Development of 300 °C heat resistant boron-loaded resin for neutron shielding

A new neutron shielding material resistant to temperatures up to 300 °C is developed, consisting of a phenol-based resin with 6 wt% boron. The resin will be applied around the vacuum vessel of the DD plasma device to suppress the streaming neutrons and to reduce the nuclear heating of the superconducting coils. The neutron shielding performance of the newly developed resin, examined by the 252Cf neutron source, is almost the same as that of polyethylene, which is not effective above 100 °C. The new resin maintains its mechanical strength in the high temperature region. The outgas of CO2, NH3 and H2O from the resin have been measured, however, the neutron shielding performance of the resin after 200 °C baking was almost the same as that before baking. Thirteen kinds of organic gases have been observed at ∼300 °C.