Emissions Nuclear Open Thread

Fukushima Open Discussion Thread

The Open Threads on are a general discussion forum, where you can talk about whatever you like — there is nothing really ‘off topic’ here — within reason. Please use this particularly comment thread to post anything on the Fukushima Nuclear Accident that is NOT directly related to the content/intent of the other threads (including status updates, engineering details, specific perspectives, etc.).

The sort of things that belong on this thread include general enquiries, soapbox philosophy, meandering trains of argument that move dynamically from one point of contention to another, and so on — as long as the comments adhere to the general topic of nuclear energy, climate change mitigation, energy security, and the Fukushima crisis.

Do NOT post the above style of comments on any other threads. In those posts, you must STAY ON TOPIC, and make some attempt to justify/substantiate any argument you make or piece of information you present.  If you go off topic on the focused posts’ comments threads, then they will be deleted and you will be asked to repost them HERE. (Ideally, I would simply move them to this Open Thread, but unfortunately does not allow this).  If you break the other commenting rules, the comment arrives quickly in the trash.

So… I guess this is also an appropriate time to revisit BNC’s simple commenting rules:

Comments Policy — I welcome comments, posts, suggestions and informed debate, from a wide range of perspectives. However, personal attacks, insulting/vulgar posts, or repetitious/false tirades will not be tolerated and can result in moderation or banning. Trolls will be warned then banned.

Civility – Clear-minded criticism is welcomed, but play the ball and not the person. Rudeness will not be tolerated. This includes speculation about motives or what ‘sort of person’ someone is. Civility, gentle humour and staying on topic are superior debating tools.

Relevance – Please maintain focus on the topic at hand. Do not attempt to solve big problems in a single comment, or to offer as fact what are simply opinions about complex matters.

Formatting — For guidelines on how to format comments and search the website and comments, read this.

Pretty simple, hey? Obviously for an Open Thread, the relevance criteria does not apply in the same way as it does in other threads, but the others most certainly do.

Some people have recently expressed surprise, disappointment, anguish, horror, accusations of ‘bias’ or ‘censorship’, whatever, at the fact that their comments on other threads on BNC are under moderation, and others are deleted. I make no apologies for that. This is my blog, and whilst I welcome a wide range of views, and you are quite within your rights to disagree with me, I DO NOT accept comments that break the commenting rules. Not only is this discourteous to me and the rest of the community here, it also undermines your own credibility. I have particular short patience these days for comments which are ad hominems, that is, are direct criticism of, or speculation on the motives of, the person making the comment rather than on the content of their statements.

Okay. Open fire.

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

635 replies on “Fukushima Open Discussion Thread”

Shelby – with all due respect, even if everyone in the developed world did as you suggest “Workers of the world – relax”, there are several billion mired in poverty who can’t relax without risk of death. They need energy to power their lives and provide the basics for a healthy existence. That energy will be coal unless we act to assist.

Rational Debate – “I maintain people are more afraid of the human mismanagement of nuclear power rather than the nuclear power itself.” I agree.

I do not criticize the engineers nor operations workers in the nuclear plants nor those in the regulatory agencies. I am well aware of the reporting requirements and believe those people have the best of intentions and are well aware of what can and should be done.
RD, your quote ” … it is clear that the existing open disclosure isn’t even recognized…”
Again I agree. My point is that there is a great deal of public mistrust of the corporate executives, regulatory agencies and politicians whether in USA, Canada, Japan, etc. whenever there are $$ billions at stake, whatever the industry. That is the level which requires more disclosure

e.g. regulatory – look at the regulatory corruption related to the BP oil spill.

e.g. political – look at the decision by the Prime Minister of Canada that the backup / coolant pumps at the NRU (medical isotope reactor) were safe when he ordered the plant restarted then fired the head of nuclear safety agency.
The actual safety of the systems is not relevant to the issue of public trust – what is relevant is that it was a blatantly political decision.
In this case it was a balance between risk of radiation injury to the public (extremely low) versus the risk of lack of radiation (radio-isotopes for cancer treatment) which was quite high. Far more lives were saved by radiation than were put at risk. It remains a political decision about a nuclear safety issue. (and yes I do have a great deal of faith and trust in those at Chalk River)

e.g. corporate – do you think any of the decision makers at the banks (2008), or at Enron (2000) cared a whit about the public?

It is truly unfortunate that this public mis-trust of executives and politicians is compounded so much with the irrational fear of radiation. Nevertheless that’s what we have to overcome if we are to prevail and get rid of coal.


Joshua – You imply that this is a political issue with me not a technical one. Rubbish, it is a technical one, I was only showing that there is a political reason why the technical issues have been distorted.

As a matter of fact I do have the qualifications to judge the material published on this matter. This is why I can criticize the assumptions and conclusions that they come to. You assert that you have have no background to understand these matters, and then demand that I show you detailed physics or engineering that supports my position. Well I have given you the reasons within your stated ability to understand them, and I have presented as corroboration evidence the the time and effort spent by a cadet nuclear state (Pakistan) took to construct a weapon with all the resources of a nation available. I have shown that given the size of such a project, it would not be attractive to a terrorist organization based on the historical objectives and behaviors of such groups.

That you chose not to believe me is not surprising. The entire nuclear debate is filled with people that will admit to having no knowledge or background in the technical aspects of the subject that seem to think that their opinions in these same matters should be given the same weight as those that do. Pressed, like you, they fall back on appeals to authority without taking into account (or simply ignoring) the political aspects that are driving some of those authorities to take certain positions.

This is one of the reasons I avoid a pissing contest with references when discussing this particular question. Analysis of this issue requires a effort to understand the physics and the mechanics of nuclear weapons, in particular the gun-type designs, and a broader understanding of non- proliferation politics beyond knee-jerk nuclear weapons are bad, thus anything that limits them is good, ideology.

You are not an idiot, certainly you don’t write as one. You owe it to yourself to get better acquainted with this subject, and I hope that my arguments have at the very least demonstrated that things are not as straight forward as it has been made out to be.


Jess, on 28 March 2011 at 10:44 AM said:

Rational Debate – “I maintain people are more afraid of the human mismanagement of nuclear power rather than the nuclear power itself.” I agree.

