Neutronic Analysis for Feasibility of Fusion-Driven Subcritical System with Constant Fusion Power by Online Feeding of Molten Salt Fuel

Abstract

To enhance the practical application of a fusion-driven subcritical reactor, a system with constant fusion power by online feeding of molten salt fuel was designed. The system satisfies multiple purposes including waste transmutation, tritium breeding (TB), and energy multiplication (EM) through constant fusion power. All neutronic calculations were performed by SERPENT2.1.29 with the ENDF/B-VII.0 neutron cross-section library in order to simulate the online-feeding process.

A constant k-eff is maintained by the amount of the feeding being larger than the amount of the removed fission products. However, system performance is significantly improved by just reducting the reactivity swing with the feeding. Compared to a once-through cycle (OTC), the performance of TB and EM is significantly improved as the feeding rate increases. However, there is no deep burning effect like the OTC for waste transmutation.

The performance of waste transmutation is changed in the feeding scenarios. For the scenario with a high plutonium ratio, transmutation with plutonium is increased. On the other hand, for the feeding scenario with a high minor actinide ratio, transuranic waste is burned. However, the transmutation performance is degraded due to a low fission-to-capture ratio.

Keywords:

• Fusion-driven subcritical reactor
• online feeding
• molten salt
• waste transmutation
• tritium breeding

Acknowledgments

This work was supported by National Research Foundation of Korea programs (number NRF-2017M2B2B1072803 and number 2017M1A7A1A01016257). The authors also appreciate support from the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning, a granted financial resource from the Ministry of Trade, Industry & Energy, Korea (number 20184030202170).

Additional information

Funding

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning: [Grant Number 20184030202170]; National Research Foundation of Korea: [Grant Number 2017M2B2B1072803].