IONISING RADIATION SAFETY MANUAL

Transcription

1 IONISING RADIATION SAFETY MANUAL Version 1 Area Radiation Safety Officers (RSO) (After hours call: Security ) Area RSO Contact # Biological Sciences Dr Peter Anderson 15269/13752 SCaPS Dr Rachel Popelka-Filcoff FMC School of Medicine Mrs Angela Binns (Internal) (from FMC) University campus wide Dr Kent Gregory Emergency Services (only contact these services in an emergency) Fire, Police, Ambulance Hospital: FMC Medical treatment Emergency only Radiation Protection Division (EPA Emergency Response) Dial and ask for the service(s) you require. Tell them the University is in South Australia. Make sure that you inform them radiation is involved. Then dial Security on so that a security officer can meet the service at the University entrance and escort it to the required location (calling from Flinders University) (FMC internal call) (business hours) If the University RSO is not available Occupational Health and Safety Unit January 2009

2 Table of Contents PART 1 POLICY, GENERAL RULES AND CONTACT INFORMATION INTRODUCTION POLICY ORGANISATIONAL STRUCTURE FOR MANAGEMENT OF RADIATION SAFETY RESPONSIBILITIES VICE-CHANCELLOR MANAGER, OCCUPATIONAL HEALTH AND SAFETY UNIVERSITY RADIATION SAFETY OFFICER COST CENTRE HEADS MANAGERS AND SUPERVISORS AREA RADIATION SAFETY OFFICERS STAFF AND STUDENTS UNDERGRADUATE STUDENTS THE LEGAL FRAMEWORK FOR CONTROLLING RADIATION HAZARDS LICENCES, REGISTRATIONS AND APPROVALS Licences Registrations Approvals WORKER REGISTRATION AND MONITORING Worker Registration Personal Monitoring EXEMPTIONS AND SPECIAL CASES Licensing Registration Monitoring REPORTING AND RECORDS ACCIDENTS INVOLVING RADIATION SPECIAL CIRCUMSTANCES PREGNANCY HUMAN RESEARCH ENTRY TO REGISTERED PREMISES BY NON-RADIATION WORKERS FLINDERS STAFF AND STUDENTS USING IONISING RADIATION AT OTHER LOCATIONS CONTACTS AREA RADIATION SAFETY OFFICERS (RSO) EMERGENCY SERVICES EMERGENCY PROCEDURES FOR ACCIDENTS INVOLVING RADIATION... 9 PART 2 AIMS OF THE RADIATION PROTECTION PROGRAM RADIATION QUANTITIES BIOLOGICAL EFFECTS OF IONISING RADIATION SOMATIC AND GENETIC EFFECTS Somatic effects Genetic effects MEDICAL EFFECTS Deterministic effects Stochastic effects Ionising Radiation Safety Manual_Feb09.doc Page i

3 3 SOURCES OF RADIATION EXPOSURE CONTROL OF RADIATION DOSE DOSE LIMITS DOSE CONSTRAINTS CONCEPTS OF RADIATION PROTECTION GENERAL PRINCIPLES FOR CONTROLLING RADIATION HAZARDS ALARA EXPOSURE TO RADIATION CONTROLLING EXPOSURE EXTERNAL EXPOSURE Distance Time Shielding General INTERNAL EXPOSURE Inhalation Ingestion Absorption through the skin Committed Dose CONTROL OF INTERNAL RADIATION HAZARD ANNUAL LIMIT OF INTAKE, ALI Derived Limits PART 3 GUIDELINES FOR UNSEALED RADIOACTIVE MATERIAL HAZARD CLASSIFICATIONS RADIONUCLIDES LABORATORIES CONTROL OF THE HAZARD SHIELDING AND DISTANCE Gamma Emitters Beta Emitters MONITORING MONITORING TECHNIQUES External radiation fields Contamination Objectives of Surface Monitoring Area, Equipment and Personal Surveys Wipe Tests GENERAL LABORATORY RULES FOR UNSEALED RADIOACTIVE MATERIAL FAMILIARITY WITH PROCEDURES WORKING RULES FOR HANDLING RADIONUCLIDES DISTANCE TIME SHIELDING PROTECTIVE CLOTHING CONTAINMENT MONITORING THE WORK AREA AND YOURSELF WASTE DISPOSAL SPILLS AND CONTAMINATION RECORD KEEPING FOR RADIONUCLIDES STORAGE OF RADIONUCLIDES Ionising Radiation Safety Manual_Feb09.doc Page ii

