5 th ISOE European Workshop on Occupational Exposure

5 th ISOE European Workshop on Occupational Exposure Management at Nuclear Facilities The New ICRP Recommendations Essen, 15 March 2006 Lars-Erik Holm INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

ICRP’s 2006 Recommendations Volume 36, Issue 4, 2006 • • • • Aims and scope Biological aspects Dosimetric quantities The system of radiological protection Medical exposures Recommendations of the International Commission on Natural exposures Radiological Protection, 2006 Potential exposures Emergency situations The scope of regulating radiological protection Protection of the environment Implementation of the Commission’s recommendations The radiological protection paradigm Glossary References INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

More Continuity than Change in the 2006 Recommendations • Most recommendations will remain - because they work and are clear … and some things are to • Be explained - because more guidance is needed • Be added - because there has been a void • Differ - because understanding has evolved INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Major Features I • Maintaining the 3 principles of radiological protection, and clarifying how they apply to sources and the individual; • Updating the radiation and tissue weighting factors; • Maintaining the dose limits that represent the most that will be accepted in planned situations by regulatory authorities; • Using the concept of constraints in the source-related protection to all situations. The constraints quantify the most fundamental levels of protection for workers and the public from single sources; INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Major Features II • Replacing ’practices’ and ’interventions’ with 3 types of exposure situations which address all conceivable circumstances: - planned situations; - emergency situations; and - existing exposure situations. • Including a policy for protection of the environment. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

The Aim of the Recommendations • To provide an appropriate standard of protection for people and the environment, without unduly limiting the beneficial actions giving rise to radiation exposure. * * • The new recommendations consolidate and add to previous recommendations issued in various ICRP publications. • The existing numerical recommendations in the policy guidance given since 1991 remain valid unless otherwise stated. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Building Blocks C 1: Low-Dose Extrapolation of Radiation-Related Cancer Risk C 1: Biological and Epidemiological Information on Health Risks Attributable to Ionising Radiation C 2: Dosimetric Quantities Used in Radiological Protection C 3: Radiological Protection in Medicine C 4: Optimisation of Protection C 4: Assessing Dose to the Representative Individual MC: The Scope of Radiological Protection Regulations MC: The Radiological Protection Paradigm INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Radiation Weighting Factors, w. R Type and energy range Publication 60 2006 Photons, all energies 1 1 Electrons and muons, all energies 1 1 Protons 5 2 Alpha particles 20 20 Stepwise function Continuous function Neutrons INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

New Reference Phantoms MIRD Phantom Voxel Male and Female Phantoms INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Main Conclusions on Biology • Dose-response for cancer and hereditary effects: A simple proportionate relationship at low doses between dose and risk. • DDREF: Retain a value of 2. • Nominal probability coefficients for cancer: 5. 5 10 -2 Sv-1 for whole population and 4. 1 10 -2 Sv-1 for adult workers. • Nominal probability coefficients for heritable diseases: Up to 2 nd generation: 0. 2 10 -2 Sv-1 for whole population and 0. 1 10 -2 Sv-1 for adult workers. • Risks of non-cancer diseases: Great uncertainty on dose response < 1 Sv; no judgement on low dose risk possible. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Tissue Weighting Factors, w. T Tissue w. T ∑ w. T Bone-marrow, breast, colon, lung, stomach, remainder tissues 1 0. 12 0. 72 Gonads 0. 08 Bladder, oesophagus, liver, thyroid 0. 04 0. 16 Bone surface, brain, salivary glands, skin 0. 01 0. 04 1 Nominal w divided equally between 14 tissues. T INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

