Tag Archives: nuclear

Estimating the strength of an atom bomb

As warfare is a foundation of engineering, I thought I’d use engineering to evaluate the death-dealing power of North Korea’s atomic/hydrogen bomb, tested September 3, 2017. The key data in evaluating a big bomb is its seismic output. They shake the earth like earthquakes do, and we measure the power like earthquakes, using seismometers. I’ve seen two seismographs comparing the recent bomb to the previous. One of these, below, is from CTBTO, the Center for Test Ban Treaty Oversight, via a seismometer in western Kazakhstan (see original data and report).

Seismic output of all North Korean nuclear tests.

Seismic output, to scale, of all declared DPNK nuclear tests as observed from IMS station AS-59 in Western Kazakhstan

North Korea’s previous bomb, exploded 9 September 2016, was reported to be slightly more powerful than the ones we dropped on Hiroshima and Nagasaki, suggesting it was about 20 kilotons. According to CTBTO, it registered 5.3 on the Richter scale. The two tests before that appear somewhat less powerful, perhaps 7-10 kilotons, and the two before that appear as dismal failures — fizzles, in atomic bomb parlance. The MOAB bomb, by comparison, was 9 Tons, or 0.009 kiloTons, a virtual non-entity.

To measure the output of the current bomb, I place a ruler on my screen and measure the maximum distance between the top to bottom wiggles. I find that this bomb’s wiggles measure 5 cm, while the previous measures 5 mm. This bomb’s wiggles are ten times bigger, and from this I determine that this explosion registered 6.3 on the Richter scale, 1.0 more than the previous — the Richter scale is the logarithmic measure of the wiggle amplitude, so ten times the shake magnitude  is an addition of 1.0 on the scale. My calculation of 6.3 exactly matches that of the US geological survey. The ratio of wiggle heights was less on the, NORSAR seismometer, Norway, see suggesting 5.8 to 5.9 on the Richter scale. The European agencies have taken to reporting 6.1, an average value, though they originally reported only the 5.8 from NORSAR, and a bomb power commensurate with that.

We calculate the bomb power from the Richter-scale measure, or the ratio of the wiggles. Bomb power is proportional to wiggle height to the 3/2 power. Using the data above, ten times the wiggle, this bomb appears to be 10^3/2 = 31.6 times as powerful as the last, or 31.6 x 20kTon = 630kTon (630,000 tons of TNT). If we used the European value of 6.1, the calculated power would be about half this, 315 kTons, and if we used the NORSAR’s original value, it would suggest the bomb had less than half this power. Each difference of 0.2 on the Richter scale is a factor of two in power. For no obvious reason we keep reporting 120 to 160 kTons.

NORSAR comparison of North Korean bomb blasts

NORSAR comparison of North Korean blasts — suggests the current bomb is smaller; still looks like hydrogen.

As it happens, death power is proportional to the kiloton power, other things being equal. The bombs we dropped on Hiroshima and Nagasaki were in the 15 to 20 kTon range and killed 90,000 each. Based on my best estimate of the bomb, 315 kTons, I estimate that it would kill 1.6 million people if used on an industrial city, like Seoul, Yokohama, or Los Angeles. In my opinion, this is about as big a bomb as any rational person has reason to make (Stalin made bigger, as did Eisenhower).

We now ask if this is an atom bomb or a hydrogen-fusion bomb. Though I don’t see any war-making difference, if it’s a hydrogen bomb that would make our recent treaty with Iran look bad, as it gave Iran nuclear fusion technology — I opposed the treaty based on that. Sorry to say, from the seismic signature it looks very much like a hydrogen bomb. The only other way to get to this sort of high-power explosion is via a double-acting fission bomb where small atom bomb sets off a second, bigger fission bomb. When looking at movies of Eisenhower-era double-acting explosions, you’ll notice that the second, bigger explosion follows the first by a second or so. I see no evidence of this secondary-delay in the seismic signature of this explosion, suggesting this was a hydrogen bomb, not a double. I expect Iran to follow the same path in 3-4 years.

As a political thought, it seems to me that the obvious way to stop North Korea would be to put pressure on China by making a military pact with Russia. Until that is done, China has little to fear from a North Korean attack to the south. Of course, to do that we’d likely have to cut our support of NATO, something that the Germans fear. This is a balance-of-power solution, the sort that works, short of total annihilation. It was achieved at the congress of Vienna, at the treaty of Ghent, and by Henry Kissinger through détente. It would work again. Without it, I see the Korean conflict turning hot again, soon.

Robert Buxbaum, September 11, 2017.

