Japan Atomic Energy Agency

The Japan Atomic Power Company

Other

Japan Atomic Energy Research

Eisuke Minehara

Ryoichi Hajima

Nobuyuki Nishimori

Ryoji Nagai

The laser decontamination device includes: a laser oscillator; a scanning device provided with an XY axis scanner and a Z axis scanner to condense the laser beam emitted from the laser oscillator onto the surface of the contaminated article without the intervention of any compound lens such as an f &#x3b8; lens so as to optically scan the surface; and a surface shape measuring device to measure the surface shape of the contaminated article, the Z axis scanner being provided with a focus position controlling section to automatically adjust a focus position in accordance with an irradiation position such that a focus of the laser beam comes on the surface of the contaminated article based on a shape data obtained at the surface shape measuring device.

Laser decontamination device

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 includes a piping structure with which a substance to be irradiated that has been deposited on outer and inner surfaces of a nuclear reactor pressure vessel, and a nuclear reactor container tank, and the internal nuclear reactor structures all having been contaminated with radioisotopes, can be removed in the water environment. The piping structure, to secure a region in a water environment that is gas pressurized to discharge the water and filled with the gas to not interfere with laser irradiation, has a semi-hermetically closed, incomplete water seal that is half-open with a siphon provided downward, a mechanical structure that withstands water pressure in a radial direction, and an extendable bellows-like tube to enable the piping structure to tilt.

Apparatus for decontaminating radioisotope-contaminated surface vicinity region by use of nonthermal laser peeling

Parts, structural components, etc. that have their surfaces contaminated by radioisotopes in the accelerators, nuclear reactors, RI product manufacturing factories, nuclear fuel factories, nuclear fuel reprocessing factories, etc. are decontaminated by non-thermal laser peeling without suffering re-melting, re-diffusing and re-contaminating such that upon non-thermal laser irradiation, areas near the irradiated surface are evaporated and removed faster than the heat generated in the irradiated surface is transmitted to nearby areas.

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

A method for realizing both high extraction efficiency of laser light from electron beams and femto-second ultra-short pulses in a free-electron laser, wherein the peak current of electron pulses from a superconducting or normal conducting linear accelerator serving as a driver for the free-electron laser is adjusted to be greater than a certain lower limit and electron beams are brought into perfect synchronism with light or the time of duration for which the electron pulses are repeated is made longer than the time to saturation of light oscillation (the time during which light is emitted due to the increase of optical output by an amount corresponding to the gain up to the point where the optical output does not increase any more), whereby the oscillation of light is facilitated, wherein the extraction efficiency of laser light from electron beams is increased to exceed the theoretical limit which is expressed by 1/(2 Nw)&#x2dc;1/(4 Nw) (Nw=the number of undulator periods) of electron beam power or rendered proportional to the square of N, or the number of electrons in a micropulse, and wherein ultra-short pulses of the femto-second range are generated.

Method and a device for realizing both high extraction efficiency of laser light from electron beams and femto-second ultra-short in free-electron lasers pulses

Growing community of inventors

Ibaraki, Japan

Eisuke Minehara