Physical Insights

An independent scientist’s observations on society, technology, energy, science and the environment. “Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.” – Carl Sagan

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Helen Caldicott and the fine art of making up nonsense.

with 12 comments

Here’s a particularly egregious and scientifically vapid (as you’d expect, of course) interview with Helen Caldicott… recorded recently on some kind of “environmentalist” podcast.

Now… I could write a comprehensive technical deconstruction and debunking of essentially the whole lot… but I’m only one person, with a finite amount of time.

I’ll get started, just for now, by taking a look at just one particular sentence of nonsense from Caldicott.

Ask questions. Seek the evidence. Ask everybody questions, and never take anybody’s word for it. Are factual statements backed up by evidence? Are quantitative statements backed up by measurements, calculations, or derivations? Can those measurements or derivations be described and reproduced? Read everything you possibly can, and you decide.

Do people like Caldicott have the right idea? Or do people like George Monbiot have the right idea – that beneath the FUD, rhetoric and hysteria, these people have absolutely no real evidence, facts, knowledge or technical literacy at all?

HC: “Well it won’t recover. These accidents go on forever because plutonium’s half-life is 24,400 years. It lasts for half a million years. Thirty tons of plutonium got out at Chernobyl.”

Thirty tons of plutonium “got out” at Chernobyl!?

Personally, that reads many thousands of counts per minute on my baloney detector.

Let’s follow Dr. Caldicott’s favourite piece of advice… let’s read her book. Surely, just like all of Caldicott’s other “references” usually are, it’s got to be “in my book”, right?

“Plutonium is so carcinogenic that the half-ton of plutonium released from the Chernobyl meltdown is theoretically enough to kill everyone on Earth with lung cancer 1100 times, if it were to be uniformly distributed into the lungs of every human being.”

(From Nuclear Power is Not The Answer).

Hmmmm. Curious. It looks like we’ve gone from “a half-ton” in the book to “thirty tons” in this recent interview. Well, so much for “you should read my book… it’s all in the book!”

(By the way… that “kill everyone on Earth with lung cancer 1100 times…” bit is complete baloney. But that’s a story for another day.)

Reactor-grade plutonium typically consists of approximately 1.3% 238Pu, which has a half-life of 87.7 years and a specific activity of 634 GBq/g, 56.7% 239Pu, which has a half-life of 24,110 years and a commensurately far smaller specific activity of 2.3 GBq/g, 23.2% of 240Pu, with a half-life of
6564 years and a specific activity of 8.40 GBq/g, 13.9 % of 241Pu, with a half-life of 14.35 years and a specific activity of 3.84 TBq/g, and 4.9% of 242Pu, with a half-life of 373,300 years and a specific activity of 145 MBq/g.

Taking the weighted sum of all the above, we find that the overall specific activity of reactor-grade plutonium is 545.3 GBq/g, predominantly due to the 241Pu and the 238Pu content.

(Reactor-grade plutonium is considerably more radioactive than weapons-grade plutonium, due to the presence of substantial concentrations of these relatively unstable, high-activity plutonium nuclides. Weapons-grade plutonium is almost entirely 239Pu, which despite being a good fissile fuel, is more stable and less radioactive. The radiological heat output of 238Pu, gamma-radiation (from the 241Am daughter of 241Pu) and the high rate of neutron emission from the spontaneous fission of 240Pu all make these nuclides extremely deleterious and undesirable in nuclear weapon design and engineering.)

The best value determined based on the available data for the quantity of plutonium (a reactor-grade cocktail of different plutonium nuclides) released at Chernobyl is, as published in the reports of the Chernobyl Forum, 3 PBq (3×1015 Bq).

The approximate total mass, based on the best available data, of plutonium released into the environment at Chernobyl is 3 PBq divided by 545.3 GBq/g.

As the British physicist David Mackay put it, I’m not trying to be pro-nuclear. I’m just pro-arithmetic.

It’s 5.5 kilograms.

Incidentally, that’s a very small amount of plutonium compared to the amount of plutonium that has been dispersed around the environment from half a century of nuclear weapons testing. 5.5 kilograms of plutonium is, approximately, the amount of plutonium in the pit of a single nuclear weapon. A single zero-yield “fizzle” of a nuclear weapon with no fission, or a zero-yield one-point-implosion safety test, or the accidental HE explosion (without proper implosion of the primary, as in the Palomares and Thule accidents) of a single nuclear weapon will disperse a roughly comparable mass of plutonium into the environment. (But less radioactivity, since weapons-grade Pu is less radioactive than reactor-grade Pu.)