I actually said that. RD was quoting me. Thanks.


Shelby – Oops. Yes, I did lose track. I do agree with that statement.
And I agree with DV8 (and others) that people are irrationally afraid of radiation.

While apparently contradictory I support both statements. Dualities exist in life, and even physics (wave-particle duality of light).
My point is that rather than argue as to which is more important or relevant, I believe we must recognize that both these fears/mistrusts exist and both must be addressed if we are to prevail.

In a similar manner we should pursue renewables (including reduce, reuse, re-cycle for those in wealthy nations), including use of spent nuclear fuel to generate energy for all humanity. Spent fuel reserves plus thorium likely represent millennia of power, so are virtually sustainable (we will find better solutions long before then). The priority is to stop coal ASAP.


Re DV82XL re Qualifications to understand


I accept that you have a technical basis for your position an that I misconstrued your political reference.

Unless I am mistaken I have made precisely two statements about my qualifications. The first is that I am not a nuclear weapons builder or designer, how you get that I am not qualified to judge technical material from that I am not certain. The second was in my last post where I mentioned dealing with these issues at Johns Hopkins (if you are not from the US look it up) I have made no representations about my background. I will say that I do not come to my position by ideology or political persuasion and that my understanding of proliferation issues, at least well into the 90’s, is better than a layman’s.

If you would like, please present your argument as if I would have no problems understanding it. I am not asking to start a pissing contest, I am genuinely interested in your reasons and would be grateful to have my understanding increased. I imagine that others here with a technical background who would be interested in a detailed refutation of this issue as well. If not I have enjoyed out discussion and hope for more in the future.
This, in answer to DV8, is an example of what we try to avoid at BNC . Heated words, uncouth language, incivility etc understandably leads to an escalation and animosity back and forth. Please, everyone – even on Open Thread keep it civil and don’t presume to “know” the other person’s motives. Otherwise your comments will be deleted.


@Joshua – I don’t know about you, but these long exchanges are getting exhausting and difficult to follow. Therefore I suggest that we look at one aspect at a time.

Consider the fissile material itself. Estimates from the Nuclear Control Institute document you linked to suggest that a bare minimum of 25lbs (~12kg) of at least 94 percent enriched uranium to meet so-called bare crit mass. In reality, (they admit in that same document) it would likely require much more for a crude gun-type device.

Now given the masses of material interdicted to date (again from a link you provided on nuclear trafficking) we see that almost all of the material involved was in much smaller amounts, and of varying levels of enrichment, physical state, isotopic composition, and other chemical constituents This presents to the clandestine bomb constructor a huge problem; the distinct possibly that he will not know the composition of the material at hand. This would make the necessary calculations to create a supercritical mass that is likely to fission impossible to do without access to specialized equipment. Even if they were able to make these determinations, the processing required to convert a mixed lot or substandard sample to weapon-grade requires facilities that are far outside something that could be hidden on a university campus. Just obtaining the equipment, would draw considerable attention.

Even assuming a homogeneous sample, it would have to be in the proper metallurgical state (uranium metal may exist in three allotropic forms) to machine properly, or if it is an oxide, in a powder having the proper mechanical properties to be pressed and sintered. Even assuming that it is fit for processing, special tools and skills are needed to machine metallic uranium given that it rapidly oxidizes, (to the point where it is pyrophoric) and has poor general machinablity and working oxide powder require specialized equipment and techniques, not all that common, or easy to obtain.

These are not trivial issues, in fact they represent severe limitations, not only in obtaining the material itself, but in obtaining specialized tooling, and specialized skills as well. And the latter would have to be chosen not only on the basis of their technical knowledge, but also on their willingness to apply their talents to such a project.

Even if all of these criteria are met, there is no guarantee that the device would work, there are too many places where something can go wrong, and very likely will. Given these facts, it is highly unlikely that a device consisting of two lumps of uranium of unspecified enrichment, of the sort that has been seized in interdictions, driven together by an arbitrary charge, would even fizzle, as you suggest.

I’m going to stop here to give you an opportunity to respond.


@MODERATOR I am positive that Joshua meant no insult, nor was any taken by me. I hardly see how anything we have written could be interpreted as anything other than lively debate.

While I appreciate the need to maintain some level of control, please don’t suck the life out of these exchanges, by too much rein.
Point Taken – however sometimes, if it isn’t nipped in the bud, things get worse and I am not here 24/7 to control it.


Mike, on 27 March 2011 at 6:14 PM:

Mike, we had best agree to disagree. You referenced two articles in support of your notion thar evacuation to the 30km range was on safety grounds.

You subsequently agreed that the first article supported the notion that it was due to difficulties providing basic services that drove the decision to increase the evac area on a voluntary basis.

I have re-read the second article and still believe that it swings both ways, with no evidence of knowledgeable opinion to support your position and some opinion to support my interpretation of the events.

This is an example of a situation where two well-meaning observers can draw conflicting opinions from inadequate data, so rather than clog this thread up further, I will wait for further data before reviewing my opinion, as, no doubt, will you.

Fair enough.

TO THE MODERATOR: I apologise in hindsight for responding to EL’s post yesterday on the daily update thread – I didn’t twig that the subject had drifted off topic. Many thanks for your efforts… we users of this site benefit greatly from your efforts to maintain focus.


I’m not sure if this will be seen, or if everyone has shifted to the new open thread… but for whatever it’s worth:

re post by: Jess, on 28 March 2011 at 12:01 PM said:

Shelby – Oops. Yes, I did lose track. I do agree with that statement.
And I agree with DV8 (and others) that people are irrationally afraid of radiation.

While apparently contradictory I support both statements. Dualities exist in life, and even physics (wave-particle duality of light).
My point is that rather than argue as to which is more important or relevant, I believe we must recognize that both these fears/mistrusts exist and both must be addressed if we are to prevail.

This is exactly what I was trying to get at. Shelby had made such an extreme “it’s only this way” sort of statement that I felt I had to point out that there are many people who are more afraid of radiation itself – e.g., that both exist, not one or the other. In reality, I’m sure that both exist to varying degrees in the same person.

