Annual report of department of research reactors and tandem accelerator, JFY2005. Operation, utilization and technical development of JRR-3, JRR-4, NSRR and tandem accelerator

The Department of Research Reactors and Tandem Accelerator is responsible for the operation, utilization and technical development of JRR-3 (Japan Research Reactor-3), JRR-4 (Japan Research Reactor-4) and NSRR (Nuclear Safety Research Reactor) as well as Tandem Accelerator. The following services and technical developments were achieved in Japanese Fiscal Year (JFY) 2006: 1) JRR-3 was operated for 156 days in 7 cycles and JRR-4 for 145 days in 37 cycles. They provided neutrons for research and development of internal and external users. 2) JRR-3 and JRR-4 were utilized through deliberate coordination as follows, a) Neutron irradiations of 633 such as neutron transmutation doping of silicon, b) Capsule irradiations of 2922 such as neutron activation analyses, c) Neutron beam experiments of 5511 (cases * workdays). 3) According for the plan increasing cold neutron beam strength 10 times, Integrity of moderator vessel at liquid-hydrogen-evaporation events was confirmed by the stress analyses. Also, it was confirmed by optical tests that glass type carbon plates promising as radiation-resistant neutron guides possesses the same performance of glass plates, and irradiation tests of glass type carbon plates was prepared. 4) In Born Neutron Capture Therapy using JRR-4, an extended collimator that enable clinical trials for head-and-neck cancer were put into practical use. 5) In NSRR, pulse operations of 4 were carried out as planed, to experiment the high bum-up fuel of LWR. The capsule loading facility Type B was completed for to high-plutonium-content and high-burn-up MOX fuel. 6) Tandem accelerator was operated for 182 days to carry out all the scheduled experiments with heavy ions for internal and external users. The multi-charge ion injector in the high voltage terminal was moved to the other side in the terminal so that the beam stability was improved. (author)