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Cadarache, building 519, 14 February 2007 Henri Maubert

Cadarache, building 519, 14 February 2007 Henri Maubert. Radiological Protection Training. Dose limit. exposure. Threshold zone. Radiological Protection Principles 1. Prompt effects of radiation exposure the severity of the effect depends on the dose.

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Cadarache, building 519, 14 February 2007 Henri Maubert

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  1. Cadarache, building 519, 14 February 2007Henri Maubert Radiological Protection Training Radiological Protection, Cadarache, 14 February 2007

  2. Dose limit exposure Threshold zone Radiological Protection Principles 1 Prompt effects of radiation exposure the severity of the effect depends on the dose Effect of radiation exposure : threshold model Probability of occurrence of an effect Ex: erythema 1 0 footer text, location, date

  3. Radiological Protection Principles 2 • Delayed effects of radiation exposure • Example : cancer and leukemia • Severity not dependent on the dose • Probability of occurrence increasing with the dose • Uncertainty about the existence of a threshold • Assumption that there is no threshold For more information : http://www.ccnr.org/ceac_B.html footer text, location, date

  4. Radiological Protection Principles 3 • No threshold linear hypothesis One time dose Probability of occurrence of an effect Homothetical factor Chronic dose Dose (Sv) 0,2 0,5 footer text, location, date

  5. Radiological Protection Principles 4 • Probability of occurrence of a cancer : P = 5.10-5 mSv-1 100 000 people with 1 mSv each will lead to 5 more cancers Normal occurrence 25 % 2500 cancers • No threshold means that the risk is never equal to zero • Look for an exposure As Low As Reasonnably Achievable footer text, location, date

  6. Radiological Protection Principles 5 • Justification • The benefits for the society justify the potentially harmful effect of exposure • Optimisation • Demonstrate that the exposure is as low as possible, taking into account sociological and economic factors • Limitation • Regulatory safety net footer text, location, date

  7. Legal framework of radiological protection • European directives • 96/29 protection of workers and general public against the danger of ionising radiations • 97/43 protection in relation to medical exposure • French decrees • 2002-460 about public protection • 2003-296 about workers protection • 2003-295 about protection in emergency situation • 2003-270 for medical exposure footer text, location, date

  8. Architecture of documents European Directives 96/29 and 97/43 public health code work code Decree 2003-270 medical Decree 2002-460 public Decree 2002-295 emergency Decree 2002-296 workers For wastes, pollution and fire : Ministerial order 31/12/1999 Ministerial order 26 October 05 Tests and measurements Ministerial order 15 may 06 Radiological zoning footer text, location, date

  9. Decree 2002-460 • Limitation of dose • 1 mSv/year individual dose in the population • Authorization regime for all the sources of ionising radiations, • Radioactive materials in processes, • Nuclear fuel, • Radioactive sources, including in devices • Particles accelerators footer text, location, date

  10. Decree 2003-296 (1) • The head of the establishment (HE) is responsible for Radiological Protection • Ensures the coordination of safety measures • Nominates a Person Competent at Radiological protection (PCR) • Follows the ALARA process • ALARA in design • ALARA for each work task and individual • Sets up a dose monitoring program footer text, location, date

  11. Decree 2003-296 (2) • Dose limitation for 1 year • 20 mSv effective dose • 500 mSv pour les extrémities (hands, feet) and skin >1 cm² • 150 mSv for the lens of the eye • For pregnant women, < 1mSv for the child to be born • 16 to 18 y < 6 mSv, 150 mSv extremities, 50 mSv lens • These limits may be exceeded by a factor of 2 with special authorization • Measurement of doses • Passive (film, TLD, RPL), reference validated by the work doctor • Active, real time electronic device with alarm footer text, location, date

  12. Decree 2003-296 (3) • Arrangements in work space • Around the source, after taking the advice of the PCR, the HE sets up • a supervised zone • if dose on 12 months : [1 à 6[ mSv(1) • a controlled zone • if dose on 12 months > 6 mSv(1) (1) 6 mSv, or 3/10 of other limits for extremities, crystalline… (1) In normal conditions of work Zoning is based on the potential dose to workers footer text, location, date

  13. Matière radioactive Decree 2003-296 (4) • Inside the zones : • The sources should be signaled, • Prohibited to eat, drink, smoke, no relaxation room in controlled zone • The HE sets up a program of radiological surveillance (Ministerial order 26 oct 05) • The HE defines protective measures • Collective and individual • Takes advice from the PCR, and CHSCT(1) • The work doctor gives an advice for special equipment like complete suits, respirators… (1) Committee for Hygiene and Safety, (Direction + labor unions) footer text, location, date

  14. Decree 2003-296 (5) • Classification of workers (by HE with work doctor advice) • If exposed to more than 6 mSv/12months in normal condition of work : • Category A • If exposed, and not category A, • Category B • Training • workers must benefit from a training at least every 3 y • must be informed about the risks (especially women) • must be given a note about risks, a job description including all risks must exist footer text, location, date

  15. Decree 2003-296 (6) • Nominative dosimetry record • Confidential (worker, work doctor, personal doctors, PCR, in case of death or disability eligible party (spouse)), HE only for active dosimetry) • Statistical dosimetry records • Same + HE • Organization of radiological protection • The HE nominates a PCR, and coordinates the safety, if there are contractors • For each contractor, the employer is responsible for the safety of his employees footer text, location, date

  16. Decree 2003-295 ; emergency situation (1) • Intervention personnel • Group 1 • Dose < 100 mSv, 300 mSv to save people • List established before hand, volunteer at the time of intervention with proper information • Group 2 • Dose < 10 mSv footer text, location, date