4 7 INFORMATION ON PARTICULAR RADIONUCLIDES LOW ENERGY EMITTERS: TRITIUM, CARBON-14, AND SULFUR PHOSPHORUS IODINE PART 4 GUIDELINES FOR USING X-RAY APPARATUS X-RAY ANALYSIS APPARATUS ENCLOSED X-RAY APPARATUS PARTLY ENCLOSED X-RAY APPARATUS OPEN BEAM X-RAY APPARATUS GENERAL REQUIREMENTS FOR X-RAY TUBES GENERAL REQUIREMENTS FOR X-RAY ANALYSIS APPARATUS LIGHTS SIGNS HAZARD PRIMARY BEAM SCATTERED BEAM CONTROL OF THE HAZARD ENGINEERING OPERATIONAL RULES MONITORING CABINET X-RAY EQUIPMENT PART 5 GUIDELINES FOR SEALED RADIOACTIVE MATERIAL TYPES OF SEALED SOURCES HAZARD EXTERNAL RADIATION CONTAMINATION MAINTENANCE AND CHECKING OF SEALED SOURCES NO REPAIRS WIPE TESTS GENERAL REQUIREMENTS FOR SEALED SOURCES REGISTER SIGNS CONTROL OF THE HAZARD ENGINEERING OPERATIONAL RULES MONITORING MAINTENANCE STORAGE TRANSPORT DISPOSAL PART 6 REFERENCE INFORMATION FOR RADIATION PROTECTION UNITS ASSOCIATED WITH RADIATION PROTECTION DOSE Ionising Radiation Safety Manual_Feb09.doc Page iii

5 1.1.1 Absorbed Dose Dose Rate Equivalent Dose Radiation Weighting Factor w R Effective Dose ACTIVITY OLD UNITS DOSE LIMITS AND DERIVED LIMITS DOSE LIMITS DOSE CONSTRAINTS ANNUAL LIMIT OF INTAKE, ALI DERIVED LIMITS Derived Air Concentration, DAC Derived Limit for Surface Contamination CLASSIFICATION OF RADIONUCLIDES AND LABORATORIES RADIONUCLIDES LABORATORIES GENERAL WORKING RULES FOR UNSEALED RADIOACTIVE MATERIALS THE LABORATORY PERSONAL BEHAVIOUR CONTAMINATION EXTERNAL RADIATION HAZARD HOUSEKEEPING MONITORING RECEIVING AND STORING RADIOACTIVE MATERIAL RADIOACTIVE WASTE EMERGENCIES AND ACCIDENTS - UNSEALED RADIOACTIVE MATERIAL RADIOACTIVE SPILLS Remedial Action RADIATION EMERGENCIES Radiation Incidents Radiation Accidents INGESTION EXPOSURE SUMMARY OF EMERGENCY ACTIONS DECONTAMINATION GENERAL Physical methods Chemical treatments PERSONAL DECONTAMINATION Skin Face and Eyes Other Parts of the Body Wounds INGESTION AND INHALATION LABORATORY DECONTAMINATION SPILL KITS General Type C Laboratory Type B Laboratory Using I GENERAL WORKING RULES FOR X-RAY ANALYSIS UNITS THE LABORATORY PERSONAL BEHAVIOUR OPERATIONAL RULES MONITORING AND SAFETY CHECKS Personal monitoring EMERGENCY PROCEDURES Ionising Radiation Safety Manual_Feb09.doc Page iv

6 6.6 EXPOSURE TO THE PRIMARY BEAM Remedial Action SUMMARY OF EMERGENCY ACTIONS GENERAL WORKING RULES FOR SEALED RADIOACTIVE SOURCES GENERAL WORKING RULES FOR THE NEUTRON IRRADIATION SOURCE EMERGENCY PROCEDURE FOR LOSS OF WATER FROM THE NEUTRON SOURCE Immediate Action Emergency Removal of the Source GENERAL WORKING RULES FOR NEUTRON MOISTURE METERS THE METER PERSONAL BEHAVIOUR OPERATIONAL RULES MONITORING AND SAFETY CHECKS Personal Monitoring Source Monitoring TRANSPORT AND FIELD USE Transport Arrangements Temporary Storage Vehicle Labels and Notices EMERGENCY ACTION Vehicle Accident Field Breakdown REFERENCE MATERIAL SA LEGISLATION NHMRC PUBLICATIONS TRANSPORT CODE AUSTRALIAN STANDARDS BOOKS TABLE PROPERTIES OF RADIONUCLIDES Ionising Radiation Safety Manual_Feb09.doc Page v

7 Part 1-1 PART 1 POLICY, GENERAL RULES AND CONTACT INFORMATION 1 INTRODUCTION This Ionising Radiation Safety Manual provides details of how the University, its staff, students, visitors and contractors meet their obligations under the Act, and the University s general policy on the use of ionising radiation and must be read in conjunction with the Ionising Radiation Safety Policy. 2 POLICY The University requires that ionising radiation is managed in accordance with relevant legislation and the principles and standards outlined in its Ionising Radiation Safety Policy policy; and all work involving ionising radiation is performed in a safe manner and conforms to relevant legislation. In work with ionising radiation, the ALARA (As Low as Reasonably Achievable, economic and other factors being taken into account) dose minimisation principle must be used to ensure that exposures to staff, students, contractors, visitors, the public and the environment are minimised. All research, teaching or operational activities using Ionising radiation must be undertaken in accordance with the University s Hazard Management Policy. 3 ORGANISATIONAL STRUCTURE FOR MANAGEMENT OF RADIATION SAFETY The University implements the requirements of the legislation by means of the management structure and chain of responsibility shown in the diagram. Managerial responsibility Offers radiation safety advice Vice-Chancellor Director, Human Resources Manager, OHS University Radiation Safety Officer Cost Centre Heads Area Radiation Safety Off Heads of School Licensed supervisors Licensed staff and students Unlicensed staff and students Ionising Radiation Safety Manual_Feb09.doc Page 1 of 47

