GSG-7 Occupational Radiation Protection

Establishing an effective legal and regulatory framework for protection and safety in all exposure situations;

Establishing legislation that meets specified requirements;

Establishing an independent regulatory body with the necessary legal authority, competence and resources;

Establishing requirements for education and training in protection and safety;

Ensuring that arrangements are in place for the provision of technical services and education and training services.

Establishing requirements for applying the principles of radiation protection;

Establishing a regulatory system that meets specified requirements;

Ensuring the application of the requirements for education and training in protection and safety;

Ensuring that mechanisms are in place for the dissemination of lessons learned from incidents and accidents;

Setting acceptance and performance criteria for sources and equipment with implications for protection and safety;

Making provision for the establishment and maintenance of records.

Shall involve workers, through their representatives where appropriate, in optimization of protection and safety;

Shall establish and use, as appropriate, constraints as part of optimization of protection and safety.”

Considers all possible actions involving the source(s) and the way workers operate with or near the source(s).

Implies a ‘management by objective’ process with the following sequence: planning, setting objectives, monitoring, measuring performance, evaluating and analysing performance to define corrective actions, and setting new objectives.

Can be adapted to take into account any significant change in the state of techniques, the resources available for the purposes of protection or the prevailing societal context.

Encourages accountability, such that all parties adopt a responsible attitude to the process of eliminating unnecessary exposures.

The resources available for protection and safety;

The distributions of individual exposure and collective exposure in different groups of workers;

The probability and magnitude of potential exposure;

The potential impact of actions for the purposes of radiation protection on the level of other (non-radiological) risks to workers or to members of the public;

Good practices in relevant sectors;

Societal and economic aspects.

The rationale for proposed operating, maintenance and administrative procedures, together with other options that have been considered and the reasons for their rejection;

Periodic review and trend analysis for doses due to occupational exposure of individuals in various work groups, and other performance indicators;

Internal audits and peer reviews, and the resulting corrective actions;

Incident reports and lessons to be learned.

To determine optimized measures for protection and safety for the prevailing circumstances, with account taken of the available options for protection and safety as well as the nature, magnitude and likelihood of exposures;

To establish criteria, on the basis of the results of the optimization process, for restriction of the magnitudes of exposures and of their probabilities by means of measures for preventing accidents and mitigating their consequences.

Identify all practicable protection options that might potentially reduce the occupational exposure;

Identify all relevant economic, societal, radiological and, where appropriate, non-radiological factors for the particular situation under review that distinguish between the identified options (e.g. collective dose, distribution of individual dose, impact on public exposure, impact on future generations and investment costs);

Quantify, where possible, the relevant factors for each protection option;

Compare all options and select the optimum option(s);

Where appropriate, perform a sensitivity analysis (i.e. evaluate the robustness of the solutions obtained by testing using different values for the key parameters for which recognized uncertainties exist).

Occupational exposure is controlled so that the relevant dose limits for occupational exposure specified in Schedule III are not exceeded”.

An effective dose of 20 mSv per year averaged over five consecutive years⁶⁶ (100 mSv in 5 years) and of 50 mSv in any single year;

An equivalent dose to the lens of the eye of 20 mSv per year averaged over five consecutive years (100 mSv in 5 years) and of 50 mSv in any single year;

An equivalent dose to the extremities (hands and feet) or to the skin⁶⁷ of 500 mSv in a year.

An effective dose of 6 mSv in a year;

An equivalent dose to the lens of the eye of 20 mSv in a year;

An equivalent dose to the extremities (hands and feet) or to the skin67 of 150 mSv in a year.

The general approach to the application of the dose limits where full flexibility is used (i.e. averaging of doses over five years) can be summarized as follows:

In general, the exposure of an individual worker should be controlled so that the effective dose does not exceed 20 mSv in a year. This includes the external dose as well as the internal dose received by the worker during the period.

Where the exposure of an individual worker results in an effective dose exceeding 20 mSv in a year but within the dose limit of 50 mSv, the management should do the following, as appropriate: (i) Carry out a review of exposure to determine whether exposures were as low as reasonably achievable and, where appropriate, to take the necessary corrective action; (ii) Consider ways to restrict further exposures of the individual worker to ensure that the effective dose over the chosen five year averaging period is less than 100 mSv; (iii) Notify the regulatory body of the magnitude of the dose and the circumstances leading to the exposure.

Engineered controls;

Administrative controls;

Personal protective equipment.”

The sources of routine exposure and reasonably foreseeable potential exposure, such as surface contamination, airborne contamination and sources of external radiation.

The nature and magnitude of exposures in normal operations.

The nature, likelihood and magnitude of potential exposures. This should include the ways in which structures, systems and components, and procedures relating to radiation protection or safety, might fail, singly or in combination, or otherwise lead to potential exposures, and the consequences of such failures.

The measures for protection and safety that are necessary to implement the optimization process.

Appropriate monitoring systems.

An assessment of potential public exposure due to radioactive effluents from the facility.

Use of workplace monitoring. This method can give a good assessment of the doses that workers will receive, provided that the radiological conditions in the workplace are reasonably predictable over a long period (at least for several months). Workplace monitoring should be repeated at appropriate intervals, and certainly when the working conditions change significantly.

Use of data from the scientific literature and information from comparable facilities. Some dose values are given in the literature for various workplace situations. These can, in principle, be used to judge whether monitoring is needed.

Use of simulations. Numerical simulations can be powerful and can provide information instantly on the parameters that influence doses that would be received in given exposure situations. The results of simulations should be verified by measurement.

Use of confirmatory measurements. Performing confirmatory measurements with personal dosimeters can help to determine whether individual monitoring is needed.

The assignment of responsibilities for protection and safety for workers to different management levels, including corresponding organizational arrangements and, if applicable (e.g. in the case of itinerant workers), the allocation of the respective responsibilities between employers and the registrant or licensee;

The designation and functions of qualified experts, as appropriate (see paras 3.65–3.71);

The integration of occupational radiation protection with other areas of health and safety, such as industrial hygiene, industrial safety and fire safety;

The system for the accountability for radiation generators and radioactive sources (see paras 3.72–3.74);

The designation of controlled areas and supervised areas (see paras 3.75–3.86);

The local rules for workers to follow and the supervision of work (see paras 3.87–3.92);

The provision of personal protective equipment, if applicable (see paras 3.93 and 9.53–9.64);

The arrangements for monitoring workers and the workplace, including the acquisition and maintenance of suitable instruments (see paras 3.97–3.128 and Section 7);

The system for recording and reporting all of the relevant information relating to the control of exposures, the decisions regarding measures for occupational radiation protection and safety, and the monitoring of individuals (see paras 3.132–3.140 and Section 7);

The education and training programme on the nature of the hazards and on measures for protection and safety (see paras 3.141–3.151);

The methods for periodically reviewing and auditing the performance of the radiation protection programme (see paras 3.157 and 3.158);

The emergency plan, where the need for such a plan is indicated by the safety assessment (see paras 4.5 and 4.6);

The programme for workers’ health surveillance (see Section 10);

The requirements for the assurance of quality and process improvement.

Radiation protection;

Internal and external dosimetry;

Workplace monitoring;

Ventilation (e.g. in underground mines);

Occupational health;

Radioactive waste management.

Controlling exposures or preventing the spread of contamination in normal operation;

Preventing or limiting the likelihood and magnitude of exposures in anticipated operational occurrences and accident conditions.

Shall delineate controlled areas by physical means or, where this is not reasonably practicable, by some other suitable means.

Shall, where a source is only intermittently brought into operation or energized, or is moved from place to place, delineate an appropriate controlled area by means that are appropriate under the prevailing circumstances and shall specify exposure times.

Shall display the symbol recommended by the International Organization for Standardization...and shall display instructions at access points to and at appropriate locations within controlled areas.

Shall establish measures for protection and safety, including, as appropriate, physical measures to control the spread of contamination and local rules and procedures for controlled areas.

Shall restrict access to controlled areas by means of administrative procedures such as the use of work permits, and by physical barriers, which could include locks or interlocks, the degree of restriction being commensurate with the likelihood and magnitude of exposures.

Shall provide, as appropriate, at entrances to controlled areas: (i) Personal protective equipment; (ii) Equipment for individual monitoring and workplace monitoring; (iii) Suitable storage for personal clothing.