  17. Cosmétiques Ef. pers Fumer Manger Boire Order of 15 may 2006 ; radiological zoning (1) • Purpose of the order • Set up the zones according to actual risks • Source characteristics, results of radiological surveillance program • Define reference values to classify the rooms • Risk without individual protective equipment • External and internal exposure • Values readily measurable • Define rules of behaviour for safety footer text, location, date

  18. Radiation source Increasing risk Facility Zone I Zone E Zone C Zone D Zone G Zone B Zone A Zone H Zone F Order of 15 may 2006 ; radiological zoning (2) • Easy to understand for workers footer text, location, date

  19. regulated zones Specially regulated zones Order of 15 may 2006 ; radiological zoning (3) E potential effective dose in 1 hr, DR dose rate, H equivalent dose in 1 hr Whole body Zone without Supervised zone Controlled zone Controlled zone Controlled zone Restricted zone regulation green yellow orange red - Dose D< 80 µSv / month E> 100 mSv E< 2 mSv E< 7,5 µSv E< 25 µSv E< 100 mSv & & - Radiological surveillance for zones adjoining regulated areas, if there is a contamination risk DR < 2 mSv/h DR < 100 mSv/h Extremities H < 0,2 mSv H < 0,65 mSv H < 50 mSv H < 2500 mSv H > 2500 mSv T T T T T footer text, location, date

  20. Order of 15 may 2006 ; radiological zoning (4) • Examples of layout Add rules of entrance controlled Access supervised footer text, location, date

  21. Order of 15 may 2006 ; radiological zoning (5) • Air Contamination • No reference values in the decree • Equivalence between internal and external doses • Zoning should be determined without the use of individual protection devices • Proposed operational derived value • ODV such that dose rate = 25 µSv/h • Limit between green and yellow zone • Equals 2.5 DAC • Surface contamination : do a specific study ! footer text, location, date

  22. Air Concentrations ; Operational Derived Value • Air concentration for HTO • Calculation 1 ODV = 25E-6 [Sv/h]/ (1.2 [m3.h] * 2.7E-11 [Sv/Bq] ) Dose coefficient takes into account the skin transfer 2.7E-11 = 1.8E-11*1.5 (inhalation dose coeff 1.8E-11 Sv/Bq from directive 96/29) supervised controlled controlled controlled controlled Resctricted HTO, Bq.m-3 < 2.3E5 < 7,7E5 < 6.2E7 < 3.9E9 > 3.9E9 HTO ODV < 0.3< 1 < 80 < 4000 > 4000 footer text, location, date

  23. Order of 15 may 2006 ; radiological zoning (6) • Inside the regulated areas • the sources should be clearly signaled • only a part of a room may be regulated • signaling should be such that it is impossible to enter by mistake • in red zones, the limits are the walls • red zones should be locked • If the source is not continuous ( X-rays generator for example), zoning may evolve according to the use of the device, with safety arrangement Device not working Supervised Device working Controlled footer text, location, date

  24. Zone without Supervised zone Controlled zone Controlled zone Controlled zone Restricted zone regulation green yellow orange red Passive dosimeter Active and passive dosimeters No temporary contracts PCR authorization HE aut. Order of 15 may 2006 ; radiological zoning (7) • Access conditions footer text, location, date

  25. Entrance in regulated areas • If there a possibility of contamination • Avoid all personal belongings (other than necessary, glasses, notebook, for example) • Install a contamination survey at the exit of zones with a risk of contamination • For ITER that means a change room in the personnel access building, and according to the room or type of work, contamination surveys, airlocks, permanent or temporary footer text, location, date

  26. Order of 15 may 2006 ; radiological zoning (8) • General arrangements • Zoning should be defined in an internal document that may be inspected • Reference values should easy to check • A test plan should be established and run • There are sections about mobile apparatus and transport • Zoning is not the only tool for radiological protection • ALARA studies • Work task description • Dose rates at the work station lower than limits footer text, location, date

  27. ALARA in design (1) COST TOTAL Protections Detriment Optimum footer text, location, date

  28. ALARA in design (2) footer text, location, date

  29. ALARA in design (3) • Dose target at the start of the design is not mandatory • It useful to get one that will act a constraint, on a basis of social acceptance for example • ITER • Collective dose < 0.5 Sv/y • Individual dose < 10 mSv/y • Proportionate the volume of the ALARA study to the issue • Use of a threshold, for example 5% of total dose footer text, location, date

  30. DOSE TARGET ALARA PROCESS ANALYSIS OF PERFORMANCE FEEDBACK ANALYSIS ALARA in operation (1) • Two levels • Optimize the doses for a specific task, ex : • maintenance of a component • repetitive work in controlled area… • Optimize for each worker • A worker may have different tasks • Think about equity • Avoid transfers of risk footer text, location, date

  31. Waste zoning : Ministerial order of 31 Dec 1999 • Mandatory to make a study about wastes in order to reduce their volume and toxicity • Chemical, radiological, biological… • Sort the wastes according to their characteristics and disposal channels • Define zones for • radiological wastes • conventional wastes Radiological cleanliness Find NO Bq where there should not be any footer text, location, date

  32. Definition of contaminating zone • Presence in the room of • loose contamination • possible activation • potential confinement loss in normal operation • past contamination incident • Indicative clearance threshold • Detection limits of measurement equipment and level less than 1/10 of exemption levels in Directive 96/29 (1/100 for tritium) footer text, location, date

  33. Contaminanting Zone CZ Radiaoctive wastes Non Contaminanting Zone NCZ Coventional wastes Waste zoning • All wastes from a CZ go to radwastes • When going out of a CZ there is contamination check, (and an airlock on the path to exit) • Equipment must be checked for contamination with a clearance threshold footer text, location, date

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