PROCEDE ET APPAREILLAGE POUR LE PERFECTIONNEMENT DANS OU EN CE QUI CONCERNE LA DECONTAMINATION DE SURFACES METALLIQUES DANS DES REACTEURS DE CENTRALE NUCLEAIRE ET SOLUTION OXYDANTE UTILISEE

A.PROCEDE ET APPAREILLAGE POUR LE PERFECTIONNEMENT DANS OU EN CE QUI CONCERNE LA DECONTAMINATION DE SURFACES METALLIQUES DANS DES REACTEURS DE CENTRALE NUCLEAIRE ET SOLUTION OXYDANTE UTILISEE.B.PROCEDE CARACTERISE EN CE QU'IL COMPORTE UNE PREPARATION D'UNE SOLUTION DE DECONTAMINATION COMPORTANT DE L'EAU, DE 0,02 A 0,5 D'UN ACIDE ORGANIQUE SOLUBLE DANS L'EAU, UN CHAUFFAGE DE CETTE SOLUTION DE DECONTAMINATION DE 70 A 200C, UNE CIRCULATION DE CETTE SOLUTION DE DECONTAMINATION SUR LES SURFACES METALLIQUES PRECITEES, UNE PREPARATION D'UNE SOLUTION OXYDANTE COMPORTANT DE L'EAU, DE 0,02 A 2,5 D'UN PERMANGANATE DE METAL ALCALIN ET DE 0,02 A 2,5 D'UN HYDROXYDE DE METAL ALCALIN, UN CHAUFFAGE DE CETTE SOLUTION OXYDANTE DE 70 A 200C, UNE CIRCULATION DE CETTE SOLUTION OXYDANTE SUR LES SURFACES METALLIQUES, UNE CIRCULATION DE LA SOLUTION DE DECONTAMINATION SUR LES SURFACES METALLIQUES.L'INVENTION CONCERNE UN PROCEDE POUR DECONTAMINER LES SURFACES METALLIQUES. Method of decontaminating metal surfaces having radioactive oxide deposits thereon which comprises preparing a decontamination solution having a pH of from 1.5 to 4 comprising water, from 0.02 to 0.5% of a water soluble organic acid which has an equilibrium constant in a complex with ferric ion of at least about 10 and which is capable of producing a pH of from 2 to 3 in water, and from 0.01 to 0.4% of a chelate in free acid form which has an equilibrium constant in a complex with ferric ion of from to 10 to 10 and which is soluble at at least 0.4% at 40 DEG C in water having a pH of from 2 to 3. The decontamination solution is heated to from 70 to 200 DEG C and is placed in contact with the deposits on the metal surfaces until the level of radioactivity in the solution ceases to increase significantly. The metal surfaces are rinsed with water heated to from 70 to 200 DEG C. An oxidizing solution is prepared comprising water, from 0.2 to 2.5% of an alkali metal permanganate, and from 0.2 to 2.5% of an alkali metal hydroxide. Preferably, the amount of the permanganate exceeds the amount of the hydroxide when less than a 3% solution is used. The oxidizing solution is heated to from 70 to 200 DEG C, and is placed in contact with the deposits on the metal surfaces until the level of dichromate in the oxidizing solution ceases to increase significantly. The metal surfaces are rinsed with water, radioactive ions are removed from the decontamination solutions. the heated decontamination solution is placed in contact with