1. OCCUPATIONAL RADIOLOGICAL PROTECTION OPTIMIZATION IN THE NUCLEAR FUEL CYCLE AND IN MEDICAL APPLICATIONS.
2. METHODS FOR THE PRACTICAL IMPLEMENTATION OF THE ALARA PRINCIPLE.
The overall objective of the project was to develop case studies of optimisation for occupational radiological protection in the nuclear fuel cycle and in the domain of nedical activities. 2 aspects were considered with particular attention given to the role of work management actions within dose reduction policies and the integration of dose distribution in the optimisation process.
Statistics on occupational exposures generally available in nuclear installations are not adapted to perform as low as reasonably achievable (ALARA) studies. A new generation of dosimetry systems allowing the link between elementary tasks performed by workers and corresponding exposures needs to be developed.
Beside actions to directly reduce sources or increasing protection to decrease ambient dose rates, there is a large potential for dose savings through work management actions which can reduce significantly exposed working time in controlled areas. First attempts to quantify such actions in an ALARA perspective have been successfull and it is worthwhile to continue in this field in the future to enlarge the integration of the optimisation principle within the operating and maintenance procedures for nuclear installations.
The as low as reasonably achievable (ALARA) principle is a workable concept and that tools for structuring optimisation problems and aiding decisions, such as the ALARA procedure, exist and have been shown to work in practice. It is also clear that a structured approach can be applied to all levels of radiation protection problems, but that the resources allocated to each problem need to be commensurate with the level of decision involved. For example, in many cases of low level decision, intuitive thinking by experts coupled with ALARA awareness may be all that is necessary. At high levels of investment, an extensive desk top ALARA study involving several man months of effort may be needed. It is also clear that methods for incorporating these ideas into radiation protection programmes (eg ALARA audits and ALARA predictive plans) exist, and again have been demonstrated to work in practice.
What is required now is that these ideas, principles, tools, and methods be actually used widely in radiation protection programmes. The document produced on ALARA is an important step in this, but there is additionally a need to provide manuals of good practice, training on the implementation of these methods, and simple computer tools to aid decision making as well as guidance on the application of these methods to more complex problems. It has also been recognised that there is a lack of relevant data on dose saving techniques and associated costs for detailed application of quantitative methods to operations warranting them. Future work is needed to address these specific areas.
A. OPTIMIZATION OF OCCUPATIONAL EXPOSURES.
THE OBJECTIVE OF THE RESEARCH IS MAINLY TO DEVELOP CASE STUDIES OF OCCUPATIONAL RADIOLOGICAL PROTECTION OPTIMIZATION IN THE NUCLEAR FUEL CYCLE AND IN THE DOMAIN OF MEDICAL ACTIVITIES. THIS RESEARCH IS SUPPOSED TO PROCEED THE STUDIES ON OPTIMIZATION PREVIOUSLY CARRIED OUT WITHIN CEPN SINCE SEVERAL YEARS, ON PUBLIC EXPOSURES RELATED TO FUEL CYCLES ACTIVITIES. THE PROJECT AIMS AT COMPLETING THESE FIRST ATTEMPTS IN THE AREA OF OCCUPATIONAL EXPOSURE, PUTTING THE EMPHASIS ON TWO ASPECTS WHICH HAVE NOT YET BEEN TREATED SYSTEMATICALLY AND IN OPERATIONAL PERSPECTIVE :
- TAKING INTO ACCOUNT WORK MANAGEMENT AS AN IMPORTANT DIMENSION OF DOSE REDUCTION POLICIES,
- INTEGRATING SOCIAL VALUES IN THE OPTIMISATION PROCESS, PARTICULARLY CONCERNING THE ETHICAL ASPECT OF RISK CONTRIBUTION AND PERCEPTION.
THE CASE STUDIES ENVISAGED WILL MAINLY DEAL WITH OCCUPATIONAL EXPOSURES IN THE NUCLEAR FUEL CYCLE AND THOSE RESULTING FROM MEDICAL ACTIVITIES.
B. METHODS FOR PRACTICAL IMPLEMENTATION OF THE ALARA PRINCIPLE. THE OBJECTIVES OF THIS STUDY, TO BE CLOSELY COORDINATED WITH NRPB (UK) ARE :
1) TO DEVELOP A SIMPLE, GENERAL FRAMEWORK FOR FUTURE ALARA STUDIES;
2) TO DEMONSTRATE THE USE OF THIS FRAMEWORK BY APPLYING IT IN EX. STUDIES.
THE OBJECTIVES WILL BE ACHIEVED BY FIRSTLY REVIEWING THE DIFFICULTIES WHICH HAVE ARISEN IN THE PRACTICAL IMPLEMENTATION OF ALARA, AND THEN SUGGESTING AND APPLYING METHODS BY WHICH THESE DIFFICULTIES MAY BE RESOLVED. THE REVIEW IS TO BE CARRIED OUT BY REFERENCE TO STUDIES REPORTED IN THE LITERATURE AND TO WORK IN PROGRESS AT CEPN AND NRPB. THE EXAMPLES CHOSEN WILL CONCERN A RANGE OP PRACTICES INVOLVING RADIATION EXPOSURE, INCLUDING BUT NOT CONFINED TO, THE NUCLEAR INDUSTRY. THEY WILL BE SELECTED SO AS TO ILLUSTRATE THE SCOPE OF ACTUAL PRACTICAL DIFFICULTIES, RATHER THAN THOSE WHICH COULD THEORETICALLY ARISE. IN SUGGESTING METHODS TO RESOLVE THESE DIFFICULTIES AND IN DERIVING THE GENERAL FRAMEWORK PARTICULAR ATTENTION WILL BE PAID TO INDICATING THE CAPABILITIES OF THE VARIOUS DECISION-AIDING TECHNIQUES (E.G. MULTI-CONTRIBUTE ANALYSIS, COST BENEFIT ANALYSIS) AND TO IDENTIFYING THE AREAS WHERE JUDGEMENTS ARE REQUIRED BY THOSE RESPONSIBLE FOR TAKING ALARA DECISIONS.