So, Caldicott has gone from exaggerating the true number by a factor of approximately 100 to exaggerating the true number by a factor of approximately 6000.

Anyway… let’s just step back a minute. 30 tons of plutonium released at Chernobyl? Let’s apply what scientists, engineers and technologists sometimes refer to as the “reasonableness test” or the “smell test”. Can you quickly “smell” the data and determine if it is roughly plausible or not?

The total mass of uranium dioxide fuel in the fuel assemblies of a fully fueled RBMK reactor is about 180 tonnes. That’s about 159 tonnes of uranium, if you take off the mass of the oxygen in the uranium dioxide. When LEU fuel is irradiated at a typical burnup in a nuclear power reactor, about one percent of the mass of the original uranium ends up as transuranic actinides, mostly plutonium, by the time the fuel is removed. So, that’s a total plutonium inventory in the Chernobyl reactor of approximately 1.6 tonnes.

So, if we make a conservative, pessimistic and entirely unrealistic assumption that 100% of the plutonium inventory in the nuclear fuel was entirely vaporised and released into the environment during the Chernobyl accident, that would be 1.6 tonnes of plutonium released to the environment. (In reality, that fraction was something more like 0.34% of the total inventory of plutonium within the irradiated uranium dioxide fuel.)

So, does “thirty tons” pass the smell test? Not by a long shot.

Written by Luke Weston

April 23, 2011 at 6:47 am

Blog Action Day

with 3 comments

Well, long time no post. I hope all my readers are well.

So, apparently today is something called “Blog Action Day“, and this year the topic of interest is anthropogenic forcing of the climate system, and mitigating the potential thereof.

So, OK, I thought I’ll write a blog post about it. The day is supposed to be about action, as the name suggests, so let’s talk about specific actions, with a view towards making a significant mitigation, in a realistic way, of Australia’s anthropogenic carbon dioxide emissions.

Australia’s brown coal (lignite) fired electricity generators have by far the highest specific carbon dioxide emissions intensity per unit of electrical energy generated, since they’re burning relatively high moisture brown coal. They are the most concentrated point contributors to the anthropogenic GHG output. Therefore, these are the “low-hanging fruit” – a very valuable target to look at first and foremost if we want to make the greatest realistic mitigation of the country’s carbon dioxide emissions in a practical way, followed by black coal-fired generators.

Australia’s total net greenhouse gas emissions in 2006 were 549.9 million tonnes of CO2 equivalent.

If we look at the three main sets of lignite-fired generators in the Latrobe valley in Victoria, they represent a very concentrated point source of CO2 output, so they’re a very good case to focus on specifically.

In 2006, Hazelwood generated 11.6 TWh of electrical energy, and 16,149,398 tonnes of carbon dioxide to atmosphere.

In 2006, Loy Yang A generated 15.994 TWh of electrical energy sent out to the grid and 19,326,812 tonnes of carbon dioxide to atmosphere.

I’ll exclude Loy Yang B from this list for the moment, since its numbers are eluding me.

In 2006, the Yallourn power station generated 10.392 TWh of electrical energy sent out to the grid and 14,680,000 tonnes of carbon dioxide to atmosphere.

If you look at the the total contribution of just those three brown-coal-fired plants combined, you’re looking at 9.12 percent of Australia’s total anthropogenic carbon dioxide emissions. If you replace those with clean technology that can deliver an equivalent electricity output, you get a 9.12 percent reduction in Australia’s CO2 emissions. (When you include Loy Yang B, I think it’s approximately 11-12%.)

That’s not a bad target for Australia to implement for the relatively short term for a real reduction in CO2 emissions. It can actually be done, if the real political will exists to do it.

Now, I’m not interested in this “100% renewable energy by 2020” business from the extremist any-excuse-for-a-protest Socialist Alternative set, because it is nonsense.

Replacing all the coal-fired and gas-fired generators in this country inside 10 years (and presumably only using wind turbines and solar cells, not nuclear energy of course since it doesn’t fit their para-religious ideology)? That’s complete bullshit, of course, because in the real world it cannot be done.

