Investigations and Design Studies on the Ultra High Flux Research Reactor

Basic design studies of the Ultra-High-Flux Research Reactor （Advanced Neutron Source）ANS) are being carried out between Japanese university researchers and Oak Ridge National Laboratry（host institute of the US side） under the searcher level's cooperation. the target of the study isthe unprecedented high flux of 10^<16> n/cm^2·sec. Various scientific and engineering problems arebeing examined by the joint study (1) Neutronics calculations have been carried out by means of twodimensional transport code for "Off-set" type reference core By using new cross-section set（ENDF-B/IV） higher reactivity as 1.091 was obtained. Experimental verifications will be必要性.(2) Various characteristics of beam tubes While Various characteristics of beam tubes While two dimensional transport code. Whiletangential beam tube is better than radial one for diminishing fast neutron and gamma raycontaminations . however,(3)能源规范（Energy spectra of）：核心的可调节距离是必要的，以监测辅助效果。neutrons examined by adjusting energy range due to ANS标准。

Basic design studies of the Ultra-High-Flux Research Reactor (Advanced Neutron Source, ANS) are being carried out between Japanese university researchers and Oak Ridge National Laboratry (host institute of the US side) under the researcher level's cooperation. The target of the study is the unprecedented high flux of 10^<16> n/cm^2・sec. Various scientific and engineering problems are being examined by the joint study (1) Neutronics calculations have been carried out by means of two dimensional transport code for "Off-set" type reference core. By using new cross-section set (ENDF-B/IV) higher reactivity as 1.091 was obtained. Experimental verifications will be necessary. (2) Various characteristics of beam tubes were calculated by two dimensional transport code. While tangential beam tube is better than radial one for diminishing fast neutron and gamma ray contaminations. However, considerable distance from core is required for obtaining sufficient effects. (3) Energy spectra of neutrons were examined by adjusting energy range due to ANS standard.