Topographical classification of dose distributions: implications for control for worker exposure.

This paper deals with classification of dose distributions of nuclear workers based on antikurtosis (Q) and entropy coefficients (K) and their relationship presented in QK-diagrams. It is shown that determination of the most appropriate distribution to adopt, for a specific data set of a wide range of input data, requires building and analysing QK-diagrams for distributions of logarithms of individual doses. Actual dose distributions for emergency and occupational exposure situations were then considered, as well as doses for one day of work during clean-up and routine activities. It is shown that, in all cases, three types of distributions of logarithms of individual doses were present: normal, Weibull and Chapeau. The location of the representation point of a dose distribution reflects the degree of dose control of the group of workers whose individual doses are collectively displayed in the QK-diagram. The more the representation point of the analysed distribution of the logarithms of the individual dose of a given contingent of workers deviates from the point of the lognormal distribution, the more there was intervention in the process of individual dose accumulation. Thus, QK-diagrams could be used to develop a dose control function. It is shown that the hybrid lognormal distribution, which is widely used in the field of radiation safety, for the purpose of approximation of real dose distributions, is unable to satisfactorily describe many dose distributions arising in aftermath operations and occupational exposure.

Methods of minimising doses incurred by external exposure while moving in radiation hazardous areas.

Radiation doses received by workers during their movement within areas contaminated as a result of events and activities, leading to emergency or existing exposure situations, may provide a substantial contribution to total external exposure during remediation work. This paper describes an approach to minimise worker external exposure in these circumstances, based on graph theory. The paper describes several tasks, including: searching for a route with the lowest dose, searching for an optimal bypass with a given set of control points and searching for the optimal road network coverage. Classical graph theory algorithms have been used (Dijkstra's algorithm, Chinese postman problem and travelling salesman problem). Algorithms for solving the above mentioned problems have been developed and were included in the information-analytical system for radiation safety. This software has been applied for optimisation of protection during remediation work at the Andreeva Bay site of temporary storage for spent fuel and radioactive waste in the Kola Peninsula, both in the context of existing exposure situations and improving the preparedness for emergency exposure situations.

Local Radiolesion in X-Ray Inspection Specialists.

As a result of some deviations in the installation of the X-ray inspection plant 'Extravolt-225/1600' two workers of an X-ray inspection laboratory were exposed to the radiation in a dose enough to cause an acute local radiolesions (LRs). The first patient was diagnosed with an acute LR of the hands of severe and extremely severe degree. The second patient was diagnosed with a mild LR of her right hand. The first patient received a surgical treatment followed by subcutaneous introduction of the autologous mesenchymal stem cells. The second patient received only conservative treatment. The complete epithelization of the traumatic surface was achieved. Modeling the incident with the following EPR analysis of the compact substance of the ablated bone structures made it possible to specify the spatial-temporal properties of the exposure.