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

Morioka, Atsuhiko; Sakurai, Shinji; Okuno, Koichi*; Sato, Satoshi; Verzirov, Y. M.; Kaminaga, Atsushi; Nishitani, Takeo; Tamai, Hiroshi ; Shibama, Yusuke; Yoshida, Shigeru*; Matsukawa, Makoto

A 300C heat-resistant neutron shielding material is newly developed, which consists of phenol-based resin with 6 weight-% boron. The neutron shielding performance of the developed resin, examined by the Cf neutron source, is almost the same as that of the polyethylene. The neutron shielding characteristic was also estimated by 3D Monte Carlo Code MCNP-4C2 using the continuous energy cross section data sets based on the JENDL-3.2. The calculation result agrees well with the experimental result. To understand the kinds of the outgas from the developed resin in the high temperature region, the mass spectrum of the outgas was measured until 300C by Thermal Desorption Specroscopy (TDS). The observed mass number was 2, 17, 18, 28, 32, and 44. The number corresponds to hydrogen (H), ammonia (NH), water (HO), carbon monoxide (CO), oxygen (O), carbon dioxide (CO), respectively. The main outgas component from the resin at 100150C was NH and HO. The outgas of NH and HO from the resin have been measured, however, the neutron shielding performance of the resin after 200C baking was almost the same as that before baking. The quantitative analysis of the outgas from the resin in the high temperature region was done by the Temperature Programmed Desorption (TPD) / Gas Chromatography and Mass spectrometry (GC/MS). The 13 kinds of organic gases have been observed by the amount of g/g at 300C. The neutron shielding performance of the developed resin at 300C was simulated by the 3D analysis. The resonance cross section of the nucleus is broad at the high temperature region by the Doppler effect. The calculation results using 327C library and 20C library are almost same.