Neutron-physical characteristics of a VVER-1000 core with 100% fuel load consisting of a mixture of recovered uranium and plutonium and enriched uranium

Abstract

The results of a calculation of the neutron-physical characteristics of different variants of the fuel load of a VVER-1000 core are presented. The load completely consists of either enriched natural uranium (standard fuel) or recovered fuel, consisting of a uranium-plutonium mixture of recovered material, recovered plutonium, and highly enriched uranium. The mass fraction of plutonium isotopes in the recovered fuel ranged from 2 to 5%. All load variants examined have the same energy potential. The neutron-physical characteristics of a core with a full load of uranium are compared for a core with recovered uranium-plutonium fuel. Analysis of the neutron-physical characteristics did not show any fundamental limitations on the possibility of a VVER-1000 core load consisting entirely of recovered uranium-plutonium fuel.It is proposed in [1] that fuel based on recovered uranium-plutonium (an unseparated mixture of isotopes) which is separated from the spent fuel from thermal reactors and from which other actinides and fission products are removed and is mixed (taking account of the compensation and even isotopes of uranium and plutonium) with enriched natural uranium be used in thermal reactors. The specific consumption of natural uranium in the production of such fuel is approximately 20% lower than for fabrication of uranium fuel, and the specific separation work required to enrich the uranium part of the mixture remains almost unchanged [2]. The neutron-physical characteristics of a core with a 100% load of uranium and recovered uranium-plutonium fuel which affect the VVER-1000 operating safety differed negligibly, since the mass fraction of plutonium in the recovered fuel is approximately 1% [2].The required content of fissile nuclides in the fuel can be obtained by adding to the reprocessed uranium-plutonium and mixture, together with enriched natural uranium, the plutonium separated from spent VVER-440 fuel. Many years of European experience has validated the possibility of using in PWR plutonium mixed with uranium-plutonium fuel (mixture of recovered plutonium and depleted uranium) with mass fraction of plutonium fissile isotopes 4-6% [3].

A new approach to the recycling of spent nuclear fuel in thermal reactors within the REMIX concept

“…Since 2005, the V.G. Khlopin Radium Institute in collaboration with the Kurchatov Institute has been developing REMIX fuel (REMIX -REegenerated MIXture of U-Pu oxides), which involves recycling both reprocessed uranium and plutonium to load the entire core of existing VVER-1000/1200 reactors (Fedorov et al 2001, Pavlovichev et al 2006, Pavlovichev et al 2008, Zilberman et al 2012, Dekusar et al 2013, Postovarova et al 2016.…”

Radiation characteristics of REMIX-fuel multirecycling in VVER-1000 reactor

“…В работе рассмотрено три вида РЕМИКС топлива: типы А, А2 и Б. РЕМИКС А [1,4] представляет собой неразделенную смесь регенерированных урана и плуто ния после добавления 17 -20% по массе обогащенного природного урана (ОПУ) с содержанием 19,75% 235 U. Топливо РЕМИКС А2 отличается от РЕМИКС А более вы соким содержанием плутония [5]. В расчетах принимается массовое содержание плутония в топливе РЕМИКС А2 равным 3%.…”

The choice of the fuel assembly for VVER-1000 in a closed fuel cycle based on REMIX-technology

“…In papers [2][3][4], it has been proposed to use in thermal reactors fuel made from unseparated mixtures of uranium and plutonium isotopes blended with enriched natural uranium. Such fuel is called as REMIX-fuel.…”