Estimation of stack parameter for prototype fast breeder reactor - radiological considerations

A radiological assessment of the air-borne effluent discharges under normal operating conditions of Prototype Fast Breeder Reactor has been carried out based on long-term meteorological data of Kalpakkam. Simulation of building wake effects and the coastal terrain effects were carried out and their impact on the dose at the site boundary and inside plant premises taken into consideration. The apportioned dose of 90 mSv/a for PFBR at the site boundary, the design criterion dose rate of 1 mSv/h for freely accessible areas (zone 1), and a derived annual dose limit of 2 mSv for non-monitored plant staff are taken as the exposure limits to be complied with. Potential dose values at the site boundary and for various other distances were computed as a function of release height. Although the dose at the site boundary is within the limit for lower release elevations < 100m, dose rate within the plant premises is found to exceed the design criterion dose rate for zone 1 areas, and the annual exposures exceed the derived annual dose limit for non-monitored workers. From these studies, a release height of 100m is recommended for PFBR. (author)