8 Part RESPONSIBILITIES 4.1 Vice-Chancellor The Vice-Chancellor is responsible for ensuring that the University meets its legislative responsibilities for the security and use of ionising radiation in accordance with the provisions of the South Australian Radiation Protection and Control Act 1982 and associated Regulations, the Northern Territory Radiation (Safety Control) Act 1999 and associated Regulations and the Victorian Radiation Act 2005 and associated Regulations. 4.2 Manager, Occupational Health and Safety The Manager, OHS is responsible for ensuring that ionising radiation registration and licensing requirements are met, including the maintenance of the records of registered radiation workers, of their exposure to ionising radiation, and of radiation incidents and accidents. 4.3 University Radiation Safety Officer Responsible for coordinating, implementing and reviewing the University s Ionising Radiation Safety Policy and Manual; providing advice and assistance on ionising radiation matters, including legislative requirements, to Cost Centres through the OHS Unit; monitoring the maintenance of prescribed records, registers and inventories on ionising radiation safety matters held by the OHS unit; overseeing the radioactive waste management plans required by the EPA; overseeing security of radioactive sources; assessing registration and licence applications; responding to emergencies involving ionising radiation; and providing radiation safety training for staff and students. These duties in general are similar to those set out for a Radiation Protection Adviser in Australian Standard of Cost Centre Heads Cost Centre Heads are responsible for ensuring that the University s Ionising Radiation Policy and procedures set out in the Ionising Radiation Safety Manual are implemented in their Cost Centre; staff, students, contractors and visitors are aware of their responsibilities and are provided with adequate information, training and instruction; and there are adequate resources for effective radiation safety management, including appointment of Area Radiation Safety Officers where applicable and implementation of control measures, in their Cost Centre so that legislative requirements and University standards are achieved. 4.5 Managers and Supervisors Managers and supervisors of staff and students are responsible for ensuring that the ALARA principle is used when planning a research or teaching programme; staff and students they supervise, and who work with ionising radiation: o o are fully informed about hazards associated with activities being carried out, are trained appropriately in radiation protection, are instructed in control measures and safe working procedures and are supervised appropriately; and where necessary, they hold, or obtain, the appropriate radiation licence; the Area Radiation Safety Officer is informed of any new radiation work, and of any radiation accidents; and Ionising Radiation Safety Manual_Feb09.doc Page 2 of 47

9 Part 1-3 contractors and visitors receive appropriate information about any ionising radiation and control measures. 4.6 Area Radiation Safety Officers Area Radiation Safety Officers are responsible for day-to-day management of ionising radiation activities in their area, including ensuring the implementation and regular review of radiation monitoring and control procedures; ensuring that immediate action is taken in the event of unsafe practices, accidents or emergencies; providing training about local laboratory rules and procedures; and liaising with the University Radiation Safety Officer (URSO) on matters involving ionising radiation safety, monitoring and control procedures within their area, and informing the URSO of any changes to the radiation inventory affecting licences and registrations. 4.7 Staff and Students Staff and students are responsible for taking every precaution to avoid unnecessary exposure to radiation and ensuring that radiation doses are kept as low as reasonably achievable; the safe use of ionising radiation, including the use of the required radiation protection measures; working safely and not putting themselves or others at risk of injury from exposure to ionising radiation. In particular, each person working with ionising radiation at the University shall: strictly observe guidelines for exposure limits to ionising radiation use all personal monitoring devices issued to them inform the Area Radiation Safety Officer (RSO) in advance (through their supervisor) of any new work or altered procedures involving Ionising radiation, and provide a description of agreed methods, safety precautions and emergency procedures to be used ensure that they understand the chemical and physical properties and biological effects of the radiation or radioactive materials being used reduce to a minimum the radiation hazard of the work have a knowledge of appropriate accident and emergency procedures understand statutory regulations, codes of practice and local instructions relevant to their work. 4.8 Undergraduate Students The University is exempted from the obligation to register as radiation workers undergraduate students working with ionising radiation in laboratory classes but special care must be taken when undergraduates use ionising radiation. The general requirements for registration and licensing apply to laboratories and ionising radiation sources used by undergraduates. All work by undergraduates with ionising radiation must be under the supervision of a licensed demonstrator. The quantities of radioactive materials used should be kept to a minimum and specific instruction on handling radioactive materials must be provided. Undergraduates must not use X-ray analysis units unless these are fully enclosed X-ray units and any undergraduate operations are under continuous supervision. Ionising Radiation Safety Manual_Feb09.doc Page 3 of 47

