CHEMICAL DECONTAMINATION METHOD AND CHEMICAL DECONTAMINATION APPARATUS

WIPO Patent Application WO/2022/153646

A1

Provided is a chemical decontamination method whereby the time of decomposition of a reduction decontamination agent can be reduced.　Oxidization decontamination of a pipe of interest in a BWR plant, the decomposition of an oxidization decontamination agent, and reduction decontamination using an aqueous oxalic acid solution are performed. Subsequently, oxalic acid is decomposed (S7). That is, a portion of oxalic acid is decomposed by the irradiation of the aqueous oxalic acid solution with ultraviolet ray in an upstream of a decomposition device (S8) to convert Fe3+ in the aqueous solution to Fe2+. Hydrogen peroxide is supplied into the decomposition device (S9). In the decomposition device, oxalic acid is decomposed by the action of a catalyst and hydrogen peroxide, Fe2+ is reacted with hydrogen peroxide to produce Fe3+ and OH*, and oxalic acid is decomposed by OH*. The corrosion potential of the aqueous solution flowing out from the decomposition device is measured (S11). A concentration ratio reading device determines a Fe3+/Fe2+ ratio (concentration ratio) on the basis of the corrosion potential (S12), and a control device controls the amount of hydrogen peroxide to be supplied into the decomposition device on the basis of the Fe3+/Fe2+ value (S14 and S16).

ITOU TSUYOSHI (JP)
ISHIDA KAZUSHIGE (JP)
HOSOKAWA HIDEYUKI (JP)
YANAGISAWA SHINTARO (JP)
OOHIRA TAKASHI (JP)

PCT/JP2021/039978

July 21, 2022

October 29, 2021

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HITACHI GE NUCLEAR ENERGY LTD (JP)

G21D1/00; G21C19/02; G21F9/28

JP2017138139A	2017-08-10
JP2013095623A	2013-05-20
JP2003090897A	2003-03-28
JP2000105295A	2000-04-11
JP2018159647A	2018-10-11
JP2019529879A	2019-10-17

POLAIRE I.P.C. (JP)

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