Shall provide, as appropriate, at exits from controlled areas: (i) Equipment for monitoring for contamination of skin and clothing; (ii) Equipment for monitoring for contamination of any objects or material being removed from the area; (iii) Washing or showering facilities and other personal decontamination facilities; (iv) Suitable storage for contaminated personal protective equipment.

Shall periodically review conditions to assess whether there is any need to modify the measures for protection and safety or the boundaries of controlled areas.

Shall provide appropriate information, instruction and training for persons working in controlled areas.”

Shall delineate the supervised areas by appropriate means;

Shall display approved signs, as appropriate, at access points to supervised areas;

Shall periodically review conditions to assess whether there is any need for further measures for protection and safety or any need for changes to the boundaries of supervised areas.”

Shall establish in writing local rules and procedures that are necessary for protection and safety for workers and other persons;

Shall include in the local rules and procedures any relevant investigation level or authorized level, and the procedures to be followed in the event that any such level is exceeded”.

Monitoring of exposures and contamination;

Engineered controls such as ventilation systems;

Use of personal protective equipment;

Personal hygiene;

Workers’ health surveillance;

Management of radioactive waste;

Environmental monitoring;

Management system;

Training;

Development of a safety culture;

Keeping of records;

Reporting;

Emergency preparedness and response, where appropriate.

Information from similar work completed previously;

Time for starting the work, its estimated duration and the human resources involved;

Maps of estimated dose rates;

Operational state of the plant (e.g. for a nuclear power plant, cold or hot shutdown, and operation at full or reduced power);

Other activities in the same area which could interfere with the work;

Preparation and assistance in operations (e.g. isolation of the process, scaffolding and insulation work);

Protective clothing and tools to be used;

Communication necessary to ensure supervisory control and coordination;

Management of any radioactive waste arising from the work;

Coordination with protective measures for conventional safety.

A detailed dose rate map of the working area and possible hot spots, produced from a survey made prior to the work or otherwise estimated;

An estimate of contamination levels and how they could change during the course of the work;

Specification of any additional workplace monitoring of radiation levels to be carried out before or during the work;

An estimate of individual exposure and collective exposure for each work step;

Specification of any additional dosimeters to be used by workers;

Specification of personal protective equipment to be used in different phases of the work;

Details of any time restrictions or dose restrictions;

Instructions on when to contact the radiation protection officer.

Assessing the exposure of workers and demonstrating compliance with regulatory requirements.

Confirming the effectiveness of working practices (e.g. the adequacy of supervision and training) and engineering standards.

Determining the radiological conditions in the workplace, whether these are under adequate control and whether operational changes have improved or worsened the situation.

Evaluating and improving operating procedures from a review of the collected monitoring data for individuals and groups. Such data may be used to identify both good and bad features of operating procedures and design characteristics, and thereby contribute to the development of safer working practices in relation to radiation.

Providing information that can be used to enable workers to understand how, when and where they are exposed, and to motivate them to take steps to reduce their exposure.

Providing information for the evaluation of doses in the event of accidental exposures.

Routine monitoring is associated with continuing operations and is intended to meet regulatory requirements and to demonstrate that the working conditions, including the levels of individual dose, remain satisfactory.

Special monitoring is investigative in nature and typically covers a situation in the workplace for which insufficient information is available to demonstrate adequate control. It is intended to provide detailed information to elucidate any problems and to define future procedures. It should normally be undertaken at the commissioning stage of new facilities, or following major modifications to facilities or procedures, or when operations are being carried out under abnormal circumstances, such as an accident.

Confirmatory monitoring is performed where there is a need to check assumptions made about exposure conditions (e.g. to confirm the effectiveness of protective measures).

Task related monitoring applies to a specific operation. It provides data to support the immediate decisions on the management of the operation. It may also support the optimization of protection.

Individual monitoring comprises measurements made using equipment worn by individual workers, or measurements of quantities of radioactive substances in or on their bodies, and the interpretation of such measurements.

Workplace monitoring comprises measurements made in the working environment and the interpretation of such measurements.

The amount of radioactive material present and the radionuclides involved;

The physical and chemical form of the radioactive material;

The type of containment used;

The operations performed;

The expected levels and likely variations in the doses or intakes;

The complexity of the measurement procedures and interpretation procedures of the measurement programme;

The general working conditions.

The handling of large quantities of gaseous or volatile materials, for example of tritium and its compounds in large scale production processes, in heavy water reactors and in manufacturing of gaseous light sources;

The processing of plutonium and other transuranic elements;

The maintenance of reactor facilities, which can lead to exposure due to fission products and activation products;

The bulk production of radioisotopes;

The production and handling of large quantities of radiopharmaceuticals, such as ¹⁸F for diagnostics by positron emission tomography or ¹³¹I for therapy;

The mining of high grade uranium ores, processing of uranium mineral concentrates and production of nuclear fuel;

The processing of mineral concentrates, such as monazite that is rich in thorium, and the production of products containing thorium.

Shall be sufficient to enable: (i) Evaluation of the radiological conditions in all workplaces; (ii) Assessment of exposures in controlled areas and supervised areas; (iii) Review of the classification of controlled areas and supervised areas.

Shall be based on dose rate, activity concentration in air and surface contamination, and their expected fluctuations, and on the likelihood and magnitude of exposures in anticipated operational occurrences and accident conditions.

Demonstrate compliance with regulations;

Identify significant changes to the working environment;

Give details of radiation surveys, for example date, time, location, dose rate, airborne activity concentration, instruments used, surveyor or other comments;

Give details of any reports received about the workplace, whereby compliance with relevant requirements could be adversely affected;

Give details of any appropriate actions taken.

The circumstances leading to the suspected exposure;

Verification of the dosimetric results;

The probability that dose limits or levels will be exceeded under current working conditions;

Corrective actions to be taken.

Shall provide workers with access to records of their own occupational exposure;

Shall provide the supervisor of the programme for workers’ health surveillance, the regulatory body and the relevant employer with access to workers’ records of occupational exposure;

Shall facilitate the provision of copies of workers’ exposure records to new employers when workers change employment;

Shall make arrangements for the retention of exposure records for former workers by the employer, registrant or licensee, as appropriate;

Shall, in complying with (a)–(d) above, give due care and attention to maintaining the confidentiality of records.

Shall provide all workers with adequate information on health risks due to their occupational exposure in normal operation, anticipated operational occurrences and accident conditions, adequate instruction and training and periodic retraining in protection and safety, and adequate information on the significance of their actions for protection and safety;

Shall provide those workers who could be involved in or affected by the response to an emergency with appropriate information, and adequate instruction and training and periodic retraining, for protection and safety;

Shall maintain records of the training provided to individual workers.”

The main risks associated with ionizing radiation;

Basic quantities and units used in radiation protection;

Requirements for radiation protection (including optimization of protection and limitation of doses);

The fundamentals of practical radiation protection (e.g. use of personal protective equipment, shielding and behaviour in designated areas);

Specific task related issues;

Responsibility to advise a designated person immediately if any unforeseen occurrence involving increased radiation risk arises;

Where appropriate, actions that may need to be taken in the event of an accident.

When required by the regulatory body;

When a systematic independent assessment of the programme is considered necessary by the management;

Following the implementation of a new radiation protection programme or substantive elements of the radiation protection programme;

When significant changes are made to functional areas of the radiation protection programme, such as significant reorganization or procedural revision;

When necessary to verify implementation of previously identified corrective actions.

If, in any process material, the activity concentration of any radionuclide in the ²³⁸U decay series or the ²³²Th decay series exceeds 1 Bq/g, or if the activity concentration of ⁴⁰K exceeds 10 Bq/g, the industrial activity is regarded as a practice and the requirements for planned exposure situations apply.

If, in every process material, the activity concentrations of all radionuclides in the ²³⁸U decay series and the ²³²Th decay series are 1 Bq/g or less and the activity concentration of ⁴⁰K is 10 Bq/g or less, the material is not regarded as naturally occurring radioactive material, the industrial activity is not regarded as a practice and the requirements for existing exposure situations apply.

