Damage on the JMTR hot laboratory by the 2011 Great East Japan Earthquake

An earthquake with magnitude 9.0 hit eastern Japan on 11th March 2011. It was the most powerful earthquake since records began in Japan. It is known as 'The 2011 Great East Japan Earthquake (also known as the 2011 earthquake off the Pacific coast of Tohoku)'. The JMTR hot laboratory was damaged by the earthquake. This paper describes various damages on the JMTR hot laboratory caused by the earthquake. The JMTR hot laboratory has three kind of hot cells; steel cells, lead cells and concrete cells. At the concrete cell, an electric lock of the shielding door of a hot cell was broken by the earth quake. Cracks were found in the walls of hot laboratory building. The exhaust stack of JMTR Hot laboratory is a part of gaseous waste treatment system. Thinning was found at anchor bolts on base of the stack in 2015. When thinning of anchor bolts were investigated, gaps between anchor bolt nuts and flange plate were found. It was concluded that the thinning was caused by water infiltration over a long period of time and the gaps were caused by elongation of thinning part of anchor bolts by series of earthquakes start from the 2011 Great East Japan Earthquake. (author)