It is a huge conundrum, however – one that is very difficult to deal with. Look at the latest with TEPCO – they are being blamed for lying and withholding and failing to take actions as quickly as they should, failing to provide information – and yet a single, and apparently in error rad tech reading winds up being worldwide news in two seconds flat.

So it is very difficult to even address fears – in part because often they are unwarrented and based on a lack of understanding, in part because we are all human and want someone ‘to pin it on’ and blame, in part because the media is out there chumming for any juicy tidbit that they can sensationalize – and it very much seems that with the 24/7 news cycle now that problem has gotten to be vastly worse than it used to be. How can people trust anything when reporters won’t bother to get all the relevant facts and present a fair picture, and instead are intent on record setting world breaking screaming headlines?


Chris Harries, on 28 March 2011 at 7:39 AM said:

# Shelby, on 28 March questioned the veracity of negative or doomsday predictions for the future.

I don’t think he /she was claiming to be a climate change sceptic. When predictions for the future are based on hard science or hard economics, backed by ample data, then it is prudent to take note, and adopt sensible measures to avoid or mitigate what can happen. (snip)


Many of your comments are valid. I snipped the begging just to add; currently unknown solutions to known problems can also change the outcome of dire predictions. This could be from new technology (such as a breakthrough in solar or geo), or changes in the environment, including shifts in the philosophy or policies of a society (such as a policy shift to conservation). The variables are not only in the prediction of an outcome given a known situation, but also in the solutions yet unknown. You may be good at predicting the outcome based on a known set of parameters, but the mathematical prediction of yet unknown solutions if very poor. Otherwise we would have no need for dreamers, designers, and philosophers, in this world.


For example, here is one dream…….

The mantle is divided into sections which are based upon results from seismology. These layers (and their depths) are the following: the upper mantle (starting at the Moho, or base of the crust around 7 to 35 km, downward to 410 km). In the mantle, temperatures range between 500 to 900 °C (932 to 1,652 °F) at the upper boundary with the crust.

If we were able to drill two wells and connect them in the upper mantle just below the crust (7 to 35 km) then fill it full of water, the temp (932 to 1,652 °F) could drive a steam / condensing turbine on the surface, providing endless 24/7 electric energy. Multiply that by thousands of wells and we have yet another green power source.

It’s a dream as of today, but you get my point.


Re DV82XL Characteristics if U Metal

If anything I wrote was taken as offense I apologize it was not intended. I too thought we had a good debate going, lively, but I hope not uncivil. Thank you for taking the time to go into more depth about the reasoning of your position. 

With mixed source metals I had thought that blending would deal with that, although thinking about it a huge issue would be getting the metal, whether single or multiple source, even into the shape of a blank to machine it. I had known that machining U metal was a big issue but simply considered it “previously solved”. It seems that what you are saying is that machining the metal is the limiting case not the physics or the assembly, correct? I saw on your page that your background is in materials science so in that I will bow to you professional opinion and state categorically that I am not qualified to doubt it, understand well enough and ask questions about what I don’t yes but doubt no :)

I have a feel for how hard the physics is… Hard, and for how hard it is to make a device to assemble the core once made… Hard but doable by a non trivial number if people. Is it your assessment that it is effectively impossible for a skilled technician to learn even with a large supply of depleted U to practice on?  

Does the same limitation apply to the core of an implosion device ( U or Pu) where spheres and hemispheres are used. I would think that pressing could be used there and most of the machining issues could be bypassed. Could pressing possibly be used to make gun core assemblies or to limit the machining required to a lower plateau of skill? Again for the physical possibility for that as well as whether the press for forming the metal is as big of a flag as the press for dealing for the uranium oxide I will accept your professional opinion.

I had considered the phases of uranium (allotropes) to be a machining issue which would be present whether single source or mixed source. My understanding was that it’s phases were temperature dependent and, I do not know the right word so … plastic ie if you heat it up it starts alpha -> beta -> gamma -> melt and cooling it would go in reverse maybe with some funky things happening to the lattice as it cools. Not like carbon (coal, graphite, diamond) Is this the issue you are talking about? I would think one phase is better for working and it would be kept within whatever bound to minimize transitions, just a guess. If true that would increase the difficulty.  I understand these issues are even greater with plutonium. (not that Pu would be used in a gun)

Just going from first principals I can make a stab at what the special equipment might be like. A machining environment that can either be filled with a neutral atmosphere and possibly needing to keep a very high temp. Or a pressurized water environment ( heat and maybe prevent oxidation) I do not want to know specifics but if this is the general type of equipment it seems technically solvable. Even easier (in relative terms) if other things are machined in similar devices. These are just first blush guesses to see in I have a grasp of the issues.

The possibility of different crystal densities would seem to be a major issue. I would think that the difference could be identified by displacement although I do not know. The compressing and sintering being an issue was mentioned  in one of the prior articles in our discussion. I agree, on short consideration, that it could be a show stopper for a gun device.

I assume that you have other reasons for why it is impossible for a not state actor to assemble a device. Just your last post made me consider issues that decrease the likelihood that I had not previously considered. If you are willing, and the Moderator concurs that we have not strayed off topic, I would greatly enjoy continuing.

May I suggest, if we continue, since this started out about HEU security at research reactors, that we consider a case study. I propose we use the Serbian Vinca reactor as it stood before  the HEU  first was removed in 2002 since that was an at risk stockpile. And proceed one issue at a time. The below press release said it had 48 kgs of HEU removed in 2002. For equipment let us consider a well equipped university. The question is can that material be used to create a gun or implosion device capable of at least a sub kiloton fizzle.

Click to access release_082302.pdf


@Joshua – Frankly I haven’t the faintest idea what set MODERATOR off on what you wrote. I’ve seen nothing I could even vaguely construe as an insult from you, and I consider the matter closed.

I think you will agree that we can dismiss the mixed source case altogether as requiring too great an infrastructure for a subnational actor to likely have at its disposal.

For the single source case one can ether have specialized equipment, which would include specialized machines, specialized cutting tools, and I believe there is a special type of cutting fluid used, or someone willing to spend a great deal of time learning to work this material on standard equipment. So while machining uranium is possible, it still creates another layer of complexity.

