Removal of JRR-3 biological shield concrete and mock-up tests of diamond sawing and coring technique of JPDR biological shield concrete

Japan Research Reactor No. 3 (JRR-3) of the Japan Atomic Energy Research Institute (JAERI), was removed to a storage facility between October 14th and November 7th, 1986. This removal of the 2250 ton reactor block (10x10x10m) was performed as a part of the program to replace the JRR-3's core (10-MW thermal) with an upgraded research reactor core. After the removal of the reactor, a new 20 MW thermal, light water moderated and cooled JRR-3 core will be built. Criticality is scheduled for 1989. The Japan Power Demonstration Reactor (JPDR) was the first power plant in Japan and was shut down in 1976 after 13 years of operation. The JPDR decommissioning program began in 1981 in order to develop future commercial power plant decommissioning techniques and demonstrate reactor decommissioning techniques under the sponsorship of the Science and Technology Agency in Japan. The biological shield surrounding the pressure vessel is massive, is made up of heavily reinforced concrete and is partially activated. A diamond sawing and coring technique has been developed for the highly activated concrete dismantlement along with an abrasive water jet cutting technique