Entombing the radiation, a brick wall blocks the entrance to the control room of reactor #4 where the fatal mistake occurred. It created a safer passage for workers who have to walk through the area. Background Info: After the Chernobyl Nuclear accident, a concrete and steel encasement, the so-called sarcophagus, was hastily erected to contain the radioactive remnants inside the failed reactor. Only intended to be temporary, it is leaky and structurally unsound. Scientists agree that it will ultimately give way, shaking loose enough radioactivity to cause a second disaster of even greater magnitude.