Subcritical Thorium Reactors: Dr. Rubbia’s Really Bad Idea

The Telegraph (hattip Insty) turned the hype level to max in a recent article about the potential of thorium reactors.  According to the headline, “Obama could kill fossil fuels overnight with a nuclear dash for thorium.”  Against all odds, this is to happen in three to five years with a “new Manhattan Project,” and a “silver bullet” in the form of a new generation of thorium reactors.  The author is so vague about the technologies he’s describing that it’s hard to avoid the conclusion that he simply doesn’t know what he’s talking about, and couldn’t be bothered to spend a few minutes with Google to find out.  I’ll try to translate.

It’s claimed that thorium “eats its own waste.”  In fact, thorium is very promising as a future source of energy, but this is nonsense.  Apparently it’s based on the fact that certain types of thorium reactors actually could burn their own fuel material, as well as plutonium scavenged from conventional reactor waste and other transuranics, much more completely than alternative designs.  This is certainly an advantage, but the fission products (lighter elements left over from the splitting of uranium and plutonium) would still be highly radioactive, and would certainly qualify as waste.  Such claims are so obviously spurious that they play into the hands of opponents of nuclear power.

It is also claimed that “all (thorium) is potentially usable as fuel, compared to just 0.7% for uranium.”  In fact, thorium is not a fissile material, meaning that, unlike uranium 235 (U235), which is the 0.7% of natural uranium the author is referring to, it cannot sustain a nuclear chain reaction on its own.  It must first be converted to a lighter isotope of uranium, U233, which is fissile.  In fact, the U238 that makes up most of the rest of the leftover 99.3% percent of natural uranium is “potentially usable as fuel” in that sense as well, by conversion to plutonium 239, also a fissile material.

The author is vague about exactly what kind of reactors he is referring to, lumping Dr. Carlo Rubbia’s subcritical design, which depends on a proton accelerator to provide enough neutrons to keep the fission process going, and molten fluoride salt reactors, which do not necessarily require such an accelerator.  He claims that, “Thorium-fluoride reactors can operate at atmospheric temperature,” which they certainly could not if the goal were to generate electric power.  I suspect that what he means here is that, unlike plutonium breeders, which require a high energy neutron spectrum to produce more fuel than they consume, thorium breeders could potentially use “thermal” neutrons that have been slowed to the point that their average energy, when converted to a “temperature,” would be much closer to that of the other material in the reactor core. 

In any case, the design he seems to be so excited about is Dr. Rubbia’s “energy amplifier,” which, as noted above, would be subcritical, requiring a powerful, high current proton accelerator to keep the fission process going.  It would do this via spallation, a process in which a copious source of the neutrons required to keep the reaction going would be provided via interaction of the protons with heavy nuclei such as lead, or thorium itself.  This is the process used to produce neutrons at the Oak Ridge Spallation Neutron Source.  Such reactors could easily be “turned off” by simply shutting down the source of neutrons.  However, the idea that they would be inherently “safer” is dangerously inaccurate.  In fact, they would be an ideal path to covert acquisition of nuclear weapons.  Thorium reactors work by transmuting thorium into U233, which is the isotope that fissions to produce the lion’s share of the energy.  It is also an isotope that, like U235 and Pu239, can be used to make nuclear bombs. 

The article downplays this risk as follows:

After the Manhattan Project, US physicists in the late 1940s were tempted by thorium for use in civil reactors. It has a higher neutron yield per neutron absorbed. It does not require isotope separation, a big cost saving. But by then America needed the plutonium residue from uranium to build bombs.

“They were really going after the weapons,” said Professor Egil Lillestol, a world authority on the thorium fuel-cycle at CERN. “It is almost impossible make nuclear weapons out of thorium because it is too difficult to handle. It wouldn’t be worth trying.” It emits too many high (energy) gamma rays.

What Lillestol is referring to is the fact that, in addition to U233, thorium reactors also produce a certain amount of U232, a highly radioactive isotope of uranium with a half life of 68.9 years whose decay does, indeed, release potentially deadly gamma rays.  It would be extremely difficult, if not impossible, to remove it from the U233, and, if enough of it were present, it would certainly complicate the task of building a bomb.  The key phrase here is “if enough of it were present.”  Thorium enthusiasts like Lillestol never seem to do the math.  In fact, as can be seen here, even conventional thorium breeders could be designed to produce U233 sufficiently free of U232 to allow workers to fabricate a weapon without serious danger of receiving a lethal dose of gamma rays.  However, large concentrations of highly radioactive fission products would make it very difficult to surreptitiously extract the uranium, and it would also be possible to mix the fuel material with natural or depleted uranium, reducing the isotopic concentration of U233 below that necessary to make a bomb.

With subcritical reactors of the type proposed by Rubbia, the problem of making a bomb gets a whole lot easier.  Rogue state actors, and even terrorists groups if we “succeed” in coming up with a sufficiently inexpensive design for high energy proton accelerators, could easily modify them to produce virtually pure U233, operating small facilities that it would be next to impossible for international monitors to detect.  There are two possible pathways for the production of U232 from thorium, both of which involve a reaction in which a neutron knocks two neutrons out of a heavy nucleus of Th232 or U233.  Those reactions can’t occur unless the initial neutron is carrying a lot of energy as can be seen in figure 8 of the article linked above, the threshold is around 6 million electron volts (MeV).  That means that, in order to produce virtually pure U233, all that’s necessary is to slow the incoming spallation neutrons below that energy.  That’s easily done.  Imagine two billiard balls on a table.  If you hit one as hard as you can at the other one, what happens when they collide?  If your aim was true, the first ball stops, transferring all its energy to the second one.  The same thing can be done with neutrons.  Pass the source neutrons through a layer of material full of light atoms such as paraffin or heavy water, and they will bounce off the light nuclei, losing energy in the process, until they eventually become “thermalized,” with virtually none of them having energies above 6 MeV.  If such low energy neutrons were then passed on to a subcritical core, they would produce U233 with almost no U232 contamination. 

