17/05/2015radiation safety - level 51 Radiation safety level 5 Frits Pleiter

17/05/2015radiation safety - level 52 Contents  atomic and nuclear physics(1)  interaction with matter(3) o sources and x-ray equipment (2) o shielding (3) o detection (4) o radiobiology (6) objective risk of radiation (6) subjective risk acceptation (6)  quantities and units(5)  regulations(7) o practical health physics (8 - 10) o waste (11)

17/05/2015radiation safety - level 53 Dosimetry source constant and inverse square law dose is proportional to the activity and to the irradiation time dose decreases with the square of the distance from the source D =   A  t / r 2 the constant  in this equation is called "source constant" it makes it possible to convert activity to external dose   E  / 7  Gy m 2 MBq -1 h -1 (E  in MeV)

17/05/2015radiation safety - level 54 Dosimetry source constant and inverse square law nuclide  (  Gy m 2 MBq -1 h -1 )T ½ 22 Na j 60 Co j 99m Tc h 125 I d 131 I d 137 Cs j 192 Ir d 201 Tl h 241 Am j

17/05/2015radiation safety - level 55 Dosimetry rules of thumb at 1 m from a  -source of 1 MBq  dose rate  10 µGy/h at 1 m from a  -source of 1 MBq  dose rate  E  / 7 µGy/h at 1 m from an x-ray tube  dose rate  10 mGy/min a  -contamination of 1 kBq per cm 2  skin dose rate rate  2 mGy/h

17/05/2015radiation safety - level 56 Dosimetry effective dose coefficient E(50) = e(50)  A the "effective dose coefficient" e(50) depends on radiotoxicity of the nuclide chemical composition of the radioactive substance contamination route (ingestion, inhalation, injection, wound, skin) it makes it possible to convert activity to internal dose especially tritiated water can penetrate skin and even gloves

17/05/2015radiation safety - level 57 Dosimetry effective dose coefficient nuclidee(50) inh (Sv/Bq)T ½ 3 H (H 2 O)1.8  j 14 C (CO 2 )6.5  j 22 Na2.0  j 32 P2.9  d 35 S1.2  d 45 Ca2.3  d 99m Tc2.9  h 125 I7.3  d 131 I1.1  d 226 Ra1.2  j natural Th6.2   j natural U5.7   10 9 j

17/05/2015radiation safety - level 58 Safety measures nominal working hours 8 hours per day 5 days per week  40 hours per week 50 weeks per year  2000 hours per year

17/05/2015radiation safety - level 59 Safety measures organisational measures maintain a correct administration system for sources and devices mark each source and device with a warning sign when in use store unused sources in a vault remove the key of an x-ray device when not in use

17/05/2015radiation safety - level 510 Safety measures sealed sources protection against external radiation use as little activity as possible (ALARA) reduce exposure time increase working distance (inverse square law) apply shielding (lead, lucite) measure the dose rate periodic leak test take regular smear tests (limit is 185 Bq) direct activity measurent with a contamination monitor is pointless

17/05/2015radiation safety - level 511 Safety measures x-ray devices protection against external radiation do not irradiate more often than necessary (ALARA) reduce exposure time increase working distance (inverse square law) apply shielding (lead apron) use a dose rate meter that is sensitive at low energy check the equipment periodically check filter and leakage radiation leave maintenance to the supplier of the equipment watch out for scattered radiation reduce exposed area (diaphragm, light visor)

17/05/2015radiation safety - level 512 Safety measures open radioactive substances protection against external radiation see sealed sources protection against internal contamination use as little activity as possible (ALARA) prevent spreading (containment, splash tray) remove air born activity (ventilation, fume hood) prevent intake of activity (work discipline, protocol) check for contamination by periodic laboratory surveys immediately warn responsible radiation expert evacuate laboratory and check workers when leaving determine extent of contamination (dose rate meter is useless) decontaminated surface (limit is 4 Bq/cm 2 )