Why I don’t like the Iran deal

Treaties, I suspect, do not exist to create love between nations, but rather to preserve, in mummified form, the love that once existed between leaders. They are useful for display, and as a guide to the future, their main purpose is to allow a politician to help his friends while casting blame on someone else when problems show up. In the case of the US Iran-deal that seems certain to pass in a day or two with only Democratic-party support, and little popular support, I see no love between the nations. On a depressingly regular basis, Iranian leaders promise Death to America, and Death to America’s sometime-ally Israel. Iran has acted on these statements too, funding Hezbollah missiles and suicide bombers, and hanging its dissidents: practices that lead it to become something of a pariah among its neighbors. They also display the sort of nuclear factories and ICBMs (long-range rockets) that could make them much bigger threats if they choose to become bigger threats. The deal just signed by US Secretary of State and his counterpart in Iran (read in full here) seems to preserve this state. It releases to Iran $100,000,000,000 to $150,000,000,000 that it claims it will use against Israel, and Iran claims to have no interest in developing multi-point compression atom bombs. This is a tiny concession given that our atom bomb at Hiroshima was single-point compression, first generation, and killed 90,000 people.

Iranian intercontinental ballistic missile, several stories high, brought out during negotiations. Should easily deliver nuclear weapons far beyond Israel, and even to the USA.

Iranian intercontinental ballistic missile, new for 2015. Should easily deliver warheads far beyond Israel -even to the US.

The deal itself is about 170 pages long and semi-legalistic, but I found it easy to read. The print is large, Iran has few obligations, and the last 100 pages or so are a list companies that will no longer be sanctioned. The treaty asserts that we will defend Iran against attacks including military and cyber attacks, and sabotage –presumably from Israel, but gives no specifics. Also we are to help them with oil, naval, and fusion technology, while leaving them with 1500 kg of 20% enriched U235. That’s enough for quick conversion to 8 to 10 Hiroshima-size A-bombs (atom bombs) containing 25-30 kg each of 90% U235. The argument in favor of the bill seems to be that, by giving Iran the money and technology, and agreeing with their plans, Iran will come to like us. My sense is that this is wishful-thinking, and unlikely (as Jimmy Carter discovered). The unwritten contract isn’t worth the paper it’s written on.

As currently written, Iran does not recognize Israel’s right to exist. To the contrary, John Kerry has stated that a likely consequence is further attacks on Israel. Given Hezbollah’s current military budget is only about $150,000,000 and Hamas’s only about $15,000,000 (virtually all from Iran), we can expect a very significant increase in attacks once the money is released — unless Iran’s leaders prove to be cheapskates or traitors to their own revolution (unlikely). Given our president’s and Ms Clinton’s comments against Zionist racism, I assume that they hope to cow Israel into being less militant and less racist, i.e. less Jewish. I doubt it, but you never know. I also expect an arms race in the middle east to result. As for Iran’s statements that they seek to kill every Jew and wipe out the great satan, the USA: our leaders may come to regret hat they ignore such statements. I guess they hope that none of their friends or relatives will be among those killed.

Kerry on why we give Iran the ability to self-inspect.

Kerry on why we give Iran the ability to self-inspect.

I’d now like to turn to fusion technology, an area I know better than most. Nowhere does the treaty say what Iran will do with nuclear fusion technology, but it specifies we are to provide it, and there seem to be only two possibilities of what they might do with it: (1) Build a controlled fusion reactor like the TFTR at Princeton — a very complex, expensive option, or (2) develop a hydrogen fusion bomb of the sort that vaporized the island of Bimini: an H-bomb. I suspect Iran means to do the latter, while I imagine that, John Kerry is thinking the former. Controlled fusion is very difficult; uncontrolled fusion is a lot easier. With a little thought, you’ll see how to build a decent H-bomb.

My speculation of why Iran would want to make an H-bomb is this: they may not trust their A-bombs to win a war with Israel. As things stand, their A-bomb scientists are unlikely to coax more than 25 to 100 kilotons of explosive power out of each bomb, perhaps double that of Hiroshima and Nagasaki. But our WWII bombs “only” killed 70,000 to 90,000 people each, even with the radiation deaths. Used against Israel, such bombs could level the core of Jerusalem or Tel Aviv. But most Israelis would survive, and they would strike back, hard.

To beat the Israelis, you’d need a Megaton-size, hydrogen bomb. Just one Megaton bomb would vaporize Jerusalem and it’s suburbs, kill a million inhabitants at a shot, level the hills, vaporize the artifacts in the jewish museum, and destroy anything we now associate with Israel. If Iran did that, while retaining a second bomb for Tel-Aviv, it is quite possible Israel would surrender. As for our aim, perhaps we hope Iran will attack Israel and leave us alone. Very bright people pushed for WWI on hopes like this.

