1. Tsinghua University, Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084, China
2. Karlsruhe Institute of Technology, Institute of Nuclear and Energy Technologies, 76021 Karlsruhe, Germany
3. University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, Michigan 48103