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RADIATION SAFETY T RAINING. Presented by: Ali Shoushtarian Office of Risk Management, Environmental Health and Safety Service. Last revised Jan. 2007. Manager, Radiation and Biosafety Lois Sowden-Plunkett ext. 3058 lsowden@uottawa.ca Compliance Inspector
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RADIATIONSAFETYTRAINING Presented by:Ali Shoushtarian Office of Risk Management, Environmental Health and Safety Service Last revised Jan. 2007
Manager, Radiation and Biosafety Lois Sowden-Plunkett ext. 3058 lsowden@uottawa.ca Compliance Inspector Ali Shoushtarian ext. 3057 ashousht@uottawa.ca Radiation Safety Program Web Page http://www.uottawa.ca/services/ehss/ionizing.htm
REGULATORY AGENCIES • Canadian Nuclear Safety Commission (CNSC) • City of Ottawa • Ontario Fire Marshall • Transport Canada • Ontario Ministry of Labour
Radiation Safety Committee Reports to the Board of Governors Chaired by Vice-Rector, Research Ensures compliance with CNSC regulations and license conditions, issues permits Office of Risk Management – EHS Manages the radiation safety program Conducts inspections Monitors doses, inventory Conducts training STAKEHOLDERS
STAKEHOLDERS Radioisotope Permit Holder • Ensures all University regulations, policies and requirements are met • Adheres to all permit limits and conditions • Ensures a safe work environment Radioisotope User • Complies with all elements of radiation safety program • Works in a safe fashion (self, colleagues, environment) • attends all appropriate training
PERMITS 1. Open Sources 2. Sealed Sources 3. Sealed Sources incorporated in a device 4. Exempt Quantities with associated permit conditions
COURSE OUTLINE GENERAL INTRODUCTION physical and biological characteristics risk analysis units and calculations OPERATIONAL PROCEDURES ordering and receipt of material inventory and disposal monitoring SAFE PRACTICES personal protection handling procedures laboratory safety MOVIE
WHAT IS RADIATION ? WHAT IS RADIATION ?
RADIATION • Spontaneous decay • Half-life • 4 geometry
RADIATION Excess p & n alpha particles Excess p positron ( + ) Excess n negatron ( - ) Excess nuclear E gamma ray Excess orbital E X-ray
ALPHA EMISSION • origin: DISINTEGRATING NUCLEUS (Mainly heavy nuclei) • form of radiation: PARTICLE • energy range: 4-8 MeV • range of travel: 2-8 cm in air • other characteristics: LARGE MASS, DOUBLE CHARGE, HIGH SPECIFIC ACTIVITY
BETA EMISSION • origin: DISINTEGRATING NUCLEUS • form of radiation: NEGATRON (electron) POSITRON (similar to an electron but positive charge) • energy range: 0.02 - 4.8 MeV • range of travel: 0 - 10 m in air • other characteristics: DIFFERS FROM AN ELECTON IN ORIGIN AND ENERGY; TRAVELS ALMOST THE SPEED OF LIGHT; ALMOST NO MASS (9.1x 10-31 kg)
GAMMA EMISSION • origin: NUCLEUS • form of radiation: ELECTROMAGNETIC RADIATION (emr - photon) • energy range: 10 keV - 3 MeV • range of travel: 100 m in air • other characteristics: ZERO MASS, ELECTRICALLY NEUTRAL
X-RAY EMISSION • origin: ORBITAL ELECTRON • form of radiation: ELECTROMAGNETIC RADIATION (emr - photon) • energy range: 10eV - 120 keV • range of travel: 100 m in air • other characteristics: ZERO MASS, ELECTRICALLY NEUTRAL
INTERACTION WITH MATTER IONIZATION • Electron is removed from an electron shell leaving a charged particle. EXCITATION • Electron is raised to a higher energy level but isn’t knocked out of the shell
BREMSSTRAHLUNG • A negatron approaches the nucleus and is accelerated. • As it leaves the nucleus it decelerates and emits excess energy as emr. INTERACTION WITH MATTER
DIRECT vital cell structures INDIRECT ionizes H2O forms peroxides interacts with the vital cell structure INTERACTION WITH BIOLOGICAL MATTER
RADIATION RANGES IN TISSUE (average linear dimension of a cell = 17.1 m ) • alpha particles of 210Po ……… 15m • beta particles of 3H …………… 5 m • beta particles of 32P ……….. 300 m • gamma rays of 60Co …………. infinity
RADIOSENSITIVITY OF CELLS • Blood producing and reproductive cells are the most sensitive • Muscle, nerve and bone cells are the least. At low doses, the effects of radiation are not known.