Robert E. Buxbaum. September 9, 2015. Here’s a thought about why peace in the middle east is so hard to achieve,

Nuclear fusion

I got my PhD at Princeton University 33 years ago (1981) working on the engineering of nuclear fusion reactors, and I thought I’d use this blog to rethink through the issues. I find I’m still of the opinion that developing fusion is important as the it seems the best, long-range power option. Civilization will still need significant electric power 300 to 3000 years from now, it seems, when most other fuel sources are gone. Fusion is also one of the few options for long-range space exploration; needed if we ever decide to send colonies to Alpha Centauri or Saturn. I thought fusion would be ready by now, but it is not, and commercial use seems unlikely for the next ten years at least — an indication of the difficulties involved, and a certain lack of urgency.

Oil, gas, and uranium didn’t run out like we’d predicted in the mid 70s. Instead, population growth slowed, new supplies were found, and better methods were developed to recover and use them. Shale oil and fracking unlocked hydrocarbons we thought were unusable, and nuclear fission reactors got better –safer and more efficient. At the same time, the more we studied, the clearer it came that fusion’s technical problems are much harder to tame than uranium fission’s.

Uranium fission was/is frighteningly simple — far simpler than even the most basic fusion reactor. The first nuclear fission reactor (1940) involved nothing more than uranium pellets in a pile of carbon bricks stacked in a converted squash court at the University of Chicago. No outside effort was needed to get the large, unstable uranium atoms split to smaller, more stable ones. Water circulating through the pile removed the heat released, and control was maintained by people lifting and lowering cadmium control rods while standing on the pile.

A fusion reactor requires high temperature or energy to make anything happen. Fusion energy is produced by combining small, unstable heavy hydrogen atoms into helium, a bigger more stable one, see figure. To do this reaction you need to operate at the equivalent of about 500,000,000 degrees C, and containing it requires (typically) a magnetic bottle — something far more complex than a pile of graphic bricks. The reward was smaller too: “only” about 1/13th as much energy per event as fission. We knew the magnetic bottles were going to be tricky, e.g. there was no obvious heat transfer and control method, but fusion seemed important enough, and the problems seemed manageable enough that fusion power seemed worth pursuing — with just enough difficulties to make it a challenge.

Basic fusion reaction: deuterium + tritium react to give helium, a neutron and energy.

Basic fusion reaction: deuterium + tritium react to give helium, a neutron and energy.

The plan at Princeton, and most everywhere, was to use a TOKAMAK, a doughnut-shaped reactor like the one shown below, but roughly twice as big; TOKAMAK was a Russian acronym. The doughnut served as one side of an enormous transformer. Hydrogen fuel was ionized into a plasma (a neutral soup of protons and electrons) and heated to 300,000,000°C by a current in the TOKOMAK generated by varying the current in the other side of the transformer. Plasma containment was provided by enormous magnets on the top and bottom, and by ring-shaped magnets arranged around the torus.

As development went on, we found we kept needing bigger and bigger doughnuts and stronger and stronger magnets in an effort to balance heat loss with fusion heating. The number density of hydrogen atoms per volume, n, is proportional to the magnetic strength. This is important because the fusion heat rate per volume is proportional to n-squared, n2, while heat loss is proportional to n divided by the residence time, something we called tau, τ. The main heat loss was from the hot plasma going to the reactor surface. Because of the above, a heat balance ratio was seen to be important, heat in divided by heat out, and that was seen to be more-or-less proportional to nτ. As the target temperatures increased, we found we needed larger and larger nτ reactors to make a positive heat balance. And this translated to ever larger reactors and ever stronger magnetic fields, but even here there was a limit, 1 billion Kelvin, a thermodynamic temperature where the fusion reaction went backward and no energy was produced. The Princeton design was huge, with super strong, super magnets, and was operated at 300 million°C, near the top of the reaction curve. If the temperature went above or below this temperature, the fire would go out. There was no room for error, but relatively little energy output per volume — compared to fission.

Fusion reaction options and reaction rates.

Fusion reaction options and reaction rates.

The most likely reaction involved deuterium and tritium, referred to as D and T. This was the reaction of the two heavy isotopes of hydrogen shown in the figure above — the same reaction used in hydrogen bombs, a point we rarely made to the public. For each reaction D + T –> He + n, you get 17.6 million electron volts (17.6 MeV). This is 17.6 million times the energy you get for an electron moving over one Volt, but only 1/13 the energy of a fission reaction. By comparison, the energy of water-forming, H2 + 1/2 O2 –> H2O, is the equivalent of two electrons moving over 1.2 Volts, or 2.4 electron volts (eV), some 8 million times less than fusion.

