What are uses of laser in nuclear decontamination?

Answer 1

High energy lasers, either continuous or pulsed, can be used to remove surface contamination from virtually any solid surface.

A laser beam hitting a surface can bring the surface temperature to 2,000 degrees F or higher within microseconds. Any Organic materials (such as paint) are vaporized, ejected (violently) from the surface and any inorganic debris can be collected using a vacuum system and appropriate filters. The amount of surface removed and the depth of penetration of the beam are a function of the energy level, type (wavelength) of laser/light used, and scan rate. The controls of such a system are so fine that one layer of paint can be remove to expose a prior layer of a different color.

Because of the inherent dangers in such a high energy beam, all operations should be computer/robot controlled. Operations can be previewed by scanning the surface with a low energy laser to verify the coverage area before initiating the high energy process.

There are two other attractive features that can be designed into this system. First, by using a pulsed beam or by interrupting the continuous beam, the light being emitted by the hot surface (plasma) can be read spectroscopically, revealing the elemental species present in the ejecta. Thus with a feedback loop, the system can scan the surface repeatedly until it is "cleaned" of the target contaminant.

Second, adjustment of the laser (with wattage of 2000 or more, continuous) can cut 1/2 inch steel (for example) at the rate of 20 inches per minute, or other materials at equivalent rates. This permits the dissecting of the cleaned equipment into small disposable sections, without the necessity of retooling the operation.

Note: This very attractive De-con technology has been rejected in some government applications because of supposed "safety" concerns. Those concerns came from poorly conceived testing with hand held rather than robotic end effectors and without the use of computer controls. The operator flinched during the test, which resulted in the beam going in unintended directions, the accidental cutting of an oxygen line, and a resultant fire (metal at 2,000 degrees in an oxygen atmosphere WILL burn remarkably well.) Conversely automobile manufacturers have used such lasers for over two decades for many cutting and welding operations, computer controlled, with no major adverse effects.

Source: WHC-SA-3110-S , Dann J. Flesher and Rand D. Miller, "Light Aided Decontamination 1996 (LAD), Surface Cleaning, Cutting, and Welding With Light: A Now Technology" Westinghouse Hanford Company

posted by Alkem