Exposure due to ²²²Rn, ²²⁰Rn and their progeny in workplaces in which occupational exposure due to other radionuclides in the ²³⁸U decay series or the ²³²Th decay series is controlled as a planned exposure situation;

Exposure due to ²²²Rn and its progeny in workplaces in which the annual average activity concentration of ²²²Rn in the air remains above the reference level (see paras 5.19–5.23).

Mining and processing of uranium ore;

Extraction of rare earth elements [25];

Production and use of thorium and its compounds;

Production of niobium and ferro-niobium;

Mining of ores other than uranium ore;

Production of oil and gas [26];

Manufacture of titanium dioxide pigments [27];

Activities in the phosphate industry [28];

Activities in the zircon and zirconia industries [29];

Production of tin, copper, aluminium, zinc, lead, and iron and steel;

Combustion of coal;

Water treatment.

The economic importance of many industries involving naturally occurring radioactive material.

The large volumes of residues and process wastes that can be generated, and thus the limited options for their management.

The potentially high cost of regulation in relation to the reductions in exposure that can realistically be achieved when exposure levels and the associated radiation risks are already rather low.

The recognition that doses are always expected to be well below the threshold for deterministic health effects; in addition, there is never any real prospect of a radiological emergency.

The main radionuclides of natural origin contributing to gamma exposure are ²¹⁴Pb and ²¹⁴Bi from the ²³⁸U decay series, and ²²⁸Ac, ²¹²Pb and ²⁰⁸Tl from the ²³²Th decay series. The highest gamma energy (2614 keV) is associated with ²⁰⁸Tl. Exposure to gamma radiation arises mainly from accumulations of mineral concentrates or residues. Dose rates are generally highest near process tanks, piping, filters and large stockpiles of material.

Airborne dust particles arise from the resuspension of contamination on floors and other surfaces, from releases from processing operations and from the conveying of minerals. For inhalation of such particles by workers in industrial activities involving naturally occurring radioactive material, exposure due to radionuclides in the ²³⁸U decay series and the ²³²Th decay series may be of concern for the purposes of radiation protection.

Advising management on all matters relating to ventilation and air purification systems;

Ensuring the proper operation of the ventilation systems (including auxiliary ventilation systems, which may be prone to rapid deterioration in underground mines), initiating any necessary modifications and ensuring that any deficiencies are promptly addressed;

Ensuring that air flows and velocities are measured in accordance with good ventilation practice;

Ensuring that properly calibrated instruments are used;

Conducting programmes for sampling and control of dust, in conjunction with the radiation protection officer;

Participating in training programmes and developing or approving all training material on ventilation and control of dust;

Being familiar with the properties of ²²²Rn, ²²⁰Rn and their progeny, where applicable.

The properties and hazards associated with radionuclides in the ²³⁸U decay series and the ²³²Th decay series (including ²²²Rn and ²²⁰Rn, where relevant);

The application of the principles of time, distance and shielding to minimize exposure to gamma radiation near large accumulations of naturally occurring radioactive material, especially where activity concentrations are high;

The measurement of airborne activity in the form of dust, and ²²²Rn and its progeny;

The need for controlling and suppressing airborne dust, and the methods employed;

The functioning and purpose of the ventilation system, and its importance for protection and safety.

Emergency workers who have specified duties;

Workers performing their duties in workplaces and not being involved in the response to a nuclear or radiological emergency;

Workers who are requested to stop performing their duties in workplaces and to leave the site;

Workers who are accidentally exposed as a result of an accident or other incident at a facility or during the conduct of an activity and whose exposure is not related to the emergency response.

The persons or organizations responsible for ensuring compliance with requirements for protection and safety for workers in a nuclear or radiological emergency, including those for controlling the exposure of emergency workers;

Specified roles and responsibilities of all workers involved in the response to a nuclear or radiological emergency;

Details of adequate protective actions to be taken, personal protective equipment and monitoring equipment to be used, and dosimetry arrangements;

Consideration of access control for workers in a nuclear or radiological emergency on the site.

Training of emergency workers designated as such in advance;

Providing instructions immediately before their use to those emergency workers not designated as such in advance⁸ on how to perform their specified duties under emergency conditions and on how to protect themselves (‘just in time training’);

Managing, controlling and recording the doses received;

Provision of appropriate, specialized personal protective equipment and monitoring equipment;

Provision of iodine thyroid blocking, where appropriate;

Medical follow-up and psychological counselling, as appropriate;

Obtaining the informed consent of emergency workers to perform specified duties, where appropriate.

For the purposes of saving life or preventing serious injury;

When undertaking actions to prevent severe deterministic effects and actions to prevent the development of catastrophic conditions that could significantly affect people and the environment; or

When undertaking actions to avert a large collective dose.”

The dose from external exposure to strongly penetrating radiation for Hp(10). Doses from external exposure to weakly penetrating radiation and from intake or skin contamination need to be prevented by all possible means. If this is not feasible, the effective dose and the RBE weighted absorbed dose to a tissue or organ have to be limited to minimize the health risk to the individual in line with the risk associated with the guidance values given here.

The total effective dose E and the RBE weighted absorbed dose to a tissue or organ AD_T via all exposure pathways (i.e. both dose from external exposure and committed dose from intakes) which are to be estimated as early as possible in order to enable any further exposure to be restricted as appropriate.

Category 1. Emergency workers undertaking mitigatory actions and urgent protective actions on the site, including lifesaving actions, actions to prevent serious injury, actions to prevent the development of catastrophic conditions that could significantly affect people and the environment, actions to prevent serious deterministic effects and actions to avert a large collective dose. Emergency workers in Category 1 are required to be designated as such at the preparedness stage. They are likely to be operating personnel at the facility or undertaking the activity, but they may be personnel from the emergency services. They are employed either by a registrant or licensee (operating organization) or by a response organization, and they should receive training in occupational radiation protection.

Category 2. Emergency workers undertaking urgent protective actions off the site (e.g. evacuation, sheltering and radiation monitoring) to avert a large collective dose. They are most likely to be police, firefighters, medical personnel, and drivers and crews of evacuation vehicles. Every effort should be made to designate emergency workers in Category 2 as such at preparedness stage. They are to have pre-specified duties in an emergency response and should receive training in occupational radiation protection on a regular basis as first responders. They are not normally considered to be occupationally exposed to radiation, and their employers are response organizations.

Category 3. Emergency workers undertaking early protective actions and other response actions off the site (e.g. relocation, decontamination and environmental monitoring) as well as other actions aimed at enabling the termination of the emergency. Emergency workers in Category 3 may or may not be designated as such at the preparedness stage. They may or may not normally be considered to be occupationally exposed to radiation, and they may or may not have received any relevant training, including training in radiation protection.

Category 1 emergency workers should carry out actions to save lives or prevent serious injury, actions to prevent severe deterministic effects and actions to prevent the development of catastrophic conditions that could significantly affect people and the environment.

Category 2 emergency workers should not be the first choice for taking lifesaving actions.

Category 1 and Category 2 emergency workers should carry out actions to avert a large collective dose.

Category 3 emergency workers should carry out those actions in which they will not receive a dose of more than 50 mSv⁹.

Performing an immediate medical examination, consultation and indicated treatment;

Carrying out control of contamination;

Carrying out immediate decorporation¹⁰ (if applicable);

Carrying out registration for longer term medical follow-up;

Providing comprehensive psychological counselling.

Exposure due to contamination of areas by residual radioactive material deriving from:

• (i) Past activities that were never subject to regulatory control or that were subject to regulatory control but not in accordance with the requirements of these Standards;

• (ii) A nuclear or radiological emergency, after an emergency has been declared to be ended….”

Materials (in a natural or processed state) in which the radionuclides are essentially all of natural origin;

²²²Rn and ²²⁰Rn, together with their progeny, as specified in para. 3.161;

Cosmic radiation.

Remedial actions in an existing exposure situation involve removal of the source or reduction of its activity or amount. An example of a remedial action is the removal of residual radioactive material from a contaminated site.

Protective actions in an existing exposure situation involve measures that act on the exposure pathways rather than on the source itself. Examples of protective actions are the control of access to a contaminated site and restrictions on the use of contaminated water for drinking purposes.

Workers who are exposed while carrying out remedial actions. The exposures of these workers may be increased as a direct result of their work (i.e. when such action involves the handling, transport or disposal of residual radioactive material).

