Assessing the Otto Option: Thorium-Cycle Experimental Power Reactor Spent Fuel Characteristics

Abstract

also be considered for the simplicity it offers and thus potentially lower cost. Due to different neutronic and burnup profile between the two, the resulting spent fuel characteristic is also different and possibly requires different handling mechanism. This paper assesses the characteristics of OTTO-scheme RDE spent fuel using thorium fuel cycle to provide preliminary data and insight for its spent fuel management. The assessment is performed employing ORIGEN2.1 code. At day 30 of cooling after determined end-of-cycle (EOC), each spent fuel yields 234.9 Curies of radioactivity, emitting 66.26 neutrons/second, 1x10 13 photons/second, and releasing 0.7675 watts of decay heat. These numbers must be taken into consideration regarding spent fuel management and spent fuel cask design. Tl-208 isotope characteristics, whose existence is unique to thorium fuel cycle, were also determined. It is found to be yielding 3.42x10-3 Curie of radioactivity and releasing 1.2x10 8 photons/second at its peak. Understanding its high-energy gamma release, proper radiation protection mechanism must be implemented.

Characterising U-232 and Tl-208 Buildup and Decay on Thorium-fuelled RGTT200K

“…The key issue in Tl-208 was its peculiar behaviour in the first 10 years of decay, of which its activity is increased instead of decreased. This behaviour was discussed in 7 Sigma Epsilon previous publications [10,11], and considered to be the main difference of spent fuel management in thorium fuel cycle.…”