Investigation on integrity of heat exchanger and tanks in primary cooling system of JMTR

The Japan Materials Testing Reactor (JMTR) is a light water moderated and cooled tank-type reactor using LEU silicide plate-type fuels. First criticality was achieved in March 1968, and its operation was stopped from August, 2006 for the refurbishment. The refurbishment is scheduled from the beginning of FY2007 to the end of FY2010. An investigation on aged components was carried out for concrete structures of the JMTR building and for aged components of tanks in the primary cooling system, heat exchangers and so on, in order to identify their integrity. The investigation was carried out from the beginning of FY2007. In this paper, the aged-investigations for heat exchangers and tanks in the primary cooling system are presented. The integrity of three heat exchangers was confirmed by the eddy current testing for heat exchanger tubes, visual observation using endoscope, liquid penetration test of tube plates and thickness measurement of the main body. The visual inspection test and liquid penetration test were carried out to confirm the integrity of tanks in the primary cooling system. The heat exchangers and tanks in the primary cooling system will be continuously used in the future operation of the JMTR by appropriate maintenance activities based on the long-term maintenance program. (author)