17/05/2015radiation safety - level 513 Safety measures open radioactive substances principle of "containment" glas tube, beaker glas, splash tray, fume hood, radionuclide laboratory

17/05/2015radiation safety - level 514 Safety measures open radioactive substances avoid oral uptake don't eat at the work place don't drink at the work place don't smoke at the work place don't apply make-up at the work place

17/05/2015radiation safety - level 515 Safety measures open radioactive substances avoid uptake via lungs risk of aerosol formation while shaking and vortexing centrifuging opening bottles sanding risk of tritium vapour tritium in condens is released when defrosting a refrigerator risk of iodine vapour avoid formation of iodine vapour (keep pH > 4) iodine in condens is released when warming up a "cold room" keep lid on waste bin

17/05/2015radiation safety - level 516 Safety measures open radioactive substances avoid direct uptake in blood system don't work with open wounds avoid uptake of 3 H via skin (use double gloves)

17/05/2015radiation safety - level 517 Radionuclide laboratory regulations work with open radioactive substances is only permitted in a radionuclide laboratory there are B-, C- en D-laboratories building requirements are most stringent for a B-laboratory building requirements are least stringent for a D-laboratory maximum allowed activity is largest in a B-laboratory maximum allowed activity is smallest in a D-laboratory

17/05/2015radiation safety - level 518 Radionuclide laboratory guideline radionuclide laboratories there are two different opinions 1.the risk is determined by regular uptake of small quantities of radioactive substances (National Health Council, 1985) 2.the risk is determined by incidents (HARAS-report, 1997) the Guideline Radionuclide Laboratories is based on opinion 1

17/05/2015radiation safety - level 519 Radionuclide laboratory guideline radionuclide laboratories A max = 0.02  10 p+q+r / e(50) inh A max = maximum allowed activity in Bq p = dispersion parameter q = laboratory parameter r = local ventilation parameter (note that r  q) e(50) = dose conversion coefficient in Sv/Bq

17/05/2015radiation safety - level 520 Radionuclide laboratory guideline radionuclide laboratories p application -4highly splashing substance powder in open system -3labelling using volatile nuclide boiling liquid in closed system -2labelling using nonvolatile nuclide simple chemical work (RIA) short, very simple work with liquid storage of waste in working area

17/05/2015radiation safety - level 521 Radionuclide laboratory guideline radionuclide laboratories q work place 0outside radionuclide laboratory 1D-laboratory ancillary space of radionuclide laboratory 2C-laboratory 3B-laboratory

17/05/2015radiation safety - level 522 Radionuclide laboratory guideline radionuclide laboratories r local ventilation 0no ventilation 1fume hood (not NEN-NE 14175) 2fume hood (NEN-NE 14175) 3closed system (glove box)

17/05/2015radiation safety - level 523 Regulations radioactive waste radioactive waste is waste in which both the activity concentration exceeds the exemption level and the activity exceeds the exemption level radioactive waste is also waste that looks like radioactive waste  no radioactivity stickers in normal industrial waste disposal is expensive (in 2005 about € 1300 per 100 liter) only COVRA is allowed to collect radioactive waste

17/05/2015radiation safety - level 524 Regulations radioactive waste avoid waste production use as little activity as possible use short-lived nuclides if not active, dispose as normal industrial waste separate waste dry and liquid waste organic and inorganic waste long-lived and short-lived waste counting vials cadavers sealed sources hand waste over to COVRA in standard drums

17/05/2015radiation safety - level 525 Regulations radioactive waste radioactive substances may be handed over to another person provided either the activitity concentration is less than the exemption level or the activity is less than the exemption level

17/05/2015radiation safety - level 526 Regulations radioactive waste nuclideconcentration (Bq/g) activity (Bq) 3 H C P S m Tc I I Ra U1010 4

17/05/2015radiation safety - level 527 Regulations disposal there are strict rules for discharge to air discharge to sewer dose rate at border of the location knowledge of these rules is not required for the course level 5