OPERATIONAL EXPERIENCES OF FAST NEUTRON SOURCE REACTOR 'YAYOI' AS A PULSED FAST REACTOR

摘要

University of Tokyo research reactor ' YAYOI' was intended to be operated as a dynamic fast neutron source reactor as well as a stationary one. It was equiped with reactivity adding devices with both slow and quick action. The unique idea of fly-through type poise reactivity addition into the core lends itself to minimizing thermal shock problems pertaining to fast burst reactors thereby increasing safety of a single shot type burst reactor. Operational experience of YAYOI obtained during the dynamic testing of prompt supercritical state are descried here with some explanation of design aspects of YAYOI as a fast pulsed reactor. Throughout present experiments, the prompt supercritical state reactivity of about up to 29 cents was realized for YAYOI core, and it was confirmed that the sizes of pulse power were well controllable with this reactivity pulser (R-P) mode pulse operation.