It gets worse.  Unlike Pu239, U233 does not emit a lot of spontaneous neutrons.  That means it can be used to make a simple gun-type nuclear weapon with little fear that a stray neutron will cause it to fizzle before optimum criticality is reached.  And, by the way, a lot less of it would be needed than would be required for a similar weapon using U235, the fissile material in the bomb that destroyed Hiroshima. 

We’re quite capable of blowing ourselves up without Rubbia’s subcritical reactors.  Let’s not make it any easier than it already is.  Thorium reactors have many potential advantages over other potential sources of energy, including wind and solar.  However, if we’re going to do thorium, let’s do it right.

The Case of the Contraband Uranium

It appears that authorities in Moldova seized about four pounds of contraband uranium and arrested several suspects. The material in question turned out to be the isotope uranium 238 (U238), meaning that, unlike the fissile isotope U235, it couldn’t be used to make a bomb. Maybe it’s just me, but it seems that whenever I have personal knowledge of what happened in an incident that makes the news, or expertise regarding its subject, the mainstream media, with their layers of editors and fact checkers, manage to botch the story. For example, CNN uncritically quotes Kirill Motspan, a spokesman for Moldova’s Interior Ministry as saying that, “…it was his understanding that 1 kilo of uranium costs $6.3 million on the black market and that is what the smugglers were expecting to get.” I seriously doubt that Motspan meant just any uranium, and especially not U238. If that were the case, the guys who fly A10 Warthog ground support planes armed with Gatling guns that pump out rounds that contain just under a pound each of the stuff at 4,200 rounds per minute must be using caddies to recover them. He was probably referring to uranium highly enriched in isotope 235, which can be used to make a bomb. In other words, the smugglers were intending to snooker their customers. Anyone can Google the fact that natural uranium, which contains at least a little (about 0.71%) U235, is currently selling for just under $50 per pound.

Not to be outdone, the Telegraph reports that the material seized was “enriched uranium.”  Since the caption of the figure that appears in the article notes that the material was U238, commonly referred to as depleted uranium, none of their “fact checkers” apparently has a clue what they’re talking about.

BTW, have you noticed that whenever contraband radioactive and special nuclear material is seized, its usually due to good old fashioned police work, and not to those snazzy new radiation detectors that are being installed hand over fist at ports and border crossings?  That’s not a coincidence.

The Hiroshima Fallacy Lives On

In a briefing at the start of President Obama’s nuclear security summit on Monday, his top counterterrorism advisor, John Brennan, claimed,

Developing a nuclear device involves a highly sophisticated technical process, and al Qaeda doesn’t seem to have mastered it based on what we know now.

It boggles the mind that someone in his position could believe such nonsense. Unfortunately, he’s not alone. Any number of people who should know better have fallen for the Hiroshima Fallacy; the dangerously mistaken belief that an effective nuclear device would need to be at least as sophisticated as the weapon that destroyed Hiroshima. Here’s a tutorial for the benefit of Mr. Brennan on the “highly sophisticated technical process” necessary to assemble an effective nuclear weapon:

1. Acquire a critical mass of weapons grade plutonium or highly enriched uranium, otherwise known as Special Nuclear Material (SNM), well separated into two chunks of approximately equal size.

2. Purchase a step ladder.

3. Place one of the two pieces of SNM on the ground at your chosen target location.

4. Climb the step ladder with the other piece of SNM.

5. Take careful aim, and drop the piece of SNM you are holding on top of the other piece.

How’s that for a “highly sophisticated technical process,” Mr. Brennan?

The result of such a nuclear attack would not be a 20 kiloton explosion. It might not even cause any fatalities, assuming the attacker could run really, really fast. However, the effect would be the same as detonating a big “dirty bomb.” The immediate area would be poisoned with radioactivity, and the economic impact would be great. The political impact would be incalculable. Assuming the attacker cared to bother with an even more “highly sophisticated technical process,” the critical masses could be accelerated together with a strong spring, or a small explosive charge. One might add a crude gun barrel to enhance the effect. At each stage, more radioactivity would be released, and distributed more widely. Eventually, the device would explode. The size of the explosion would be unpredictable. It would all depend on when a stray neutron happened along.

I have a suggestion for Mr. Brennan. He should contact the weapon designers at Los Alamos and Livermore and ask them to fire up their codes and prepare a study on the likely effects of the weapons described above. He should then gather together as many members of Congress and high government officials as possible and sit down and listen to what they have to say. I can assure Mr. Brennan that, if he really believes the Hiroshima Fallacy, it will be an epiphany for him. If time allowed, it might also be useful for the weapons guys to describe how one might assemble a simple gun type nuclear weapon with an explosive yield in the kiloton range. I rather suspect Mr. Brennan will be surprised to learn the real level of sophistication necessary to build such a weapon.