Workers who are exposed in the existing exposure situation but who do not carry out any remedial action. The exposures of these workers might eventually be reduced as a result of remedial or protective actions.

Specification of the general principles underlying the protection strategies;

Assignment of responsibilities for the development and implementation of the protection strategies to the regulatory body or other relevant authority (e.g. a health authority or an environmental protection agency)¹¹ and to the parties involved in the implementation process;

Provision for the involvement of interested parties in the decision making process, as appropriate.

An evaluation of the exposure situation, including any potential exposure;

Identification of the possible protection options expressed in terms of justified remedial actions and/or protective actions;

Selection of the best option under the prevailing circumstances;

Implementation of the selected option.

The nature of the exposure and the practicability of reducing the exposure;

Societal implications;

National or regional factors;

Past experience in the management of similar situations;

International guidance and good practice elsewhere.

Determining the nature and extent of the contamination;

Identifying exposure pathways for workers;

Assessing individual doses via all routes of exposure;

Evaluating health and safety issues during remediation work, including the use of appropriate personal protective equipment.

Descriptions of activities performed;

Data from monitoring and surveillance programmes;

Records of occupational health and safety for remediation workers;

Records of the types and quantities of radioactive waste generated and of its management;

Data from environmental monitoring;

Records of financial expenditures;

Records of the involvement of interested parties;

Records of any continuing responsibilities for the site;

Identification of locations that were remediated and those with residual contamination;

Specifications of any areas to which access remains restricted and the restrictions that apply;

Statements of any zoning or covenant restrictions or conditions;

Statements of lessons identified.

Preparing and applying appropriate protection and safety procedures;

Applying good engineering practice;

Ensuring that the staff are adequately trained, qualified and competent;

Ensuring that protection and safety is integrated into the overall management system.

Galactic cosmic radiation from sources outside the solar system. Galactic cosmic radiation incident on the upper atmosphere consists of a 98% nucleonic component (mainly protons and helium ions) and 2% electrons. With increasing solar activity, the fluence rate decreases but the maximum of the energy spectrum is shifted to higher energies.

Solar cosmic radiation generated near the surface of the sun by magnetic disturbances. This radiation originates from solar flares and coronal mass ejections when the particles produced are directed towards the Earth. These solar particles comprise mostly protons. Only the most energetic particles contribute to doses at ground level.

Radiation from the Earth’s radiation belts (the Van Allen belts). The Van Allen radiation belts are formed by the capture of protons and electrons by the Earth’s magnetic field. There are two Van Allen belts: an inner belt centred at about 3000 km and an outer belt centred at about 22 000 km from the Earth’s surface. In a region east of Brazil known as the South Atlantic Anomaly, the inner Van Allen belt descends to within a few hundred kilometres to the Earth’s surface.

The regulatory body or other relevant authority is required to establish a framework that includes a reference level of dose and a methodology for the assessment and recording of doses received by aircrew from occupational exposure to cosmic radiation. A reference level of about 5 mSv might be considered reasonable.

Where the doses of aircrew are likely to exceed the reference level, employers of aircrew are required: (i) to assess and keep records of doses; and (ii) to make records of doses available to aircrew.

Employers are required: (i) to inform female aircrew of the risk to the embryo or fetus due to exposure to cosmic radiation and of the need for early notification of pregnancy and (ii) to apply the requirements of para. 3.114 of GSR Part 3 [2] in respect of notification of pregnancy¹⁴, which states that:

The regulatory body or other relevant authority should establish, where appropriate, a framework for radiation protection that applies to individuals in space based activities.

All reasonable efforts should be made to optimize protection by restricting the doses received by space crew while not unduly limiting the extent of the activities that they undertake.

Female workers during and after pregnancy, with implications of exposure not only for themselves but also for the embryo or fetus or the breastfed infant.

Workers who regularly carry out their work on the premises or site of another employer and who may be exposed due to the site operator’s use of radiation; and workers who may take onto a site their own source of radiation, with implications for exposure both for themselves and for the employees of the site operator. Such workers, referred to as itinerant workers, are often employed by contractors.

In utero:

• (i) External exposures due to sources of radiation external to the body of the female worker that irradiate not only maternal tissues but also the embryo or fetus.

• (ii) Internal exposures due to the incorporation of radionuclides by the female worker (or are present in maternal hollow organs, such as the urinary bladder or bowel) that transfer to the fetus through the placenta; or exposure of the fetus to penetrating radiation from radionuclides deposited in maternal tissues (or that are present in maternal hollow organs).

Breastfed infant:

• (i) External exposures due to penetrating radiation from radionuclides in maternal tissues or present in maternal hollow organs such as the urinary bladder or bowel.

• (ii) Internal exposures from the intake of radionuclides by the breastfed infant via transfer from maternal tissues to breast milk and subsequent ingestion during breast-feeding.

Maintenance workers in the nuclear power industry — employed by a contractor providing services during normal operations, shutdown or maintenance outages;

Personnel for quality assurance, in-service inspection and non-destructive examination or testing in the nuclear power industry and other industries;

Maintenance staff and cleaning staff in general industry who could be exposed to radiation from a wide range of applications;

Contractors providing specialized services — for example removal of scale and sediment from within pipes and vessels (for the decontamination of equipment), the transport of radioactive waste, or the loading or changing of radioactive sources at irradiation facilities;

Contracted workers in mining and minerals processing facilities who could be exposed to naturally occurring radioactive material;

Industrial radiography companies contracted to work at a facility operated by a management other than their own;

Workers performing contracted security screening using X ray machines or radioactive sources;

Contracted workers involved in the decommissioning of facilities of various types, and in the decontamination of associated buildings and the remediation of outside areas;

Contracted workers of companies installing and servicing medical equipment;

Medical staff who work in supervised areas or controlled areas in several hospitals or clinics (whether fixed or mobile) not operated by their employer.

The operation of a facility has the potential to cause exposure of the contractor’s employees, who themselves do not possess a radiation source. In such cases, the management of the facility is the registrant or licensee and the contractor is merely an employer.

The contractor’s employees bring their own source of radiation to a facility and, hence, have the potential to cause exposure of the employees of that facility. In such cases, the contractor is the registrant or licensee and the management of the facility is merely an employer.

A combination of (a) and (b), whereby the operation of the facility and the activities of the contractor on-site both have the potential to cause exposure to each other’s employees. In such cases, both the management of the facility and the contractor are registrants or licensees.

The development and use of specific restrictions on exposure and other means of ensuring that the measures for protection and safety for workers who are engaged in work that involves or could involve a source that is not under the control of their employer are at least as good as those for employees of the registrant or licensee;

Specific assessments of the doses received by workers as specified in (a) above;

A clear allocation and documentation of the responsibilities of the employer and those of the registrant or licensee for protection and safety.

Shall obtain from the employers, including self-employed persons, the previous occupational exposure history of workers...and any other necessary information;

Shall provide appropriate information to the employer, including any available information relevant for compliance with the requirements of these Standards that the employer requests;

Shall provide both the worker and the employer with the relevant exposure records.”

Optimization of protection and safety (including any associated dose constraints);

Dose limitation;

Establishment of classified areas;

Use of personal protective equipment;

Local rules and procedures;

Monitoring and dose assessment;

Dose records;

Information and training;

Workers’ health surveillance.

Details of any radiological hazards and associated controls, and an estimate of the maximum radiation doses likely to be received by the contractor’s employees in the work under the contract;

Details of any additional training that will be needed and that, therefore, should be provided either by the contractor or by the management of the facility;

Information on whether the contractor’s employees need to wear individual dosimeters and, if so, what arrangements are in place;

Details of non-radiological hazards such as chemicals, dust and heat;

Provision of personal protective equipment, if required.

Details of appropriate qualifications of the employee (training, experience and certification);

Details of the employee’s dose history;

Any relevant information on the employee’s fitness for work.

The review of engineered controls relating to protection and safety;

The formulation of suitable local rules and procedures;

Appropriate dosimetry arrangements;

The requirement for personal protective equipment;

The use of radiation monitoring equipment;

Record keeping;

Emergency procedures.

A telephone number that the contractor can be contacted in the event of an emergency.

The name(s) of the radiation protection officer(s) who will be present during the work.

The type of radiation generator or radiation source to be used.

A copy of the contractor’s local rules and procedures, which should provide sufficient information about the proposed work; if adequate local rules are not available, the contractor should not be allowed to undertake the work.

