Design of auxiliary shield for remote controlled metallographic microscope

Matsui, Hiroki; Okamoto, Hisato

The remote controlled optical microscope installed in the lead cell at the Reactor Fuel Examination Facility in Japan Atomic Energy Agency has been upgraded to a higher performance unit to study the effect of the microstructural evolution in clad material on the high burn-up fuel behavior under the accident condition. The optical pass of the new microscope requires a new through hole in the shielding lead wall of the cell. To meet safety regulations, auxiliary lead shieldings were designed to cover the lost shielding function of the cell wall. Particle and Heavy Ion Transport Code System (PHITS) was used to calculate and determine the shape and setting positions of the shielding unit. Seismic assessments of the unit were also performed.