Evaluation of the drying behavior of fuel debris covered with water glass based neutron absorber

荒井 陽一  ; 鈴木 誠矢 ; 岡村 信生 ; 渡部 雅之; 川野 昌平*; 川原田 義幸*; 松浦 由幸*; 山崎 誠志*

Arai, Yoichi; Suzuki, Seiya; Okamura, Nobuo; Watanabe, Masayuki; Kawano, Shohei*; Kawaharada, Yoshiyuki*; Matsuura, Yoshiyuki*; Yamazaki, Satoshi*

Preventing re-criticality is an important safety issue in fuel debris removal operations. As one of the technologies to prevent re-criticality, we have been developing neutron absorbers. The water glass based neutron absorber is a type of solidified non-dissolvable neutron absorber, which is applied to the surface of fuel debris in water. The water glass based neutron absorber gradually increases in viscosity and hardens in close contact with the fuel debris surface. Since the fuel debris is water-cooled in the reactor and it is assumed to be porous, the water glass based neutron absorbent material coats the fuel debris while retaining water inside the fuel debris. In order to prevent hydrogen generation due to radiolysis of water, fuel debris is dried after removal operations. However, there is concern that water glass based neutron absorbent material adhering to the fuel debris may prevent the fuel debris from drying. Therefore, we started to investigate the effect of the water glass based neutron absorber coating on the drying behavior of fuel debris.