ICRP’s 2007 Recommendations on Radiological Protection CIEMAT, Madrid, Spain - 13 March 2007

1. ICRP’s 2007 Recommendations on Radiological Protection CIEMAT, Madrid, Spain - 13 March 2007 Lars-Erik Holm Chairman of ICRP

2. The System of Radiation Protection • Types of exposure situations • Types of exposure • Identification of the exposed individuals • Source-related and individual-related assessments • The three fundamental principles of protection • Levels of individual dose that require protective action • Safety of radiation sources • Implementation

3. What is “new”? • Moving from the previous process-based approach of practices and interventions to an approach based on the radiation exposure situation. • Emphasising the similarity of the protective actions taken regardless of exposure situation. • Increasing the attention to the process of optimisation in all radiation exposure situations.

4. So what? “Practices”: Little change, if any. “Interventions”: By emphasising more the process of optimisation, the level of protection will be improved, compared to the recommendations in Publication 60

5. Linear-no-threshold Model This model is the basis for: • Averaging and summing of doses • The concept of effective dose • The concept of collective dose • Individual dosimetry • Keeping dose records

6. Nominal Risk Coefficients for Stochastic Effects(% Sv-1)

7. Summary of Radiation Risks • The nominal risk estimates are slightly smaller than in 1990, but in the same order of magnitude. • The overall risk of 0.05 Sv-1 continues to be appropriate for purposes of radiological protection.

8. The Use of Effective Dose, E • Mainly for planning in prospective situations • For compliance of dose restrictions to control stochastic effects • Not for detailed retrospective dose and risk assessments after exposure of individuals • Not for epidemiological studies

9. The Use of Collective Dose, S • For optimisation and for comparing radiological technologies and protection options • Not a tool for epidemiologic risk assessment • Not for predicting number of cancer deaths due to trivial exposures to large populations

10. The Principles of Protection Source related: • Justification • Optimisation Individual related: • Application of dose limits

11. The Principle of Justification • Any decision that alters the radiation exposure situation should do more good than harm. This means that by introducing a new radiation source or by reducing existing exposure, one should achieve an individual or societal benefit that is higher than the detriment it causes.

12. The Principle of Optimisation of Protection • The likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors. This means that the level of protectionshould be the best under the prevailing circumstances, maximising the margin of benefit over harm. In order to avoid severely inequitable outcomes of this optimisation procedure, there should be restrictions on the doses or risks to individuals from a particular source (constraints and reference levels).

13. The Principle of Application of Dose Limits • The total dose to any individual from all planned exposure situations other than medical exposure of patients should not exceed the appropriate limits specified by the Commission.

14. Practices and Interventions In both cases, • There is a maximum level of dose above which the regulator will demand action • Optimisation of protection will reduce the level of dose at which action is taken • No action to further reduce doses below the optimised level of protection

15. Types of Exposure Situations • Planned exposure: situations involving the deliberate introduction and operation of sources. They may give rise both to exposures that are/are not anticipated to occur (normal exposure/potential exposure). • Emergency exposure: unexpected situations that occur during the operation of a planned situation or from a malicious act, and require urgent action to avoid/reduce undesirable consequences. • Existing exposure: situations that already exist when a decision on control has to be taken.

16. Types of Exposure Situations • What the Commission has called “practices” could be the origin of planned, emergency and existing exposure situations. • The principles of protection for planned situations also apply to planned work in connection with existing and emergency exposure situations.

17. Dose Constraints and Reference Levels • The concepts of dose constraint and reference level apply to any exposure situation and are used in conjunction with the optimisation of protection to restrict individual doses. • A level of individual dose always needs to be defined, above which one plans not to go (or, not to stay), and below which one strives to reduce all actual doses as low as reasonably achievable. • All exposures, above or below this level of individual dose, are subject to optimisation of protection.

18. Dose Constraints and Reference Levels Planned exposure: Dose constraint Diagnostic reference level Emergency exposure: Reference level Existing exposure: Reference level

19. Dose Constraints and Reference Levels The difference in terminology between planned and other exposure situations has been retained to express the fact that • In planned situations, the restriction on individual doses can be applied at the planning stage and the doses can be forecast such as to ensure that the constraint will not be exceeded. • With the other situations a wider range of exposures may exist, and therefore the optimisation process may apply to initial levels of individual doses above the reference level.

20. Optimisation and Source-related Restrictions Planned exposure situations Existing and emergencies exposure situations Dose limit Reference level Dose constraint Optimisation Optimisation

21. Constraints – Reference Levels • Apply to all situations - The value will depend on the circumstances • An integral part of prospectively optimising protection at the source • If a relevant constraint or reference level was not complied with - Further protection options must be considered - Not necessarily a failure of protection

22. The Types of Dose Restrictions in the System of Protection a Long-term recovery operations should be treated as part of planned occupational exposure

23. The Use of Dose ConstraintsPLANNED EXPOSURE SITUATIONS • For occupational exposure: typically set by operators or, for small companies, by regulatory authorities • For public exposure: typically set by regulatory authorities • For patients’ comforters and carers: typically set by the medical profession

24. The Use of Reference LevelsEXISTING AND EMERGENCY EXPOSURE SITUATIONS • Prospectively as a level of ambition • Retrospectively for assessing the effectiveness of protection • Not a mandatory level that must be achieved

25. Dose Constraints and Reference Levels

26. Existing Exposure Situations • Large distributions of individual exposures • Often affecting places of living • Sometime difficult to control (most often controllable through pathways) • Time is a key parameter (step by step approach) • In many cases, the level of exposure is driven by individual behaviour

27. Dose Distribution with Time EXISTING EXPOSURE SITUATIONS Step 1 Step 2 Step 3 Number of individuals Reference level Individual dose level

28. Emergency Exposure Situations Publ. 60 and 63: No action below Action Levels Recommend values for the averted dose for SINGLE countermeasures where intervention is almost always justified: ICRP 2007: Optimisation below Reference Levels Recommends an upper value of the projected dose (= reference level) received via ALL pathways below which optimisation is applied.

29. Reference Levels for Emergency Preparedness Dose Select Option B Option A Option C Reference level = Average Dose

30. Reference Levels for Emergency Response Dose Actual dose distribution ! Reference level Optimize = Average Dose

31. Conclusion – Reference Levels • Basically, the same approach as for constraints in planned situations: • Characterizing the exposure situation • Setting a level of ambition (reference level) • Optimising protection taking into account the prevailing circumstances • Iterative process for implementing optimisation • Improvement of the level of protection for existing and emergency situations

32. Revision of ICRP’s Recommendations – Not a Hasty Procedure • The work began in 1998 • Input from many international meetings • Comments from two international consultation rounds • Comments on the Progress Report published in 2007 • Adoption of the Recommendations this year, i.e., after a 10-year period of work.