The pathological effects of ionising radiation We will not develop the management of deterministic effects; let say that respecting dose limist is enough for avoiding effects

The exposure risk relationship for radiation induced stochastic effects (ICRP 103 –Whole life) The exposure - risk relationship is assumed to be linear without any threshold

The risk for stochastic effects A worker who, during his working life (35 years), would have received 20 mSv each year, would have cumulated 700 mSv, which corresponds to a risk of death from radiological induced cancer of 2.8 % (i.e a total risk of dying from a cancer of 30,4%, in western Europe ; of 32,5 %in the USA Canada ………) Taking into account the global risk of dying from a cancer and the extra risk from ionising radiation

3 PRINCIPLES To be responsible in managing Radiological Risk Justification of practices Expected benefits must over weight detriment Optimisation of protection To maintain, the risk of exposures, the number of exposed people and the individual doses as low as reasonably achievable (ALARA) economical and social factors being taken into account Making use of risks and doses constraints for : (a) reducing inequity (b) taking care of multiple sources. Limitation of individual exposures A l'exception des expositions médicales des patients.

ALARA : a predictive approach To try to maintain exposures as low as reasonably achievable (i.e) possible, implies adopting a predictive attitude in order to: Evaluate and predict individual and collective exposures Envisage actions likely to reduce exposures Select those actions considered reasonable To what questions does the evaluation should try to answer? Who? When? How?are the doses undertaken One can even then ask for: what are the criteria to tell « it is reasonable »

Radiation Protection standards set up at international level

Safety Principles in the International Basic Safety Standards IAEA 2011 interim edition 1.7 The safety principles are presented in the introduction / background /1.7 Principle 4: Justification of facilities and activities Facilities and activities that give rise to radiation risks must yield an overall benefit. Principle 5: Optimization of protection Protection must be optimized to provide the highest level of safety that can reasonably be achieved. . The term ‘facilities and activities’ is a general term encompassing any human activity that may cause people to be exposed to radiation risks arising from naturally occurring or artificial sources. The term ‘facilities’ includes: nuclear facilities; irradiation installations; some mining and raw material processing facilities such as uranium mines; radioactive waste management facilities; and any other places where radioactive material is produced, processed, used, handled, stored or disposed of — or where radiation generators are installed — on such a scale that consideration of protection and safety is required. The term ‘activities’ includes: the production, use, import and export of radiation sources for industrial, research and medical purposes; the transport of radioactive material; the decommissioning of facilities; radioactive waste management activities such as the discharge of effluents; and some aspects of the remediation of sites affected by residues from past activities.

More on optimisation (intro, background 1.15) The optimization of protection and safety, when applied to the exposure of workers …, is a process for ensuring that the magnitude and likelihood of exposures and the number of individuals exposed are as low as reasonably achievable, with economic, societal and environmental factors taken into account. …Optimization is a prospective and iterative process that requires both qualitative and quantitative judgements to be made. . To insist on the fact that BSS are totally coherent with the above mentioned philosophy and even wording of ICRP

The radiological protection optimisation approach

One can find a lot of information on the optimisation process and procedure in the IAEA Safety report n° 21, 2002 A less recent reference, but still useful is the European commission book: “ALARA from theory towards practice” EC Report EUR 13796 EN DG Science, Research and Development, 1991

The radiological protection optimisation Procedure The procedure is a simple checklist of 5 steps and sub-steps that structure the approach to any problem or decision in radiation protection. We will select three questions for each step, and come back during the whole week to these steps and questions One can also find a lot of information in the European commission book: “ALARA from theory towards practice” EC Report EUR 13796 EN DG Science, Research and Development, 1991

Implementing the Radiological protection Optimisation procedure… Will lead to optimised dose objectives in terms of collective dose, and eventually individual doses They have to be checked against reality, to point out gaps, To keep track of actual new data, for improving situation on the spot and often… … making feedback analysis to prepare the next operations, making use again of the radiological protection optimisation procedure Also later

… Within a global ALARA approach following the operational phases of any activity See ALARA programme later