RADIATION SAFETY MANUAL辐射安全手册英 文版.docx

1、RADIATION SAFETY MANUAL 辐射安全手册英 文版RADIATION SAFETY MANUALRevision 6. 16 June 2014Contents PageIntroduction 31 General 42 Normal Operating Procedures 52.1 Basic Principles of Control 52.2 General Procedures for Working with Radioactive Materials 52.3 Methods of Protection 52.3.1 The External Radiatio

2、n Hazard 62.3.2 The Internal Radiation Hazard 72.4 Procedure for the Procurement and Use of Radioactive 82.5 Scanning Electron Microscopes MST Department 92.6 PHILIPS X-Ray Diffraction Spectroscope MST and CES Dept. 92.7 Dual Energy X-Ray Absorptiometer DXA 102.8 Sealed Radioactive Sources Physics D

3、epartment 102.9 Unsealed Radioactive Sources CES Dept. 112.10 Security and Safety of Licensed Items 12 3 Emergency Operating Procedures 133.1 Personal Contamination 133.2 Emergency Contact Details (out of hours) 134 Monitoring for Radiation and Contamination 144.1 Monitoring the Workplace 144.2 Pers

4、onal Radiation Monitoring 144.3 Portable Radiation Monitoring Equipment 154.4 Portable Surface Contamination Monitoring Equipment 154.5 Wipe Testing of Sealed Sources 154.6 Maintenance Procedures for the Irradiating Equipment 164.7 Monitoring of I-125 Contamination 164.8 Wipe-testing of Sealed I-129

5、 Source 184.9 Storage and disposal of Radioactive Waste 19 I-125 Laboratory Safety Poster 215 Radiological Protection Administration 225.1 Role of the Heads of Department 225.2 Role of the Radiological Protection Advisor 225.3 Role of the Radiological Protection Officer 225.4 Role of the Departmenta

6、l Radiological Protection Supervisors 225.5 Administration for Radiological Protection at the University of Limerick 236 Intervention Plan and Emergency Plan for Radiological Accidents 6.1 Introduction 266.2 Purpose of plan 266.3 Organisational structure and responsibilities 266.4 Team responsibilit

7、ies 296.5 Crisis scenarios involving radioactive sources or X-ray apparatus 306.6 Call out procedures 32References 33Tables Table 1 Main types of ionising radiations and their hazardsIntroductionThe Statutory requirements for the protection of workers and general public against the danger of radiati

8、on are based on the following three fundamental principles:-(a) every activity resulting in an exposure to ionising radiation shall be justified by the advantages which it produces;(b) all exposures shall be as low as reasonably achievable (the ALARA principle);(c) the dose equivalent to individuals

9、 shall not exceed the prescribed limits.For the purposes of this manual radioactive materials can be classified into two groups - unsealed dispersible radioactive material and sealed sources. The following definitions apply:-(a) a radioactive substance is any substance which is suspected to have an

10、activity concentration greater than the value stated in SI 125 of 2000;(b) a sealed source is a radioactive material wholly bonded within a solid inactive material or encapsulated in a receptacle so that no leakage can occur during storage or foreseeable conditions of use (Refer to ISO 2919);(c) uns

11、ealed dispersible radioactive material is radioactive material not considered to be a sealed source.Work with radioactive substances is perhaps more stringently controlled than some aspects of chemical research, and this is reflected in Irish legislation for the handling of radioactive materials.Sec

12、tion 11. General1.1 The University of Limerick academic Departments shall comply with the conditions of the RPII License in the control and use of radioactive substances and irradiating apparatus.1.2 The Radiation Safety Manual is for the use and guidance of all University staff for whom it is relev

13、ant. The provisions of the Radiation Safety Manual are to supplement the requirements of the RPII Licence and shall be observed in full.Section 22 Normal Operating Procedures2.1 Basic Principles of ControlThere are three main principles of control against the internal radiation hazard:(a) containmen

14、t;(b) cleanliness;(c) use of the least toxic radioactive material that is suitable, and the minimum quantities in all experiments.The two methods of containment of operations most widely used are partial containment by means of fume cupboards, and complete containment by means of glove boxes.2.2 Gen

15、eral Procedures for Working with Radioactive MaterialsThe following working practices and procedures should be adopted:(a) the laboratory bench should be maintained in a tidy and orderly state;(b) there should be no unnecessary accumulation of radioactive materials;(c) any surface contamination aris

