Laser lights renders radioactive waste safe

[Submariner]

What a great technology find if this laser procedure works. Time will tell.

JAMES REYNOLDS

DANGERS associated with radioactive waste, and the problems and huge expense of its disposal could soon end after a Scottish researcher discovered how to neutralise its harmful effects using light.

New research by a leading scientist at the University of Strathclyde could revolutionise the waning fortunes of the nuclear power industry - restoring both political and public faith in an energy source that was once hailed as the future of clean, green energy.

Using a laser, Professor Ken Ledingham has successfully transformed one of the deadliest products of nuclear fission into inert matter in minutes.

Snip >

http://www.news.scotsman.com/scitech.cfm?id=849072003

[treepig]

1. there are several 'fuel reprocessing' methods to dramatically reduce

and even 'reuse' nuclear waste that are out there. this website discusses the issue in some detail:

http://lpsc.in2p3.fr/reacteurs-hybrides/english/NEWNRW/NEWNRW.html


Fuel Reprocessing
In the reactor, as fissions occur, increasing amounts of fission products, what we called the "ashes", are produced. Fission products are liable to capture neutrons, thus decreasing the number of neutrons available for fissions. These captures do not release energy since, the nuclei being relatively light, they cannot fission. The neutrons captured by the fission products are lost for all practical purposes. Fission products are said to "poison" the fuel, they must be removed from the reactor.

Computer simulations of the fuel reprocessing considered here have been done at the "Institut des Sciences Nucléaires'' (ISN) in Grenoble. It consists in extracting the fission products from the fuel, letting only heavy nuclei remain in the fuel, but leaving all the heavy nuclei in the fuel: the fertile nuclei, the fissile nuclei, and all the minor actinides, in order to satisfy the condition that all heavy nuclei will eventually fission. If the reactor is a breeder reactor, some of the fissile nuclei, the "extra" ones, are removed. If the reactor is a simple converter reactor, the fissile nuclei are left as is; by definition, there are enough to continue the chain reaction. Finally, the fertile nuclei consumed are replaced. After these reprocessing steps, the fuel is ready to be loaded in the reactor. The new fuel is actually the old fuel which has been cleaned of its fission products and supplemented with new fertile material, it is recycled fuel.


the conclusion is that it's mostly political ill will towards all things nuclear that's preventing these technologies from being implemented more than technological or even economical factors.

[DarkPhenyx]

2. Really?

So cool!

<on edit>

I think iodine is a photo-sensitive chemical anyway. It is entierly possible that the laser is simply degrading the iodine and not the radioactivity. If this is the case then it wouldn't work on otehr transuranics or isotopes.

I could be wrong though. Crap, now I have to go read again.

[cprise]

3. A clue

"It is forecast that such lasers could achieve pulse powers greater than the electrical power generated by all the world’s power plants combined."

This may take too much energy to be practical.

[pw]

4. This is a tiny little step

Basically, it's using an enormous amount of energy to transmute one of the dozens of dangerous components of radioactive waste to a safe element. It's very nice, but it doesn't address the whole problem by a long shot.

[treepig]

5. like most science-related articles you find in the popular media

this one is poorly enough written as to be close to meaningless. for example, the sentence

"It is forecast that such lasers could achieve pulse powers greater than the electrical power generated by all the world’s power plants combined."

makes it sound like a huge amount of energy is required.



indeed, from a webpage describing pulsed lasers,

http://physics.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html

we find the laser has a focus intensity of 1x10e19 W/cm2. even if the laser is focued over a very small area, say a square millimeter, a pulse would still require 1x10e17 (that's a 1 followed by 17 zeros) watts of power. from the following website, http://www.columbia.edu/cu/mechanical/mrl/ntm/level3/ch02/html/l3c02s03.html , we find that the average power consumption of the entire planet is 13.5 terawatts (or 13.5 followed by 12 zeros). so, indeed, a laser pulse covering even a small area such as one square millimeter requires 10,000 times the world's average power output (hence, the article is technically accurate).

however, it boggles the mind - where are you going to get 10,000 times the entire power output of the earth to run this device. well, what was not explained was that this pulse only lasts for 10e-15 seconds.

[treepig]

7. ok, it won't let me edit to include the punchline,

so let's try this (presenting the final paragraph in its entirety):


however, it boggles the mind - where are you going to get 10,000 times the entire power output of the earth to run this device. well, what was not explained was that this pulse only lasts for 10e-15 seconds. (that's a decimal point followed by fourteen zeroes and then a 1). consequently, the energy required for this incredibly powerful pulse is only 100 joules (energy is power * time). one gallon of gasoline contains about 1.3 x 10e8 joules of energy, and could therefore generate about about 1.3 million of these pulses. i have no idea how much nuclear waste 1.3 million such pulses would de-contaminate, but i merely suggest that the energy requirements for this process are not as outlandishly high as implied in the original article.

[sam sarrha]

16. probably take a nuclear power plant to run it....

