Assessment of the Size of the Khmelnytskyi NPP Sanitary Protection Zone Taking into Account the Construction of Power Units No. 5, 6 with AP1000 Reactor
Authors:   Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Тalerko М. М. , Lev Т. D. , Nosovskyi А. V. , Rudko V. М. , Piskun V. М. , Novikov А. М. , Shedemenko І. P. , Blokhina O. V. ,   Separate Division “Atomproektengineering” of JSC NNEGC “Energoatom”
Published: February 2025

The size of the sanitary protection zone (SPZ) of the Khmelnytskyi NPP was evaluated, taking into account the potential impact of power units No. 3, 4 with VVER-1000 reactor and No. 5, 6 with AP1000 reactor
by Westinghouse Electric Company. The calculations were carried out taking into account the requirements of the standard SOU NAEK 023:2014 “The procedure for establishing the dimensions of the sanitary protection zone of nuclear power plants”. The size of the SPZ were determined on the basis of not exceeding certain radiation levels at the boundary of the SPZ for conditions of normal operation, anticipated operational occurrences and the maximum design basis accident. For emissions during normal operation of facilities at the industrial site of the Khmelnytskyi NPP, the criterion of not exceeding the effective dose of exposure to the population is met at distances of 450–650 m from power units No. 1–4. Radionuclide emission from power units with AP1000 reactors do not lead to exceeding the dose criterion during normal operation at any distance from the power unit. It was found that under the conditions of normal operation of power units with AP1000 reactors, 14C makes the main contribution to the formation of the effective radiation dose within the SPZ (about 87% of the total). However, in general, the contribution of emissions from AP1000 is insignificant compared to emissions from VVER-1000. It is shown that not exceeding the criterion for the effective dose of exposure of the critical reference age group “1 year” in the case of the maximum design basis accident at power units with VVER-1000 reactors is decisive for establishing the dimensions of the SPZ. The contributions of the “air” component (inhalation path and external radiation from activity in the air) and external radiation from depositions on the earth’s surface to the calculated value of the effective dose for the maximum design basis accident at power units with VVER-1000 reactors are 88% and 12%, respectively. The main part of the effective dose is formed due to the contribution of the aerosol component of the emission, primarily 141,144Ce (almost 63%), as well as 134,137Cs, 90Sr and 103,106Ru. The calculated boundary of the SPZ of the Khmelnytskyi NPP, taking into account the potential impact of all 6 power units, is an elliptical figure with the lengths of the semi-axes of 2,600 m and 2,200 m. The calculated boundaries of the SPZ of the Khmelnytskyi NPP almost completely fit into the existing boundaries (a circle with a radius of 2700 m). A conclusion was made that re-establishment of the dimensions of the sanitary protection zone of the Khmelnytskyi NPP is not advisable after the commissioning of the new units No. 3, 4 with VVER-1000 reactors and No. 5, 6 units with AP1000 reactors.