10 Part THE LEGAL FRAMEWORK FOR CONTROLLING RADIATION HAZARDS The use of ionising radiation at workplaces owned, managed or controlled by Flinders University is governed by the following legislation: South Australia Radiation Protection and Control Act 1982 Radiation Protection and Control (Ionising Radiation) Regulations 2000 Radiation Protection and Control (Transport of Radioactive Substances) Regulations 2003 Where University staff are based in University premises in other States, the following legislation applies: Victoria Radiation Act 2005 Radiation Regulations 2007 Northern Territory Radiation (Safety Control) Act 1999 Radiation (Safety Control) Regulations 2007 NOTE The SA Regulations apply to persons employed (or a student) in SA even when working in another jurisdiction. A copy of the regulations is held by each Area Radiation Safety Officer and by the OHS unit and can be accessed at the EPA website The legislation imposes responsibilities on those who work with ionising radiation and their employers, and on those who own radiation apparatus or radioactive materials, or premises in which radioactive materials are used or stored. Students working with ionising radiation are classed as radiation workers but are exempted from some licensing requirements. 5.1 LICENCES, REGISTRATIONS AND APPROVALS Licences The regulations require that individuals carrying out radiation work must be licensed but some exceptions are made. All supervisors (defined broadly as the equivalent of principle and associate investigators in grant applications) must be licensed. Licences are issued by the Radiation Protection Division, Environment Protection Authority, after sitting for an examination and must be renewed annually. Everyone (staff and students) who works in a Class B registered premise (such as the iodination laboratory in Biology) must be licensed. Everyone who uses a sealed source must be licensed. Everyone who uses an X-ray generator (other than a fully enclosed or cabinet X-ray set) must be licensed. The University Radiation Safety Officer can provide advice on whether a person should be licensed. Assistance with the licence requirements and examination syllabus is available from the University Radiation Safety Officer Registrations More or less permanent sources of Ionising radiation such as X-ray generators and sealed sources of radioactive material must be registered. Ionising Radiation Safety Manual_Feb09.doc Page 4 of 47

11 Part 1-5 Premises (rooms, laboratories etc.) in which unsealed sources of radioactive material are used or stored must be registered. These are classified according to the hazard, with Class C being the lowest hazard Approvals The University can only dispose of radioactive waste in accordance with an annual plan approved by the EPA. Approval is required for the disposal of an X-ray set or sealed radioactive source by sale, gift or decommissioning. Approval is required for the transfer of unsealed radioactive material to another owner. 5.2 WORKER REGISTRATION AND MONITORING Worker Registration In addition to licensing and registration, the University must keep a register of all radiation workers. This is done through the Radiation Worker Registration Form kept by the OHS unit. All staff and research students who are using ionising radiation must be included in the University s list of registered radiation workers. Supervisors must inform the OHS Unit when someone begins work with ionising radiation and the worker must complete and return the registration form available from the OHS Unit Personal Monitoring The University is required to monitor the radiation dose (the amount of radiation received) of the registered workers. People working with very low energy sources (tritium, carbon-14, sulfur-35) where the radiation does not penetrate the cover of a dosimeter such as the common thermo-luminescence dosimeters (TLD) are not issued with a TLD. People with a very small chance of receiving a dose greater than 1 msv in a year (determined by the type and the maximum quantity of radionuclide they are handling) are not normally issued with a TLD. Monitors are issued to users of X-ray machines and sealed sources because the risk of a large dose is higher with these sources. Anyone who believes they should be issued with a TLD monitor should contact the University Radiation Safety Officer who can provide advice on the monitoring program. WARNING The rules for wearing personal monitors are set down by the supplier of the service (ARPANSA) and must be followed. If you are issued with a personal monitor you must never allow it to be worn by another under any circumstances. If someone else wears it, the point of the monitoring program is defeated, and you will be recorded as having received the dose of the other person. 5.3 EXEMPTIONS AND SPECIAL CASES Some general exemptions apply to the application of the regulations Licensing The hazard determines who should be licensed. Those who work under supervision in Class C registered laboratories do not need to be licensed but their supervisors must be licensed. The supervisor is the person who has determined the nature of the work and can be equated to a principle investigator. Students, including graduate students, and technical staff are not usually supervisors. Reminder Ionising Radiation Safety Manual_Feb09.doc Page 5 of 47

12 Part 1-6 Everyone working in a Class B laboratory must be licensed. All users of open-beam, or partly enclosed, X-ray generators must be licensed. Users of fully enclosed units who work under supervision need not always be licensed. Users of sealed sources of radioactive materials must be licensed. Students using these sources under supervision in a laboratory need not be licensed. Everyone using a neutron source in field experiments must be licensed Registration Very small quantities of radioactive materials are exempted from the regulations, and so do not need to be handled in a registered premise or registered. The exemption levels are set out in Part 1, para. 8 of the Regulations Monitoring Where no simple personal monitoring devices exist (low energy radiation) and where there is a very small risk that radiation workers will receive a radiation dose more than one-tenth of the annual limit for workers, the requirement to supply personal monitors may be relaxed. The University Radiation Safety Officer is involved in decisions on whether personal monitoring is needed. 5.4 REPORTING AND RECORDS The University is required to maintain records of a. registered workers and the dose reports from personal monitoring b. registered premises, sources and Ionising apparatus c. purchases and disposals of unsealed radioactive materials d. the movements and locations of sealed sources e. monitoring of the dose from X-ray machines f. the disposal of any radioactive waste under the approved plan g. the licences of staff and graduate students. 5.5 ACCIDENTS INVOLVING RADIATION Abnormal events involving radiation are classed as incidents (less serious) and accidents (major). The University is required to investigate incidents and accidents and reports both to the Radiation Protection Division of the EPA. Ionising Radiation Safety Manual_Feb09.doc Page 6 of 47

