debate and justification as to the correct level of designation( particularly where an area has been designated for reasons of radioactive contamination). There are often also“ custom and practice” considerations to be taken into account, especially in the university sector. Nevertheless, keeping the designation options simple does encourage a consistent understanding of their meaning and implications.
Designating areas in the nuclear sector isn ' t always so straightforward, and can sometimes lead to confusion, especially among non-radiation professionals. As there can be significant differences in the level of radiological hazard present in different areas of plant, it is most common to sub-divide designated areas based on the magnitude of hazard present. The designation options are extended beyond the simple categories of“ supervised” or“ controlled” with specific categories to identify areas with increased external radiation hazards( i. e. dose rates) or contamination levels.
Each nuclear operator in the UK sets their own criteria for subdividing controlled and supervised areas based on the hazard. There is no consistent guidance as to how this should be done and subdividing designated areas is not a requirement of( or included within) the Ionising Radiations Regulations.
The only regulatory reference to subdivision of designated areas is given in the Office for Nuclear Regulation ' s( ONR)“ Safety Assessment Principles for Nuclear Facilities” which states“ where appropriate, designated areas should be further divided, with associated controls, to restrict exposure and prevent the spread of radioactive material”. The subdivision of controlled and supervised area on most nuclear sites is therefore a regulatory expectation, rather than a statutory requirement.
The lack of guidance around categorising designated areas has led to a variety of approaches across the nuclear industry over the years. The most common approach is to
use“ C”( contamination) and“ R”( radiation) combined with numerals to denote increasing hazard( e. g. a controlled area may be categorised as“ C2” for contamination and“ R3” for radiation). However, there is no consistency between operators on the definition of each numeral or even the number of subdivisions. Some nuclear operators miss out numbers within their contamination subdivisions and some do not use numerals in favour of descriptive terms such as“ contamination – low; radiation – moderate”.
Although this lack of consistency may not be a problem when the workforce at a specific nuclear site remains constant( and thus only requires familiarity with a single set of designation requirements), in today ' s contracting and decommissioning era, there is a substantial mobile workforce that frequently works at various nuclear sites. As an RPA, I am frequently asked by engineers to advise on likely area designations for new or modified nuclear plant and there is almost always confusion when I explain this depends on the site at which the proposed plant will be located.
Whilst recognising that there are different hazards at different nuclear sites, perhaps some non-mandatory guidance to encourage consistency in designation of areas across the UK nuclear sector would be of benefit. This would encourage nuclear operators to gradually migrate towards clear definitions that help prevent confusion and enable training to be streamlined.
But why is this article entitled“ Star Wars Droids and Designation of Areas”? It doesn ' t mention“ Obi-Wan Kenobi” or“ Jabba the Hut” and all those“ lightsabers” are more likely to be powered by non-ionising radiation. The link is that while a nuclear design engineer almost certainly knows what“ R2D2” refers to( a small droid and hero of the rebel alliance from Star Wars), they may be unable to explain the meaning of“ R2C2”….
16 Radiation Protection Today www. srp-rpt. uk