Konomo Sanokawa

Impurity gas effects on friction and wear of high-temperature materials for VHTRs

In a very high temperature gas-cooled reactor developed at the Japan Atomic Energy Research Institute, reactor components, such as heat transfer tubes (Hastelloy-XR) of an intermediate heat exchang...

Water-Cooled Target of 14 MeV Neutron Source

A cooling system of a stationary target for the Fusion Neutronics Source (FNS) has been designed to satisfy the structural, thermal and hydraulic requirements. Two square tubes for ion beam and for cooling water were concentrically placed and the target was mounted on the top of the beam guide tube. The end plate of the outer tube was devised to be removable for easier replacement of the target. In order to test the cooling capability of the system, dummy target assemblies with electical heaters were used in the experiment of heat transfer in place of using an accelerator. Correlations of heat transfer and head loss were obtained experimentally as a function of Reynolds number. The extrapolation of the data has shown that for the present target system, about 2.3 kW is the maximum power for the beam in diameter of 15 mm. This value was sufficiently large compared with the required heat load of FNS.

Stress analysis of core support post in a very high-temperature reactor

Abstract A very high-temperature gas-cooled reactor (VHTR) has been developed by Japan Atomic Energy Research Institute and its core consists of so-called fuel blocks, removable reflector blocks and so on. These graphite blocks are supported by thin cylindrical graphite bars called support posts. These posts are in contact with the blocks through hemispherical seats to absorb the relative displacement of blocks by small inclination or rotation of the posts. Stress distributions and stress concentration coefficients of the support post under the reactor core weight are analysed by means of photoelastic experiment and compared with two-dimensional calculation by using the finite element method. The following are the conclusions we have derived: 1. (1) Stress concentration coefficients of the post are expressed uniquely as a function of Ed( 1 r p − 1 r p ) σ g regardless of the shapes of model and material properties. 2. (2) Inclination of the post caused by small rotation has little effect on the stress concentration coefficients.