13 Part SPECIAL CIRCUMSTANCES 6.1 PREGNANCY The risk of Ionising radiation causing detriment to the foetus is higher than the risk to the worker. The normal dose limit for a worker is therefore reduced during pregnancy. The ICRP (International Commission on Radiological Protection) recommends a dose limit of 2mSv to the surface of the abdomen during pregnancy whereas the NHMRC (National Health and Medical Research Council) recommends the same level of protection as for a member of the public. This is a dose of 1 msv in a year, which is equivalent to a limit of 0.75 msv to the abdomen during the pregnancy. In practice the doses to workers in the university are normally well below 0.2 msv per year and the risk to the foetus is very small. If a radiation worker becomes pregnant the following steps must be taken: The University RSO (OHS Unit) must be informed Supervisors should be informed of the pregnancy A pregnant worker should re-evaluate her work practices and radiation exposure in order to minimise radiation exposure during pregnancy The basis of these requirements is Regulation HUMAN RESEARCH The exposure of human subjects to ionising radiation for the purposes of research (as distinct from diagnosis or therapy) is strictly controlled. Explicit permission must be received from the statutory authority for every research project involving ionising radiation and humans. Some hospital ethics committees have been granted the delegated power to approve such research. Note that the special requirements for ionising radiation are in addition to any other ethical requirements and special justification is required. A copy of all research proposals involving human subjects and ionising radiation must be sent to the University Radiation Safety Officer. 6.3 ENTRY TO REGISTERED PREMISES BY NON-RADIATION WORKERS The University requires that all people who are not radiation workers, including staff, students and outside contractors, obtain permission from the licensed supervisor of registered radiation areas before entry. Such persons are considered by Regulation 17 (2) of the SA Radiation Protection and Control Act to be members of the public. 6.4 FLINDERS STAFF AND STUDENTS USING IONISING RADIATION AT OTHER LOCATIONS The responsibilities of Flinders University towards its staff and graduate students remain the same when the staff and students work with ionising radiation at institutions other than those controlled by Flinders University*. In practice it is normally the host institution that manages radiation safety at the host location. Within Australia the requirements of legislation controlling work with ionising radiation are broadly similar. The University requires staff and students working in Australia institutions to obey the local rules and regulations of the host organisation. The University must be made aware that staff and students are working with ionising radiation at other institutions. These staff and students must be registered as radiation workers and the registration must include details of the host institution and the work being done there. The University may require the host institution to provide details of their radiation safety programme and evidence that University staff and students have complied with the requirements of the host, including the records of any doses received. Ionising Radiation Safety Manual_Feb09.doc Page 7 of 47

14 Part 1-8 The regulatory frameworks for work outside Australia may differ markedly from Australian practice. In general in North America, Japan and Europe the overall basic safety standards of the IAEA apply but there are many special requirements particularly for security clearance. * examples include CSIRO laboratories, the Australian Synchrotron, and ANSTO, as well as overseas facilities. 7 CONTACTS 7.1 AREA RADIATION SAFETY OFFICERS (RSO) (After hours call: Security ) Area RSO Contact # Biological Sciences Dr Peter Anderson 15269/13752 SCaPS Dr Rachel Popelka-Filcoff FMC School of Medicine Mrs Angela Binns (Internal) (from FMC) University campus wide Dr Kent Gregory EMERGENCY SERVICES Only contact these services in an emergency Fire, Police, Ambulance Hospital: FMC Medical treatment Emergency only Radiation Protection Division (EPA Emergency Response) Dial and ask for the service(s) you require. Tell them the University is in South Australia. Make sure that you inform them radiation is involved. Then dial Security on so that a security officer can meet the service at the University entrance and escort it to the required location (calling from Flinders University) (FMC internal call) (business hours) If the University RSO is not available Ionising Radiation Safety Manual_Feb09.doc Page 8 of 47

15 Part EMERGENCY PROCEDURES FOR ACCIDENTS INVOLVING RADIATION IT IS IMPORTANT TO REFER TO THE MORE DETAILED EMERGENCY PROCEDURES OUTLINED LATER IN THIS MANUAL ONLY AFTER THESE IMMEDIATE STEPS HAVE BEEN TAKEN. Radiation + Fire and /or Explosion Injured persons After the fire has been put out the Area RSO is responsible for directing decontamination procedures. The University RSO must be contacted: Manager, OHS or Contact the Radiation Protection Division on (business hours) or EPA Emergency Response (all hours) on If the University RSO is not available If the injured person is likely to be contaminated, first aid treatment must occur in a contained area and the hospital must be advised that the person is contaminated. Major Spill Persons not involved must vacate the area immediately. Arrange for air conditioning to the area to be switched off Notify your Area RSO immediately. Exposure to irradiating apparatus Switch off apparatus Notify your Area RSO immediately Exposure to sealed sources Do NOT attempt to remedy the situation without expert advice Leave the area under supervision and use warning signs and tape Notify your Area RSO and the University RSO immediately Ionising Radiation Safety Manual_Feb09.doc Page 9 of 47

