Dominant role of scattered radiation over direct radiation in shielding design of fuel transfer room in 500 MWe PHWR

Normally, for any bulk radiation shielding design, the role of direct radiation is considered sufficient to work out the details. But, sometimes the scattered radiation plays such a dominant role that almost entire radiation shielding design is dictated by scattered radiation and direct radiation takes a back seat. Such a situation arises when the arrangement among the room, the source and the observer assumes shape of a labyrinthine structure. Presence of spent fuel bundles in fuel transfer room and the requirement of access to the platform on the top of fuel transfer magazine give rise to this phenomenon. (author). 4 refs., 1 ill., 2 figs