Designs of control rods with strong absorption ability for small fast reactors
| Autor: | L. Buiron, P. Sciora, T. Kooyman, H. Guo |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Long cycle
Nuclear and High Energy Physics Materials science Hydride 020209 energy Mechanical Engineering Nuclear engineering Control rod 02 engineering and technology Hydrogen desorption 01 natural sciences 010305 fluids & plasmas Nuclear Energy and Engineering 0103 physical sciences 0202 electrical engineering electronic engineering information engineering General Materials Science Neutron Safety Risk Reliability and Quality Waste Management and Disposal High absorption Burnup Leakage (electronics) |
| Zdroj: | Nuclear Engineering and Design. 368:110799 |
| ISSN: | 0029-5493 |
| Popis: | Small fast reactors usually exhibit high neutron leakage and low breeding capability, while modular design demands long cycle length and compact core. These characteristics raise the requirement of control rods with strong absorption ability and long operating lifetime. In this paper, control rods with 90% 10B enriched B4C, 90% 10B enriched HfB2-90, and HfH1.62 are designed and assessed in a small sodium fast reactor. Results show that the operating lifetime of high 10B enriched B4C is limited by its burnup and temperature. Even with small pin design, 90% 10B enriched B4C is not able to stay safe as long as the fuel in a no refueling scenario. HfB2 can tolerate a longer residence time compared to the fuel. The absorption ability of HfB2 can be higher than B4C if the geometry effect is accounted for. HfH1.62 absorber is feasible in normal situations, but its absorption ability is inferior to B4C or HfB2 and will be significantly reduced at high temperature due to the hydrogen desorption issue. The spatial self-shielding effect increases with the absorption ability of control rods. In order to mitigate the heterogeneous distribution, two solutions are investigated in this paper. The radially mixed designs, with HfB2 at the outermost pins and B4C in the inner pins, do not extend the operating lifetime but increase the manufacturing complicity and the cost of raw materials. The substitution of absorber with a hydride moderator is able to keep high absorption ability and long operating lifetime of control rods while saving the investment of expensive absorber. Moreover, the local effects and hydrogen desorption of hydride moderators are acceptable. |
| Databáze: | OpenAIRE |
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