There’s a difference between setting a challenging target and setting a nonsense target. Unless you’re only trying to implement a political bullshit stunt instead of actually trying to hit your targets.

Of course, you don’t just close down the coal-fired generators. You’ve actually got to build their clean replacements first. So what do you use that can realistically replace a coal-fired power station? Nuclear power, of course.

Now, again, to be realistic, we probably can’t build LFTR/MSR, PBMR/HTGR, IFR/PRISM or any kind of nuclear fusion based generation capacity on a large scale to generate grid-connected energy right now. That’s not to say that pilot-scale research and development on those very cool technologies shouldn’t continue, but right now, getting more nuclear energy on the grid means advanced light water reactors – or maybe heavy water CANDU-type things, or conventional sodium-cooled fast reactors maybe. The most practical thing for serious deployment in the relatively short term is advanced LWR technology. In the slightly longer term, there is certainly a place to be encouraging both Gen. IV and fusion.

To get the same amount of energy as the total output from those coal plants, as above, which we’re talking about replacing, we need 4.56 GW of installed nuclear capacity, assuming a 95% capacity factor.

With 4 x 1154 MWe Westinghouse AP1000s, with a 95% capacity factor, you’ve got 4.62 GW, which is a little more than what’s needed.

You can easily have four nuclear power reactors integrated into one nuclear power plant.

Now, how much does it cost?

On March 27, 2008, South Carolina Electric & Gas applied to the Nuclear Regulatory Commission for a COL to build two AP1000s at the Virgil nuclear power plant in South Carolina. On May 27, 2008, SCE&G and Santee Cooper announced an engineering, procurement, and construction contract had been reached with Westinghouse. Costs are estimated to be approximately $9.8 billion for both AP1000 units, plus transmission facility and financing costs.

That gives you an idea of how much a nuclear power plant costs today, in the current financial environment, in the current regulatory environment.

If we double that figure of USD$9.8 billion, it’s AUD $21.4 billion. There will be some saving since we’re considering building four reactors at one plant, not two independent two-reactor plants.

How much that saving will be, quantitatively, I don’t really know. If the cost is reduced by 30%, we’re looking at 15 billion Australian dollars.

How long would it take? If the real political will exists to do it, 10 years is heaps of time. We could probably do even more in that timeframe if we really, really wanted to. AP1000 construction takes 36 months from first concrete poured to fuel load, if you ignore any political protest rubbish.

This is really just a base-line relatively achievable “base case”. After this decade, of course, the rate of nuclear power deployment – and related GHG emissions mitigation – could foreseeably accelerate.

What about the uranium input? About 600 tonnes of natural uranium per year total, for all four reactors. Australia’s present production, off the top of my head, is something like 10,000-11,000 tonnes. Australia’s present uranium production can very, very easily provide for Australia’s total electricity production even without expansion of uranium production – again, considering the inefficient once-through use of low-enriched uranium in conventional LWRs.

What about the so-called “waste”?
Roughly 80-85 tonnes of used uranium fuel per year. 96% of that is unchanged uranium, so that 76.8 tonnes of uranium can be seperated and re-used. It’s just uranium, so it’s not going to hurt you.

The remaining 3200 kg is made up of the valuable, interesting and unique byproduct materials from a nuclear reactor – unique resources with all kinds of different technological applications, which aren’t all radioactive, which you cannot get anywhere else.

Anyway, that’s one scenario which I happen to think has a lot of merit.

Maybe you don’t agree – but if you don’t agree, I’d love to see you elucidate an alternative scenario which can deliver the equivalent greenhouse gas emissions mitigation – shown to be accurate in a quantitative way – within a comparable timeframe and within a comparable cost.

It will not be inexpensive, and it will not happen overnight – but I have yet to see any scenario which can honestly do the same job faster and cheaper, when some real quantitative analysis is applied.

Written by Luke Weston

October 15, 2009 at 12:45 pm

Conspiracy at Three Mile Island…

with one comment

I wrote this in response to a comment over at Brave New Climate (shameless plug), but I thought it was quite a nice little post, so as not to waste it, I’ll re-post it.

PS: Sorry about my lack of blog activity lately, sometimes real life seems to eat up my time. Extra apologies, especially, if you’ve posted comments that the software has kept from being posted pending manual moderator approval, and therefore your comments haven’t been getting through.

