Potential of ²³¹Pa for Gas Cooled Long-life Core

Abstract

Feasibility study of the long-life core loaded with ²³¹Pa, which has very large capture cross-section, has been performed in the pebble bed-type gas cooled reactor. The results of infinite cell burn-up calculations show that ²³¹Pa has attractive potential to reduce the initial excess-reactivity and to be effectively converted to fissile nuclides ²³²U and successively ²³³U with the burn-up. These characteristics enable the reactor to sustain nuclear reactions for a longer time. Based on the optimization of the fuel composition and the moderator to fuel ratio, it is found that the high fuel burn-up of about 700GWd/t is achievable in consideration of the material restriction of coated fuel particles. Safety studies show negative temperature coefficients during the irradiation.

KEYWORDS:

• protactinium 231
• long-life core
• high burn-up
• gas cooled reactors
• uranium 233
• pebble bed reactors
• coated fuel particles
• high neutron fluence
• neutron flux
• feasibility studies
• safety analysis