METHOD OF CLEANING INNER SURFACES OF PIPES FROM RESIDUES OF ALKALI METAL AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2025 - IPC G21F9/28 

FIELD: performing operations.

SUBSTANCE: invention relates to processing of non-drained alkali metal residues, for example, sodium in dismantled pipes of nuclear power plants with fast neutron reactors. Method of cleaning internal surfaces of pipes from residues of alkali metal consists in passing decontaminating substances through the pipe. Small sealed dissolution chamber is created in the pipe, which is made of the main piston and an additional piston moving relative to it on the screw. Chamber moves in the pipe with increase in the length of the composite rod made of pipes or cable. Oxygen-free medium is created in the chamber, then a reagent is introduced: water, released hydrogen, an aqueous solution of metal hydroxide and other impurities are removed from the chamber. After cleaning of one section the sealed chamber is successively moved along the pipe; at that, gases and other wastes are discharged from the chamber into a sealed vessel for their neutralization.

EFFECT: invention widens the range of technical means for cleaning inner surfaces of pipes from residues of alkali metals.

4 cl, 1 dwg