16 Part 2-10 PART 2 AIMS OF THE RADIATION PROTECTION PROGRAM The Radiation Protection program at Flinders University is intended to minimise the possible effects on staff, students and the general public of Ionising radiation used in the University. The program includes meeting the legislative requirements, the practice of the ALARA principle at all levels, the setting of institutional standards, and education and training. This Radiation Safety manual is part of the training program in radiation protection. 1 RADIATION QUANTITIES The effects of Ionising radiation are largely dependent on the radiation dose, or the amount of energy absorbed from the radiation. The absorbed dose measures the energy absorbed per unit mass of the absorbing material from the radiation field. The absorbed dose rate is the absorbed dose per unit time, usually per hour. The word dose is often used instead of the more correct absorbed dose. A more detailed account of radiation quantities and units is contained in Part 6. 2 BIOLOGICAL EFFECTS OF IONISING RADIATION Ionising radiation is harmful to life because it acts at the molecular level on cells and their constituents. Absorption of energy from Ionising radiation may result in changes to the molecules, destruction of cellular elements, and altered function or death of the cell. At low doses Ionising radiation may cause cancers and induce genetic defects. At high doses it can kill cells, damage organs, and cause rapid death. 2.1 SOMATIC AND GENETIC EFFECTS The biological effects are somatic if they appear in the exposed individuals themselves or genetic (hereditary) if they affect their offspring Somatic effects These are the result of direct cell damage, such as the death of a brain cell. They are acute if they appear within a short time of the exposure (hours or days) or delayed if they appear after months or years. The damage done by high doses normally becomes evident within hours or days. Cancers take many years to emerge Genetic effects These are the result of damage to the DNA of germ cells and may occur at low doses. The effects are only apparent in offspring and are difficult to observe even in large populations. Hereditary malformations and diseases caused by genetic damage may take generations to show in the descendants of those irradiated. 2.2 MEDICAL EFFECTS These are divided into Deterministic effects where the severity of the effect increases with the dose and there is a threshold dose below which no detrimental effects are seen. These are produced by relatively high doses. The effects vary considerably from one organ to another and the more radiation sensitive tissues or organs are the ovaries, testes, bone marrow and the lens of the eye. and Ionising Radiation Safety Manual_Feb09.doc Page 10 of 47

17 Part Stochastic effects which are statistical or random in nature (stochastic) and occur with a probability that depends on the radiation dose. In general only the probability of an effect can be established. The probability of the effect occurring is very low at low doses and it is assumed to be proportional to the dose. There are two types of stochastic effects. The first may result in the induction of cancer in the exposed person (somatic). The second may result in genetic (hereditary) disorders. Martin and Harbison (see Part 6 Section 8) give some indication of the deterministic and stochastic effects of radiation doses. 3 SOURCES OF RADIATION EXPOSURE Everyone is exposed to natural radiation from cosmic rays and radioactive elements in the earth, the atmosphere and our own bodies. The dose from natural radiation background radiation in South Australia is about 2 msv per year. People are also exposed to radiation sources in medical and dental procedures, and may be occupationally exposed to Ionising radiation because of their work. The largest sources of exposure to radiation are the medical and dental uses of X-rays and radioactive substances. 4 CONTROL OF RADIATION DOSE The radiation protection program is concerned with the control of occupational exposures and radiation doses. 4.1 DOSE LIMITS Dose limits are like speed limits - they do not mean there is zero risk for a dose less than the limit. The NHMRC and the State Regulations set down dose limits for occupational exposures. In general the limits are designed to ensure that the risk of death to a radiation worker through exposure to Ionising radiation is no more than the average risk of death in all occupations. This limit is below the levels at which deterministic effects will occur. Currently the effective dose limits for radiation workers are 20 msv per year and for the public 1 msv per year. The NHMRC recommendations on dose limits are included in Part DOSE CONSTRAINTS Institutions may establish constraints on the dose received by workers limits. It is important to recognise that dose limits do not mean that below these doses there are no biological effects. University policy is that occupational doses should be As Low As Reasonably Achievable, economic and social factors being taken into account (ALARA). With this aim in mind it is expected that no individual at the University will receive an occupational dose greater than 1 msv a year. This 1 msv per year is a dose constraint. 5 CONCEPTS OF RADIATION PROTECTION The aim of a radiation protection program in an institution is to reduce the radiation doses and the risks of receiving a significant radiation dose to the lowest possible levels that are reasonably achievable for radiation workers and members of the public. The reduction in dose is achieved by limiting the exposure of people to Ionising radiation. Exposures can be controlled by engineering, training and operational means and may involve the source (minimum source, shielding and containing the source), work practices and the use of protective clothing and equipment. The reduction in the risk of receiving a dose is achieved through similar means, by monitoring radiation doses and by planning so as to reduce the effects of unexpected events. Radiation protection is based on: Ionising Radiation Safety Manual_Feb09.doc Page 11 of 47

