CHEMICAL DECONTAMINATION METHOD

PROBLEM TO BE SOLVED: To provide a chemical decontamination method which can decontaminate a ring header, in a PLR pipe. SOLUTION: An A circulation pump 4, a surge tank 1 equipped with a heater 2, a mixed bed resin tower 8, a cation resin tower 7 and a B circulation pump 5 are placed in a pipe 30 connected to the PLR pipe 22 to be decontaminated. Oxidization decontamination is carried out, by supplying an oxidization decontamination liquid from the pipe 30 into the PLR pipe 22 and reduction decontamination is carried out by supplying a reduction decontamination liquid from the pipe 30 into the PLR pipe 22. In the case of each decontamination, the decontamination liquid is supplied to the ring header 23, by making the discharge flow rate of the decontamination liquid from the A circulation pump 4 exceed that from the B circulation pump 5, to supply a portion of the decontamination liquid produced by the difference in flow rates from the inside of the surge tank 1 into the PLR pipe 22 and raise the decontamination liquid level in the PLR pipe 22. The ring header 23 in the PLR pipe 22 can be chemically decontaminated, by making the decontamination liquid level in the PLR pipe 22 fluctuated during the decontamination. COPYRIGHT: (C)2005,JPO&NCIPI