The Princeton design involved reacting 40 gm/hr of heavy hydrogen to produce 8 mol/hr of helium and 4000 MW of heat. The heat was converted to electricity at 38% efficiency using a topping cycle, a modern (relatively untried) design. Of the 1500 MWh/hr of electricity that was supposed to be produced, all but about 400 MW was to be delivered to the power grid — if everything worked right. Sorry to say, the value of the electricity did not rise anywhere as fast as the cost of the reactor and turbines. Another problem: 1100 MW was more than could be easily absorbed by any electrical grid. The output was high and steady, and could not be easily adjusted to match fluctuating customer demand. By contrast a coal plant’s or fuel cell’s output could be easily adjusted (and a nuclear plant with a little more difficulty).

Because of the need for heat balance, it turned out that at least 9% of the hydrogen had to be burnt per pass through the reactor. The heat lost per mol by conduction to the wall was, to good approximation, the heat capacity of each mol of hydrogen ions, 82 J/°C mol, times the temperature of the ions, 300 million °C divided by the containment time, τ. The Princeton design was supposed to have a containment of about 4 seconds. As a result, the heat loss by conduction was 6.2 GW per mol. This must be matched by the molar heat of reaction that stayed in the plasma. This was 17.6 MeV times Faraday’s constant, 96,800 divided by 4 seconds (= 430 GW/mol reacted) divided by 5. Of the 430 GW/mol produced in fusion reactions only 1/5 remains in the plasma (= 86 GW/mol) the other 4/5 of the energy of reaction leaves with the neutron. To get the heat balance right, at least 9% of the hydrogen must react per pass through the reactor; there were also some heat losses from radiation, so the number is higher. Burn more or less percent of the hydrogen and you had problems. The only other solution was to increase τ > 4 seconds, but this meant ever bigger reactors.

There was also a material handling issue: to get enough fuel hydrogen into the center of the reactor, quite a lot of radioactive gas had to be handled — extracted from the plasma chamber. These were to be frozen into tiny spheres of near-solid hydrogen and injected into the reactor at ultra-sonic velocity. Any slower and the spheres would evaporate before reaching the center. As 40 grams per hour was 9% of the feed, it became clear that we had to be ready to produce and inject 1 pound/hour of tiny spheres. These “snowballs-in-hell” had to be small so they didn’t dampen the fire. The vacuum system had to be able to be big enough to handle the lb/hr or so of unburned hydrogen and ash, keeping the pressure near total vacuum. You then had to purify the hydrogen from the ash-helium and remake the little spheres that would be fed back to the reactor. There were no easy engineering problems here, but I found it enjoyable enough. With a colleague, I came up with a cute, efficient high vacuum pump and recycling system, and published it here.

Yet another engineering challenge concerned the difficulty of finding a material for the first-wall — the inner wall of the doughnut facing the plasma. Of the 4000 MW of heat energy produced, all the conduction and radiation heat, about 1000 MW is deposited in the first wall and has to be conducted away. Conducting this heat means that the wall must have an enormous coolant flow and must withstand an enormous amount of thermal stress. One possible approach was to use a liquid wall, but I’ve recently come up with a rather nicer solid wall solution (I think) and have filed a patent; more on that later, perhaps after/if the patent is accepted. Another engineering challenge was making T, tritium, for the D-T reaction. Tritium is not found in nature, but has to be made from the neutron created in the reaction and from lithium in a breeder blanket, Li + n –> He + T. I examined all possible options for extracting this tritium from the lithium at low concentrations as part of my PhD thesis, and eventually found a nice solution. The education I got in the process is used in my, REB Research hydrogen engineering business.

Man inside the fusion reactor doughnut at ITER. He'd better leave before the 8,000,000°C plasma turns on.

Man inside the fusion reactor doughnut at ITER. He’d better leave before the 8,000,000°C plasma turns on.

Because of its complexity, and all these engineering challenges, fusion power never reached the maturity of fission power; and then Three-mile Island happened and ruined the enthusiasm for all things nuclear. There were some claims that fusion would be safer than fission, but because of the complexity and improvements in fission, I am not convinced that fusion would ever be even as safe. And the long-term need keeps moving out: we keep finding more uranium, and we’ve developed breeder reactors and a thorium cycle: technologies that make it very unlikely we will run out of fission material any time soon.

The main, near term advantage I see for fusion over fission is that there are fewer radioactive products, see comparison.  A secondary advantage is neutrons. Fusion reactors make excess neutrons that can be used to make tritium, or other unusual elements. A need for one of these could favor the development of fusion power. And finally, there’s the long-term need: space exploration, or basic power when we run out of coal, uranium, and thorium. Fine advantages but unlikely to be important for a hundred years.

Robert E. Buxbaum, March 1, 2014. Here’s a post on land use, on the aesthetics of engineering design, and on the health risks of nuclear power. The sun’s nuclear fusion reactor is unstable too — one possible source of the chaotic behavior of the climate. Here’s a control joke.

