METHOD OF DECONTAMINATING RADIOISOTOPE-CONTAMINATED SURFACE VICINITY REGION BY USE OF NONTHERMAL LASER PEELING WITHOUT RE-MELTING, WITHOUT RE-DIFFUSION AND WITHOUT RE-CONTAMINATION, AND APPARATUS THEREFOR

• Main Author: MINEHARA, EISUKE
• Format: Patent
• Language: English; French; Japanese
• Published: 06.12.2007
• Subjects: BASIC ELECTRIC ELEMENTS; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; DECONTAMINATION ARRANGEMENTS THEREFOR; DEVICES USING STIMULATED EMISSION; ELECTRICITY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; PERFORMING OPERATIONS; PHYSICS; PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULARRADIATION OR PARTICLE BOMBARDMENT; SOLDERING OR UNSOLDERING; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; TRANSPORTING; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; WELDING; WORKING BY LASER BEAM

With respect to the method of removing a surface-adhering coating contaminated with radioisotope, as the applicability conditions, such as object, place and configuration, are strict, the scope of application thereof is quite limited. Thus, 100% decontamination cannot be attained, and while half or more can be decontaminated, substantial portion of the adhering radioisotope remains, that is, the decontamination capacity effect is very limited. There is provided a method of decontamination by the use of nonthermal laser peeling without re-melting, without re-diffusion and without re-contamination, in which parts, structures, etc. with surface contaminated with radioisotope of an accelerator, atomic reactor, radioisotope production plant, nuclear fuel plant, nuclear fuel reprocessing plant, etc. are exposed to nonthermal laser irradiation so that laser-irradiated surface vicinity regions are evaporated off faster than the transfer of heat generated in the vicinity of irradiated surface to its periphery. Les conditions d'applications, tels un objet, un emplacement et une configuration, d'un procédé de retrait de revêtement, adhérant à une surface, contaminé par des radioisotopes étant strictes, le champ d'application du procédé est assez limité. On ne peut donc parvenir à 100 % de décontamination et, alors qu'une décontamination est possible à 50 % ou plus, une partie importante du radioisotope adhérant reste, en d'autres termes, la capacité de décontamination est très limitée. L'invention porte donc sur un procédé de décontamination qui se sert d'un décollement par laser non thermique sans refusion, sans rediffusion et sans recontamination, dans lequel des parties, des structures, etc., dont la surface a été contaminée par des radioisotopes provenant d'un accélérateur, d'un réacteur atomique, d'une installation de production de radioisotopes, d'une installation de combustible nucléaire, d'une installation de retraitement de combustible nucléaire, etc., sont exposées à un rayonnement laser non thermique de telle sorte que les zones à proximité de la surface exposées aux rayons laser s'évaporent plus vite que le transfert de chaleur généré à proximité de la surface irradiée vers sa périphérie.