Upload
willa-bryan
View
217
Download
1
Tags:
Embed Size (px)
Citation preview
IAEAInternational Atomic Energy Agency
Regulations
Part III: Radiation Protection Performance Requirements
Day 8 – Lecture 5(3)
IAEA 2
To provide an understanding of the basic concepts of justification, optimization and dose limitation.
Objectives
IAEA 3
• Justification of Practices• Dose Limitation• Optimization of Protection and Safety
.
Content
IAEA 4
General principles
• Benefit to the exposed individuals or the society shall offset the radiation harm, taking into account social, economic and other relevant factors.
Justification of Practices
• Applicant for authorization provides sufficient evidence of the benefits versus harm.
• Justification is considered in the authorization process.
IAEA 5
Practical application• Overall assessment of justification is made when new
types of practices are proposed.
Justification of Practices (cont)
• For individual cases, assessment is required that the practice is or will be conducted in a manner typical for existing types of practices that are already generally considered justified.
• The Regulatory Body should review the justification of existing types of practices whenever new important evidence on their efficacy or harm is acquired.
IAEA 6
Practices deemed unjustified include: • the deliberate addition of radioactive substances in, or
activation of: food, feed, beverages, cosmetics (intake by, or
application to, a human being); toys, personal jewellery, adornments (frivolous
use of radioactive substances); human imaging using radiation used as a form of
art or for publicity purposes;
Justification of Practices (cont)
• any other practice determined by the Regulatory Body to be unjustified.
IAEA 7
Dose limits• Occupational dose limits:
workers; apprentices and students of 16-18 years of age; specially authorized exposures.
• Dose limits for the public
Dose Limitation
Dose limits are not applicable to medical exposures
IAEA 8
Workers• Effective dose • 20 millisieverts per year averaged over 5 years; • 50 millisieverts in any single year.
Dose Limits
Equivalent dose• to the lens of the eye; 20 millisieverts per year
averaged over 5 years;• extremities (hands and feet) and the skin; 500
millisieverts per year.
IAEA 9
Effective dose
• 6 millisieverts per year.
Dose Limits (cont)
Equivalent dose • to the lens of the eye 20 millisieverts per year; • extremities (hands and feet) and the skin: 150
millisieverts per year.
Apprentices and students 16-18 years of age
IAEA 10
Dose Limits (cont)
Apprentices and students 16-18 years of age (cont)
• No person under the age of 16 years shall be subjected to occupational exposure.
• No person under the age of 18 years shall be allowed to work in a controlled area unless supervised and then only for the purpose of training.
IAEA 11
Equivalent dose• to the lens of the eye; 15 millisieverts per year.• extremities (hands and feet) or the skin; 50 millisieverts
per year.
Dose Limits (cont)
Members of the public
Effective dose• 1 millisievert per year.• in special circumstances, a higher value of effective dose in a
single year provided 1 millisievert per year over 5 years is not exceeded.
IAEA 12
• Case by case approval of the Regulatory Body;• Requirements:
– radiation safety is optimized– workers involved have been consulted
Specially authorized exposures
• Temporary change in some dose limit:– for a limited period of time– relates to specified work areas
IAEA 13
For exposures from any source within a practice
• the magnitude of individual doses,
• the number of people exposed, and
• the likelihood of incurring exposures;
• shall be kept as low as reasonably achievable (ALARA).
Optimization of Protection and Safety
IAEA 14
Dose constraints
• are used in the context of optimisation within a practice;
Optimization of Protection and Safety (cont)
• are established by the Regulatory Body;
• are less than dose limits;
• are not applicable to medical exposures;
• for public exposures, are a tool for considering contributions from different practices and sources.
IAEA 15
Reference Levels:
• represent the level of dose above which it is judged to be inappropriate to allow exposures to occur;
Optimization of Protection and Safety (cont)
• used for optimization in emergency and existing exposure situations.
IAEA 16
• Diagnostic reference levels;
• Dose constraints for exposures of carers and comforters and of volunteers program biomedical research;
• Criteria and guidelines for the release of patients under therapeutic procedures.
Optimization of Protection and Safety (cont)