Patent ID: 8518331

Claim:
An apparatus with which areas near surfaces in a water environment that are contaminated by radioisotopes are decontaminated by non-thermal laser peeling without suffering re-melting, re-diffusing and re-contaminating, the apparatus comprising: a piping structure with which a substance to be irradiated that has been deposited either on both the outer and inner surfaces of a nuclear reactor pressure vessel, and a nuclear reactor container tank, and the internal nuclear reactor structures and the like, all having been contaminated with radioisotopes, can be removed in the water environment, the piping structure being such that in order to secure a region in a water environment that is gas pressurized to discharge the water and filled with the gas so that it will not interfere with laser irradiation, it has a semi-hermetically closed, incomplete water seal that is half-open with a siphon provided downward, has a mechanical structure that withstands water pressure in a radial direction, and has an extendable bellows-like tube or any other extendable telescopic structure that enables the piping structure to be tilted over a wide range in an axial direction that is generally perpendicular to the surface to be irradiated with the laser.