18 Part 2-12 Justification the use of radiation should produce a benefit to the exposed individual or to society to offset the harmful effect it causes. Optimisation exposures to Ionising radiation should be kept as low as reasonably achievable (ALARA), taking into account economic and social factors. Dose limits and constraints exposures of individuals to radiation should be subjected to dose limits and dose constraints. 6 GENERAL PRINCIPLES FOR CONTROLLING RADIATION HAZARDS 6.1 ALARA The primary objective of radiation protection procedures in the University is to ensure that the radiation exposure of radiation workers (those using Ionising radiation in the course of their employment or study) and the general public (all others), from both external and internal radiation sources is kept below the levels required by the Regulations and As Low As Reasonably Achievable, economic and social factors being taken into account (ALARA principle). 6.2 EXPOSURE TO RADIATION The use of X-ray equipment or sealed radioactive sources may result in radiation exposure from radiation sources external to the body. The handling of unsealed radioactive materials may result in radiation exposure from radioactivity both external and internal to the body (through ingestion). Exposure to radiation is acute if it occurs over a short time, e.g. exposure from a medical X-ray or a radiation accident or chronic if it occurs over a longer period of time, e.g. occupational exposure. 6.3 CONTROLLING EXPOSURE The measures required to counter external and internal radiation hazards are different. For external radiation, exposure ceases: when one leaves the radiation area the source is removed the irradiating apparatus is turned off. External radiation can be measured with relative accuracy and the magnitude of the hazard can be estimated. For internal radiation from ingested radioactive material, the contaminated person continues to be exposed to radiation even after the external contamination is removed. 6.4 EXTERNAL EXPOSURE External radiation may come from X-ray generators or sealed radiation sources such as neutron sources. Unsealed radionuclides used in a laboratory with nuclides like P-32 the external radiation hazard can be large. Exposure to external radiation may be controlled by: maximising the distance from the radiation source. minimising the time of exposure. shielding the radiation source Distance Increasing the distance from the source is the most effective and economical means of reducing radiation exposure. Ionising Radiation Safety Manual_Feb09.doc Page 12 of 47

19 Part 2-13 For point sources the intensity of the radiation varies inversely with the square of the distance from the source. By doubling the distance from the source the radiation intensity falls to a quarter of the original value. The variation of the radiation intensity with distance is more complex if the source is large compared with the distances involved (non-point source). The intensity decreases with distance but does not follow a simple law. As a rough guide the inverse square law can be applied if the distance from the source is greater than about 5 times the dimensions of the source. Distance should be used whenever possible to minimise radiation exposure. Use tongs or other long handled tools rather than fingers for handling radioactive materials. Even short forceps provide a large reduction in the radiation dose from that given to the skin by direct contact Time Decreasing the time of exposure decreases the dose proportionally. Any new procedure should be practised with non-radioactive materials or as dummy procedures so that the final work with Ionising radiation takes the minimum time Shielding Shielding placed between the source and the worker absorbs the Ionising radiation and therefore reduces the dose rate outside the shielding. It should be used whenever maximum distance and minimum time are not sufficient to reduce exposure to an acceptable level General All three concepts (time, distance and shielding) must be taken together. It is useless to add shielding, or use 2 metre tongs, if these increase the difficulties of working, and increase the time. The dose may be greater than it would be without the shielding! 6.5 INTERNAL EXPOSURE Internal radiation exposure occurs when the body is contaminated internally or externally with a radionuclide through breathing, swallowing or contact with the skin Inhalation Breathing radioactive dust and gas introduces soluble and insoluble air borne radioactive materials not only into the lungs but also into the gastro-intestinal and upper respiratory tracts. Different radionuclides have different long-term fates in the body and may present different hazards. Iodine poses a special problem because of its volatility. All work with materials containing free radioactive iodine requires special precautions Ingestion By drinking contaminated water, eating contaminated food or generally by transferring radioactive material to the mouth, radioactive material may enter the body. Ingested material is taken up by various organs depending on the chemical nature of the radionuclide, the biochemistry, and the biological pathways Absorption through the skin The absorption of radionuclides through intact skin as well as the more obvious open wound is a hazard as well as the retention of radionuclides in the skin itself Committed Dose Radioactive material that is absorbed by the body represents a different hazard from external radiation, because in general there is no way to force the elimination of the material by the body. Someone who has ingested radioactive material has a committed dose we can calculate the dose they are committed to receiving over time. 6.6 CONTROL OF INTERNAL RADIATION HAZARD Internal radiation exposure is controlled by: Ionising Radiation Safety Manual_Feb09.doc Page 13 of 47

20 Part 2-14 limiting the dispersal of the material so that it cannot be breathed or ingested limiting contact with the material. Control is achieved by: using the radionuclides in properly designed laboratories. confining the handling of the radionuclide preparations in well-defined and separate areas of the laboratory. wearing appropriate protective clothing. following clearly defined procedures and working rules and good housekeeping. Careful monitoring of workplaces, gloves and protective clothing after use. 6.7 ANNUAL LIMIT OF INTAKE, ALI For the internal radiation hazards produced by ingesting or inhaling radioactive material, the radiation dose received depends on the nature of the radionuclide, the chemical and biochemical properties of the material and its interaction with the organs of the body. To help in controlling the internal radiation dose, the Annual Limit of Intake, ALI, is used. This limit on the amount of a radionuclide that can be taken into the body is dependent on the radionuclide and its biological properties. The ALI may depend on the physical or chemical form of the nuclide. The ALIs are designed to ensure that the 20 msv per year limit on the dose received by a radiation worker is not exceeded Derived Limits The concentrations of radionuclides, which can be present in the laboratory air, and the amounts of the radionuclides, which can be present as contamination on laboratory surfaces, are limited by the ingestion hazard, the Annual Limit of Intake, ALI, and the dose which might be received by the hands from a contaminated surface. Limits for air concentration and surface contamination are called Derived Limits. They are Derived Air Concentration (DAC) in Becquerel per cubic metre for breathing Derived Limit for Surface Contamination in Becquerel per sqare cm for contamination These are explained more fully in Part 6 Section 2.3. Ionising Radiation Safety Manual_Feb09.doc Page 14 of 47