While the fabrication of a so-called ‘pit,’ for an implosion device, may on paper be simple. Casting one with the required geometry, to the tolerances necessary is not a trivial exercise. As well the physics of the charge is far more complicated, and requires highly specialized detonators.

Working with previously irradiated HEU fuel from a reactor has its own set of unique problems. Fuel elements of any type will have to be subjected to chemical processing to separate the fissile material they may contain from the inert cladding material, fission products, and other diluents. This process would also require specialized equipment, a supply of appropriate reagents, well-developed techniques specific to the materials handled. It would also contain enough radioactive fission fragments that the chemical separation process would have to be carried out by remote operation, a very complicated undertaking.

In all cases, it still would need someone with both the background in the metallurgy of these materials, and access to the instruments to analyze the stock material such that the physics could be done. While a good university may have both, it becomes a security issue for the group if they turned to such a place for support.

Add to this the steps and equipment required to make a blank for machining and this is a limiting factor in that it sets a lower limit to the degree of sophistication and access to technology any group would need to have to contemplate such a project; less than the mixed source case perhaps, but not by much.

This is not even taking into account that the actual amounts of fissile material necessary would tend to be large certainly several, and possibly up to ten times, the so-called formula quantities due to the accumulated uncertainties inherent in a ‘crude device’

We are setting a rather low bar for the device contemplated in that we are allowing that a fizzle is as good as a full detonation. With that in mind consider that Pakistan’s first five tests were in fact fizzles, as determined by comparing the seismographic data with the yields reported by government to the press, the same with the two North Korean nuclear tests. These are state actors with full blown programs, and while Pakistan’s later tests were more successful (and they now have an arsenal of approximately eighty warheads) it still underlines the difficulties of making a device that would even work badly.

At some point Occam’s Razor cuts in; we have to make too many assumptions to conceive a path where an undertaking like this would be even marginality successful. Obtaining the necessary quantities of fissile material, recruiting the necessary skills, and access to specialized equipment places this project above the level that any non-state actor could achieve. This is why the politics of this issue irritate me so. Clearly those that have examined this have come to the same conclusion, you can see it in the material they publish, like the Nuclear Control Institute document you linked to up thread, but chose to report that there is still a risk.


Sure thing, # Shelby, spot on. We will see some amazingly ingenious things happen. Some will be very beneficial.

I made the earlier point because I think too many people, especially political decision makers, have no concept of finiteness. All the amazing ingenuity in the world can’t enable asymptotic growth to spiral out of control when we are up against a growing array of physical limits.

If technical ‘solutions’ are applied in a reductionist manner, i.e. turning a blind eye to the bigger picture, then they serve to just support business-as-usual and amplify the larger problem.

We’ve reached a stage in history where retreating to an earlier mode of civilisation is not on – there are too many people – and at the same time we can’t keep brutally exploiting all available resources in a vain attempt to keep our current non-sustainable trajectory going. We may ‘fix’ one problem, but there is a litany of problems lining up behind it, everything from desertification, to biodiversity losses, to depletion of world fish stocks.

As part of a wider matrix of change, nuclear energy can serve as a partial ‘solution’ to the overall sustainability dilemma. However, if the technology simply enables millions more people to enter the consumer world – owning ever more appliances, bigger TVs, enormous houses and so forth – then its role will be perverse. Much of the struggle in these debates is really about values, not technology.

(By the way, the same argument holds true in the renewables arena, there is even less ability for those technologies to support exponential consumerism.)


Re DV82xL Material Characteristics of U Metal as Limiting Condition


I find that I agree with you that the fabrication of the uranium is likely the limiting task. Both the physics of criticality and assembly can be worked on without drawing too much attention. To learn the machining techniques for U requires that some be acquired even if it is DU. Although I remember when Pakistan got caught buying krytrons or some such back in the 80s and said they needed them for the flashers in their ambulances… Cheeky buggers :)

Actually, thinking about it, DU munitions can be manufactured in industrial quantities along with tank armor etc. I know that they are not made anywhere close to the tolerances needed but that implies that the requirements are not so constrained as to preclude mass production.

While I still question it’s impossibility I do agree that the improbability of a non state actor creating a device has been greatly understated in the mass media as well as in non proliferation and counterterrorism circles. That is, unfortunately, the whole problem with a Black Swan, it is already very unlikely so it can be hard to get a grip on the improbabilities.

You have convinced me that it is much more difficult than I thought and that the chance of a terrorist group that is independently organized is unlikely, to the point of practical impossibility to construct a viable device. 

There are however some groups that exist who potentially do have access to the money, knowledge, equipment and other resources of nuclear knowledgable states without, nessisarialy, being agents of the state itself. Some examples of these are: Hamas and Hezbollah, both have access to specialists from Syria and Iran; The whole brew which is Pakistan although I do not know of any technophilic groups that are active there, not that means much. The threat of loss of control of actual weapons is probably significantly greater though lower than the pundits declaim; Most interesting is Aum Shinrikyo, an apocalyptic group in Japan. They are the ones who did the sarin attack in the Tokyo subway, several smaller sarin attempts and a poorly executed anthrax attempt on a US base. They are reported to have many highly educated members, including those with doctorates in physics, chemistry and biology among others. They also have an ideology which does not speak for their restraint if they had a device. The actual execution of some of these attack makes me and many others question the technical skills of some of their operatives though.

The reason I set the bar for success of a non state actors device or any terror centric device so low, arbitrarily as a 100 ton TNT equivalent fizzle, is that for a terrorist it is the fear generated in the audience that they are wanting, the destruction is often secondary. Think of how 9/11 changed the very nature of the United States and the world all out of proportion to the destruction and loss of life actually inflicted. People are so terrorized by nuclear weapons that so long as the explosion is nuclear in nature the effect will be massive. Further, peoples terror of fallout would cause effective loss of a city even if the buildings were left standing. From that perspective the actual destructive powers is almost irrelevant.