It is not a good thing for the officials responsible for protecting us from nuclear attack to be ignorant about nuclear weapons. It would not be difficult, nor would it take a great deal of their time, to learn some of the elementary facts alluded to above from people at the weapons labs who know what they’re talking about. I appeal to them to do so.

Worker with plutonium disk

The Nuclear Posture Review and the Future of the Arsenal

The right and the left in this country have achieved a state of MAD (Mutually Assured Demonization). The recent attempts by the legacy media to whip up hysteria over threats of violence to those who voted for the health bill is a case in point. There was a time, not that long ago, when these “objective journalists” would have gotten away with it. There was no comparably audible public voice on the right to oppose them. Now there is, in the form of talk radio, powerful blogs, and Foxnews. Result: They only succeeded in, once again, making themselves look silly. The Right was in their face immediately, pointing out, among other things, the gross hypocrisy in the double standard they applied to violence and threats of violence depending on whether they come from the right or the left.

Overall, this form of MAD is a good thing. The sanctimonious, condescending attitude of the journalists of yesteryear was getting very old by the time Rush Limbaugh finally appeared on the scene. However, it does have its drawbacks, in the form of increasing levels of political polarization and the associated pious posing on both the right and the left. Indeed, when it comes to the ostentatious striking of sanctimonious public poses, the right has, at long last, achieved parity with the left. Reasoned debate becomes difficult when both sides are only interested in occupying the moral high ground.

Consider, for example, the right’s overwrought response to the latest Nuclear Posture Review (NPR). The NPR is a document submitted to Congress each year by the Department of Defense setting forth what the role of nuclear weapons in U.S. security strategy should be. The latest version contains a watered down “no first use” provision according to which we won’t respond with nuclear weapons even if attacked with chemical and biological weapons, with the caveat that for nations that don’t play according to the Nuclear Nonproliferation Treaty, everything is still on the table. Some of the other more significant provisions include:

• The United States will not conduct nuclear testing, and will seek ratification and entry into force of the Comprehensive Nuclear Test Ban Treaty.

• The United States will not develop new nuclear warheads. Life Extension Programs (LEPs) will use only nuclear components based on previously tested designs, and will not support new military missions or provide for new military capabilities.

• The Administration will study options for ensuring the safety, security, and reliability of nuclear warheads on a case-by-case basis, consistent with the congressionally mandated Stockpile Management Plan. The full range of LEP approaches will be considered: refurbishment of existing warheads, reuse of nuclear components from different warheads, and replacement of nuclear components.

The response Tunku Daravarajan at The Daily Beast:

I despair of this latest episode of gestural theater designed to make the U.S. look exquisitely reasonable (should we call it “Jimmy-Cartesian”?), but which in truth results in the U.S. looking flaccid, or worse, complacent. After all, who gains from a presidential posture that has, in effect, stigmatized our most potent deterrent? In terms of foreign policy—or, better put, foreign clout—the U.S. is going through a startling period of auto-emasculation.

and from Roger Simon at PajamasMedia:

Like some looney member of Code Pink, our president is abandoning the nuclear deterrent adhered to by every American president since Truman. And he is doing it in a manner that makes absolutely no sense… What are we to make of this and the man who is adopting this policy? Does he hate us? Does he hate this country? What would he do if there was, for example, a massive small pox attack on the U.S.? Send in the infantry? Call in the Marines? Try to reason with whoever did it and recommend they negotiate as the fatal disease spreads to millions of people?… Now I detest nuclear weapons as much as the next person, but this approach seems — I hate to repeat myself, but I will — deranged.

Now let’s think about this for a moment. Suppose, just for the sake of argument, that the ultimate reason for having a nuclear arsenal in the first place is to protect our security. What if Tunku and Roger, being human, and therefore not infallible, are wrong? What if, just hypothetically, the policy set forth in the NPR really will make us more safe, and the policy they prefer less safe. They have not limited themselves to a reasoned response to the NPR, setting forth, in their opinions, why they think it will not enhance our safety. Rather, they have villified the people who support it, accusing them, not only of being wrong, but of being crazy. When you demonize people, you make it very difficult for them to respond to your objections in a reasoned manner. Being human, they are more likely to strike back, trading tit for tat. I would even go so far as to say that, in some cases, that is the only rational way to respond. It seems rather obvious that convergence to correct policy decisions is not a likely outcome of this process of mutual demonization.

That is the reason that, as I have maintained elsewhere, when it comes to policy decisions as weighty as those relating to nuclear policy, moralistic posing, with all the associated pushing of emotional hot buttons, should be set aside in favor of some semblance of rational discussion. The goal here, I assume, is to survive. Let us, then, dispassionately consider what we should best do in order to survive.

According to Steve Schippert ant Liberty Pundits, the NPR not only does not serve that goal but is, in fact, pointless.  In his words:

There is none, really. Not beyond rhetoric and “historic” moments and – dare the Los Angeles Times say it – a “manifesto.”

No point at all – but for one critical aspect lost in all of the arguing back and forth. Clarity is dead. Nuance and the foolish self-assurance of perceived superior intellectual and/or moral capacity have rightly replaced clear understanding.

Admitting in advance my own fallibility, I beg to differ. In the first place, we have kept the nuclear genie in the bottle now for going on 65 years. I am far from believing that an all out nuclear exchange would result in the extinction of humanity, or anything close to it. It is, nevertheless, an understatement to say that it would be extremely destructive. That being the case, it would be well if, to the extent possible, we maintained a taboo on the first use of nuclear weapons.

