Core support device for sodium-cooled fast reactor

摘要

PROBLEM TO BE SOLVED: To obtain a reactor core support device for restricting so that an invalid flow of a primary coolant for damaging reactor core cooling performance is reduced by shortening a gap between reactor core forming elements at the time of a reactor operation, and that the gap is widened up to a range required for a fuel replacement work at the time of fuel replacement, relative to 'the open type reactor core' of a ductless type fuel assembly. SOLUTION: Vertical and horizontal loads of a reactor core are supported allottedly by a lower-part reactor core support structure combined with a constraining band and a side-part reactor core support structure. The lower-part reactor core support structure 8 is composed of connecting tubes 16 arranged dispersedly on core support plates 8b, 8c for supporting uprightly reactor core forming elements 15 respectively, and the constraining band 17 for constraining a bundle of the connecting tubes 16 from the circumferential side. The connecting tubes 16 are formed by having external shapes of hexagons and having key ways 16a on the peripheral faces, and fitted loosely with the core support plates 8b, 8c, and connected mutually so as to constrain each other. Besides, the bundle of the connecting tubes 16 is constrained from the circumferential side by the constraining band 17 having an equivalent thermal expansion coefficient adjusted beforehand so as to be smaller than the thermal expansion coefficient of the reactor core forming elements 15 through a load transmitting block 18 and a presser plate 19.