Tag Archives: nuclear

Nuclear bomb blast videos redux!

Tobias Buckell’s brief 2007 post of a video snippet showing a Russian weapons test described as the world’s biggest ever nuclear blast has long been the most popular post on this site for search engine traffic. And rather than kvetch about people not coming here for more high-brow entertainment (!), I’m gonna make like a Roman emperor and give out more bread and circuses… pageviews is pageviews, AMIRITE? 😉

So thanks to Wired for rounding up a bunch of video clips from assorted atomic weapons tests; there’s eight over there, if you include the rather harrowing one about the Hiroshima after-effects (which you should surely watch, if only to balance any OMGZ-awesome-big-explosionz!! vibe you get from the others). These two are my personal favourites, though – this one because the mushroom cloud formation is rather beautiful (albeit in a horrifying way):

And this one because it takes you right inside the physical brutality of the blast (not to mention reminding me of a movie about the atomic test programs that I watched as a teenager, the name and basic plot of which is long gone, but the imagery of which haunts me to this day – a Futurismic big-helper gold star to anyone who can point me in the right direction):

Aren’t you glad the prospect of nuclear war is a thing of the past? Oh, wait…

Natural nuclear reactors

My magical statistics monkeys tell me that last week’s post on dissociative fugues was surprisingly popular, so I thought I’d share another article I found fascinating. Yet another hat-tip to Geoff Manaugh at BLDGBLOG for this one; it’s a Scientific American report on naturally occuring nuclear reactors. Yes, you read that right – nuclear power plants that just happened by geological chance.

More than two tons of this plutonium isotope were generated within the Oklo deposit. Although almost all this material, which has a 24,000-year halflife, has since disappeared (primarily through natural radioactive decay), some of the plutonium itself underwent fission, as attested by the presence of its characteristic fission products. The abundance of those lighter elements allowed scientists to deduce that fission reactions must have gone on for hundreds of thousands of years. From the amount of uranium 235 consumed, they calculated the total energy released, 15,000 megawatt-years, and from this and other evidence were able to work out the average power output, which was probably less than 100 kilowatts—say, enough to run a few dozen toasters.

(Or a few dozen highly-efficient computers, perhaps?)

It is truly amazing that more than a dozen natural reactors spontaneously sprang into existence and that they managed to maintain a modest power output for perhaps a few hundred millennia. Why is it that these parts of the deposit did not explode and destroy themselves right after nuclear chain reactions began? What mechanism provided the necessary self-regulation? Did these reactors run steadily or in fits and starts?

Go read the whole thing; the science isn’t too heavy, and it’s a pretty wild idea. I’m pretty sure I’ve read about something similar in a Stephen Baxter novel (though I can’t for the life of me remember which one); at the time I assumed he was speculating in a vacuum, but I guess I should have known better. 🙂

Regarding the popularity of the dissociative fugues post, I’ve been wondering whether perhaps I should be spending more time linking to interesting stuff and less time waffling around on tangents? It’s you guys who read this stuff, so what would you like to see here – more random points of interest, more speculative ramblings, or a blend of the two?

Charlie Stross on the future of nuclear power

power_plantCharles Stross has made an interesting point on the view that there is only a very short supply of useable nuclear fuel:

firstly, the supply of known uranium deposits will only last 80-100 years if we don’t recycle it and start burning MOX. I’d like to note that today’s light water reactors are horribly inefficient — they only extract 3% of the available energy from their fuel before it is considered “spent” and reclassified as waste. If we use high burn-up reactors such as the EPR, we can get a whole load more energy out of the same amount of fuel. And if we use fast breeders and run a plutonium cycle we can convert U238 into Pu239 and burn that instead of U235: there’s 500 times as much U238 lying around.

Secondly, we haven’t even tried to build a thorium reactor yet, although we’ve got good reason to believe it would work — and thorium is considerably more abundant than uranium.