Ah, the old Three Mile Island conspiracy theory, the notion that there were enormous amounts of radioactivity released, and people who experienced acute radiation poisoning, that was somehow covered up.

Let’s look, for a moment, at the Chernobyl disaster. When the Chernobyl disaster happened, we didn’t see the Soviet premier calling up Reagan to tell him all about this catastrophic accident and large release of radioactivity, did we? Of course, they tried to keep it a secret.
So, how did we in the industrialised world find out about the Chernobyl accident and this large release of radioactivity? We found out about it when all the radiological sensors and alarms started going off at the Forsmark nuclear power plant in Sweden.

As another example, we all know today that it is possible, if you live in an area of relatively uranium-rich geology, for significant amounts of radioactivity in the form of radon to leach into your basement naturally from the surrounding rock.
But how was this radon issue first discovered? It was discovered when a person employed at a nuclear power station in the United States kept setting off the radiological sensors when he arrived at work every day.

Those incidents show you just how sensitive the detectors and monitors used at facilities like nuclear power plants are.

In the modern world, if there is some sort of massive release of radioactivity into the atmosphere it is impossible to hide it or to cover it up.

If this massive release of radioactivity at TMI isn’t just a myth, then you would have recorded clear evidence of it on every bit of photographic film for miles around. After the accident, all such photographic film was collected and analysed by Kodak, and no such evidence was found.

There are many other nuclear power plants in Pennsylvania and neighbouring states which aren’t too far away from TMI. They would have recorded real evidence of a large cloud of radioactivity in the environment, if it was really present to that extent.

You’d record real evidence of it anywhere where photographic film is stored or used. You’d record it at every nuclear power plant, or anywhere else where radioactive materials are stored or used where health physics controls are implemented. You’d record real evidence of it anywhere where medical or industrial X-ray images are made. You’d record it anywhere where radioactivity is used for scientific or medical purposes. You’d record it everywhere where particle detectors are used for physics experiments. You’d maybe even detect it on every old duck-and-cover civil defence radiological detector that someone might have had laying around as an unpleasant relic of history.

But no such real physical recorded evidence to support the theory was ever recorded, anywhere. People went looking for it, but it wasn’t there.

There are people who claim they got sick as a result of the Three Mile Island accident, who claim that they exhibited symptoms consistent with acute radiation poisoning, and massive doses of ionising radiation.

There are also people who claim that they have been made sick by witches who put a curse on them – once upon a time, upon hearing these stories, we’d have them tell us the identity of the witch so the witch could then be tortured and murdered, based on these stories.

There are people who tell stories about how they’ve been beamed aboard the extraterrestrial flying saucer, and sexually molested by the aliens – but once again, as with the above examples, there are mere stories but there is no actual real evidence that stands up to scientific enquiry.

Shortly after the TMI accident, people like Helen Caldicott went and gathered up local residents and described to them the scary sounding symptopms of acute radiation poisoning from acute exposure to massive doses of ionising radiation, and implied that that’s what would happen to them. With that kind of fear and stress, it’s no surprise that we can see mass hysteria, and we can see people who say that they think they might be starting to exhibit those symptoms that they’ve been told about.

But instruments and detectors and photographic films and thermoluminescent dosimeter crystals aren’t subject to fear, panic and mass hysteria – and they recorded nothing.

A common claim of TMI conspiracy theorists such as Caldicott is that longer lived radionuclides, such as Cs-137, Sr-90, Pu-239 (or pick your favourite moderate-to-long half-life well-known reactor-produced radionuclide) were released into the environment at TMI, not just short-lived gaseous fission products.

But if such nuclides were released, you could go and take some soil from TMI, and physically show the evidence of such release, because those radionuclides would still, mostly, be there. They can show us real, undeniable, physical evidence today, if that hypothesis is true. But that evidence is never forthcoming.

Written by Luke Weston

October 3, 2009 at 12:06 pm

Posted in Uncategorized

A bit of an apology…

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…I’ve been a little busy lately, and you may have noticed the absence of many new posts.

More regrettably, though, is that there seem to be a large number of comments accumulating in the pending-comment-moderation queue, and they haven’t been posted.

