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TWI reveals handheld 5 kW laser torch


October 25, 2013

The TWI 5 kw laser torch in operation (Photo: TWI)

The TWI 5 kw laser torch in operation (Photo: TWI)

Image Gallery (3 images)

To address the challenges encountered in decommissioning a nuclear facility, the UK-based firm TWI has since 2009 been developing laser tube-cutting methods for the UK's Nuclear Decommissioning Authority. It has now demonstrated a 5 kW fiber laser projector, configured rather like a rifle, that can be wielded by a single person.

Metal pipework forms a surprisingly large proportion of the total volume of contaminated material that must be removed and treated when a nuclear facility is decommissioned. Laser cutting offers benefits for cutting of contaminated tubing, in that the cutting rate can be quite fast, no reaction forces result from the cutting process, and very little spread of contaminated material occurs. However, past laser cutting systems have generally been unwieldy, cumbersome, and used cutting geometries not well suited to the nuclear jungle of densely interwoven stainless steel tubing.

The TWI handheld laser cutting torch uses laser light generated by an IPG Photonics YLS-5000 5 kW ytterbium fiber laser (Larger fiber lasers are available, and could be used to enable more powerful laser torches). Ytterbium is the same laser element as is found in YAG lasers, which share the 1.06 micron laser wavelength. While this unit is rather large (1.4 m/55 in tall, 0.85 m/33 in on a side, and weighing in excess of half a ton), it can be connected to the torch through hundreds of meters of fiber, if required.

Laser cutting is a well established manufacturing process, but the cutting geometries encountered in demolition work are very different than the usual cutting on a flat table. In particular, very little study has been made of cutting tubing from a single side, rather than cutting by rotating the tube with a fixed laser directed at the desired kerf.

The above sketch of the TWI laser cutting torch explains how single side cutting is accomplished. The output from the optical fiber is collected by a first lens, and then focused into a fine cone by a second lens. The cone must be very narrow, so that there is sufficient laser power density to cut metal at all positions within the tube walls. In the unit shown above, the focusing lens has a 500 mm (20 in) focal length, ensuring that the laser beam would be tightly focused over a wide range of distances from the torch output.

In experimental cutting of stainless steel tubes ranging in size from 25-150 mm (1-6 in) diameter, with walls from 1.5-11 mm (0.11-0.45 in) in thickness, it became clear that it was more effective to take two quick passes with the laser torch, rather than trying to sever tubes in a single pass. Otherwise, there is too much distortion of the cutting beam from penetrating the near wall of the tube to allow enough power density for a clean cut at the far wall. The cutting process is fast, with the laser torch being capable of cutting through a 150-mm (6-in) stainless steel tube with a 1.5 mm (0.06 in) thick wall in less than 30 seconds.

You can get an idea of the impact of a tool like this in the very enjoyable video below. Also, the image gallery has a picture of the result of 15 minutes of demolition using the laser torch on a mixed bag of tubes and fixtures.

Source: TWI

About the Author
Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer. All articles by Brian Dodson

When I was working in turbine engine logistics one of our problems was "demilling" (or damaging) used up bearings so that the military would be certain not to buy back the decommissioned bearings. It was typical to use hammers and chisels, but we went through thousands of dollars of tools every year. All we needed to do was damage the bearings. This technology could damage them sufficiently in a second with no tools to replace.


Vault-crackers of the world are rejoicing as we read this. Put the laser in a stolen 'white van', run the cable to the vault and bingo!

The Skud

If there are any original series Star Trek fans out there who watched the 'enhanced editions', you'll know that the enhanced version added a 'red beam' effect to scotty's laser when he used it to cut through the bulk head.. well, they should have left it alone, the original 'invisibale beam' was correct. Actually, it's uncanny how similar this looks to the scene in the original version.. flying sparks and all...

Simon Sammut

I can see this gun finding its way into video games....

Nitrozzy Seven

Can I assume that someone is working on building shields to block this thing? Scottie?


I thought that was a piece of 2'' cold roll steel, turns out it's a week piece of pipe. nukes are known for the use of thin steel, what a joke !

Jay Finke

Oh please stop using glorified steam kettles for power the whole building is a toxic mess, they don't last long the wasted radioactive material is deadly for thousands of years. Fukushima is a perfect example of what goes wrong with these stupid things. Go thorium reactors and burn up the waste produced from the retardo version of nuclear power we have now.

By the way no rebreather or airline, rad shielding for that poor guy operating the really excellent laser means he is a dead man walking if that was used in a real nuclear power plant vaporized radioactive material by the lungful so nice.

Joseph Mertens

Is this cutting torch uses only the laser beam or any abrasive method for cutting?

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