[en] FBR 1 & 2 is a pool type homogeneous fast reactor of thermal power 1500 MWth and electrical power 600 MWe. In a pool type fast reactor, intermediate heat exchanger is immersed in primary sodium pool. Secondary sodium flowing through tube side of IHX gets activated which then goes to steam generator building and results in radiation doses at steam generator building. Due to large neutron flux and harder neutron spectrum, limited choice of materials in high temperature and restricted space available for shielding makes it a difficult task to design in-vessel shield. Especially in the case of FBR 1 & 2, leakage in the top axial direction has increased due to removal of top axial blanket to minimize sodium void. In this paper, calculation and design of top shield has been carried out to achieve minimum primary sodium gamma dose rate in top shield working platform