:freak: :nuke:

[Scottie72]

6. hmmm

Sounds interesting.. but there are no journal links. I would be interested in learning more about the actual process.

[Submariner]

9. The university link indicates the applicable laser research

but your right, not in the science journals yet. I'll post them when I see them.

http://www.photonics.phys.strath.ac.uk/

[treepig]

8. tangentially, laser-driven processes are used in fusion efforts

http://www.research.ucla.edu/chal/8.htm

[damnraddem]

10. Seems doubtful.

Lasers might effect some transitions, but the right ones, in many different isotopes of different elements?

I suspect that someone is using smoke as well as mirrors.

[dfong63]

11. this research will be used as a great excuse by wishful thinkers

Prof Ledingham said: "The question of transmutation of all radioactive waste is a long way down the track, probably ten to 20 years. The only way of doing this at present is by building huge accelerators. However, in the same time lasers will develop enormously and so there will be two players on the block."

a great excuse for wishful thinkers to postpone the day of reckoning on the nuclear waste issue. just as they have been doing from day one.

20 years ago, they were saying the problem will be solved soon. the problem will be solved in 10 years. then 20 years. now it's another 10-20 years for this farce. how stupid do they think we are?

[treepig]

12. excellent points!

for a while there, i thought this scientifically sound, but early stage research was worthwhile. but now that you have pointed out that

"20 years ago, they were saying the problem will be solved soon. the problem will be solved in 10 years. then 20 years. now it's another 10-20 years for this farce. how stupid do they think we are?"

it's clear to me we shouldn't throw any more money down this rat hole.

and while we're at it, let's stop the assinine funding of solar panel and wind generation technologies, those granola eating leftist proponents of these technologies have been playing us for chumps for at least 20 years now - furthermore, i've recently seen projections that large-scale deployment sufficient to make a significant dent in fossil fuel dependency won't occur for another 20 years at the earliest. god, am i ever tired of their lies and empty promises.

and cancer research - that boondoogle has been going on even longer. nixon promised to have cancer cured in 5 years over 30 years ago and cancer rates have barely trended downwards at all despite $20 billion of research a year and $140 billion spent on clinical treatment costs. yikes, those trough-feeding, pathetically incompentent free-loading biomedical researchers and doctors have to be cut off of the public dole now!

[dfong63]

13. there's a huge flaw in your analogy

and while we're at it, let's stop the assinine funding of solar panel and wind generation technologies,

there's a huge flaw in your analogy. wind and solar power technologies have delivered handsomely on their promise. the same can't be said of nuclear, even though it has received and continues to receive massive government subsidies that dwarf anything received by the former. 40 years after we were told that nuclear power would be safe and the waste problem would be solved, we're still finding surprising defects in power plants, and the nuke waste problem is spreading.

and then there's the proliferation threat from nuclear power plants. we can't very well deny Iran or North Korea the right to develop nuclear power if we're doing it ourselves.

the technologies are not really comparable. wind and solar don't have a radioactive waste problem in the first place. if wind and solar turn out to be infeasible for some reason (unlikely), at least we won't be stuck with millions of tons of lethal waste that we don't know what to do with.

[Kolesar]

14. I really think that treepig was being sarcastic about defunding solar/wind

He was mocking the "official line" as spoken by the established power industries (coal, oil, etc.). (Perhaps I should let treepig answer this, though.)

[treepig]

15. ok, my answer

perhaps i was mocking something - not quite sure what, but if anything it would be the attitude that we've spent so much time, money and effort over the past 20 years developing technological solutions to the nuclear waste disposal problem. quite frankly, from what i've seen is that almost all effort has gone into a storage solution (e.g., yucca mountain) which i think we can all agree on is not much of a solution at all.

so now when someone presents a reasonable technological solution to actually eradicating the waste, it's a bit frustrating to see it dismissed flatly out of hand with absolutely no scientific reason being provided as to why the laser technology will not work. there seem to be powerful forces at play that don't want it to work or be adapted (note the article itelf set the technology up as being impractical by making the misleading claim about the power requirements - something i tried to debunk in posts found above).

to be fair, there actually are reasonable scientific reasons why the laser technology is not a panacea to cure all nuclear waste problems. all the original article did not describe the laser process in any detail, from the cryptic description that the I-129 isotope is rendered safe in less than an hour, i'm assuming that they must be using a 'neutron separation energy' approach - in effect running the normal neutron capture process in reverse.

neutron capture is the process by which fission of U-235 occurs. a nice animation of this process is provided at:

http://earthsci.terc.edu/content/visualizations/es0702/es0702page01.cfm?chapter_no=visualization

what happens is the a neutron is 'captured' by a U-235 nucleus converting it to the unstable U-236 form which then disintegrates into smaller atomic nuclei while releasing addition neutrons and 'energy' - what is not explained clearly in the animation (but is shown visually) is that some of this energy is released as very high energy photons in the form of gamma rays.