Land use nuclear vs wind and solar

An advantage of nuclear power over solar and wind is that it uses a lot less land, see graphic below. While I am doubtful that industrial gas causes global warming, I am not a fan of pollution, and that’s why I like nuclear power. Nuclear power adds no water or air pollution when it runs right, and removes a lot less land than wind and solar. Consider the newly approved Hinkley Point C (England), see graphic below. The site covers 430 acres, 1.74 km2, and is currently the home of Hinkley Point B, a nuclear plant slated for retirement. When Hinkley Point C is built on the same site, it will add 26 trillion Watt-hr/ year (3200 MW, 93% up time), about 7% of the total UK demand. Yet more power would be provided from these 430 acres if Hinkley B is not shut down.

Nuclear land use vs solar and wind; British Gov't. regarding their latest plant

Nuclear land use vs solar and wind; British Gov’t. regarding their latest plant

A solar farm to produce 26 trillion W-hr/year would require 130,000 acres, 526 km2. This area would suggest they get the equivalent of 1.36 hours per day of full sun on every m2, not unreasonable given the space for roads and energy storage, and how cloudy England is. Solar power requires a lot energy-storage since you only get full power in the daytime, when there are no clouds.

A wind farm requires even more land than solar, 250,000 acres, or somewhat more than 1000 km2. Wind farms require less storage but that the turbines be spaced at a distance. Storage options could include hydrogen, batteries, and pumped hydro.; I make the case that hydrogen is better. While wind-farm space can be dual use — allowing farming for example, 1000 square km, is still a lot of space to carve up with roads and turbines. It’s nearly the size of greater London; the tourist area, London city is only 2.9 km2.

All these power sources produce pollution during construction and decommissioning. But nuclear produces somewhat less as the plants are less massive in total, and work for more years without the need for major rebuilds. Hinkley C will generate about 30,000 kg/year of waste assuming 35 MW-days/kg, but the cost to bury it in salt domes should not be excessive. Salt domes are needed because Hinkley waste will generate 100 kW of after-heat, even 16 years out. Nuclear fusion, when it comes, should produce 1/10,000 as much after-heat, 100W, 1 year out, but fusion isn’t here yet.

There is also the problem of accidents. In the worst nuclear disaster, Chernobyl, only 31 people died as a direct result, and now (strange to say) the people downwind are healthier than the average up wind; it seems that small amounts of radiation may be good for you. By comparison, in Iowa alone there were 317 driving fatalities in 2013. And even wind and solar have accidents, e.g. people falling from wind-turbines.

Robert Buxbaum, January 22, 2014. I’m president of REB Research, a manufacturer of hydrogen generators and purifiers — mostly membrane reactor based. I also do contract research, mostly on hydrogen, and I write this blog. My PhD research was on nuclear fusion power. I’ve also written about conservation, e.g. curtainsinsulation; paint your roof white.

Fractal power laws and radioactive waste decay

Here’s a fairly simple fractal model for nuclear reactor decay heat. It’s based on one I came up with over he past few weeks for dealing with the statistics of crime, fires, etc. — looking at the tail wither Poisson fails. Anyway, I find that the analysis method works pretty well for looking at nuclear power problems and comparing fission vs fusion.

If all nuclear waste had only one isotope and would decay only to non-radioactive products, the decay rate would be exponential. Thus, one could plot the log of the decay heat rate linearly against linear time (a semi-log plot). But nuclear waste generally consists of many radioactive components, and they typically decay into other radioactive isotopes (daughters) that then decay to yet others (grand-daughters?). Because the half-lives can barry by a lot, one would like to shrink the time-axis, e.g. by use of a log-log plot, perhaps including a curve for each isotope, and every decay mode. I find these plots hard to produce, and hard extrapolate. What I’d like to propose instead is a fractal variation of the original semi-log plot: a  plot of the log of the heat rate against a fractal time, time to the 1/4 power in this case. The plot is similar to a fractal decay model that I’d developed for crimes and fires a few weeks ago

A plausible justification for this fractal semi-log plot is to observe that the half-life of daughter isotopes relates to the parent isotopes. I picked  to plot time to the 1/4 power because it seemed to work pretty well for fuel rods (below) especially after 5 years of cool-down. Note that the slope is identical for rods consumed to 20 or 35 MW-days per kg of uranium.

