A novel concept of QUADRISO particles. Part II: Utilization for excess reactivity control

Abstract

In high temperature reactors, burnable absorbers are utilized to manage the excess reactivity at the early stage of the fuel cycle. In this paper QUADRISO particles are proposed to manage the initial excess reactivity of high temperature reactors. The QUADRISO concept synergistically couples the decrease of the burnable poison with the decrease of the fissile materials at the fuel particle level. This mechanism is set up by introducing a burnable poison layer around the fuel kernel in ordinary TRISO particles or by mixing the burnable poison with any of the TRISO coated layers. At the beginning of life, the initial excess reactivity is small because some neutrons are absorbed in the burnable poison and they are prevented from entering the fuel kernel. At the end of life, when the absorber is almost depleted, more neutrons stream into the fuel kernel of QUADRISO particles causing fission reactions. The mechanism has been applied to a prismatic high temperature reactor with europium or erbium burnable absorbers, showing a significant reduction in the initial excess reactivity of the core.

Increasing efficiency of nuclear fuel using burnable absorbers

“…Therefore, burnable absorbers also have an impact on nuclear safety. Boron, gadolinium, and to a small extent europium (Talamo, 2010) and erbium (Fedosov, 2018) are currently the only materials used in power nuclear reactor operation serving as burnable absorbers. Main form is the integral part of the fuel matrix or a thin layer applied to the outer surface of the fuel pellet.…”

Conceptual design of quadriso particles with europium burnable absorber in HTRS.

“…5 The QUADRISO concept has been applied in seperate studies for transmuting Neptunium and Plutonium from Light Water Reactors waste and for producing 233 U from thorium. [6][7][8][9][10]…”