The specifics of personnel exposure during the repair of nuclear maritime facilities

The development strategy for Russia's shipbuilding industry anticipates a multi-fold increase in the capacity of ship repair enterprises servicing nuclear maritime facilities, which underscores the need to enhance radiation safety for personnel. The aim of the study was to determine the conditions and levels of occupational radiation exposure at the workplaces of various personnel categories at a nuclear ship repair enterprise, including under increased production loads. Materials and methods : The study was conducted at a major nuclear ship repair facility. The ambient dose equivalent rate of gamma radiation and beta contamination levels were measured at workplaces of main, auxiliary, and administrative personnel (Group A). Data from the plant's radiation monitoring and five-year statistical reports on individual doses (Form No. 1-DOZ, 2016– 2020) were analyzed. Individual thermoluminescent dosimeters were used to estimate potential maximum doses. Results and discussion : During periods when no radiation-hazardous work was being performed, the ambient dose equivalent rate at most workplaces did not exceed background levels (0,16 μSv/h), except near a tank with liquid radioactive waste (up to 6,75 μSv/h). During potentially hazardous operations (primary circuit maintenance, dismantling of safety mechanisms), the ambient dose equivalent rate reached 4,91– 7,15 μSv/h. The highest five-year average individual effective doses were recorded for flaw detection inspectors (6,89 mSv/year). Calculations for a hypothetical scenario of full workload revealed a potential risk of exceeding dose limits for certain occupations (fitter-installer, flaw detection inspector), especially for the lens of the eye. Conclusion: Radiation exposure conditions for personnel vary significantly depending on profession and type of work. To ensure radiation safety, a differentiated approach to planning repair work is required, taking into account personnel specialty, the nature of operations, and strict adherence to safety protocols, especially during high-load periods and for high-risk groups.