The key output of the ICRP and its historic predecessor has been the issuing of recommendations in the form of reports and publications. The contents are made available for adoption by national regulatory bodies to the extent that they wish. Early recommendations were general guides on exposure and thereby dose limits, and it was not until the
nuclear era that a greater degree of sophistication was required.
1951 recommendations In the "1951 Recommendations" the commission recommended a maximum permissible dose of 0.5 roentgen (0.0044
grays) in any 1 week in the case of whole-body exposure to X and gamma radiation at the surface, and 1.5 roentgen (0.013 grays) in any 1 week in the case of exposure of hands and forearms. The significance of stochastic effects began to influence the commission's policy and a new set of recommendations was published as Publication 9 in 1966. However, during development its editors became concerned about the many different opinions on the risk of stochastic effects. The Commission therefore asked a working group to consider these, and their report, Publication 8 (1966), for the first time for the ICRP summarised the current knowledge about radiation risks, both somatic and genetic. Publication 9 then followed, and substantially changed radiation protection emphasis by moving from deterministic to stochastic effects.
Reference man In October 1974, the official definition of
Reference man was adopted by the ICRP: “Reference man is defined as being between 20-30 years of age, weighing 70 kg, is 170 cm in height, and lives in a climate with an average temperature of from 10 to 20 degrees C. He is a
Caucasian and is a Western European or North American in habitat and custom.” The reference man was created for the estimation of radiation doses without adverse health effects.
Principles of protection In 1977 Publication 26 set out the new system of dose limitation and introduced the three principles of protection: With the global expansion of nuclear reactors and reprocessing it was feared global doses could again reach the levels seen from atmospheric testing of nuclear weapons. So, by 1977, the establishment of dose limits was secondary to the establishment of cost–benefit analysis and use of collective dose. By 1989, the commission had itself revised upwards its estimates of the risks of
carcinogenesis from exposure to ionising radiation. The following year, it adopted its 1990 Recommendations for a 'system of radiological protection'. The principles of protection recommended by the Commission were still based on the general principles given in Publication 26. However, there were important additions which weakened the link to cost benefit analysis and collective dose, and strengthened the protection of the individual, which reflected changes in societal values: • No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to society to offset the radiation detriment it causes. (The justification of a practice) • In relation to any particular source within a practice, the magnitude of individual doses, the number of people exposed, and the likelihood of incurring exposures where these are not certain to be received should all be kept as low as reasonably achievable, economic and social factors being taken into account. This procedure should be constrained by restrictions on the doses to individuals (dose constraints), or on the risks to individuals in the case of potential exposures (risk constraints) so as to limit the inequity likely to result from the inherent economic and social judgements. (The optimisation of protection) • The exposure of individuals resulting from the combination of all the relevant practices should be subject to dose limits, or to some control of risk in the case of potential exposures. These are aimed at ensuring that no individual is exposed to radiation risks that are judged to be unacceptable from these practices in any normal circumstances.
21st century In the 21st century, the latest overall recommendations on an international system of radiological protection appeared. ICRP Publication 103 (2007), after two phases of international public consultation, has resulted in more continuity than change. Some recommendations remain because they work and are clear, others have been updated because understanding has evolved, some items have been added because there has been a void, and some concepts are better explained because more guidance is needed. ==Radiation quantities==