Because of that I feel that fizzle devices are a potential threat that has been under researched and possibly under addressed IF they are indeed easier to produce than a militarily significant fission device. For instance what us the limiting case creating a fizzle using implosion. There are some geometries other than the classic soccer ball which could possibly change the limiting task to precision machining of the chamber rather than precision timing of the explosives, thus might be easier for an illicit bomb maker to fashion.

I was trained not to over value the outlier event in the threat matrix but never to discount or forget it either. So far your input has moderated my thoughts on non state actor produced devices.  It has also brought up another related question; the security of those places which manufacture DU munitions and the people who work there. That is not paranoia, I am not saying it is some big thing to be afraid if, it is just an element I had not considered in my analysis. 


@Joshua, – Fabrication of DU munitions is not relevant here because the uranium is alloyed with other metals to enhance workability. These adulterants would denature weapons-grade uranium rendering it unsuitable for the task under examination. As well munitions are produced on numerically controlled production machinery, purpose designed and built for producing a single type of round. The people that operate these machines are not considered skilled labor, but rather production workers, and they could not leverage what they know to the task of making a bomb core.

As for an implosion device, I touched on the difficulties of fabricating a proper charge of explosives needed to even make any geometry fizzle. As well there is the problem of obtaining weapons-grade Pu. Talk of obtaining weapons-capable Pu from spent reactor fuel is nonsense, as the difficulties of working with this type of core are exponentially more difficult than with pure (or reasonably pure) Plutonium-239.

All in all, the difficulties of fabricating an implosion device are insurmountable for even most state actors. For a non-state actor, it would not pass the initial planning stage.

I have no issue with setting the bar low on what would constitute an effective device, and I agree that for all intents and purposes a poorly preforming device is, in this instance, just as effective.

Groups like Hamas and Hezbollah, which have the backing (or at least the tacit support) of a state have to be looked at in a different light. The bottom line is that for millennia, it has been a standard rule that you don’t give your auxiliaries better arms than you hold your self. The reason is obvious: you will loose control the moment you do. A nuclear weapon of any sort in the hands of someone you do not have full control of is an incubus for all sorts of grief. As well having an independent actor working on such a project inside your borders is a serious threat to the host state. Even if such a weapon was not turned on the government in power, that same government could not risk the chance that its use elsewhere could not be traced back, and guaranteed they would be held just as responsible by the rest of the world. In other words, the risks of any state facilitating such a project, even with a group that is nominally a client, is just too high. In the end too, having the help of a state would make a devise a state sponsored weapon, which we already know is possible and not germane to the question in front of us.

Leaving the issue of the difficulty of making a core for this device, we must consider that there are other limiting factors

First the size of the device. It would have to be at least two meters long, and would probably weigh a minimum of a thousand kilograms. This is not tiny. The only reasonable delivery system that would be available to a subnational actor, that would not draw unwanted attention when acquired is a truck.

This sets severe limits on target selection vs construction site, and precludes deployment over great distances. Given that should a sufficient quantity of weapons-grade material, in the order of a hundred kg or more go missing, there would be a hunt on, thus moving even the separate components to a distant target would have a low probability of success.

As for the terror aspect, I think you are overstating the case. The two cities that have been attacked by nuclear weapons, were rebuilt, and re-inhabited, in a very short time. Humans have a way of dealing physiologically with this sort of thing. We continually rebuild in areas subject to natural disasters, and while there might be a number of people afraid to reenter an attacked area, I doubt it would be a majority.

In the end, we must put ourselves in the position of a non-state actor contemplating a nuclear weapons program. The leadership would necessarily begin by obtaining the opinions of any knowledgeable people they had access to. Those folks would impress on the leadership the size of problems, as I have outlined in this thread, AND they would also have to point out that the chances of even obtaining a low-yield event are far from high. In fact there is at least a fifty percent chance that the device would do little damage beyond that done by the chemical charge. Weighing the effort against the very high chance of failure, and the associated secondary risks of interference that would have to be assumed by the very nature of this type of protect, I suspect that it would be seen as more trouble than it is worth.

In fact, I suspect that this has happened already -and likely more than once.


Just a quik note.

I just noticed even HEU reactor fuel is not elementally pure. A lot is U Mo alloy. With several others

Fukushima fuel was also prob a U Mo alloy, of course at normal reactor enrichments. I saw Te99m in some of the nucleotide analysis and wondered where the Mo came from.


Notes U Alloy vs U Metal, Social Effect of Detonation, Mideast Countries

Sorry for taking so long. Some days are still better than others and the last couple have not bee. I fear my coherence suffered. 

Your mention that uranium used in DU munitions are various alloys with different material properties was interesting to me so went and started reading about uranium alloys. It appears that all reactor fuel is made from alloys of uranium not elementally pure U Metal. Just a few are: UAl and UMo which seem to have been used in research and normal reactors. Also a USiO for use in LEU blends. While munitions seem to be UTi and a lot of documents on UNb ( just a neat aside it seems that UNb increases in strength as it ages) *links at end

I do not know if these would cause a problem with using reactor fuel or not. It obviously does not hurt it’s use in reactors and it is possible that it would change the mechanical properties to either help or hinder someone trying to work it. It is obvious from a cursory look at the material that the characteristics of U Metal can be changed a lot with the addition of other metals in low proportions by weight and by atom. There is also a large body of research into this where the equipment and skills for manipulation of uranium can be learned and a lot of fields where it’s investigation would not draw attention. It gives me the beginning of a better idea of the materials environment vs physics etc.

I do not dispute that people would ultimately rebuild and/or resettle an attacked city. The problem it that it will be REbuilding and REsettlement. People will leave for weeks or longer and will demand massive decontamination efforts. Insurance rates will go through the roof because of perceived health risks. It is unlikely that people will be quick to accept government assurances that the area is safe, the EPA lost a lot of credibility saying the air was safe in Manhattan right after 9/11. A dirty bomb would have similar effects but I believe that the psychological impact of an actual nuclear detonation would have a quantitatively and qualitatively more severe effect on the population than a dirty bomb even if the actual effects on the environment of the two events were similar.

