of electricity generation (Ministry of Energy, Water and
Communications: ‘National Energy Balance, 2007,(http://www.
kettha.gov.my/), new-build adding to this in the near future. The
assessment of public radiation exposure fromfly- and bottom ash in
the vicinity of a power station fueled by coal is critically dependent
on the concentration of radioactive elements in the source medium
and ash, the modes of dispersal to the environment (the pathways)
as well as the nature of intake and the duration of exposure.
The amount of natural radionuclides discharged into the atmosphere viafly ash from a coal-fired power plant also depends on the
ash content of the coal (typically ranging from a few percent to
excess of 10%), the temperature of the combustion, partitioning
between bottom ash andfly ash, and the efficiency of the emission
control devices. Dispersal from the stack is typically modelled as a
Gaussian plume (Clarke, 1979), the ground level footprint being
heavily dictated by prevailing wind direction, characterised by the
wind-rose. Climatic variations, including prevailing wind directions,
humidity and rainfall around the present site of interest has been
studied in detail bySabuti and Mohamed (2012). As a result of such