Afterheat of fuel rods used to generate 20 kW/kg U; Top graph 35 MW-days/kg U; bottom graph 20 Mw-day /kg  U. Data from US NRC Regulatory Guide 3.54 - Spent Fuel Heat Generation in an Independent Spent Fuel Storage Installation, rev 1, 1999. http://www.nrc.gov/reading-rm/doc-collections/reg-guides/fuels-materials/rg/03-054/

After-heat of nuclear fuel rods used at 20 kW/kg U; Top graph 35 MW-days/kg U; bottom graph 20 Mw-day /kg U. Data from US NRC Regulatory Guide 3.54. A typical reactor has 200,000 kg of uranium.

This plot also works if there is one type of radio-isotope (tritium say), but in this case the fractal power should be 1. (My guess is that the fractal time dependence for crime is 1/2, though I lack real crime statistics to check it on). Unless I find that someone else has come up with this sort of plot or analysis before, I’ll call it after myself: a Buxbaum Mandelbrot plot –Why not?

Nuclear power is attractive world-wide because it is a lot more energy dense than any normal fuel; at 35 MW-days per kg, 1 kg will power an average US home for 8 years. By comparison, even with fuel cell technology, 1 kg of hydrogen can only power a US home for 6 hours. While hydrogen is clean, it is often made from coal, and (at least in theory*) it should be easier to handle and store 1 kg of spent uranium than to deal with many tons of coal-smoke produced to make 35 MW-days of electricity.

Better than uranium fission is nuclear fusion, in theory*. A fission-based nuclear reactor to power 1/2 of Detroit, would contain some 200,000 kg of uranium, and assuming a 5 year cycle, the after-heat would be about 1000 kW (1 MW) one year after removal.

Afterheat of a 4000 MWth Fusion Reactor, from UMAC III Report. Nb-1%Zr is a fairly common high-temerature engineering material of construction.

After-heat of a 4000 MWth Fusion Reactor built from niobium-1%zirconium; from UWMAC III Report. The after heat is far less than with normal uranium fission.

For comparison, I show a and as another demonstration of the Buxbaum-Mandelbrot plot for after-heat of a similar power fusion reactor. It drops from 1 MW at 3 weeks to only 100 W after 1 year. Nb-1%Zr is a fairly common engineering material used for high temperature applications. Nuclear fusion is still a few years off, so for now fission is the only nuclear option for clean electrical generation.

This plot was really designed to look at the statistics of crime, fires, and the need for servers / checkout people. I’d predicted that a plot of the log of the number of people needed to fight crime, fires, etc., is a straight line against the a fractal power of the number of hours per year that this number of people is needed. At least that was the theory.*

Dr. R.E. Buxbaum, January 2, 2014. *A final, final thought about theory from Yogi Berra: “In theory, it matches reality.”

Hormesis, Sunshine and Radioactivity

It is often the case that something is good for you in small amounts, but bad in large amounts. As expressed by Paracelsus, an early 16th century doctor, “There is no difference between a poison and a cure: everything depends on dose.”

Aereolis Bombastus von Hoenheim (Paracelcus)

Phillipus Aureolus Theophrastus Bombastus von Hoenheim (Dr. Paracelsus).

Some obvious examples involve foods: an apple a day may keep the doctor away. Fifteen will cause deep physical problems. Alcohol, something bad in high doses, and once banned in the US, tends to promote longevity and health when consumed in moderation, 1/2-2 glasses per day. This is called “hormesis”, where the dose vs benefit curve looks like an upside down U. While it may not apply to all foods, poisons, and insults, a view called “mitridatism,” it has been shown to apply to exercise, chocolate, coffee and (most recently) sunlight.

Up until recently, the advice was to avoid direct sun because of the risk of cancer. More recent studies show that the benefits of small amounts of sunlight outweigh the risks. Health is improved by lowering blood pressure and exciting the immune system, perhaps through release of nitric oxide. At low doses, these benefits far outweigh the small chance of skin cancer. Here’s a New York Times article reviewing the health benefits of 2-6 cups of coffee per day.

A hotly debated issue is whether radiation too has a hormetic dose range. In a previous post, I noted that thyroid cancer rates down-wind of the Chernobyl disaster are lower than in the US as a whole. I thought this was a curious statistical fluke, but apparently it is not. According to a review by The Harvard Medical School, apparent health improvements have been seen among the cleanup workers at Chernobyl, and among those exposed to low levels of radiation from the atomic bombs dropped on Hiroshima and Nagasaki. The health   improvements relative to the general population could be a fluke, but after a while several flukes become a pattern.