I do see the detonation of a nuclear explosive device in the USas an existential threat to the United States (my overriding concern) and to the continuing operation of the world system. The detonation of a device outside the US would not be much better but with proper management the US electorate might be calmed down enough to allow a semi rational response. A detonation inside the US would leave no room for rational response fear, grief and rage would be fanned by our media, pundits, our more rabid politicians and most importantly those interests that want reasons to project US force, into a need to Sirius at anything that even looks antiAmerican or against our interests. If it happened outside our borders there is a chance that a counter weight to the hawks would arise with those people who want to give help but a strike to CONUS would leave any voice of restraint insignificant and quite possibly lynched.

For this reason any potential for a non state or sub state actor to obtain a device by construction, gift, purchase or theft (I acknowledge that the last three are more likely than the first) to be strictly unacceptable and one of the very few things that I can not conceive anything I would not do to prevent.

A concern that I have with implosion devices is with a fizzle being an acceptable outcome it might become a goal. The book about thermonuclear devices I revered to in an earlier post about ( which anyone researching explosive compression would find quickly) has several ideas about how to convert a small number (1-4) of point source detonations into spherical shock waves. There is also the question of whether a spherical compression is needed for a fizzle. There are several techniques any explosives person would know about which could possibly be used as a starting point like shaped charge penetrators or earmuff charges on tamper/reflector. Neutron injection is an issue however the higher neutron flux of dirty Pu might be an aid when trying only for a fizzle, more neutrons in the early generations of supercriticality. None of those would work without a lot of research and hopefully not even then. The point is that there are potentially less difficult ways to get a boom out of fissile material when the goal is several orders of magnitude less than what the original design goal was.

**Note the designed fizzle device in not something that drives my assessment of proliferation risk. It is just an “I wonder if..” thing. I do hope it has been examined and discarded simply to close off the second order threat matrix, for completeness sake. I raise it because I am sure the bad guys will at least ask the question.

On Iran, Hamas, Hezbollah. The bit about auxiliaries and arming while good policy is not something which can be counted on in the middle east. Westerners, in general, see the nation state as paramount and as having the ultimate call on the loyalty of it’s citizens and as sovereign within it’s borders. This idealization is what our concept of the international system is based on. The problem is that the farther from European states you get the less it holds true. For instance, many Kurds in Syria and Shia  tribesmen in Saudi while being born and living within their borders are not considered citizens.  The idea of Westphilian nation states is what is meant when people talk about secular democracy.

Once you get into the realms of the Ottoman Empire and east the concept of the nation state falls apart almost completely for the average person.  In the middle east the clan, tribe, sept and sect have the greatest pulls on a persons loyalty. This might be changing some for the younger generation, I hope that is what is driving, at least in part, the protests and revolutions we are now seeing. For our purposes here an example is probably better than an explaination. In the US a person  is an American but can also be a Catholic. If another Catholic from say France were to ask for something against US interests a Catholic American would, baring fanaticism, at the very best refuse politely. While someone attempting to draw on common Christianity would not even get a listen. In the Middle East loyalty is first, for Muslims, to Islam then sect ie Shia or Suni, school or Tariqah (Sufi religious groups which cut across clan, family and sometimes even sect boundaries  which causes confusion) Then you get family, tribe, sept and clan. Finally after all those loyalties comes loyalty to country. If a westerner betrayed his country for any of the loyalties I mentioned they would be a traitor plain and simple. For most middle easterners to support a country against any of those loyalties would be unthinkable. In fact only those called secular in current parlance would consider it.

What that little digression was in service of is that to think of a national control authority like we have in the west is to grossly overestimate the willingness of powerful individuals, clans or organizations to subordinate their goals and desires to a national policy in Iran. 

Syria, on the other hand, can rigidly subordinate resources and individual desires to the policy of the regime for the same reasons. Bashar al Assad is an Alawite and the Alawites control the major organs of power absolutely. Any mischief using Syrian resources would need to have at least tacit approval. 


Good bibliography on uranium metallurgy. Old but the annotations make interesting reading just to get a feel.

Links for various uranium alloys used in DU and reactor fuel
U Ti U Nb in DU Munitions

Click to access 323805.pdf

W Ni Cu alloy for DU 76mm proj from biblo.

U Al fuel element
U Si fuel

U Mo fuel


@Joshua I am very familiar with the properties of uranium alloys, however they almost all render uranium unsuitable for weapons. Most reactor fuel in in the form of an oxide of uranium, although some other mixtures are being used as well. The critical thing to understand is the need for high purity fuel if there is any hope of making a successful improvised device of this kind, and how rapidly the difficulty increases without this.

Engineering odd-geometry implosive devices, are harder, not easer and I challenge the assumption that a low-yield device is less trouble. Keep in mind that no test that did fizzle was designed to do so. The builders designed and constructed those devices to work to maximum achievable yield, and were disappointed.

I have written on this site at length on the non threat of radiation dispersal devices, so called dirty bombs. You can find those places wit the search function if you wish. The short answer is that extensive testing by the US and the UK in past have show these highly infective, and very difficult to construct for efficient dispersal of material.

I’m afraid I find your views on Muslims somewhat one dimensional, and overly influenced by propaganda. Current events in the Middle East if nothing are demonstrating that the culture there is somewhat more complex, and nuanced that what we have been led to believe. It is beginning to look like the appeal of fundamentalism was more about it being able to confront corrupt civil regimes, rather than religious fervor per se. The rise of secular opposition movements may well diminish the influence of the faith.

If you look at the size and complexity of fabricating a nuclear weapon project, the layers of difficulties both in the physical and human-factor domain inherent to the undertaking, and the very high chance that there will be nothing at all to show for the effort, (not even a fizzle) it is difficult to see this as a meaningful threat from a non-state actor.

I believe the available public evidence and common sense show that the spread of nuclear weapons is not as simple or as easy as it seems to have been made out to be by the non-proliferation community. There are security threats, and targets of opportunity that we need to identify and defend, that are more likely by orders of magnitude to be of interest to groups involved in asymmetrical warfare, that should be considered long before paying much attention to this theoretical possibly.


Re DV82XY Middle East Culture, U Alloy, Dispersal Device etc.