21 Part 3-15 PART 3 GUIDELINES FOR UNSEALED RADIOACTIVE MATERIAL This part contains some general principles governing the use of unsealed radioactive materials. More detailed rules are contained in Part 6. 1 HAZARD CLASSIFICATIONS 1.1 RADIONUCLIDES The precautions for handling unsealed radioactive substances depend upon the properties of the nuclide (type of radiation, half-life etc) the type of compounds containing the radionuclides their specific activity their chemical and physical properties the type of operations being carried out. Radionuclides are classified into four groups according to their relative hazard. Radionuclides in Group 1 are the most hazardous and those in Group 4 the least. Section 6 contains a table of common radioactive nuclides with their classification. 1.2 LABORATORIES Laboratories in which radionuclides are used are classified into three types, A, B and C. The type is based on the quantities of radionuclides that can most safely be used in the laboratory. Type C is the most commonly used laboratory and is the one where the least quantities of radionuclides are used. Type B is designed for more hazardous situations such as iodinations. Part 6 Section 3 contains Tables 6.1 and 6.2 with details of the operations that can be performed with various nuclides in Type B and C laboratories. 2 CONTROL OF THE HAZARD The control of the hazard of unsealed radioactive substances depends the type of radiation emitted (whether the radiation hazard is due to emission, emission or both. - unsealed sources of alpha emitters are not used in the University). The emitters normally used in the University can be divided into two groups for hazard assessment: low energy (tritium, carbon-14, and sulphur-35) and high energy (phosphorus-32). In general other β emitters will also emit γ rays which can increase the hazard. Nuclides which are α emitters can be very hazardous, but natural uranium and thorium are classified as equivalent in hazard to tritium and are the only α emitters used in the University. Specific information for handling common radioactive nuclides can be found in Section SHIELDING AND DISTANCE The dose constraint of 1 msv per year applied by the University to radiation workers is equivalent to about 0.5 µsv per hour for an exposure of 40 hours per week. In practice no one is exposed for this time, and the dose constraint will be met if workers are not normally exposed to radiation fields which will deliver more than 1 µsv per hour to the body. A field of 1 µgray per hour will deliver approximately 1 µsv per hour to the body for the radionuclides used in the University. Shielding and distance should be used to reduce radiation fields to a norm of 1 µgy per hour. The shielding reduces the external dose to workers by absorbing the energy of the Ionising radiation in the shielding material. The type and thickness of the shielding are dependent on the kind of radiation emitted by the nuclide. The intensity of the radiation field should be checked whenever a new procedure or batch of radioactive material is used and if necessary shielding and distance used to reduce the dose rate. For most work in the University, the external radiation hazard is very small and the risk of Ionising Radiation Safety Manual_Feb09.doc Page 15 of 47

22 Part 3-16 ingestion is the main concern, but the external radiation field may be important when handling large quantities Gamma Emitters The absorption of gamma radiation depends on the electron density of the material, so that dense materials like lead are the best absorbers. Other substances can be used but the thickness required to reduce the dose will be larger. The thickness of lead required to reduce the radiation field by a factor of 10 is included in the data for common radionuclides in Section 6. In general the combination of distance (the trunk will normally be 50cm or more from a source on a laboratory bench) and minor shielding will be sufficient for a few MegaBecquerel of unsealed gamma emitters Beta Emitters Many radionuclides used in biological laboratories are beta emitters tritium, carbon-14, sulfur-35 and phosphorus-32 or phosphorus-33. The beta particles are relatively easily absorbed in any material, but X-rays called bremsstrahlung are produced when the betas (electrons) are slowed down in the shielding material. The bremsstrahlung from low energy beta materials such as H-3 and C-14 are not particularly hazardous but they must be considered when using more energetic beta emitters such as P- 32. In general a few mm of glass or Perspex are sufficient to absorb all low energy betas; for P mm of Perspex is sufficient, but lead may also be needed after the Perspex to absorb the bremsstrahlung. 3 MONITORING Two types of monitoring are used in laboratories with unsealed radioactive materials: measurement of the external radiation field (should be less than 1 µsv per hour at body) measurement of the contamination of benches, equipment and workers by the radioactive material Monitoring of the external radiation fields is not necessary in laboratories where only H-3, C- 14, S-35 are used. Monitoring for contamination should be carried out routinely to ensure that surface contamination levels are lower than the limits in Section 6, and especially to check that hands have not been contaminated by the work. Monitoring should be carried out with a survey meter suitable for the type of radiation being used. In some cases contamination will have to be checked using a wipe test. It is essential that each laboratory and area have ready access to a contamination detector that can be used to monitor surface contamination and spills. 3.1 MONITORING TECHNIQUES External radiation fields Always measure the external field from a new supply of radionuclide before opening it. Accidents have occurred due to incorrectly labelled or packaged material! Measure the radiation field close to the source and also at the distances where you will be using the material (hands, body). Estimate your body dose from the measured dose rate and your expected working time. This should be less than 1 µsv per hour. If it is more than this consult your supervisor and area radiation safety officer Ionising Radiation Safety Manual_Feb09.doc Page 16 of 47