Analysis of fuel assemblies inclination due to upper core support plate deflection for reactivity evaluation

Yoshimura, Kazuo; Doda, Norihiro  ; Igawa, Kenichi*; Uwaba, Tomoyuki ; Tanaka, Masaaki  ; Nemoto, Toshiyuki*

To investigate possibility of the insertion of the reactivity by the deflection of the upper core support plate, structural mechanics analyses of the domain consisting of the fuel assemblies and core support plates and evaluation of the reactivity due to the inclination of the fuel assemblies in EBR-II were carried out. As a result, it was indicated that the upper core support plate deflected downward larger at the low flowrate condition than that at the high flowrate condition and positive reactivity was inserted due to the inclination of the fuel assemblies at the low flowrate condition.