INTERNAL DOSES • CRITICAL ORGANS • 3H – Body water or tissue • 14C – Fat tissue • 32P – Bones • 35S – Gonads • 125I – Thyroid • 57Co – Large Intestine PREGNANCY
EXTERNAL DOSES Gamma rays Beta particles Alpha particles
BIOLOGICAL RESPONSE TO RADIATION • No change • Mutation and repair • Permanent change with limited effect • Changes leading to cancer or other effects • Death of cell / organism (minutes - years)
THE EFFECTS OF RADIATION ON THE HUMAN BODY • Genetic • appears in latter generations • due to cell damage of the reproductive organs • Somatic • appears in the irradiated individual • immediate or delayed effects • Stochastic • refers to probability of biological effect due to ionizing radiation • assumes effect is proportional to dose / dose rate, i.e., no safe threshold
non-NEWNEW Whole body, gonads, 1 mSv 50 mSv bone marrow Skin, thyroid, bone 50 mSv 500 mSv Tissue of hands, feet, 50 mSv 500 mSv and forearms Dose Limits: THERMOLUMINESCENT DOSIMETRY
COMPARISON OF RISK • exposure to 100 Sv ionizing radiation • smoking 1.5 cigarettes • travelling 50 miles by car • being male and 60 years old for 20 minutes • canoeing for 6 minutes
UNITS OF RADIATION • ACTIVITY • ABSORBED DOSE • DOSE EQUIVALENT
ACTIVITY UNITS Non - S.I.(Système international) CURIE (Ci) 1 Ci = 3.7 x 1010 dps S.I. BECQUEREL (Bq) 1 Bq = 1 dps
ABSORBED DOSE UNITS Non - S.I. RAD (rad) 1 rad = 100 ergs of energy/g S.I. GRAY (Gy) 1 Gy = 1 joule of energy/kg
DOSE EQUIVALENT UNITS Non - S.I. REM (rem) 1 rem = rad x Quality Factor S.I. SIEVERT (Sv) 1 Sv = Gy x Quality Factor
CALCULATIONS TWO IMPORTANT CALCULATIONS: 1. Decay correction 2. Converting cpm to Curies
CALCULATIONS 1. DECAY CORRECTION A = Aoe - t A = activity at time “t” Ao= activity at time zero t = elapsed time = decay constant ( = 0.693 / t 1/2)
CALCULATIONS Example: • 250 Ci of 35S arrived on May 19, 2005 • 100 Ci was removed and used the same day. • The remaining amount was stored in a freezer for future use. • On June 30, 2005, it is decided to repeat the experiment. ? Does another order of 35S have to be placed or is there enough remaining activity that the experiment may proceed?
CALCULATIONS Solution: A = A0e - t A = activity at time ‘t’ ( ? ) A0= activity at time zero (250 - 100 = 150 Ci) t = elapsed time (42 days) = decay constant (0.693 / 87 days = 0.00797) A = (150)e - (0.00797)(42) A = 107.32 Ci (** SAVINGS **)
CALCULATIONS 2. CONVERTING CPM TO CURIES Step 1 Determine counting efficiency of the detector. Step 2 Convert cpm to dpm. Step 3 Convert dpm to Curie.