Placement of barriers to prevent access to controlled areas in which dose rates exceed predetermined levels;

Posting of sufficient warning notices;

Provision of warning signals (that do not have any other local meaning or significance) prior to and during the exposure;

Display of explanatory notices at access points;

Inspections of equipment and radiation monitors prior to and after use;

Replacement or repair of equipment identified as inoperable prior to use;

Searching of the controlled area before starting and periodically thereafter;

Patrolling of the barrier to prevent unauthorized access;

Use of a suitable, calibrated radiation monitor in setting or verifying placement of the barrier and confirming expected dose rates after exposures (this is especially important where pulsed X ray fields might be present);

Provision of adequate storage facilities;

Formulation of emergency plans;

Use of appropriate personal monitoring devices.

Provision of direct supervision by the site operator;

Replacement of certain contractor personnel;

Documentation of additional experience, training or education.

Any changes in the professional qualifications required;

Any changes in legislation;

Lessons to be learned from experience at the facility and other facilities;

The worker’s dose record;

The ongoing adequacy and effectiveness of the level of training acquired;

The need for refresher training;

Any change in fitness for work;

Any changes in facilities, operations or work practices.

At a nuclear power plant, the management will have acquired extensive knowledge of the radiation risks associated with the operation and maintenance of the facility, will have already carried out a detailed safety assessment for its own employees (and likely for those employees of contractors that are foreseen to be used for assessed tasks) and will have established a comprehensive radiation protection programme. In this instance, therefore, it would be appropriate for the management of the facility: to communicate the relevant information on safety assessment to the contractor; to discuss work related circumstances and any identified concerns with the contractor; and to draw up a simplified radiation protection programme that covers the work of the contractor.

An industrial radiography company working at a chemical plant will already have developed its own radiation protection programme for work on-site, but it will need to liaise with the safety officers at the facility and to provide them with appropriate information from the radiation protection programme. That information will include the arrangements for management and supervision, and the procedures to be used to ensure radiation protection of the employees at the facility.

The nature of the work to be carried out in the foreseeable future;

The potential for exposure associated with this work;

The extent of training already provided and qualifications obtained;

Site specific requirements at the facilities to be visited (e.g. entry procedures, the use of personal protective equipment, and emergency procedures).

Changes in the working environment;

Legislative and regulatory changes;

Any modifications to working practices;

The level of adherence to current arrangements;

The practicability of current arrangements;

The adequacy of emergency plans;

The effectiveness of previously used arrangements and current arrangements in maintaining doses as low as reasonably achievable;

The need for changes to the radiological evaluation, the safety assessment for the planned work and the level of interaction with the regulatory body;

Lessons to be learned and operational experience.

The contractor should enter the following information on an access approval form: (i) individual information regarding the worker; (ii) the contract reference; (iii) details of the employer; (iv) the professional skills of the worker together with relevant certificates; and (v) the expected duration of the operation. The contractor should then send the form to the management of the facility who should then add a description of the areas where access is permitted and the period of validity of the access permit to the facility and to the supervised areas and the controlled areas therein. For access to areas with high (or potentially high) dose rates, a specific type of permit should be used. The access procedure for a nuclear power plant can take several days to process.

On arrival of the itinerant worker at the nuclear power plant, a check should be made of all the information mentioned in para. 6.82(a), as well as: (i) the worker’s fitness for work; and (ii) the worker’s dose record over the current calendar year, over the past twelve months and the past five years.

Specific training should be provided on particular facility conditions and for actions required in the event of an emergency.

A check should be made of the compatibility of the skills of the itinerant worker with the work to be performed.

Itinerant workers should be able to justify their access to a controlled area by producing a radiation work permit developed in accordance with the facility’s work management system (see para. 3.96).

An individual dose objective for the itinerant worker should be established.

An individual dose objective should be calculated on a pro rata temporary basis.

Access to areas of high (or potentially high) levels of radiation should be restricted or prohibited.

A pre-work review, involving a detailed description of the work to be done, technical data, and dosimetric and environmental conditions.

A preliminary procedure to carry out the work, together with an associated dose estimate.

Training on a mock-up or, where reasonably feasible, a representative simulation of the actual job site or, if necessary, a briefing using descriptors of the job site (e.g. photographs or videos).

Feedback on this training, including the exposure time, difficulties in carrying out tasks, phases to be improved, specific tools to be developed and the number of people in the workplace simultaneously.

Anticipation, to the extent possible, of potential breakdowns of tools or equipment and of other operational incidents. This facilitates the formulation of corrective actions and the training of workers to carry out such actions in a manner that keeps doses as low as reasonably achievable.

Improvement of working procedures and estimated doses, and optimization of protection and safety.

Final training in accordance with such optimized procedures.

Sometimes, when itinerant workers perform maintenance services, changes are made to the default settings of the system (e.g. fluoroscopy modes in which the X ray beam is pulsed). Such changes should be registered so that the users of the systems are aware of them, and the responsible medical physicist at the facility should be informed personally.

To avoid the possibility of an accident resulting from the temporary deactivation of a safety interlock during maintenance of a system by an itinerant worker, backup measures should be in place to prevent the clinical use of the system in such circumstances.

After any work performed by an itinerant worker that affects radiation aspects or image quality aspects of the system, a detailed report should be prepared and submitted to the head of the service where the work was performed.

After any maintenance is performed on a system by an itinerant worker, the system should be left in a state ready to be used with patients. Sometimes, after repair of a film processor, the cassettes are loaded with exposed films, and this can lead to some patients being irradiated twice when the system is next used because the first images were not usable.

In some mines, contractors are hired to carry out normal day to day mining operations that may be conducted on a large scale and may continue for a long time. In such situations, it may be best to place responsibility for the management and control of radiation exposure of itinerant workers with the management of the mine. The management should already have the necessary competence and infrastructure in place, and this competence and infrastructure will almost certainly be greater than that possessed by the contractor.

Contractors may be hired to carry out specialized, non-routine tasks that do not form part of the day to day operation of the mine, such as the installation and maintenance of plant and equipment in the mine, excavation of ore passes¹⁵ and sinking of shafts. Such tasks may sometimes involve higher exposure levels than those encountered during normal operations. It is possible, in such circumstances, that the contractor may be better placed to take responsibility for the radiation protection of its employees because of the specialized nature of the work and because the contractor performs this work on a routine basis and is likely to be more familiar with the particular radiation hazards involved. The contractor also has the advantage of being more easily able to keep track of its employees’ radiation doses over long periods. On the other hand, the contractor’s experience in carrying out such specialized work may have been gained mostly in situations where the radiological hazards were insignificant, in which case the responsibility for radiation protection may be better placed with the management of the mine, even though the work is of a specialized nature. The mine management should then familiarize itself with the radiation hazards associated with such specialized work.

The hazards posed by sealed sources (e.g. nuclear gauges) and by naturally occurring radioactive material (e.g. radium rich scale) in various parts of the plant;

The presence of controlled areas or supervised areas;

Procedures to be followed to optimize protection so that exposure is as low as reasonably achievable;

The use of appropriate personal protective equipment;

Supervision;

Dose assessment and maintenance of dose records;

Waste management;

Training;

Actions to take if ventilation, dust control or other relevant control systems fail or are taken out of service.

Monitoring of hands and fingers should be considered for workplaces where extremities are particularly close to the radiation emitter or radiation beam, such as in situations where radioactive sources are handled in research, nuclear medicine and dismantling operations.

Monitoring of extremities, including monitoring of feet, should be considered in interventional cardiology or radiology and in workplaces in nuclear medicine.

Monitoring of skin should be considered for workplaces where skin is close to the radiation emitter or radiation beam or can become contaminated, for instance in the handling of unsealed sources.

Monitoring of the lens of the eye should be considered in workplaces where the eyes are particularly close to the radiation emitter (which can also be a source of stray radiation) or the radiation beam. Workers for whom exposure of the lens of the eye might be important and for whom monitoring should be considered include workers in the medical sector, such as staff working in close proximity to patients in image guided interventional procedures, staff carrying out certain activities in nuclear medicine, staff involved in manual brachytherapy, staff involved in computed tomography guided biopsy and cyclotron engineers. Other examples of workers who could receive significant doses to the lens of the eye include workers in nuclear facilities such as those involved in the fabrication of mixed oxide fuels, in laboratory studies using glove boxes and in decommissioning.