So, if you’ve been trying to post comments without success, this is why, and I will make sure they’re all posted now. (Unless there are any I really insist on moderating, but that’s unlikely.) I will have to try experimenting with the WordPress settings regarding spam filtering and automatic comment approval a little bit.

Written by Luke Weston

May 3, 2009 at 8:16 am

Posted in Uncategorized

Looking for a particular graphic.

with 7 comments

Dear readers;

There’s a certain image that I’ve seen when browsing the web before which I found useful. I’m trying to find this image again, but haven’t seen any success in finding it again.

It’s a pie chart which shows the physical composition of typical used LWR nuclear fuel, showing a breakdown of x % uranium, y % Zircaloy cladding, z % hardware, w % fission products and so forth. This was notable in that it included the portion of the fuel element’s mass which is the cladding and hardware, not just the uranium oxide fuel matrix itself.

Does anybody recognise the graph I’m referring to, and know where to find it online?


Written by Luke Weston

March 25, 2009 at 12:52 am

Posted in Uncategorized

The argument from appeal to hatred of Howard.

with 5 comments

Here’s a comment I received recently, in the context of talking about nuclear power.

“remember John Howard sold his soul to GW Bush, why would yoy [sic] trust anything he supports ?”

We see this occasionally in discussions about nuclear power. It’s the appeal to hatred of Howard, an argumentative technique, similar to a kind of contemporary derivative of the good old fashioned argumentum ad hominem, that goes something like this:

i) John Howard was actively interested in investigating the use of nuclear power in Australia, and was open to the idea.

ii) Of course, everybody obviously knows that Howard is literally pure immoral evil, and he feasts on babies, or something.

iii) Ergo, nuclear power is bad.

You sometimes have the persuasive appeal to hatred of the GOP or hatred of Bush, or something similar, it works in exactly the same way.

Written by Luke Weston

March 11, 2009 at 12:54 pm

Posted in Uncategorized

Well, it looks like the Obama administration is going to pull the plug on Yucca Mountain.

with 2 comments

Well, there will be no Yucca Mountain facility opening in the US any time soon. But is that a big deal? No. There never was any urgent need for Yucca Mountain. The used nuclear fuel at the civilian power reactors is quite safe where it is, and it isn’t hurting anybody. The current on-site storage can be maintained for many years to come, and it’s just not a problem that requires any pressing intractable attention.

It will be interesting to see what happens in relation to the Nuclear Waste Policy Act – obviously they will have to change the law.
I suppose that money will be put back into the hands of the nuclear utilities, or used by the government to implement recycling of fuel.
I’d be happy to see the money used by the government to implement recycling infrastructure, and/or used by the nuclear generation utilities to implement dry cask storage for all the on-site storage capacity for their fuel that they need and that they’re going to need, until reprocessing and/or central storage is implemented.

It’s worth remembering that we’re not abandoning Yucca Mountain, we’re not “wasting” billions of dollars – the Obama government is not going to backfill it with concrete and burn all the research data. We’re just putting Yucca Mountain on the back burner for a little while, that’s all. If, in 10 years, we decide that Yucca Mountain wasn’t such a bad idea after all, we can always go straight back to it where we left off.

I think that’s not actually all that bad, because it gives us time to step back, breathe, and realise that taking this used LWR fuel, which is 96% unchanged uranium, declaring it to be so-called “waste”, and throwing it in Yucca Mountain really is a little stupid.

Off the top of my head I can’t remember how deep the Yucca tunnels are, but perhaps the facility will be useful for particle physics experiments (neutrino physics, dark matter detection and the like) just like the WIPP site in New Mexico.

As much as I fully support sensible recycling of nuclear fuel, and I hate to see good useful material “wasted”, I think, yes, it’s worth ultimately having a geological repository, although it’s certainly not needed urgently.

Even with the efficient use of uranium and actinides, and the extraction of useful fission products, I think we’re going to be producing medium-lifetime radioactive fission products (such as Cs-137, Tc-99, Sr-90, or what-have-you) at a rate which will exceed their consumption for useful applications, and therefore, we will have surplus material that will probably be best going to deep geological storage. Add in the transuranic-contaminated waste from the Cold War and the weapons facilities, and industrial and scientific radioactive waste, and yes, it really doesn’t hurt to have a deep geological repository such as Yucca mountain.

Written by Luke Weston

February 27, 2009 at 6:05 pm

Posted in Uncategorized