Any first user of nuclear weapons likely would become and, it seems to me, should become, an international pariah. Roger paints a nightmare scenario in which millions of people are dying in a biological attack while our hands are tied. Given the known effects of the releases of biological and chemical agents to date, the chances of something like that happening are vanishingly small. If it did, the NPR would become a moot point, just as all our loud protestations against unrestricted submarine warfare prior to our entry into WWI became a moot point for our own submarine forces in the Pacific after Pearl Harbor. A far more likely first use scenario would be an attempt at eliminating enemy stocks of biological or chemical weapons with a nuclear bunker buster, either preemptively or after an ineffective and very ill-considered attack on the United States with such weapons. This kind of first use would be very attractive to many in the nuclear weapons community. It would, however, do anything but promote our national security. Rather, it would end the taboo on the use of nuclear weapons, greatly increasing the chances that we, in turn, would become the victims of a really devastating attack, not with ineffective chemical or biological agents, but with nuclear weapons.

I also agree with the other sections of the NPR that are major departures from past policy, or, at least, have been represented as such. One of these is the provision that the United States will not conduct nuclear testing. Again, there are many in the weapons community who would love to resume testing, basing their arguments on insuring the reliability of the stockpile. It would also help the national weapons laboratories solve the demographic problem they face with the retirement or impending retirement of most of the physicists and other technical experts who have actually taken part in nuclear tests, and the difficulty of attracting talented scientists to careers as custodians of an aging pile of nuclear weapons. It would also play directly into the hands of our enemies.

The United States has a huge advantage over potential nuclear rivals in its possession of above ground experimental facilities (known in the business as AGEX) second to none in the world. From the massive National Ignition Facility, with its ability to focus 192 powerful laser beams on a tiny point, to the Z pulsed power machine capable of producing bursts of X-rays at levels far beyond those of any comparable facility on the planet, to a host of other smaller but still highly impressive and technologically advanced experimental facilities, we can approach the physical conditions that exist within exploding nuclear devices more closely and for longer periods of time than any other nation can even dream of. To resume nuclear testing would be to stupidly throw away this huge advantage. At the same time, it would give our enemies all the moral authority they needed to resume testing or develop nuclear weapons themselves.

The decision to set in concrete in the NPR the decision not to develop new nuclear weapons is also a good one. The idea that the United States would do such a thing is anything but implausible. On the contrary, the National Nuclear Security Administration has been agitating for years to get the go-ahead to build the Reliable Replacement Warhead. When Congress wisely told them, not only no, but hell no, they kept up the pressure regardless. Congress has taken a lot of bad raps lately. They deserve a lot of credit for derailing NNSA’s determination to go ahead with the RRW. In the first place, the weapons in our stockpile are not fragile and unreliable. Any enemy that assumed so would be making a very grave mistake. In the second, if we developed the RRW, the pressure to test it would likely become irresistible. The idea of developing a nuclear weapon without testing it would never have passed the “ho-ho” test at the weapons labs back in the 70’s and 80’s. The claim that we wouldn’t need to test the RRW is likely wishful thinking. Again, all the objections to a resumption of nuclear testing I have cited above would apply. Finally, by building a new type of nuclear weapon we would once again sacrifice the moral high ground, handing our enemies all the justification they needed for building new weapons themselves. Again, we would sacrifice major advantages, simply to acquire a weapon that would be somewhat cheaper to maintain than those in the existing stockpile. For obvious reasons, the weapons designers at the labs would love it. For the rest of us, it would make no sense at all.

I am hardly in favor of unilateral nuclear disarmament. On the contrary, I am in favor of maintaining a powerful arsenal and assuring that the resources we need to keep it safe and reliable will always be available. However, the latest NPR is a reasoned response to the nuclear myopia that would have us sacrifice real advantages in return for extremely dubious returns. As such, it deserves our support.

Thorium: Wired Magazine Muddies the Water

Glenn Reynolds at Instapundit recently linked to an article by Richard Martin in Wired Magazine entitled, ‘Uranium is so Last Century:  Enter Thorium, the New Green Nuke.”  I cringed when I read it.  I suspect serious advocates of thorium did as well.  It was a piece of scientific wowserism of a sort that has been the bane of nuclear power in the past, and that its advocates would do well to steer clear of in the future.  It evoked a romantic world of thorium “revolutionaries” doing battle with the dinosaurs of conventional nuclear power.  Things aren’t quite that black and white in the real world.  Thorium breeders deserve fair consideration, not hype, as does nuclear power in general.  There are many good reasons to prefer it to its alternatives as a source of energy.  It doesn’t take a genius to understand those reasons, assuming one approaches the subject with a mind that isn’t made up in advance, and is willing to devote a reasonable amount of time to acquire a basic understanding of the technology.  Martin would be well advised to do so before writing his next article on the subject. 

In the first place, thorium is not a replacement for uranium, as implied by the title of the Wired article.  Rather, the point of putting it in nuclear reactors is to breed uranium, which remains the actual fuel material, albeit in the form of isotope U233 rather than U235.  Thus, when Martin writes things like,

Those technologies are still based on uranium, however, and will be beset by the same problems that have dogged the nuclear industry since the 1960s. It is only thorium… that can move the country toward a new era of safe, clean, affordable energy.

in comparing thorium reactors to their more conventional alternatives, it is evident he doesn’t know what he is talking about.  Referring to the physicist Alvin Weinberg, he tells us,

Weinberg and his men proved the efficacy of thorium reactors in hundreds of tests at Oak Ridge from the ’50s through the early ’70s. But thorium hit a dead end. Locked in a struggle with a nuclear- armed Soviet Union, the US government in the ’60s chose to build uranium-fueled reactors — in part because they produce plutonium that can be refined into weapons-grade material. The course of the nuclear industry was set for the next four decades, and thorium power became one of the great what-if technologies of the 20th century.