For neutron radiation, where homogenous radiation fields are usually present, separate eye lens dosimetry is not necessary because neutron whole body monitoring usually gives a conservative estimate of the dose to the lens of the eye, irrespective of the energy and direction of incidence of the radiation (see para. 246 of Ref. [9] and also table 1 in Ref. [51] in comparison with table A.41 in Ref. [9]).

For photon radiation, separate dosimetry for the lens of the eye is usually the only suitable method for determining the dose to the lens of the eye:

• (i) If the radiation field is inhomogeneous, the dosimeter should always be located near the eyes, if possible in contact with the skin and facing towards the radiation source.

• (ii) It is usually acceptable to measure H_p(0.07) but not H_p(10) [11, 52]; however, the measurement of H_p(10) may also be acceptable if the mean photon energy is greater than about 40 keV and if the radiation is incident mainly from the front or the person is moving in the radiation field [52].

• (iii) If eye shielding in the form of lead glasses is used, the dosimeter should preferably be located behind the eye shielding; where this is not practicable, the dosimeter should be worn above, or next to, the eyes and possibly covered by a filter that mimics the attenuation provided by the lead glasses.

• (iv) If shielding for the trunk (e.g. a lead apron) is used, monitoring near the eyes is necessary because monitoring behind the shielding underestimates the dose to the lens of the eye.

For beta radiation, monitoring is necessary only if the maximum beta energy exceeds 700 keV, since beta radiation of lower energy does not penetrate to the lens of the eye:

• (i) If eye shields (e.g. glasses) are used that are thick enough to absorb the beta radiation¹⁶, only photon radiation should be considered, but account should be taken of any bremsstrahlung contributions (both outside and behind the shielding) produced by high energy beta radiation.

• (ii) If adequate eye shields are not used, separate dosimetry for the lens of the eye is necessary and H_p(3) is the quantity that should be measured.

• (iii) As beta radiation fields are usually rather inhomogeneous, the dosimeter should be positioned near the eyes.

Where no substantial alterations to the protective shielding or to the processes conducted in the workplace are to be expected, routine monitoring should be used only occasionally, for checking purposes.

Where changes in the radiation field in the workplace are to be expected, but are unlikely to be rapid or severe, periodic or occasional checks, mainly at pre-established locations, should be made, which will usually give sufficient and timely warning of deteriorating conditions.

Where sudden unexpected increases in exposure might result in a significant dose being received by a worker, provision should be made for the continuous monitoring of exposures.

Where individual doses are assessed on the basis of the results of routine workplace monitoring, that workplace monitoring should be continuous and should be representative of all working areas in the workplace.

Photon dosimeters, giving information only on the personal dose equivalent H_p(10).

Beta–photon dosimeters, giving information on the personal dose equivalents H_p(0.07) and H_p(10).

Extremity dosimeters, giving information on H_p(0.07) for beta–photon radiation.

Eye lens dosimeters, giving information on H_p(3) or H_p(0.07) for beta–photon radiation (and for neutrons, if neutron sources are being handled, H_p(10) can provide an approximate estimate of H_p(3)); dosimeters designed specifically for H_p(3) are not yet widely available (however, see para. 2.38).

Neutron dosimeters, giving information on H_p(10).

The instrument should indicate the dose equivalent rate, although additional functions should sometimes be considered, such as the calculation of the accumulated dose or the time remaining for safe occupancy.

The dose rate range of the instrument should be adequate to cover the range of dose rates that could reasonably be expected to be encountered in practice.

When a monitor is exposed beyond its range, the indication should remain high and off scale.

In the region near the relevant dose limit, a factor of 1.5 in either direction is considered acceptable.

In the region of the recording level, an acceptable uncertainty of ±100% is implied.

Low cost;

Low weight, convenient size and shape, and convenient and reliable fastening clips;

Adequate mechanical strength and dust tightness;

Unambiguous identification;

Ease of handling;

Reliable readout systems;

Reliable supplier who will continue to provide dosimeters over a long period;

Adaptability to various applications (e.g. measurement of body dose and extremity dose);

Availability of, and ease of, calibration;

Suitability for automatic processing.

Ability to withstand shock and vibration;

Independence of atmospheric pressure on the response;

Dust tightness;

Water resistance;

Independence of dose rate on the response;

Correctness of the response in pulsed fields (as applicable);

Insensitivity to electric fields and magnetic fields;

Stability under extremes of temperature and humidity;

Insensitivity to radiation types not to be measured;

Response time;

Stability of response over time (minimal drift);

Sensitivity and coefficient of variation.

Defining the output quantity Y.

Determining the input quantities in array X. These are all the quantities that affect the value of the output quantity, in this case the radiation field characteristics. Typical input quantities include the following:

• (i) Dose rate, energy and angle of incidence;

• (ii) Characteristics of the measurement system (e.g. sensitivity as a function of energy and angle, dosimeter fading and characteristics of the dosimeter evaluation system such as developer temperature and reader sensitivity);

• (iii) Characteristics of the calibration system;

• (iv) The dose from exposure due to the natural background radiation, which should be subtracted (see paras 7.128–7.132).

Developing a model relating the input quantities to the output quantity. In most cases, the model is already largely available in the form of the algorithm that is routinely used to calculate the dose from film density or from track detection light output using numerous parameters such as calibration and normalization factors or coefficients.

Assigning a probability density function to each of the input quantities. This assignment is done using all available knowledge of the dosimetry system and the measurement conditions.

Measurements of film density or of light output of a thermoluminescent dosimeter reader;

Blank signal of the reader system;

Sensitivity of the individual detectors.

Characteristics of the field to which the dosimeters were exposed;

Energy and angular dependence of the dosimeter;

Non-linearity of the response;

Fading, and dependence on ambient temperature and humidity;

Effects due to exposure to light;

Effects due to exposure to ionizing radiation of types that are not intended to be measured by the dosimeter;

Effects from mechanical shock;

Calibration errors;

Variation in local natural background radiation.

The expectation value, being the central value of the probability density function that is taken as an estimate y of the dose Y;

The standard deviation that is taken to be the combined uncertainty u_c(y) in the dose Y;

A coverage interval that contains Y with a specified probability.

The framework based on the law of propagation of uncertainties and the central limit theorem [66];

The Monte Carlo method, which uses statistical sampling from the probability density functions of the input quantities to evaluate the convolution integral of the probability density functions [69].

They should be optimized for such use on the slab phantom (i.e. their energy and angular dependence should be type tested on the slab phantom and they should be calibrated on the slab phantom).

Alternatively, it should be ascertained that the dosimeters correctly detect the radiation scattered back from the body behind them (i.e. the head). This is usually the case for ring dosimeters with a back layer of plastic with a thickness of about 1–3 mm [87].

In a blind test, the dosimetry service provider is not aware of the tests and cannot use selected dosimeters or special evaluation procedures for the tests. One approach is the invention of an independent ‘dummy’ customer and irradiation of the dosimeters under controlled conditions independent of the service provider. Most service providers use a dummy customer for their internal performance testing for quality assurance.

In a surprise test, the dosimetry service provider is aware of forthcoming tests but does not know the actual test date in advance. It is possible to use selected dosimeters but not to use special evaluation procedures.

In an announced test, the dosimetry service provider is aware of the tests and can use selected dosimeters and special evaluation procedures.

For photon dose rate monitors, the 0.662 MeV gamma emission from ¹³⁷Cs;

For neutron dose rate monitors, ²⁴¹Am–Be neutrons;

For beta dose rate monitors, the 0.662 MeV gamma emission from ¹³⁷Cs plus a beta source of suitable energy;

For beta contamination monitors, beta emissions at or below the minimum energy for which the monitor is to be used;

For workplaces involving naturally occurring radioactive material, an appropriate reference source.

Most workplace monitoring instruments should be regularly checked by using a suitable check source to ensure proper functioning. These checks should be carried out monthly, weekly or even daily, depending on the type of instrument. The choice of source and ranges tested should be appropriate for the type of monitoring being conducted.

Battery checks, zeroing and tests to demonstrate an adequate response should be carried out regularly as part of the quality assurance programme to ensure that the equipment continues to function satisfactorily and has suffered no obvious damage.

