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Information × Registration Number 0217U001216, 0116U000828 , R & D reports Title Changing the characteristics of the external radiation from the dry storage of spent nuclear fuel at Ukrainian NPPs popup.stage_title Head Igor Girka, Registration Date 30-01-2017 Organization Kharkov National University named after V.N. Karazin popup.description2 The aim of this work is to develop methods for determining the contribution of certain nuclides contained in spent nuclear fuel (SNF) to the dose rate of the containers external radiation at their long-term storage, as well as methods of control for the destruction of fuel elements shells with respect to variation of the radiation characteristics and of the air temperature. The object of the research and development is the radiation fields produced by neutrons and gamma-quanta emitted by SNF when stored in ventilated storage containers (VSC) in the open air. The method of research and development is studying the processes and mechanisms of emission and propagation of gamma and neutron radiation with changes in their spectral composition in time taken into account when stored and transported in heterogeneous shielding constructions. For ventilated storage containers (VSC) of the dry storage for spent nuclear fuel (DSSNF) at the Zaporizhzhya nuclear power plant (NPP), the techniques using Monte Carlo methods were modified, the yield functions and angular distributions of ?-rays generated by primary photons in the energy range of SNF spectrum in the radial and axial directions were calculated. The use of the calculated data on the yield functions and angular distributions of ?-rays allows to determine dose rates at various distances and at different time of fuel storage for optional versions of containers loading (for different burnup and cooling time of SNF). It is shown that the dose rate (DR) outside the container at SNF storage time up to 10 years is determined by the radiation of 106Ru, 144Ce, 134Cs and 154Eu. At longer terms of SNF storage, DR is determined by the radiation of 154Eu, 90Sr and 137Cs: at SNF storage time of about 35 years the main contribution to RD? is made by 154Eu, and after that period - by 137Cs. The contribution of radionuclides to heat release at dry storage of SNF of WWER-1000 was studied. It is shown that in the range of the storage time up to 50 years the main contribution to the heat release is made by ?- and ?- emitters (fission products). The contribution of ?-radiation is determined by 90Sr (90Y) and 137Cs (137mBa). Heat release caused by ?-radiation at short cooling periods (up to ~20 years) is determined by three radionuclides: 137mBa, 134Cs and 154Eu, and at longer periods - by 137mBa. At SNF storage time over 50 years, the main contribution is made by ?-emitters (actinides) 238Pu, 239Pu, 241Am. Product Description popup.authors І. Гірка В. Пишкін В. Рудичев Г. Ветрова Г. Махненко Е. Рудичев popup.nrat_date 2020-04-02 Close