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Radiation safety level 5. Frits Pleiter. Contents. atomic and nuclear physics (1) interaction with matter (3) sources and x-ray equipment (2) shielding (3) detection (4) radiobiology (6)
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Radiation safetylevel 5 Frits Pleiter radiation safety - level 5
Contents • atomic and nuclear physics (1) • interaction with matter (3) • sources and x-ray equipment (2) • shielding (3) • detection (4) • radiobiology (6) • objective risk of radiation (6) • subjective risk acceptation (6) • quantities and units (5) • regulations (7) • practical health physics (8 - 10) • waste (11) radiation safety - level 5
Riskprinciples the risk of ionizing radiation is 0.05 per sievert occupational risk > 1 in 1000 is unacceptable occupational risk < 1 in 10 000 is acceptable risks between these values are manageable radiation safety - level 5
Riskcomparison of risks type of work mortality / year National Health Council 17-07-1984 light industry 20 per million industry 40 per million construction work 100 per million heavy transport 170 per million radiological work (20 mSv/y) 1000 per million high risk natural radiation (2 mSv/y) 100 per million cigarettes (20 per day) 4000 per million the risk of 1 cigaret corresponds with the risk of 10 µSv radiation safety - level 5
Regulationsfrom recommendation to legislation ICRP recommendation International Commission on Radiological Protection independent commission recommendation not legally binding, but almost always accepted European directive directive must be implemented in national legislation Dutch legislation Nuclear Energy Act + decrees + regulations Working Conditions Act Environmental Protection Act General Administrative Law Act radiation safety - level 5
Regulationslegislation and supervision supervision by the government Inspectorate of Social Affairs and Employment (ISZW) Environment and Transport Inspectorate (ILT) Health Care Inspectorate (IGZ) radiation safety - level 5
Regulationssystem of dose limitation justification benefits must outweigh the health detriment it may cause optimization ALARA = as low as reasonably achievable limitation limits are not a guide for the maximum permissible dose limits may never be exceeded radiation safety - level 5
Regulationsannual limits stochastic effects, exposed workers category A-workers 20 mSv category B-workers 6 mSv stochastic effects, non-exposed workers normal workers 1 mSv members of the public 1 mSv requirement for permit holder 0.1 mSv outside location these limits are meant to minimalize the risk of stochastic effects radiation safety - level 5
Regulationsannual limits harmful tissue reactions, exposed workers lens of the eye 150 mSv limbs 500 mSv skin 500 mSv harmful tissue reactions, non-exposed workers lens of the eye 15 mSv limbs 50 mSv skin 50 mSv these limits are meant to prevent harmful tissue reactions radiation safety - level 5
Regulationspermit and radioactivity a Nuclear Energy Act permit is required for possession and use of radioactivity if both the activity concentration and the activity exceed the exemption levels nuclide concentration (Bq/g) activity (Bq) 3H 106 109 14C 104 107 32P 103 106 35S 105 108 99mTc 102 107 125I 103 106 131I 102 106 226Ra 1 104 238U 10 104 radiation safety - level 5
Regulationspermit and devices an x-ray device must either be reported or be authorized a permit is required for • devices with a maximum high voltage > 100 kV • all devices used for industrial radiography processing of products medical therapy for humans and animals education (almost all) other devices must be reported radiation safety - level 5
Regulationsrisk analysis ionizing radiation may only be applied under supervision of a radiation safety expert level 2, 3, 4 or 5 the radiation expert must make (or commission) a risk inventory and evaluation before starting the application the risk inventory and evaluation must be approved by a registered coordinating radiation safety expert radiation safety - level 5
Regulationsclassification of exposed workers a worker must be classified as an exposed worker if he can receive more than 1 mSv per year as a result of his work exposed workers must be given appropriate instructions exposed workers must receive a personal dose-monitoring device which they must (visibly) wear during radiological work radiation safety - level 5
Regulationsclassification of exposed workers exposed workers must be classified in categories category possible annual dose medical check up A 6 - 20 mSv yes B 1 - 6 mSv no radiation safety - level 5
Regulationsclassification of work areas work areas must be classified in zones zone possible anual dose warning 'no entry' sign sign controlled 6 - 20 mSv required yes supervised 1 - 6 mSv required no radiation safety - level 5
Regulationstransport of radioactive substances regulations are very complicated sender is responsible leave transport to a specialized company sending radioactivity by regular mail is prohibited radiation safety - level 5