Among the comments on my post, came this link to this scholarly summary article of several studies showing that long-term exposure to nuclear radiation below 1 Sv appears to be beneficial. One study involved an incident where a highly radioactive, Co-60 source was accidentally melted into a batch of steel that was subsequently used in the construction of apartments in Taiwan. The mistake was not discovered for over a decade, and by then the tenants had received between 0.4 and 6 Sv (far more than US law would allow). On average, they were healthier than the norm and had significantly lower cancer death rates. Supporting this is the finding, in the US, that lung cancer death rates are 35% lower in the states with the highest average radon radiation levels (Colorado, North Dakota, and Iowa) than in those with the lowest levels (Delaware, Louisiana, and California). Note: SHORT-TERM exposure to 1 Sv is NOT good for you; it will give radiation sickness, and short-term exposure to 4.5 Sv is the 50% death level

Most people in the irradiated Taiwan apartments got .2 Sv/year or less, but the same health benefit has also been shown for people living on radioactive sites in China and India where the levels were as high as .6 Sv/year (normal US background radiation is .0024 Sv/year). Similarly, virtually all animal and plant studies show that radiation appears to improve life expectancy and fecundity (fruit production, number of offspring) at dose rates as high as 1 Sv/month.

I’m not recommending 1 Sv/month for healthy people, it’s a cancer treatment dose, and will make healthy people feel sick. A possible reason it works for plants and some animals is that the radiation may kill proto- cancer, harmful bacteria, and viruses — organisms that lack the repair mechanisms of larger, more sophisticated organisms. Alternately, it could kill non-productive, benign growths allowing the more-healthy growths to do their thing. This explanation is similar to that for the benefits farmers produce by pinching off unwanted leaves and pruning unwanted branches.

It is not conclusive radiation improved human health in any of these studies. It is possible that exposed people happened to choose healthier life-styles than non-exposed people, choosing to smoke less, do more exercise, or eat fewer cheeseburgers (that, more-or-less, was my original explanation). Or it may be purely psychological: people who think they have only a few years to live, live healthier. Then again, it’s possible that radiation is healthy in small doses and maybe cheeseburgers and cigarettes are too?! Here’s a scene from “Sleeper” a 1973, science fiction, comedy movie where Woody Allan, asleep for 200 years, finds that deep fat, chocolate, and cigarettes are the best things for your health. You may not want a cigarette or a radium necklace quite yet, but based on these studies, I’m inclined to reconsider the risk/ benefit balance in favor of nuclear power.

Note: my company, REB Research makes (among other things), hydrogen getters (used to reduce the risks of radioactive waste transportation) and hydrogen separation filters (useful for cleanup of tritium from radioactive water, for fusion reactors, and to reduce the likelihood of explosions in nuclear facilities.

by Dr. Robert E. Buxbaum June 9, 2013

Chernobyl radiation appears to cure cancer

In a recent post about nuclear power, I mentioned that the health risks of nuclear power are low compared to the main alternatives: coal and natural gas. Even with scrubbing, the fumes from coal burning power plants are deadly once the cumulative effect on health over 1000 square miles is considered. And natural gas plants and pipes have fairly common explosions.

With this post I’d like to discuss a statistical fluke (or observation), that even with the worst type of nuclear accident, the broad area increased cancer incidence is generally too small to measure. The worst nuclear disaster we are ever likely to encounter was the explosion at Chernobyl. It occurred 27 years ago during a test of the safety shutdown system and sent a massive plume of radioactive core into the atmosphere. If any accident should increase the cancer rate of those around it, this should. Still, by fluke or not, the rate of thyroid cancer is higher in the US than in Belarus, close to the Chernobyl plant in the prime path of the wind. Thyroid cancer is likely the most excited cancer, enhanced by radio-iodine, and Chernobyl had the largest radio-iodine release to date. Thus, it’s easy to wonder why the rates of Thyroid cancer seem to suggest that the radiation cures cancer rather than causes it.

Thyroid Cancer Rates for Belarus and US; the effect of Chernobyl is less-than clear.

Thyroid Cancer Rates for Belarus and US; the effect of Chernobyl is less-than clear.

The chart above raises more questions than it answers. Note that the rate of thyroid cancer has doubled over the past few years, both in the US and in Belarus. Also note that the rate of cancer is 2 1/2 times as high in Pennsylvania as in Arkansas. One thought is test bias: perhaps we are  better at spotting cancer in the US than in Belarus, and perhaps better at spotting it in Pennsylvania than elsewhere. Perhaps. Another thought is coal. Areas that use a lot of coal tend to become sicker; Europe keeps getting sicker from its non-nuclear energy sources, Perhaps Pennsylvania (a coal state) uses more coal that Belarus (maybe).

Fukushima was a much less damaging accident, and much more recent. So far there has been no observed difference in cancer rate. As the reference below says: “there is no statistical evidence of a difference in thyroid cancer caused by the disaster.” This is not to say that explosions are OK. My company, REB Research, makes are high pressure, low temperature hydrogen-extracting membranes used to reduce the likelihood of hydrogen explosions in nuclear reactors; so far all the explosions have been hydrogen explosions.

