ICONE15-10506 Tritium production calculation based on the depletion of lithium and beryllium in ceramic breeder blanket of fusion reactor

抄録

This paper introduces a method for calculating the depletion of Li/Be and inventory of tritium. A separated Be/Li2TiO3 layers blanket concept model was setup for depletion analysis. This work presents the neutronics design optimization analyses conducted as part of the development work for the modular cross cooled pebble bed (CCPB) blanket. The main objective has been to assess and optimize the tritium breeding performance to ensure tritium self-sufficiency and provide the data required for the thermal hydraulic blanket layout. After a long period of operation in fusion neutron environment, the depletion of both lithium and beryllium are of considerable effects to neutron and nuclear heat distributions. Reaction rate modification method is used to calculate lithium and beryllium depletion fractions, which can reduce the offset induced by neutron spectrum changing in the ceramic blanket. The effect of Lithium produced from beryllium is also seriously considered in the depletion calculation. Mean tritium breeding ratio (MTBR) is more suitable to represent the tritium breeding performance averaged over a period of operation. Different arrangements of ^6Li enrichment were studied in this paper. Results show that lower ^6Li enrichment of breeder in the front layers will lead to high depletion fractions, and considerable drop of MTBR can reach up to 4.93% even a packing factor of 60% is considered in breeder zones after 5 years operation. The more beryllium and the suitable higher the ^6Li enrichment of breeder placed in the front layers behind the first wall, the performance on MTBR would be better and the lower depletion fraction of lithium is achieved.