Abstract: This invention relates to a cold trap for collecting impurities from liquid, which comprises a mesh screen and a spacer mesh having higher strength and wider mesh holes than that of the mesh screen interposed between the windings of the mesh screen. According to the present invention, since the spacer mesh supports the mesh screen over the whole surface thereof so that the mesh screen is protected free from break or deformation, the stiffness and collecting efficiency of the mesh section can be maintained prolongedly.

Abstract: A sodium-handling apparatus is disassembled and repaired by (1) contacting an inert gas with the sodium-contacting surfaces within the apparatus after discharge of sodium from the apparatus, thereby solidifying the deposited sodium, (2) flushing the inert gas with a reacting gas capable of reacting with sodium, capable of being dissolved in sodium and capable of forming a weak alkali therein, thereby forming a solid film of a neutral salt on surfaces of the deposited sodium by reaction of sodium with the reacting gas, (3) discharging the reacting gas from the apparatus, (4) disassembling and repairing the apparatus in the atmosphere, and then (5) continuing operation of the apparatus while the solid film is being retained on the surfaces of the apparatus.