Equipments for use in nuclear reactors

Purpose: To prevent nickel from leaching into nuclear reactor coolants thereby suppress the generation of cobalt 58 due to activation. Constitution: Equipments for use in nuclear reactor cores such as control rod covering tubes, control rod sheaths, feedwater heater tubes, etc. are constituted with ferrite type stainless steels not containing nickel and containing more than 10 wt% chromium incorporated as the basic element with nitrogen at a level higher than the impurity content. While the ferrite type materials have been used for the pressure vessel, there has been a problem in view of the embrittlement under irradiation when used as the equipments in nuclear reactor cores. However, it has been found that the embrittlement under irradiation can be improved by the incorporation of nitrogen in excess of the impurity level. Accordingly, the material of the present invention can suppress the generation of cobalt 58, provide corrosion resistance and avoid embrittlement under irradiation. (Takahashi, M.)