NOMINAL RISK COEFFICIENTS FOR STOCHASTIC EFFECTS (% Sv-1) Exposed population Cancer Heritable effects Total ICRP 60 2006 Whole 6. 0 5. 5 1. 3 0. 2 7. 3 5. 7 Adult 4. 8 4. 1 0. 8 0. 1 5. 6 4. 2 INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Principles of Protection FOR SINGLE SOURCES JUSTIFICATION Any decision that alters the existing radiation exposure situation, e. g. , by introducing a new radiation source or by reducing existing exposure, should do more good than harm. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Principles of Protection FOR SINGLE SOURCES OPTIMISATION Optimisation of protection should ensure the selection of the best protection option under the prevailing circumstances, and maximising the margin of good over harm. This procedure should be constrained by restrictions on the doses or risks to individuals (dose or risk constraints). Optimisation involves keeping exposures as low as reasonably achievable, taking into account economic and social factors, as well as any inequity in the distribution of doses and benefits amongst those exposed. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Principles of Protection FOR INDIVIDUALS DOSE LIMITS In planned situations, the total dose to any individual from all the regulated sources should not exceed the appropriate dose limits specified by the Commission. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Restrictions and Reference Levels in Publication 60 Restrictions • Dose limit • Dose constraint Reference levels • Recording level • Investigation level • Intervention level • Action level • Diagnostic reference level INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Dose Constraint 2006 (I) • It is the most fundamental level of protection for the most exposed individuals from a single source within a class of exposure. • It applies to all situations; • It is used prospectively as the starting point of the optimisation process; • It is not a form of retrospective dose limitation. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Dose Constraint 2006 (II) • In planned situations, it is less than limits; • In emergency or existing exposure situations, it represents the level of dose/risk where action is almost always warranted; • The chosen value will depend upon the circumstances of the exposure; • It will be established at the national or local level by regulators or operators. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Dose Constraint 2006 (III) • The numerical criteria recommended by the Commission in Publication 60 and thereafter can all be regarded as constraints. • The values fall into three defined bands: 0. 01 -1 m. Sv, 1 -20 m. Sv and 20 -100 m. Sv. • These bands will enable selection of an appropriate value for a constraint for a specific situation that has not been addressed explicitly by the Commission. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

ICRP’s Band of Constraints from Single Dominant Sources BANDS OF PROJECTED DOSE REQUIREMENTS 20 - 100 m. Sv Benefit on a case-by-case basis. Information, training and individual monitoring of workers, assessment of public doses. 1 - 20 m. Sv 0. 01 - 1 m. Sv Individual direct or indirect benefit. Information, training and either individual monitoring or assessment. Societal benefit (not individual). No information, training or individual monitoring. Assessment of doses for compliance. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Additional Radiation Dose and Risk THE CASE FOR PLANNED SITUATIONS UNACCEPTABLE RISK DOSE LIMIT TOLERABLE RISK DOSE CONSTRAINT ACCEPTABLE RISK OPTIMISATION TRIVIAL RISK INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Constraints for Radon ICRP’s policy is based upon setting a level of effective dose from radon where action would be warranted: 10 m. Sv per year ICRP’s constraints are set where action is almost always warranted: Home 500 Bq m-3 Work 1250 Bq m-3 National regulators apply the optimisation of protection to arrive at the level at which to act. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Diagnostic Reference Level • The diagnostic reference level has as its objective the optimization of protection. • The dose to the patient from a specified diagnostic procedure should not normally exceed the diagnostic reference level for that procedure. • It does not relate to individual patients. • Conceptually, the diagnostic reference level serves as a kind of constraint for a specified examination/ procedure. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Exclusion from Legislation ICRP TG recommends to exclude radiation exposure situations that cannot reasonably be considered amenable as to control: • Cosmic radiation at ground level; • Radionuclides of natural origin in the human body; • Radon in ambient air: < 100 (or 40) Bq/m 3; and • Any other exposure situation that the legislator judge to be unamenable to control. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Exclusion or Exemption ICRP TG recommends levels for exclusion or generic exemption for: • Artificial radionuclides: < 1 Bq/kg for alpha emitters < 10 Bq/kg for beta/gamma emitters; • Natural radionuclides in materials, except building materials: < 1000 Bq/kg for the head of the 238 U and 232 Th; < 10 000 Bq/kg for 40 K • Building materials: may warrant a more restrictive consideration of the sum of 238 U, 232 Th and 40 K, and the radiological implications should be carefully analyzed. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Exemption An important component of regulatory functions. The principles for exempting a practice or a source within a practice: • individual risks must be sufficiently low as not to warrant regulatory concern (0. 01 m. Sv a-1); • radiological protection, including the efforts of regulatory control, must be optimised; and • the practice must be justified and its sources should be inherently safe. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Recommended Exemption • Devices emitting adventitious radiation of max. 5 ke. V and max. 1 Sv h-1 at 0. 1 m from any surface of the device; • Radionuclides in activity concentrations smaller than those specified by FAO and WHO for foodstuff and drinking water, and by the IAEA for non-edible commodities, for radiation sources and for materials in transport. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————

Time Schedule • March 2006: Main Commission to discuss new draft recommendations • may 2006: New international consultation of draft recommendations • November 2006: Main Commission to discuss revised draft recommendations • December 2006: Earliest possible date of ICRP adoption INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION —————————————————