 I was noting the things I had learned since you brought up the issue of the material science involved and I started reading but had not been specifically mentioned in our exchanges. Along with the various alloys used in fuel there is the question of DU. Mainly does the alloy used make the use of DU munitions recovered from the battle field useless as a tamper or reflector. This maters because that is where a non state actor is most likely to get material for these parts so if that material could somehow be rendered useless it would be a good policy.

The designed fizzle device is, as I said, just something I wonder about not something I use to inform my risk assessment. We have not discussed implosion devices or Pu. I understand, from what I have read, that Pu is a material nightmare. There is also no chance for a non state actor to pick samples off the battlefield to experiment and learn how to work on like with U. I do think that the DOE should run the numbers and see if there is a potential if they have not done so though. That is the bad thing about “what if” the bad guys can wonder too and might try if given the opportunity.

I agree that the actual effects of a radiological dispersal device would be more like an arsenic bomb or a blown transformer with PCBs than the city denier it is touted as. The problem is the fear issue. The previous American administration did it’s best to make the population fearful victims, for whatever reason, so now the terror reaction would be all out of proportion to the actual dangers. That is why slow acting stuff like radiologicals are so useful as terror weapons. With a normal obomb if you are not bleeding, concussed or otherwise blast injured, all noticeable injuries,  you are OK. With radiation people expect it to be invisible and so are scared. Remember, when you are talking about a terror weapon rather than a military weapon, perception and fear rule. The technical specifications and absolute effects are otherwise irrelevant to the fear and uncertainty it can produce.

I can definitely say that my views on the social structures of the middle east are not formed by propaganda. Among other things, I lived in The Sudan for a year while it was radicalizing in the early eighties. I watched the implementation of Sharia law there from the first week it was declared. Starting with the smashing the liquor on the banks of the Nile and release of criminals from jail,  to to the implementation of cross amputations (hand and foot), then the infiltration of the Libyan Muslim Brotherhood… Yeah the same guys who everyone thinks love democracy and we are supporting right now… Then the stoning of girls (even other western friends of mine) for wearing short sleeves, floggings for everything under the sun including my favorite, suspected attempted adultery – that is, sitting with a woman or girl alone in a room. You may say this gave me a skewed viewpoint but I bet you will not find anyone who lived in a traditional fundamentalist area of the middle east who does not have similar experiences or those even more disturbing than I have presented. I know I have a load of them and I have a pretty open mind when it comes to different customs, cultures and societies.

Those, along with more mundane experiences like having otherwise normal educated adults refer to us as “infidel” in the same off hand, casual and without malice way that an American Southerner called african-Americans “nigger” in the Old South, gave me a very good idea of what happens in a country having a fundamentalist revival. It is not a pretty thing. That is not to say that the people were bad or evil. For instance, if a taxi driver said they would take you home and you couldn’t remember how to get there they would drive you until they found it and not charge extra. If you engaged someone on a person to person level they could be very friendly and could even be friends but, like with anyone else, you had to understand what the boundries of friendship were. To know that you need to understand the religious, ethnic and tribal value systems and never mistake it for a western one. Most people have a strong sense of honor and obligation in these societies but the nature and constraints of it are not easily understandable in western terms. Remember, their history is not the same as our history. 

When I went to university several years later I got a formal background specifically in international relations, anthropology and counterterrorism. My initial concentration was dealing with the Soviets and moved through the nonRussian republics into the Middle East. My later life expanded my knowledge of those regions and required, for various reasons, that I become familiar with several other disciplines in both the hard and soft sciences. My views on the social and cultural threat environment are based on a solid foundation. I would ask that you please look more deeply into the history and culture of the region before you dismiss my thoughts. I do not mean the rabid alarmists of FOX or the bigoted polemists of the right, they do not get the nuance and the Middle East if nothing if not nuanced. Do not drink the kool-aid of the left and moderates either. Public views are based upon the people from the region who we hear talking about the issues but the only people being interviewed are those who speak English. That simple fact hugely skews the viewpoints we hear. 

The fundamentalists supposedly had little or nothing to do with the recent uprisings but I absolutely guarantee that they will start being heard within the next nine to twelve months. No matter what people may want, middle easterners are not just a bunch of oppressed people who want to grow up to be westerners. This is not the same as the fall of the Iron Curtain no matter how much the punditry wishes it were.

What we are seeing now my well include the sparks of nationalism but even if so it would be a new, young thing with huge cultural inertia to overcome and strong competing alternatives. Remember, in the middle east the only history of voting and election comes from Islam not some secular ideal like in the west. If some form of nationalism does manage to grow in the middle east it will be of a form unique to the region. That people can believe that popular American or Western European style democracies are going to start popping up simply have no concept of the culture or history of the region. That belief is dismissing as valueless and irrelevant the entire social history of the middle east by saying that it must lead them to the exact same place that our social history brought us, as if there were no difference between the two.

It is because I am so confident in my assessment of the social and cultural threat environment that I  find your assessments of the technical threat environment so valuable and why I present a lot of “yes, but…” when you say some thing is possible or not possible. I am not trying to be contrary I am taking the oportunity to get as much information as possible and understand what I can. The constraints are important as is the level of expertise to answer a “yes, but…”. Anything that can not be conclusively disproven within the likely expertise of someone trying to make a device is something which might be tried and can possibly be watched for by the people who watch for such things.

You have mostly convinced me that the only way that a non state actor could successfully build a device is if dumb luck made it work against all odds. I just can not bring myself to say the posibility is totally precluded. The pool of people who would want to build a device is fortunately very small when you factor in those with enough skill and knowledge to give it a try. Even if an objective analysis tells those people that what they are doing is practically impossible I have sincere doubts that that would prevent a group having access to material from trying. So possible or not it comes down to keeping the material under control.

I agree whole heartedly that there are asymmetrical threats out there that are thousands of times more likely than what we have been discussing here. The most cost effective terror weapon is the well trained sniper. Just look at the case of John Allan Mohammad in DC. However, what we have been discussing are proliferation threats rather than the whole universe of asymmetrical and terrorist threats. In that universe of things there are dozens to hundreds of threats which I worry about more than a constructed nuclear device or any of the other boogyman threats like dirty bombs, bioterrorism and chemical weapons. All of those are black swans but it would be irresponsible not to pay attention to them. I do not think this is the place for me to discuss my views of the overall terror threat environment.  