With all due respect to Weinberg, a brilliant scientist whose work remains as relevant to conventional reactors as to their thorium cousins, this picture of thorium knights in shining armor doing battle with the dark forces of the nuclear weapons establishment is certainly romantic, but it leaves out some rather salient facts.  In the first place, conventional power reactors do not even produce weapons grade plutonium, which contains a high concentration of plutonium 239.  Special reactors that run for a much shorter period of time are used for that purpose.    Furthermore, thorium is not a nuclear fuel.  A reactor using thorium alone would never work because thorium is not a fissile material.  In other words, unlike, for example, uranium 235 or plutonium 239, it cannot sustain a nuclear chain reaction.  The point of putting it in nuclear reactors is to breed uranium 233, another isotope that is fissile.  We began producing nuclear power with conventional nuclear reactors based on uranium 235 rather than thorium breeders because of their simplicity, not because of their usefulness as sources of bomb material.  The fuel needed to run them is available in nature as one of the isotopes in mined uranium, and doesn’t depend on a complex breeding cycle for its production.  There are other drawbacks to thorium breeders that Martin doesn’t mention in his article.  For example, in addition to uranium 233, they produce significant quantities of uranium 232, a short lived isotope with some nasty, highly radioactive daughters.  Separating it from U233 was out of the question, and its presence makes the production and handling of nuclear fuel elements a great deal more difficult. 

I’m certainly no opponent of thorium breeders.  In fact, I think we should be aggressively developing the technology.  However, before writing articles about the subject, it can’t hurt to have some idea what you’re talking about.  There are no lack of good articles about the subject on the Web within easy reach of anyone who can use Google.

The Iranian Bomb: Guessing the Date

According to the latest estimate by Israeli intelligence, Iran is capable of building a bomb by 2011. These estimates always beg the question of what kind of bomb one is talking about. In fact, Iran will have a perfectly adequate bomb or, more accurately, nuclear device, the moment it has enough bomb grade plutonium or uranium to assemble a critical mass. In the first place, it does not take a great deal of technical finesse to build a gun assembled atomic bomb. In the second, Iran needn’t bother, because, if she were really determined to carry out a nuclear attack, something much more crude would be more attractive from her point of view. By “crude” I mean, for example, a suicide bomber equipped with two subcritical masses that, when combined, would form a critical mass. This could be done by dropping one subcritical mass on top of another, or simply slapping them together. Unlike something as sophisticated as the device dropped on Hiroshima, such a “bomb” would preserve plausible denial for Iran. Even if the material could be traced to one of her reactors, she could claim that it had been stolen or diverted by terrorists. If assembled in the middle of a large city, it may not produce the familiar mushroom cloud, but it would certainly produce a radioactive mess that would inspire terror, likely cost billions to clean up, be much less likely to provoke nuclear retaliation than a high yield bomb, and spare Iran immediate relegation to the status of an international pariah for having once again unleashed the nuclear genie, committing mass murder in the process.

In a word, once Iran has sufficient special nuclear material to make a bomb, it will no longer be necessary to speculate about how long it will take her to build one. She will have the “bomb” the moment she has enough material to assemble a critical mass.

Jon Kyl and the Resumption of Nuclear Testing

In a recent article in the Wall Street Journal, Arizona Senator Jon Kyl called for a resumption of nuclear testing. Such a step would be both unnecessary and a potentially disastrous threat to our national security.

I am no pacifist, and I favor maintaining a strong and credible nuclear deterrent. It is for that very reason that I oppose a resumption of nuclear testing. It would in no way strengthen us. Rather, it would promote nuclear proliferation and result in a weakening of the nuclear posture of the United States vis-à-vis its potential nuclear armed opponents.

Obviously, Senator Kyl has heard some of these arguments, but they somehow don’t seem to sink in. He notes in his article that, “There’s a related theory, which is that the U.S. has to ratify the CTBT if it wants to have any credibility or leadership on nonproliferation,” but then dismisses these arguments with the claim that, “Aside from the fact that countries will act in their best interest whether or not the U.S. ‘leads’ them, no one can legitimately question U.S. commitment on proliferation issues.” I, for one, would question the U.S. commitment on proliferation issues if we resumed testing, whether Kyl considered it legitimate or not, and I would hardly be alone in that conclusion. Beyond that, his assertion that other countries will act in their own best interests ignores the reality that the actions of the United States can have a substantial bearing on what those best interests happen to be, particularly in matters relating to nuclear proliferation. Take, for example, Iran. If she tests a nuclear device after her oft-repeated denial of any desire to do so, she will become an international pariah, and likely subject herself to severe economic sanctions. She will also provide moral backing to those in Israel and the United States who advocate an attack on her nuclear facilities, greatly increasing the chances that one will occur. However, if she tested a nuclear device after the United States had resumed testing its own weapons, she could and would portray it as a legitimate act that had been forced on her by the actions of her enemies. The idea that the path chosen by the United States would have “no bearing” on her national interests is absurd.

