Operation and management data for the JRR-3 CNS Facility

Suzuki, Masatoshi; Hazawa, Tomoya; Ishizaki, Yoichi*; Obara, Michio*; Inada, Katsutoshi*; Yonekawa, Mitsunori*; Wakita, Hiroshi*

The cold neutron source (CNS) at JRR-3 was constructed for the purpose of improving the utilization performance of the reactor along the lines of upgrade program. There are two methods for extracting cold neutrons from a reactor, one is to filter a small fraction of cold neutrons in the Maxwellian spectrum of reactor neutrons while the other is to increase the fraction of cold neutron by inserting a cryogenic moderator. The latter is adopted as CNS facilities at almost all cases, and liquid hydrogen and its cooling system are equipped with a cold neutron source at many neutron facilities just like JRR-3. Cold neutrons generated in a cold source are extracted through a neutron guide tube, and are utilized for the purpose of neutron beam experiments such as neutron scattering which study the structures of atoms and molecules in the materials and life science fields. This report summarizes the operation data and the main technical issues which were recorded in the whole operation period from commencement date in 1989 to March 2004.