Shielding wall structure of radioactive material containing facility

In a radioactive material storing facility having radiation shielding walls therein, closed enlarged spaces are formed, as neutron decaying promoting regions, in the course of a bent cooling blow channel of a small width such as a gas supply channel and a gas exhaustion channel. In addition, a plate for inhibiting inflow of gas streams is disposed at the entrance of the enlarged space so that a gas flown from the entrance of the bent cooling blow channel proceeds straight to an exit of the bent cooling blow channel, not enters into the enlarged space. Then, when the bent cooling blow channel is formed as a gas exhaustion duct, no stagnation of heat is caused in the shielding wall. Then the increase of streaming of neutrons can be prevented while improving cooling effects by enlarging the width of the bent cooling channel. In addition, cooling air can be flown smoothly by the gas stream flow inhibiting plate disposed at the entrance of the enlarged space. (N.H.)