Kyl cites the danger that clandestine nuclear tests cannot be verified and other nations will be able to test on the sly. To “prove” this dubious assertion, he notes that monitoring systems “failed to collect necessary radioactive gases and particulates to prove that a test had occurred” following the latest test by North Korea. In fact, seismic devices did detect it, in spite of the fact that its estimated yield was only a few kilotons. I have heard no credible argument to the effect that major nuclear powers could substantially enhance the power of their arsenals vis-à-vis the United States with clandestine tests that had a significant chance of going undetected. If anyone who actually knows what they’re talking about cares to make such an argument, let them put their cards on the table.

The part of Kyl’s argument that is likely to carry the most weight is the contention that there are serious concerns about the aging and reliability of our arsenal. To bolster his argument, he cites the testimony of C. Paul Robinson, former Director of Sandia National Laboratories, before the House Armed Services Committee last year. In fact, this testimony is very interesting in its own right, and, among other things has a direct bearing on the issue of the Reliable Replacement Warhead (RRW), which was promoted by the Bush Administration, but wisely rejected by Congress. It’s exactly what one might have expected to hear from a weaponeer at Los Alamos if one were transported back in time to the 1970’s or 80’s. In fact, that’s exactly what Robinson was at the time. In those days, the suggestion that a substantially new weapon could become part of the arsenal without previous testing would never have passed the “ho-ho” test.

Referring to his position on nuclear testing at the time that the Stockpile Stewardship program was first formulated in the early 90’s, Robinson said,

I will repeat only a few of the words that most of us with responsibilities for U.S. warheads said at the time—e.g. that “there is no precedent for such complex technological devices to be depended on unless they were periodically tested” and that “fielding of first-of-a-kind new devices without testing would be the most stressful challenge.”

Note the direct reference to a “first-of-a-kind” device here. The only such device anyone has seriously discussed building since the end of testing in 1992 is the RRW. Robinson goes on,

But in other areas we are just as uncertain today. My belief is that most weapons designers have less confidence about making changes to their designs than they had in the past. I particularly found the recent colloquy between the JASON group and the lab designers most curious —as they each speculated over the difficulties of fielding designs under the contemplated Reliable Replacement Weapon (RRW) effort. Although you will doubtless find a spectrum of views at the labs, my take is that uncertainties will necessarily (and quite naturally) grow over time for several of our systems.

Here again, although he speaks of other systems in general, Robinson specifically refers to the RRW as a system that it will be particularly problematic to introduce to the arsenal without testing. It is the only one he could be referring to when he cites the concerns of weapons designers about “making changes to their designs.” In spite of this, after an interesting bit on the genesis of the RRW concept, Robinson makes a remarkable intellectual double back flip a few sentences later:

After some discussion, the key idea of the RRW then emerged —that if we incorporated designs of “different genetic diversity” in each leg of the TRIAD, there would be a much lowered likelihood that all would fail at the same time from a common problem. Yet from what I’ve read, the Congressional support for the idea has been less than lukewarm —as evidenced by your canceling of the RRW funding, with some suggesting that the labs might be trying to “create new designs that would necessitate underground testing” in order to field the RRW. I assure you that this suggestion is just not true. RRW was conceived to lessen the likelihood that testing would be needed. At the very least I must conclude that “there has been a significant failure to communicate”, and I believe we must not let such misunderstandings perpetuate, when there is so much at stake.

This remarkable juxtaposition of the contradictory assertions that 1) new designs must be tested, but 2) the RRW will reduce the need for testing, is difficult to explain as other than a variant of Orwellian “doublethink” inspired by the need to stay “on message” on both the need to build the RRW and the necessity of resuming testing. In other words, Robinson and some of his fellow weaponeers at the National Labs want to have their cake and eat it too.

As is abundantly clear from Kyl’s article, there is no lack of people, both inside and outside the weapons labs, who want to resume nuclear testing. Trust me, if the RRW is built, it will result in a ratcheting up of the pressure to do so many fold. This is one of those rare instances when Congress actually got it right. Let’s forget about the RRW.

What, then, of the general assertion that testing is required because “concerns about aging and reliability have only grown?” In fact, if we stop hankering after the RRW and devote our attention to maintaining the weapons we already have, there is no credible reason to believe that they will not work as advertised. Let those who would maintain otherwise drop their vague assertions, put their cards on the table, and explain exactly what failure modes they are referring to. The weapons in our arsenal are robust, and any opponent who assumed otherwise would be making a very disastrous mistake.

Assuming, then, that we can really dismiss the negative political effects of resuming nuclear testing as Senator Kyl does with a cavalier wave of the hand, what would be the advantages of doing so? Surely, if we took the lead, the other nuclear powers would resume testing as well. The science of nuclear weapons has reached a high level of maturity in both the United States and Russia. It is much more likely that a resumption of testing will enable countries that have joined the nuclear club more recently to substantially improve their weapons designs than it will countries that have already developed highly sophisticated weapons. At the same time, it will negate the vast advantage we currently hold in possessing by far the most capable experimental facilities for validating nuclear weapons physics of any nation on earth. The experimental assets represented by Z facility at Sandia, the National Ignition Facility at Livermore, and a host of others give us a major leg up over the rest of the world in approaching the conditions that exist in nuclear weapons and investigating the relevant physics. When combined with our superiority in supercomputing power, they insure us a decisive advantage that it would be positively foolhardy for us to cast away with a resumption of testing.

