Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

¹ National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Department of Theoretical and Experimental Physics of Nuclear Reactors, 31, Kashirskoye shosse, 115409, Moscow, Russia
² Institute for Theoretical and Experimental Physics, Department of safe nuclear reactors, 25, Bolshaya Cheremushkinskaya ul., 117218, Moscow, Russia

^* Corresponding author: GVTikhomirov@mephi.ru

Published online: 25 September 2017

Abstract

Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 10⁵ years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of ²⁴⁴Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.