Radiation consequences of scuttling of atomic-technological servicing ships

Abstract

Large quantities of radioactive wastes are produced during the operation and repair of nuclear-powered ships. The wastes, including spent nuclear fuel, are handled using specialized atomic-technological service ships, which perform a chain of operations on reloading of reactor cores and receiving, reprocessing, and transporting radioactive wastes to the locations of constant or temporary storage. An example of such vessels are the floating technological base and transport for transporting and reprocessing radioactive wastes. When such vessels are scuttled, they can be sources of stronger radioactive contamination of the environment than ships with nuclear power plants, since three or more spent cores can be present at the same time onboard such a ship.When atomic-technological service ships with radioactive wastes or elements of nuclear power plants onboard are scuttled, the radiation effect on the environment is determined mainly by the scale of the damage to or disruption of the seal of the structural safety barriers preventing the spreading of radionuclides to outside the systems and equipment in the scuttled object. The final criteria for estimating the radiation consequences of accidents are the scales of the water areas involved in the postaccident contamination, the concentration of the most important radionuclides, from the standpoint of radiation hazard, in the sea water and bottom deposits, possible levels of accumulation of radionuclides in organs and tissues of commercial marine organisms and their food base and, in consequence of this, uptake of the radionuclides by humans consuming the marine organisms.For the criteria indicated, working limits satisfying the NRB-69 hygenic requirements were proposed in [ 1] for the concentrations of radionuclides in sea water during prolonged contamination of regions with different commercial use [2]. A dose load quota for the population from contamination of the sea, equal to 10% of the maximum irradiation dose of a limited portion of the population, was introduced.The introduction of new radiation safety standards (NRB-96) [3], which establish more stringent limits of irradiation for personnel and the public, as well as the publication of the IAEA recommendations [4], which refine the limits for the accumulation of radionuclides by marine organisms, make it necessary to choose new control levels of concentrations of radionuclides in sea water. In this connection, the control concentrations of radionuclides in sea water for different industrial objects, calculated on the basis of the approach of [1] using the dose limits for individuals from the population [3] and data on the consumption of marine products and accumulation factors of radionuclides in them [4], are presented in Table 1.The scale of radiation consequences can be estimated by comparing the data presented in [1] and Table 1 with the data on radionuclide concentrations in sea water as a result of accidental sinking of atomic-technological service ships.The radiation hazardous systems and equipment in...

Analysis of the radioactive contamination of the environment due to decommissioned objects of the nuclear-powered fleet in northwestern Russia

“…As a result, the emission of fission products from nuclear fuel will depend on the degree of corrosion of the undamaged protective barriers, which according to the data in [14] does not exceed 40 µm/yr. Correspondingly, the sealing of the fuel assembly jackets can be preserved for several years, and then the emission of radionuclides into sea water will increase to ~1600 TBq/yr, and the radioactive plume will reach a length of 10 to 50 km and a width of up to 1 km [15]. The expected yearly dose for various representatives of the fauna and flora in direct proximity to a sunken vessel can be about 20 Gy.…”

Simulation of the source of contamination of sea water during the sinking of a ship containing radioactive materials

“…Then, the flux of nuclei of the ith radionuclide from the fuel is described by the expression (2) where V is the runnning value of the volume of the fuel element, m 3 . All radionuclides are distributed in the volume of a fuel element uniformly and enter the water at the rate of dissolution of the fuel composition.…”

“…Substituting expressions (2) and (3) into Eq. (1) and multiplying both sides of the equation by λ i gives (4) where A i is the total activity of the ith radionuclide in the fuel composition.…”