CALCULATIONS Step 1 Determine counting efficiency of the detector using a source with a known activity. % efficiency = observed cpm - background cpm x 100 source of emission rate (dpm) Ex. count rate = 2045 cpm background = 65 cpm source = 220 Bq = 1.32 x 104 dpm % efficiency = 2045 - 65 cpm = 15% 1.32 x 104 dpm
CALCULATIONS Step 2 Convert cpm to dpm. dpm = corrected cpm efficiency Ex. Sample = 4925 cpm background = 65 cpm efficiency = 15% dpm = 4925 - 65 = 32,400 0.15
CALCULATIONS Step 3 Convert dpm to curie. Since 1 Bq = 1 dps = 2.7 x 10-11 Ci Then 60 dpm = 2.7 x 10-11 Ci Therefore32,400 dpm = 1.48 x 10-8 Ci or, # Bq = __1.48 x 10-8 Ci_ = 540 Bq 2.7 x 10 -11 Ci/Bq
CLASSIFICATION OF LABORATORY Annual Limit on Intake (ALI) The activity, in Becquerel (Bq), of a radionuclide that will deliver an effective dose of 20 mSv after the radionuclide is taken into the body Basic: 5 X ALI Intermediate: 5-50 X ALI High: 50-500 X ALI Exemption Quantity (EQ) The quantity, in Becquerel (Bq), of a radionuclide, below which no licence is required 10000 EQ: Written approval from CNSC
CLASSIFICATION OF RADIONUCLIDES • Contamination levels • Decommissioning levels Class A (high): Na-22, Zn-65 Class B (med): Rb-86 Class C (low): H-3, C-14 , S-35, Ca-45, P-33, P-32, I-125
DECAY PRODUCTS 32P Sulphur 14C Nitrogen 35S Chlorine 3H Helium-3
OPERATIONAL PROCEDURES • Ordering • Receipt of Radioactive Material (TDG) • Inventory • Disposal • Monitoring • Inspection of Laboratories
ORDERING • Radioactive materials purchase procedures - Radioisotopes Purchase Requisition form - Form must be complete (PO number, signature) - EHSS approval before ordering - Documentation (packing slips, shipper’s declaration) • Permit conditions • Material purchased for other labs • Inventory records
PURCHASE REQUISITION FORM
RECEIPT OF RADIOACTIVE MATERIAL • TDG – Class 7 - Definition of radioactive materials - Radioactive packages - Radiation warning labels - Receipt of radioactive material
TDG – CLASS 7 DEFINITION OF RADIOACTIVE MATERIAL FOR TRANSPORT Former: - 70kBq/kg New: - radionuclide dependent - types of radiation - energies - chemical forms - potentialbiological effect on persons
TDG – CLASS 7 Radioactive packages may be shipped as: - Excepted packages - Industrial packages – Categories I, II and III - Type A packages – lower amounts - Type B (U) packages – large amounts; ≤ 700 kPa - Type B (M) packages – large amounts; > 700 kPa - Type C packages – for air transport of high activity
TDG – CLASS 7 EXCEPTED PACKAGES - The safety mark ‘RADIOACTIVE’ must be visible on opening the package - The radiation level at any point on the external surface of the package must not exceed 5 Sv/h All other packages must be categorized by radiation level and display the corresponding radiation warning labels as follows:
TDG – CLASS 7 RADIATION WARNING LABELS Category I-White: less than 5 Sv/h Category II-Yellow: less than 500 Sv/h, TI less than 1 Category III-Yellow: less than 2 mSv/h, TI less than 10 TI: maximum radiation level in Sv/h at 1 meter from the external surface of the package, divided by 10. Ex: 1 Sv/h (0.1 mrem/h) at 1 m equals a TI = 0.1
TDG – CLASS 7 RECEIPT OF RADIOACTIVE MATERIAL - Radioactive packages must be delivered to the laboratory using a cart to increase distance between the transporter and the package in order to minimize radiation exposure - Inspect packaging both externally and internally for damage or leakage - Perform contamination monitoring on the package, vial holder and vial - Deface wording and labels prior to disposal of the package - Complete an Inventory of Use and Disposition form Report any anomalies to the supervisor and RSO
INVENTORY • Sealed Sources (encapsulated, incorporated in a device, check sources) • Open Sources • Transfers ** HISTORICAL