INDUCED ACTIVITY ESTIMATE IN IRRADIATED MATERIALS WHEN USING VVER-1200 SPENT FUEL FOR RADIOTECHNOLOGY AND WAYS OF ITS ATTENUATION

Technical ability to use the VVER-1200 spent nuclear fuel as a source of γ-radiation to solve radiation technology problems is substantiated. The technology area for these sources is limited to the problems which do not require large absorbed doses. EGSnrs program is used to determine the absorbed dose in irradiated materials from the spent fuel assemblies (SFA). This program is a computer code system, which forms a versatile package for simulation by Monte Carlo method the bound transfer of electrons and gamma-rays with energy above a few keV. The design of the radiation installation with the irradiator based on the SFA or composed of a number of fuel rods is proposed. The irradiator is located on the bottom of the pool and can be raised above the water level, or remain under its surface, if necessary. This layer of water plays a role of the shield and decreases neutron activation of irradiated material to a safe level. In some cases, boric acid dissolved in water allows reduction of the thickness of the water layer. Results of the evaluation of materials irradiation time and the thickness of the water shield are presented.

1. Salnikov L.I., Dneprovskaya N.M., Kuzmin A.V., Novikov I.A., Rubin I.E., Salnikova I.A., Tetereva N.A. Evaluation of the technical possibilities of using spent fuel assemblies VVER-1200 as a source of gamma radiation for radiation-technological processes. Vestsi Natsyyanal’nai akademii navuk Belarusi. Seryya fizika-tekhnichnykh navuk [Proceedings of the National Academy of Sciences of Belarus. Physical-technical series], 2014, no 2, pp. 38-44. (In Russian).

2. Betzler B., Hadgu H., Lawrence C., Orians M., Pavlou A., Poitrasson-Riviere A. Irradiation of Food Using Spent Nuclear Fuel. Transactions of the American Nuclear Society, 2010, vol. 103, pp. 67-68.

3. EGSnrc: software tool to model radiation transport. National Research Council Canada. Available at: http://irs.inms.nrc. ca/software/egsnrc/ (accessed 10 June 2010).

4. Gomin E.A., Gurevich M.I., Maiorov L.V., Marin S.V. Application description and instruction for the user of the MCURFFI program of calculation by the Monte Carlo method of neutron and physical characteristics of nuclear reactors. Moscow, National Research Center “Kurchatov Institute”, 1994. 63 p. (In Russian).

5. Zalubovskii I.I., Pismeneckii S.A., Rudychev V.G. External radiation of a container used for dry storage of spent VVER- 1000 nuclear fuel from the Zaporozhie nuclear power plant. Atomic Energy, 2010, vol. 109, no. 6, pp. 396-403. https://doi.org/10.1007/ s10512-011-9374-8

6. MacFarlane R.E., Muir D.W. The NJOY Nuclear Data Processing System Version 91. Los Alamos National Laboratory report LA-12740-M, October 1994.