BWR type reactor and fuel therefor

In a BWR type reactor, dose rates of a reactor turbine buildings and main steam pipelines are decreased. That is, increase of the dose rate in the turbine system is caused by radioactive nitrogen 16N formed from oxygen atoms in cooling water which are actuated by high energy neutrons generated in the reactor core by way of nuclear reaction of 16O(n,p)16N and transferred to a main steam pipe. The nuclear reaction is an endothermic reaction, and the threshold energy is 9.5 MeV. Then, atoms having a great nuclear reaction area relative to fast neutrons at greater than 9.5 MeV are incorporated to reactor core materials such as fuels, fuel cans, channel boxes, control rods and peripheral equipments. Alternatively, materials containing atoms having a great nuclear reaction cross sectional area relative to neutrons having an energy of greater than 9.5 MeV are disposed to the inside or the outside of the shroud wall at the outermost circumference of the reactor core. With such a constitution, formation of radioactive nitrogen 16N is suppressed. As a result, reactor integrity and safety can be extremely improved. (I.S.)