| 摘要 |
PURPOSE:To improve reactivity by providing spacings for guiding a coolant to the inside of sheaths. CONSTITUTION:A control rod 10 for a nuclear reactor has a central tie rod 14 which has a cruciform cross section and integrally couples a front end structural material 12 and a tail end structural 13. The sheaths 15 made of a high- purity stainless steel having a deep U-shaped section is fixed to the respective projecting legs of the tie rod 14 and the wings 16 are formed. Welded films 18 made of a hafnium (Hf) metal to serve as neutron absorptive materials are formed on the inside surfaces of the sheaths 15. The films 18 are formed to the thicknesses decreasing stepwise from the structural 12 toward the structural material 11 so that the neutron absorptive characteristics are decreased stepwise. The spacings 25 are formed as coolant flow passages in wings 16. The reactivity is thus enhanced. |