Why then, the persistent pressure to resume testing? Once can only speculate. In Senator Kyl’s case, perhaps the increasing unsuitability of the Nevada Test Site as Las Vegas continues to sprawl in its direction may play a role. There are attractive alternative sites in his own state of Arizona that could potentially create many new jobs. As for the weapons designers, their lives were a lot more interesting during the era of nuclear testing. I suspect many of them would prefer a return to those “golden days of yesteryear” to their current role as custodians of an aging stockpile. These, however, are considerations that should not and cannot be allowed to play any role in our decision to resume testing or not.

Our weapons are reliable, and can be maintained with confidence. Let us preserve our advantage, and refrain from foolishly throwing it away with a resumption of nuclear testing.

Nuclear Strategery

Jonathan Tepperman has an interesting post on the Newsweek site entitled, “Why Obama should Learn to Love the Bomb.” According to Tepperman, “A growing and compelling body of research suggests that nuclear weapons may not, in fact, make the world more dangerous, as Obama and most people assume.” Yes, and there was “a growing and compelling body of research” in 1914 that suggested the great powers were so economically dependent on each other they would never risk going to war. Tepperman continues, “The argument that nuclear weapons can be agents of peace as well as destruction rests on two deceptively simple observations. First, nuclear weapons have not been used since 1945. Second, there’s never been a nuclear, or even a nonnuclear, war between two states that possess them.” That’s true, and the argument that possession of nuclear weapons reduces the chances of war between states that possess them is certainly plausible. However, the fact that, for example, there was never a nuclear exchange between the United States and the Soviet Union does not mean that the risk of such an exchange was zero. It is more likely that we dodged a bullet.

An all out conventional war between India and Pakistan would certainly result in great loss of life. An all out nuclear war would be, according to Tepperman, less likely. It would also be more costly in terms of loss of life, not to mention economic damage. Perhaps, then, a reasonable metric for assessing whether nuclear weapons make us more or less secure would be risk of war times likely human and economic cost. The problem with such a neat formula is that it would be impossible to predict or to agree on the magnitude of the different factors. For example, it was widely assumed during the cold war that a general nuclear exchange would result in the annihilation of the populations of the US and Soviet Union. However, I doubt the leaders on either side really believed that. Various attempts were made to calculate likely outcomes, but they were generally flawed by the ideological predispositions of those making the estimates.

Let’s consider what else Tepperman has to say:

Even the craziest tin-pot dictator is forced to accept that war with a nuclear state is unwinnable and thus not worth the effort. As (Berkeley Professor Kenneth) Waltz puts it, “Why fight if you can’t win and might lose everything?”

I’m not so sure that the craziest tin-pot dictator would come to such a logical conclusion. However, the statement as it stands is almost irrelevant. I suspect a nuclear exchange is far more likely to result from a miscalculation, accident, or loss of control to a rogue actor than any premeditated, deliberate attack.

Meanwhile, the nuclear powers have scrupulously avoided direct combat, and there’s very good reason to think they always will. There have been some near misses, but a close look at these cases is fundamentally reassuring—because in each instance, very different leaders all came to the same safe conclusion.

This is wrong on the face of it. Always is a long time. As long as there are nuclear weapons, there will be a finite risk of a nuclear exchange. Therefore, if states with nuclear arsenals continue to exist into the indefinite future, there will eventually be a nuclear exchange. The question is not whether it will happen, because it certainly will. The question is whether its cost, when it does happen, will be greater or less than the cost of the, presumably more frequent, conventional wars that would have occurred in the absence of nuclear arsenals. Similarly, as long as sufficient special nuclear material (SNM), such as U235 or Pu239, exists to make nuclear weapons, there will be a finite risk of it falling into the hands of non-state actors, or terrorists if you will. From this we must conclude that a terrorist nuclear attack is also inevitable. It is not a question of if. It is a question of when. It may be tomorrow, or it may be a thousand years from now, but it will happen. I rather suspect it will be sooner rather than later.

…in 1957, Mao blithely declared that a nuclear war with America wouldn’t be so bad because even “if half of mankind died … the whole world would become socialist.” Pyongyang and Tehran support terrorism—but so did Moscow and Beijing. And as for seeming suicidal, Michael Desch of the University of Notre Dame points out that Stalin and Mao are the real record holders here: both were responsible for the deaths of some 20 million of their own citizens. Yet when push came to shove, their regimes balked at nuclear suicide, and so would today’s international bogeymen.

That is an unwarranted assumption. In any case, as noted above, it is irrelevant, because the nuclear danger from accident or miscalculation is far greater than that from deliberate use.

Even if the Pakistani state did collapse entirely—the nightmare scenario—the chance of a Taliban bomb would still be remote. Desch argues that the idea that terrorists “could use these weapons radically underestimates the difficulty of actually operating a modern nuclear arsenal. These things need constant maintenance and they’re very easy to disable. So the idea that these things could be stuffed into a gunnysack and smuggled across the Rio Grande is preposterous.

Here, Tepperman’s “expert,” Michael Desch of Notre Dame, doesn’t know what he’s talking about. One wonders what sort of “constant maintenance” he has in mind. The basic design principles of both gun and implosion type weapons are well known. They certainly require maintenance occasionally, but “constant maintenance?” I think not. Any non-state actor gaining possession of an intact nuke will have plenty of time to use it. The idea that nukes are easy to disable is also poppycock. You can make the firing set as clever as you please, but the SNM would still be there. If you didn’t have an explosives guy capable of jury rigging the device, you could still simply cannibalize the material from two nukes and make a simple, but very effective device. Recall that our physicists were so confident that the gun type Little Boy would work that it was dropped without prior testing. The computer modeling tools available to anyone now are infinitely better than the rudimentary mathematical tools they had then. Building a crude bomb is simply not that difficult. As for smuggling the weapon in a gunnysack, Tepperman is right. A terrorist would have to be brain dead to even attempt it. Unfortunately, smuggling a complete weapon is completely unnecessary. It would be much simpler, and just as effective, to smuggle the SNM in small bits, and assemble it into a weapon at the target. The chances that we will be able to detect any of the material before the weapon actually goes off are virtually nil.

