation pollution problems, which had severely affected many Japanese public life and health. Therefore, it reminds us to realize the importance of radiation shielding.

 

This time, Japan’s plan of returning these plutonium to the US does not mean that Japan will reduce the frequency of nuclear research. According to the information revealed by the relevant persons, this is due to that the nuclear fuel proliferative zone of Japan's domestic fast neutron nuclear reactor "Monju" had produced a kind of super plutonium, which has a better purity than these 331KGS plutonium provided by the US. Thus the power of nuclear warhead made of the super plutonium will be stronger. According to the statistics of Japanese experts, currently, the super plutonium produced by Japan's "Joyo" and "Monju" nuclear reactor had been accumulated that exceeded 50KGS, if the "Monju" reactor regain to operate, it can produce 70kgs of super plutonium annually. Thus, it can be seen that this is the real reason for Japan to return these plutonium to the United States.

 

As mentioned above, the damage caused by super radioactive plutonium is incalculable, we must adopt some effective measures to shield the radiation. So for Japan, as well as other countries, shielding the radioactive substances is the primary task in order to protect the people's personal safety. Tungsten alloy radiation shielding has excellent shielding capability which is due to its high density and non-toxic properties and been well-known by people in various industries. Therefore, tungsten alloy can be made into the radiation shielding with various shapes so as to meet the different shielding requirements.