Submission of a report containing information about the dosimetry system. The technical documentation typically covers type test results, dosimetry procedures and calibration traceability, as well as the management system, including the organizational structure, personnel, equipment and quality control protocols and procedures.

Accreditation of the management system in accordance with a relevant international standard such as Ref. [90].

Certification that the dosimetry system is traceable to the appropriate national standard and is based on conversion coefficients for the operational quantities in accordance with international recommendations and standards.

An irradiation performance test at unknown doses in unknown situations.

On-site inspection and assessment of the laboratory by dosimetry experts who evaluate aspects such as staff (including training), equipment, facilities, calibration and dosimetry procedures, in accordance with what is stated in the approval documentation.

Radiation incident predominantly from the front half space (anterior–posterior geometry);

Radiation incident from the rear half space (posterior–anterior geometry);

Radiation incident symmetrically from all directions perpendicular to the body (rotational geometry);

Radiation incident from all directions including above and below (isotropic geometry).

Sequential measurements of radionuclides in the whole body or in specific organs, such as the thyroid or the lung;

Measurements of radionuclides in biological samples, such as excretions or breath;

Measurement of activity concentrations in air samples that are collected using personal air sampling devices worn by the worker and that are representative of the air breathed by that worker.

Air sampling, rather than biological sampling or whole body counting, should be used as the best way of assessing doses and providing the information that is needed for optimization.

Particular attention should be paid to the characterization of the airborne dust in terms of its particle size distribution, its activity concentration (which may differ from that of the bulk material) and the lung absorption class(es) of the radionuclides concerned.

The radiation emitted by the radionuclides;

The biokinetic behaviour of the contaminant;

The degree to which the contaminant is retained within the body, with account taken of both biological clearance and radioactive decay;

The necessary frequency of measurements;

The sensitivity, availability and convenience of appropriate measurement facilities.

Monitoring does not directly measure the committed effective dose received by the individual. For instance, biokinetic models are necessary: to relate the activity levels in an excretion sample to the activity levels in the body at the time the sample was taken; to relate the body content at the time the sample was taken to the original intake; and to calculate the committed effective dose from internal exposure due to the estimated intake. Further information on the biokinetic models used is given in Appendix IV.

Measurements can be subject to interference from other radionuclides present in the body, including radionuclides of natural origin. It may be necessary to establish the body content of radionuclides of natural origin and of artificial origin from previous intakes, especially where such non-occupational intakes are unusually high. Radiopharmaceuticals administered for diagnostic purposes or for therapeutic purposes can interfere with bioassay measurements for some time after their administration, depending on the properties of the agent administered and on the radionuclides present in the workplace. Workers should be requested to report any administration of radiopharmaceuticals to their supervisors so that it can be determined whether or not adequate monitoring of internal exposure can be performed.

The results of an individual monitoring programme for the estimation of chronic intakes might depend on the time at which the monitoring is performed. For certain radionuclides with a significant early clearance component of excretion, there may be a significant difference between measurements taken before and after a weekend break. Such cases should be reviewed individually [13, 16, 107]. For radionuclides with long half-lives, the amount present in the body and the amount excreted will depend on, and will increase with, the number of years for which the worker has been subject to intakes. In general, the activity retained from intakes in previous years should be taken to be part of the radiation background for the current year.

The analytical methods used for individual monitoring sometimes do not have adequate sensitivity to detect the activity levels of interest. Information on detection limits achievable for individual radionuclides is given in Ref. [13]. More specific information on detection limits for inhaled intakes of ²³²Th and its progeny for various measurement techniques is given in tables 7, 8, 94 and 95 of Ref. [25].

External contamination is to be removed, and it is to be ensured that workers have showered and washed their hair before making direct bioassay measurements.

The whole body content of radionuclides is to be established as quickly as possible.

The collection of all excretions is to be ensured.

Other biological samples, such as nasal swabs and mouth wipes, are to be collected (this can be performed during medical treatment or decontamination procedures).

Samples of the contaminant are to be collected for further analysis of the radionuclide composition and of the physical and chemical properties of individual radionuclides.

The making of objective decisions on whether the result is compatible with previous intakes or is to be considered as a new intake;

The identification of data from outliers;

Statistical analyses of the results of the fitting procedures used to evaluate intakes from more than one data point.

Counting geometry errors.

Positioning of the individual in relation to the detector and movement of the person during counting.

Determination of the thickness of the chest wall.

Differences between the phantom and the individual or organ being measured, including:

• (i) Geometric characteristics;

• (ii) Density;

• (iii) Distribution of the radionuclide within the body and organ;

• (iv) Linear attenuation coefficient.

Interference from radioactive material deposits in adjacent body regions.

Spectroscopy resolution and peak overlap.

Electronic stability.

Interference from other radionuclides.

Variation in background radiation.

Activity of the standard radionuclide used for calibration.

Surface external contamination of the person.

Interference from natural radioactive elements present in the body.

Calibration source uncertainties.

Quantification of the sample volume or weight;

Errors in dilution and pipetting;

Evaporation of solutions in storage;

Stability and activity of standards used for calibration;

Similarity of chemical yield between the tracer and radioelement of interest;

Blank corrections;

Background contributions to, and fluctuations in, radionuclide excretion;

Electronic stability;

Spectroscopy resolution and peak overlap;

Contamination of sample and impurities;

Source positioning for counting;

Density and shape variation from the calibration model;

Assumptions about homogeneity in calibration;

For liquid scintillation counting, differences in quenching between the sample and calibration standard.

A time weighted average ²¹²Pb activity concentration of 1 Bq/m³ in air corresponds to a committed annual effective dose of about 0.08 mSv.

A time weighted average potential alpha energy concentration of 1 μJ/m³ corresponds to a committed annual effective dose of about 1 mSv.

The assumption that the intake occurred at the midpoint of the monitoring period might have a tendency to overestimate the true intake.

The assumption of a constant chronic intake over the whole monitoring period produces an unbiased estimate of the true intake provided that the measurement and the excretion function are accurately known or are at least unbiased.

The structure of the biokinetic model.

The human biokinetic data used in the formulation of the model.

The extrapolation of biokinetic data from animals to humans (interspecies extrapolation).

The extrapolation of biokinetic data from one chemical element to a chemical analogue on the assumption of close physiological similarities (inter-element extrapolation).

The variability in the population.

The following physical and anatomical parameters of the computational models used to assess the dose deposited in a target region by the radiation emitted by an incorporated radionuclide:

• (i)The energy and intensity of the radiation emitted;

• (ii) The interaction coefficients of the emitted radiation in tissues;

• (iii) The elemental composition of the tissues of the body;

• (iv) The volume, shape and density of the target organs in the body;

• (v) The spatial relationship of the organs within the body.

Photon dosimeters and neutron dosimeters giving information on the personal dose equivalent H_p(10) for evaluation of AD_T in tissues and organs such as red marrow and the lung.

Eye lens dosimeters, giving information on H_p(3) for beta–photon radiation. Since such dosimeters for the lens of the eye are not yet widely available, it might be necessary to use H_p(10) as the starting point in estimating the dose to the lens of the eye in cases of accidental exposure, although in accidents in industrial radiography this is likely to underestimate the dose to the lens of the eye.

Extremity dosimeters, giving information on the skin dose at a depth of 0.4 mm, for beta–photon radiation (and for neutrons if criticality is expected) for evaluation of AD_T in the dermis for the palm of the hand and the sole of the foot.

To determine compliance with dose limits and hence, in particular, to ensure the avoidance of deterministic effects;

In the case of overexposures, to initiate and/or support any appropriate medical examinations and interventions.

Information on the general nature of the work in which the worker was subject to occupational exposure;

Information on dose assessments, exposures and intakes at or above the relevant recording levels specified by the regulatory body and the data upon which the dose assessments were based;

When a worker is or has been exposed while in the employ of more than one employer, information on the dates of employment with each employer and on the doses, exposures and intakes in each such employment;

Records of any assessments made of doses, exposures and intakes due to actions taken in an emergency or due to accidents or other incidents, which shall be distinguished from assessments of doses, exposures and intakes due to normal conditions of work and which shall include references to reports of any relevant investigations.”