As I have mentioned before, nuclear really should be part of the future energy mix of any industrialised country. Renewables can provide a large chunk (depending on local availability) of our energy needs but that still leaves a gap that needs to be plugged with something reliable and non-carbon-dioxide emitting.

David JC MacKay has more on nuclear power in his excellent free online textbook Sustainable Energy – Without the Hot Air.

[image from christian.senger on flickr]

Fusion on a budget

fusionreactorCanadian company General Fusion are developing a fusion reactor that is based on a process called magnetized target fusion:

The reactor consists of a metal sphere with a diameter of three meters. Inside the sphere, a liquid mixture of lithium and lead spins to create a vortex with a vertical cavity in the center. Then, the researchers inject two donut-shaped plasma rings called spheromaks into the top and bottom of the vertical cavity – like “blowing smoke rings at each other,” explains Doug Richardson, chief executive of General Fusion.

The last step is mainly well-timed brute mechanical force. 220 pneumatically controlled pistons on the outer surface of the sphere are programmed to simultaneously ram the surface of the sphere one time per second. This force sends an acoustic wave through the spinning liquid that becomes a shock wave when it reaches the spheromaks in the center, triggering a fusion burst.
General Fusion has just started developing simulations of the project, and hopes to build a test reactor and demonstrate net gain within five years. If everything goes according to plan, they will then build a 100-megawatt prototype reactor to be finished five years after that, which would cost an estimated $500 million.

Like general artificial intelligence, generative fusion power is one of those technologies that always seems to be 10-20 years in the future.

It is good to see alternative techniques to the well-known ITER project or Inertial Fusion Energy being adopted as it increases the chances that some genuinely practical approach will be found.

It’s also heartening to see (relatively) smaller operations engaging in generative fusion research.

[from Physorg][image from Physorg]

How to dismantle a nuclear bomb (before it dismantles you)

old Russian nuclear bombNo, it’s not a U2 reference; in the wake of the proposed nuclear reduction initiatives between the US and Russia, those helpful folk at the BBC have an article on how nuclear weapons are decommissioned – only the procedure they witnessed was a simulation. [image by mikelopoulos]

The dismantlement experiment is a joint exercise between the UK and Norway – the first of its kind – and was held a few miles from Oslo.

The five-day exercise has been keenly anticipated internationally as a way of building trust between nuclear weapons states and non-nuclear weapons states.

It is designed to see if one country can verify the disarmament of another country’s nuclear weapon, but without any sensitive information about national security and weapon design being compromised.

This is one of the things that has always baffled me about these sorts of agreements: everyone saying “oh yes, we should be mutually disarming!” but then tacitly acknowledging that “actually, we’d best be keeping the technology secret, because we don’t really trust you not to build more – and if you do we’ll want to have better ones”. So much for building trust, eh?

Still, the descriptions of the procedure are kind of interesting – not so much from a technical standpoint (you don’t get a list of the wrench sizes you’ll need) but as a physical manifestation of nation-state psychology:

From the start inspectors watch, photograph, seal and tag key items. They cover entry and exit points to the disarmament chamber, sweeping all those going in and out to ensure no radioactive material is smuggled away.

“It is a very choreographed process, almost like a ballet,” says Mr Persbo. “Timings are very precise.”

The amount of fissile material in a nuclear bomb is itself classified, so a number of techniques have to be employed by the inspectors to ensure nothing is diverted when they are not able to measure it in detail themselves.

Each country’s scientists have separately designed and built their own prototype devices known as “information barriers”, which can confirm that an agreed amount of radioactive material is present in any container.

If nothing else, you’ve got the switcheroo-loophole plot mechanics for a fissile re-run of The Italian Job right there. That should make for a cheery movie… but if you want some real nuclear angst to set you up for the weekend, you can read this (PDF) report from the International Commission on Nuclear Non-proliferation and Disarmament that looks at the possibility of the old and flaky nuclear command and control infrastructures of the superpowers being hacked by terrorists in order to kick off a modern-day Ragnarok. I can hear Dan Brown firing up his word processor as we speak… [via SlashDot]