Check out the site of the most popular and moderate Imam of the Shia to get an idea of the things that are important in the everyday life of a moderate not a fundamentalist. It is hard to get an idea about the values of the street from English language postings a good rule of thumb is that what is moderate in English is liberal in Arabic. Arabs are not 

I think I might have strayed into the non technical area a bit much here. I would be happy to continue but it is probably too far off topic for Barry’s blog. May I suggest, if you would like and our host does not object, that we address a different proliferation subject area. For instance Pakistan has recently said that it is increasing the number of nuclear warheads in it’s inventory from 60 to 110 so maybe something on the nonNPT nuclear states or possibly something on the Fuel  bank treaty you mentioned earlier. Maybe some of the lurkers will join in. 

Or, if you want, we can take a break here. In any event I have been enjoying our exchanges, they have gotten me writing again and I have learned new things about an area I have interest in.


Joshua, – I will yield to your superior knowledge of the Mid-East, however in my defense, I am getting a bit tired of the constant refrain from many that the the whole region lives and breaths hatred for the West, and will stop at nothing to attack it at every opportunity. Yes there are elements, but I suspect that they are more a reflection of local social and political conditions, than any basic ideology.

I am a scientist so I have trouble asserting that something is impossible, but I think I have shown that the the chances of an amateur nuclear weapon appearing does at least approach zero. Thus there is no real need for concern beyond the current levels of security now in force. And I reiterate, that anyone contemplating such a project would go through the same reasoning that I have, and conclude that the chance of success is too small and the expense and trouble of such an undertaking, too great, that they would drop the idea as unworkable.

As for DU, this topic has been blown far out of proportion as well. Depleted uranium first emerged as a social, political, and scientific issue after the 1991 Gulf War. The decline of rational discourse about DU can be traced to the 1999 Kosovo conflict. At that time, the DU issue took on a more overtly political role. The Yugoslav government under Sloboban Milosevic suggested the use of DU in the Balkans would have genocidal effects, and when the U.S. government refused to release information about its use of DU following the war, activists and propagandists alike suggested that the United States was responsible for causing widespread and severe effects from its use of DU munitions. Saddam Hussein similarly blamed the United States (and DU) for a sharp increase in cancers and birth defects, and Yasser Arafat joined the chorus by accusing Israel of using DU in Palestinian territories. In the years since 1999, politicians, propagandists, and activists have intoxicated each other with heart-wrenching but extremely misleading and unsubstantiated claims about the effects of DU munitions, radicalizing the issue in a way that has had a chilling effect upon serious debate.

Ironically, U.S. propaganda fueled the uncertainty surrounding the effects of DU munitions on Iraqis, which in turn facilitated the Saddam Hussein regime’s own propaganda. A policy of “proponency” to prevent DU munitions from becoming “politically unacceptable” was recommended shortly as the war ended, and in the subsequent years, Pentagon spokesmen dismissed concerns about DU munitions in the same breath as they overstated its success in defeating the Iraqi tank corps. The hype helped create the impression that the battlefield was far more contaminated by DU dust than it probably was, thereby enabling the Iraqi government to effectively exploit an reported rise in cancers and birth defects by blaming the effects on DU munitions and, more importantly, the United States.

As far as the people suffering from the health effects of being in combat, it would seem to me that it would be very, very hard to isolate exposure to any one material from the hazmat background in an active theater; such places are not exactly OSHA compliant to begin with. This stuff has been use in ordnance since 1958, but it wasn’t till two tin-pot dictators tried using the issue to discredit NATO in general and the U.S. in particular that anyone noticed it.

As well, DU is not fired randomly on the battlefield at any target. Its use is limited to its anti-armor role, where its property of burning on contact with any solid is exploited to penetrate, and as a shield on some tanks. There isn’t much left over to collect. It is also used in a few industrial applications, which would probably be a more likely supply for someone wanting to put their hands on some.

Again, the properties of material obtained this way is not likely to help make a weapon ether as a tamper or as a modeling substance, as the requirements for pure uranium is a real limiting factor to make a working device.

The thing with Pakistan is that not only does in now have a well established nuclear weapons complex, but it has indigenous supplies of uranium it can exploit. As a consequence efforts to halt their ability to build warheads cannot be prosecuted by external technical limits. This is what I mean when I write that the issue is diplomatic and military, and has little to do with nuclear energy.

Finally, the behavior of states is guided not only by normative considerations, it is also animated, and in many cases dominated, by security and economic interests. While having control over the market in uranium may comfort NPT nuclear weapon states, it does not necessarily follow that the majority of non-nuclear weapon states would support such a regime even if they were not planning to start a N-weapons program.

In the end they would have to implement it, which could entail a new set of costs, such as energy costs and a potential loss of sovereignty. In short, a state may oppose a nonproliferation measure on the grounds that it will not produce a net security, economic, or prestige benefit to them.

The whole issue is so much more complex that it is made out to be, and the public is not being informed of the consequences, but rather led to believe that there is some short path to nuclear security, that just is not there.


Joshua, on 5 April 2011 at 4:36 AM said:

Among other things, I lived in The Sudan for a year while it was radicalizing in the early eighties

I lived in the Saudi Arabia when Jimmy Carter was president. I would disagree with your assessment of the Middle East. Unfortunately it would be an extremely long discussion as to ‘why’.


Extract from an article about radioactivity leaks from Fukushima on page 9 of “The Australian” on 6th April:
“… radioactive iodine and caesium had been found in fish caught in the Pacific Ocean south of the plant since northeastern Japan was devastated by an earthquake and tsunami on March 11. The death toll has exceeded 12,000 with more than 15,000 people unaccounted for. Water sampled just off the plant – where a leak continued to emit radioactive substances into the sea – showed radioactive iodine levels of 7.5 million times the legal limit …”
Sure, they don’t say the casualties were caused by the radioactvity, but one could easily read it that way. Not very professional, Mr Murdoch!


The medis this side of the World are doing the same thing. If it is not a conspiracy…
I hope the IAEA brief which is on goind in Vienna rithg now will deserve some attention from the media!


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