it is reasonable to assume (and yes i know what happens when one does so) that the laser technology is reversing this process by directing the high energy photons into a nucleus, which in turn effects the release of a neutron. in this case, I-129 would be converted into I-128. I-128 has a half life of 25 minutes (instead of 15,700,000 like I-129) - therefore in a short time (actually a bit more than an hour, but still only a few hours/days) the I-128 would be completely inert.

so why wouldn't this process work for all isotopes? well, for one thing not all isotopes might have 'neighboring' isotopes that are more desirable to have around. however, if you consult the isotope table provided at http://www2.bnl.gov/ton/index.html , you'll see that in general there's alot of options available, and this shouldn't be a huge problem. another thing, as isotopes become larger, more energy is required to effect neutron separation:


Some low Z elements have sufficiently low neutron separation energy that photoneutron production is feasible if the incident photon energy matches or exceeds the neutron separation energy. The cross section for photonuclear absorption reactions are small compared to other nuclear cross sections such as neutron or proton capture which will be discussed later. The neutron separation energy and cross section are important values to consider when trying to determine the probability of a photonuclear reaction. The neutron production rate can be determined from the cross section for a given photon beam luminosity.

The Q-value is the net kinetic energy change for any nuclear reaction and is the same as the neutron separation energy for a (g, n) reaction . It can be calculated as the mass of the target element minus the sum of the masses of a neutron and the resulting nucleus. In table 2 the Q-values are negative, indicating that the incident photons require a certain energy for the (g, n) reaction to occur.

When a photon is incident on a target a number of possible reactions can occur. Because photons interact with the electrons in an atom, the probability of Compton scattering is high. At higher photon energies these interactions are less likely, allowing for a greater probability of photonuclear interactions.

basically 'low Z' just means smaller atoms, and I-129 is only about 60% the mass of U-235 (and plutonium, etc) so there may be difficulties constructing lasers with enough energy to apply to these larger isotopes. however, the reprocessing technologies i provided a link for up in post #1 nicely take care of these larger isotopes.

ok, i could go on, but if you're a head-in-the-sand naysayer, a nattering nabob of nuclide negatism if you will, no amount of facts will be convincing. and about the vast amounts of money thrown away at these technologies (and the other research areas i mentioned) - please compare the $ for $ amounts with how much we're now spending over in iraq with basically no public debate or accountability. so if i wasn't mocking the oil industry at first, maybe i should have been - because if all the peripheral costs are considered, they're the ones really taking us all to be suckers.

[treepig]

17. oops, too late to edit

just wanted to fix up this statement:

"I-128 has a half life of 25 minutes (instead of 15,700,000 like I-129) - therefore in a short time (actually a bit more than an hour, but still only a few hours/days) the I-128 would be completely inert."

that should be 15,700,000 years, and of course with compounds experiencing radioactive decay, they don't become 'completely inert' but rather only approach this condition considering that in each 'half life' one half of the initial radioactivity is lost.

[dfong63]

18. i'm addressing an attitude, too

perhaps i was mocking something - not quite sure what, but if anything it would be the attitude that we've spent so much time, money and effort over the past 20 years developing technological solutions to the nuclear waste disposal problem. quite frankly, from what i've seen is that almost all effort has gone into a storage solution (e.g., yucca mountain) which i think we can all agree on is not much of a solution at all.

so you're addressing an attitude? i am too. i'm addressing the attitude that every problem is solvable if enough money is thrown at it. plenty of money has been thrown at the nuclear waste problem, and if it was misdirected into the wrong avenue, it's because the folks with the big stakes in nuclear thought that was the best option. now decades down the road we see that their promises weren't worth shit. oh, but there's this "new" technology on the horizon that "may" solve the problem in another few decades. what a wonderful excuse to go on producing more nuclear waste.

how convenient for the nuclear power industry - a new pie-in-the-sky technology that "may" solve the problem.
the attitude that i hate is that it's somehow OK to make these irreversible technological commitments based on promises and wishful thinking. that we should believe the promises from an industry that has lied to us from the start.

sure, let's investigate the laser transmutation technology, let a thousand flowers blossom. but UNTIL the technology is proven, the wise course would be to embark upon a phaseout of nuclear power.

[NNadir]

19. Nothing Pie-in-the-sky about it.

The transmutation of nuclear wastes is well understood and WILL be instituted in advanced countries in the twenty-first, mainly Europe, Japan, India, and China. The processes involved will recover energy and many valuable materials.

There are many methods of doing this besides laser based methods: Spallation neutrons from accelerators, capture of neutrons in reactors have high conversion (or "breeding" ratios)and bombardment with protons.

There is nothing pie-in-the-sky about it. The National Research Council evaluated the technology in 1998 and issued a report of nearly a thousand pages.

People who advocate the abandonment of nuclear power are advocating the KILLING of people, since hundreds of thousands, if not millions of people, die each year from air pollution.

The number of people killed by nuclear POWER plants world wide since its invention is in the low thousands FOR ITS ENTIRE HISTORY, including Chernobyl.

NOBODY ANYWHERE HAS EVER BEEN KILLED BY COMMERCIAL NUCLEAR WASTE.