Sources: for Belarus: Cancer consequences of the Chernobyl accident: 20 years on. For the US: GEOGRAPHIC VARIATION IN U.S. THYROID CANCER INCIDENCE, AND A CLUSTER NEAR NUCLEAR REACTORS IN NEW JERSEY, NEW YORK, AND PENNSYLVANIA.

R. E. Buxbaum, April 19, 2013; Here are some further, updated thoughts: radiation hormesis (and other hormesis)

Nuclear Power: the elephant of clean energy

As someone who heads a hydrogen energy company, REB Research, I regularly have to tip toe about nuclear power, a rather large elephant among the clean energy options. While hydrogen energy looks better than battery energy in terms of cost and energy density, neither are really energy sources; they are ways to transport energy or store it. Among non-fossil sources (sources where you don’t pollute the air massively) there is solar and wind: basically non-reliable, low density, high cost and quite polluting when you include the damage done making the devices.

Compared to these, I’m happy to report that the methanol used to make hydrogen in our membrane reactors can come from trees (anti-polluting), even tree farming isn’t all that energy dense. And then there’s uranium: plentiful, cheap and incredibly energy dense. I try to ignore how energy dense uranium is, but the cartoon below shows how hard that is to do sometimes. Nuclear power is reliable too, and energy dense; a small plant will produce between 500 and 1000 MW of power; your home uses perhaps 2 kW. You need logarithmic graph paper just to compare nuclear power to most anything else (including hydrogen):

log_scale

A tiny amount of uranium-oxide, the size of a pencil will provide as much power as hundreds of train cars full of coal. After transportation, the coal sells for about $80/ton; the sells for about $25/lb: far cheaper than the train loads of coal (there are 100-110 tons of coal to a train-car load). What’s more, while essentially all of the coal in a train car ends up in the air after it’s burnt, the waste uranium generally does not go into the air we breathe. The coal fumes are toxic, containing carcinogens, carbon monoxide, mercury, vanadium and arsenic; they are often radioactive too. All this is avoided with nuclear power unless there is a bad accident, and bad accidents are far rarer with nuclear power than, for example, with natural gas. Since Germany started shutting nuclear plants and replacing them with coal, it appears they are making all of Europe sicker).

It is true that the cost to build a nuclear plant is higher than to build a coal or gas plant, but it does not have to be: it wasn’t that way in the early days of nuclear power, nor is this true of military reactors that power our (USA) submarines and major warships. Commercial nuclear reactors cost a lot largely because of the time-cost for neighborhood approval (and they don’t always get approval). Batteries used for battery power get no safety review generally though there were two battery explosions on the Dreamliner alone, and natural gas has been known to level towns. Nuclear reactors can blow up too, as Chernobyl showed (and to a lesser extent Fukushima), but almost any design is better than Chernobyl.

The biggest worry people have with nuclear, and the biggest objection it seems to me, is escaped radiation. In a future post, I plan to go into the reality of the risk in more detail, but the worry is far worse than the reality, or far worse than the reality of other dangers (we all die of something eventually). The predicted death rate from the three-mile island accident is basically nil; Fukushima has provided little health damage (not that it’s a big comfort). Further, bizarre as this seems the thyroid cancer rate in Belarus in the wind-path of the Chernobyl plant is actually slightly lower than in the US (7 per 100,000 in Belarus compared to over 9 per 100,000 in the USA). This is clearly a statistical fluke; it’s caused, I believe, by the tendency for Russians to die of other things before they can get thyroid cancer, but it suggests that the health risks of even the worst nuclear accidents are not as bad as you might think. (BTW, Our company makes hydrogen extractors that make accidents less likely)

The biggest real radiation worry (in my opinion) is where to put the waste. Ever since President Carter closed off the option of reprocessing used fuel for re-use there has been no way to permanently get rid of waste. Further, ever since President Obama closed the Yucca Mountain burial repository there have been no satisfactory place to put the radioactive waste. Having waste sitting around above ground all over the US is a really bad option because the stuff is quite toxic. Just as the energy content of nuclear fuel is higher than most fuels, the energy content of the waste is higher. Burying it deep below a mountain in an area were no-one is likely to live seems like a good solution: sort of like putting the uranium back where it came from. And reprocessing for re-use seems like an even better solution since this gets rid of the waste permanently.

I should mention that nuclear power-derived electricity is a wonderful way to generate electricity or hydrogen for clean transportation. Further, the heat of hot springs comes from nuclear power. The healing waters that people flock to for their health is laced with isotopes (and it’s still healthy). For now, though I’ll stay in the hydrogen generator business and will ignore the clean elephant in the room. Fortunately there’s hardly any elephant poop, only lots and lots of coal and solar poop.