The risk of an arms race—with, say, other Persian Gulf states rushing to build a bomb after Iran got one—is a bit harder to dispel. Once again, however, history is instructive. “In 64 years, the most nuclear-weapons states we’ve ever had is 12,” says Waltz. “Now with North Korea we’re at nine. That’s not proliferation; that’s spread at glacial pace.” Nuclear weapons are so controversial and expensive that only countries that deem them absolutely critical to their survival go through the extreme trouble of acquiring them. That’s why South Africa, Ukraine, Belarus, and Kazakhstan voluntarily gave theirs up in the early ’90s, and why other countries like Brazil and Argentina dropped nascent programs.

Perhaps. However, I do not find the existence of a maximum of 12 nuclear states as comforting as Tepperman.

Put this all together and nuclear weapons start to seem a lot less frightening. So why have so few people in Washington recognized this? Most of us suffer from what Desch calls a nuclear phobia, an irrational fear that’s grounded in good evidence—nuclear weapons are terrifying—but that keeps us from making clear, coldblooded calculations about just how dangerous possessing them actually is. The logic of nuclear peace rests on a scary bargain: you accept a small chance that something extremely bad will happen in exchange for a much bigger chance that something very bad—conventional war—won’t happen. This may well be a rational bet to take, especially if that first risk is very small indeed. But it’s a tough case to make to the public.

Here, Tepperman makes some good points. The real issue is one of risk. Unfortunately, for the reasons cited above, I rather suspect he is seriously underestimating it. Be that as it may, assuming one can really get a good handle on the actual risk, what he says makes sense.

Given this reality, Washington would be wiser to focus on making the world we actually live in—the nuclear world—safer. This involves several steps, few of which the Obama administration has mentioned but which it should emphasize in its Nuclear Posture Review due at the end of the year. To start, the logic of deterrence works only if everybody knows who has a nuclear arsenal and thus can’t be attacked—as Peter Sellers puts it in Stanley Kubrick’s Dr. Strangelove, “The whole point of a Doomsday Machine is lost if you keep it a secret!”

Probably true. Unilateral nuclear disarmament would certainly be suicidal. Reducing our arsenal to the point that potential enemies might find the risk of retaliation acceptable is almost equally so.

Chris Bodenner at Sully’s blog thinks a piece by Peter Scoblic at TNR’s website “scalpels” Tepperman’s piece. I think not. It’s more in the pious platitude here, anecdotal evidence there, preaching a foregone conclusion to the choir style that has become the stock in trade at TNR lately. They have seen better days (when Sully was editor, in fact. He has seen better days, too). One hopes the better days will return.

Nuclear Power: Thoughts on Thorium

Rod Adams has an interesting post on thorium power over at Atomic Insights. I tend to think that nuclear power is more environmentally benign than the alternatives, such as paving thousands of square kilometers of our environmentally fragile desert southwest with solar collectors. If we do restart the nuclear industry, it will also make a lot more sense to build breeders of the type mentioned in Rod’s post, which produce more fuel than they consume during operation, than to just burn up all the uranium 235 we can find in natural uranium.

There are two basic breeder reactor fuel cycles. In the first, uranium 238, which makes up 99.3% of natural uranium, is converted to plutonium 239. In the second thorium 232, which is more abundant than natural uranium, is converted to uranium 233. Both are fissile reactor fuels. Both can also be used to make nuclear weapons. If we breed either of these isotopes, it is essential that we be sure of one thing; that they never fall into the wrong hands, either now or in 10,000 years from now. For that reason, it seems to me that thorium breeders are the better of the two options.

As noted above, both types of breeders would produce fissile material that could be used to make a bomb. In both cases, the material could be separated from spent fuel using relatively straightforward chemical methods. However, spent reactor fuel remains highly radioactive for many years after it is removed from a reactor core. It would be lethal to work with without highly specialized equipment unlikely to be available to other than technically advanced states. In the case of thorium breeders, however, the fissile uranium 233 would be contaminated with uranium 232, a short-lived, highly radioactive isotope that could not be separated from the U233, making it even more difficult to work with than plutonium.

In both cases, the levels of radioactivity of the spent fuel would decay exponentially over time, gradually making it easier to handle the material. Eventually, it would become possible for non-state actors to separate the bomb-grade material. It is immaterial whether this happens in a thousand years, or ten thousand years. We cannot simply put such material in a nuclear storage facility and leave it for future generations to deal with. In the case of plutonium, the only way to reliably eliminate it, other than, perhaps, rocketing it into the sun, would be to burn all of it up. However, in the case of U233, it could be “denatured” by mixing it with large amounts of non-fissile U238, rendering it, for all practical purposes, as difficult to convert to a weapon as natural uranium.

Unclench Your Fist or We Will Get Vewy, Vewy Angwy!

Another “progressive” fantasy slams up against the brick wall of reality. Hillary borrows Sarah’s “pit bull with lipstick” schtick.

Update: The mullahs are impressed.