The aim of radiological protection must be to prevent unnecessary
exposures and to keep the exposures below the internationally accepted ICRP
dose limits. It is not possible to control the exposures lower than the
background radiation dose levels and hence zero or even close to zero exposures
to occupational radiation workers is neither possible or justifiable. Due to
its acceptance of LNT theory for radiological protection, and use of As Low As
Reasonably Achievable (ALARA) approach, ICRP is over-cautious in its
recommendation of ALARA. However, over the years, ALARA has become a regulatory
requirement!
The recommendation of ALARA is based on the optimization of the
protection taking into account the socio-economic considerations and should
remain as the best possible level of protection under the prevailing
circumstances. This statement makes ALARA a very uncertain
requirement which is difficult to quantify.
Risk must be averted unless there
is gross disproportion between the cost in terms of averting the risk and the
benefits of averting such a risk. A proportionate approach - ALARP is the term
used in UK legislation, as a requirement that risks to health must be reduced
to a level that is As Low As Reasonably Practicable (ALARP). It is the
tolerable risk level, which is in- between normally unacceptable and broadly
acceptable levels.
The “As Low As Technically Achievable (ALATA)” approach is to take the
protection level to a level that may be achieved using “World’s Best Practice”
utilizing grossly disproportional amount of resources (manpower, money and
technology) to reduce exposures which has trivial amount of risk.
Comment: One sensible and
practical approach is to get away from the ALARA, ALARP and ALATA, and ensure
that the occupational exposures are strictly maintained below the
scientifically derived ICRP dose limits. This will be uniformly in line with
the chemical industry where the exposures to chemicals, including carcinogens
are regulated by the Threshold Limit Values (TLVs) / Permissible Exposure
Limits (PELs). The TLV/PEL of a chemical substance is an exposure level to
which a work worker can be exposed for a working lifetime without adverse
health effects. The regulation will be through use of SOPs, regular monitoring,
periodic review and ensuring compliance.