Demonstrating the effectiveness of the optimization process;

Providing data for the compilation of dose distributions;

Evaluating trends in exposure and thus providing the information necessary for the evaluation of the radiation protection programme;

Developing effective procedures and programmes for monitoring;

Providing exposure data from new medical procedures and programmes;

Providing data for epidemiological and research studies;

Providing information that may be necessary for litigation related purposes or for workers’ compensation claims, which can arise years after the actual or claimed exposure.

A unique identification of the individual and the undertaking.

Information on doses from previous monitoring periods (i.e. for an annual period and for an appropriate five year period).

The results of dose assessments for external exposure and the method of assessment, including, as appropriate:

• (i) The personal dose equivalent for exposure to strongly penetrating radiation, H_p(10);

• (ii) The personal dose equivalent for exposure to weakly penetrating radiation, H_p(0.07);

• (iii) Other dose values, such as H_p(0.07) derived from extremity dosimeters, H_p(3) for the lens of the eye, dose values from the use of multiple dosimeters (e.g. in the case of double dosimetry with the use of a lead apron) and estimated dose values calculated from simulations (e.g. for doses received by aircrew from exposure to cosmic radiation).

The results of dose assessments for internal exposure and the method of assessment, including:

• (i) The committed effective dose E(50);

• (ii) The values of the measured quantity (e.g. retention value or daily excretion value) and details of the models used for the assessment, including the results of whole body counting, thorax counting and/or thyroid counting and the assessed committed effective dose;

• (iii) If appropriate (e.g. in the case of overexposure), the committed equivalent dose to the most highly exposed tissue, H_T(50).

The notional dose substituting for missing values, artefacts or surrogates, for instance in the case of lost or damaged dosimeters or samples (see para. 7.258).

Data on samples, such as the date and time of collection and evidence of a chain of custody;

Raw data from measurement devices, techniques used for the measurements (direct or indirect techniques) and counting rates in specific energy bands;

Measurements of background levels, and standards and calibration data for the counters;

Calculated results, such as activity content of the body or daily excretion rates, and their statistical analyses;

Calculated estimates of intake and the biokinetic models from which they were derived;

Estimated committed effective doses and the dose conversion factors used.

Access to premises, files, archives, computers and servers where personal information is handled and stored should be restricted.

The circulation of information, particularly by means of electronic information networks, should be secure.

There should be procedures for backing up dose records and equivalent security for backup copies.

Similar security measures should be taken in the use of active personal dosimeters and associated software.

Provision should be made for the destruction of documentation or other media containing confidential information that no longer needs to be kept.

The recorded data should be protected against unauthorized or unintentional modification, so as to preserve the integrity of the data.

It prevents the loss of data on individual doses in the event that the registrant or licensee ceases its activities in the State concerned.

It allows periodic analysis of all data on exposures collected in order to characterize the situation at the national level with regard to occupational exposure.

Demonstrates compliance with regulations;

Identifies significant changes in the working environment;

Includes details of radiation surveys (e.g. date, time, location, radiation levels, instruments used, surveyor and other comments);

Includes reports received about the workplace where compliance with the standards could be adversely affected;

Details any appropriate actions taken.

The equipment;

The accuracy of calibration of the equipment over its range of operation and for the type of radiation that it is intended to monitor;

The date of the test;

The calibration standards used;

The frequency of calibration;

The name and signature of the qualified person under whose direction the test was carried out.

Consultancy and maintenance services, including:

• (i) Radiation safety consultancy;

• (ii) Shielding calculations;

• (iii) Modelling for dose assessment, containment and ventilation;

• (iv) Maintenance services covering both in-house operations and services contracted with an outside organization;

• (v) Decontamination services for the decontamination of, for example, equipment and pipes.

Calibration and testing and assay services, including:

• (i) Monitoring services, including individual monitoring, workplace monitoring and environmental monitoring;

• (ii) Calibration and calibration verification services for monitoring devices and radiation sources.

Promoting the knowledge of relevant safety standards within the organization;

Carrying out a risk analysis of the procedures applied;

Establishing proper rules and procedures, and observing regulatory requirements to keep risks at a minimum;

Periodically evaluating the implementation and effectiveness of these rules and procedures;

Engaging the relevant management and staff;

Periodically training the staff, in accordance with an established training programme, to follow the rules and procedures correctly;

Discussing the established training programme with trained staff;

Periodically updating the training programmes and coordinating them with the requirements of legal and regulatory bodies, which should check the effectiveness of these programmes;

Disseminating and promoting knowledge of accidents and other incidents to learn from their occurrence, and any reoccurrence, and to improve the safety culture;

Eliciting safety related proposals from the staff through an incentive system.

A description of the management system.

Management documents, for instance documents relating to some of the topics covered in paras 8.49–8.70.

Detailed work processes and job descriptions.

Additional technical documents and data, including:

• (i) Databases of radionuclides and technical databases;

• (ii) Operating manuals for equipment and software;

• (iii) Reagent data sheets;

• (iv) Requirements of the regulatory body or other relevant authority (as established in laws and regulations);

• (v) Managerial and technical standards.

Customer requirements;

Related statutory and regulatory requirements;

Organizational resources necessary;

Requirements for communication with the customer.

Defining and maintaining the expected level of customer satisfaction;

Identifying opportunities and needs for continual improvement;

Ensuring commitment to providing the resources necessary to accomplish the task;

Ensuring contributions of suppliers and partners (confirming that suppliers and partners are capable of providing goods and services that meet the established quality standards);

Ensuring commitment to adopt professional good practices when providing services;

Making the commitment to ensure the competence (qualification) of the personnel involved in the execution of services;

Committing to meet the requirements of the relevant standards;

Ensuring the necessary attention to protection, safety, health, quality, environmental, security, societal and economic aspects, as appropriate.

Develop and manage the management system, which includes performing activities designed to ensure compliance with relevant standards, harmonizing procedures and documents, reviewing operations, identifying and reporting any non-conformance (i.e. the non-fulfilment of a requirement) to the management and conducting training in awareness of the management system for the staff;

Communicate on quality issues as may be required by the regulatory body or accreditation bodies;

Communicate directly with the senior management at all times on issues relating to the management system;

Act as the focal point for reports of problems regarding quality and suggestions for improvement;

Stop any work that is not being performed according to established procedures;

Perform periodic (usually annual) reviews of the management system.

Processes of the management system (administrative processes and key processes);

Processes to deliver the services and products of the organization (technical processes and core processes).

Timeliness;

Capability (ability to meet relevant requirements);

Efficiency (resources allocated to the process and the possibilities for their reduction without compromising quality and compliance with regulatory requirements).

For consultancy services, these measures could include the following:

• (i) Additional calculations using other algorithms;

• (ii) Checks on data entry;

• (iii) Comparison of the results with previous experience.

For measurement and calibration services, these measures could be:

• (i) Repeated tests (possibly done using different instruments for analysis);

• (ii) Checks on introduced blank or test samples;

• (iii) Plausibility tests on the results (done by applying expert knowledge).

Organizing regular meetings of key personnel;

Using communication tools (e.g. electronic billboards and intranet);

Having similar methods of internal communication.

Actions taken on an ongoing basis to monitor the overall effectiveness of the system, by identifying areas, through appropriate metrics, in which improvement may be appropriate.

Application of basic statistical methods (e.g. histograms, distributional analysis and mean values) or qualitative analytical methods for monitoring data on customer satisfaction, the performance of equipment, measurement of throughput and similar indicators of the effectiveness of services provided to the customer.

Actions taken on a proactive basis to prevent non-conformances, to improve the system and to optimize the service to the client; the internal audit process, together with activities for improvements, is part of these actions.

Actions taken on a reactive basis to correct non-conformance identified by, among other things, self-assessment, complaints by clients or recommendations of an internal or external audit.

It helps to emphasize that the internal audit process is a continual activity designed to improve the management system.

It helps to reduce the additional workload for individuals selected to conduct the audit.

It is useful in promptly identifying items of potential non-conformance and areas in which improvements may be appropriate.

It helps to monitor progress in accomplishing any corrective actions that may have been recommended in previous audits.

The persons who were involved in the review;

Factors that were considered;

Decisions that were reached;

Actions that were planned, the persons responsible for the actions and the time schedules that were decided upon;

The provision for review and approval of the report.