16、ing during an operation should be cleaned-up immediately;2.3 Methods of ProtectionEvery attempt must be made to limit the degree of exposure achieved through working with radioactive materials or radiation sources. Table 1 lists the types of radiation which may be encountered. Their range in air var

17、ies with their nature and energy and gives rise to two types of radiological hazard - internal and external.Radiation typeMain hazard to personnelProtectionAlpha particlesInternalContainmentBeta particlesInternal and external skin dose Containment, local shielding and exposure timeGamma & X-raysExte

18、rnalDistances, shielding and exposure timeNeutronsExternalSpecial shielding and exposure timeTable 1 Main types of ionising radiations and their hazards2.3.1 The External Radiation HazardThe basic methods of protection against external radiation are:-(a) restriction of the strength of every source t

19、o the minimum necessary for the task in hand;(b) the use of the maximum amount of distance between the source and the operator, compatible with the satisfactory and safe performance of the work;(c) restriction of the period of exposure to the minimum compatible with safe working; (d) the use of suit

20、able shielding.The protection necessary in any particular situation to ensure that doses are kept below the relevant limit may be achieved by a combination of these methods.(b) The Use of DistanceThe intensity of radiation from a radioactive source decreases with increasing distance. For a point sou

21、rce (and where the dimensions of the source are small compared with the distance from the source to the point of interest), the dose rate is inversely proportional to the square of the distance, i.e., by doubling the distance the dose rate is reduced by a factor of 4 and so on. For example, the gamm

22、a dose rate from a 1 GBq cobalt-60 source decreases with increasing distance as follows. at 1 cm 3.5 Sv h-1 at 10 cm 35 mSv h-1 at 100 cm 350Sv h-1Radioactive sources should therefore never be handled with bare hands, or with gloved hands unless the thickness of the glove is sufficient to reduce the

23、 radiation to reasonable levels.(c) The Use of TimeThe acceptable dose must be kept both within statutory dose limits and ALARA - As Low as Reasonably Achievable.Exposure to high dose rates calls for careful pre-planning, and sometimes for dummy runs. On the job discussions in a radiation field shou

24、ld be avoided.(d) The Use of ShieldingBeta Radiation. The most suitable shielding materials for beta radiation are sheets of light metals such as aluminium or Perspex. The absorption of beta particles in matter gives rise to bremsstrahlung radiation (electromagnetic radiation resulting from the reta

25、rdation of charged particles). For sources of energetic beta radiation, a combination of Perspex and lead makes the best shielding material.Gamma rays cannot be completely absorbed by a shield; they are only reduced in intensity. Of course, any degree of attenuation is possible if the shield is made

26、 thick enough. The approximate thicknesses of various materials required to attenuate 1 MeV gamma rays by a factor of 10 are:LEADIRONCONCRETEWATER3.5cm6cm20cm40cm(These figures refer to broad beam geometry)2.3.2 The Internal Radiation HazardRoutes of Entry:(a) Ingestion. Contamination on surfaces ma

27、y lead to ingestion of activity through the mouth. Control is based on a combination of rules and procedures and strict laboratory discipline, e.g. in the correct use and removal of gloves, correct monitoring procedures after working in contaminated areas, and no eating, smoking, drinking, or applyi

28、ng make-up in contamination-controlled areas.(b) Inhalation. Work carried out in a laboratory or workshop can be accompanied by the formation of airborne contamination. The assessment of the significance of radioactive airborne contamination is a difficult problem due to the influence of many factor

29、s such as breathing characteristics (rate of breathing, whether the individual breathes through the nose or the mouth etc.), the size, shape and density and the chemical properties of the airborne particles (which will affect lung deposition and subsequent metabolism), and the ventilation pattern in

30、 the working area. Control is largely based on proper containment and ventilation coupled with correct working discipline. Before a job is carried out consideration must be given to the possibility of airborne contamination.(c) Absorption. Radioactive contamination may penetrate the skin by diffusio

31、n through the skin barrier or via cuts and wounds. Radioactive materials deposited on the skin and absorbed through the skin may subsequently disperse via the blood stream. Organic solvents are particularly dangerous in that they can penetrate the skin easily. In general, however, the skin forms an efficient barrier to contamination. Control is based largely on correct laboratory discipline and techniques, e.g. when using