Wednesday, June 22, 2011

More Radiation Stuff - Hot Particles

I touched on hot particles previously. They are still somewhat in the news with the west coast of the US testing for up to 5 hot particles per day estimated per person.

A hot particle is a microscopic bit of a radioactive substance. The size of the particle can range from a few nanometers (a billionth of a meter) to a few micrometers (millionths of a meter). An atom of Cesium-137 has a diameter of about 0.4 nanometers. So a molecule of Cesium-137 oxide or whatever it happens to react with would be a little larger. For the sake of simplicity, let's say 1 nanometer since the particle may contain a little of something else.

Then a hot particle of Cesium-137 will contain anywhere from a few hundred Cesium-137 atoms to a few hundred thousand. For simplicity, let's say 100,000.

With a half life of 30 years, there would be 50,000 decays in 30 years, around 1700 decays per year, about 5 decays per day, per hot particle. With the bad luck of inhaling all 5 hot particles per day, that would be about 1 decay per hour. So if your bad luck continues, in sixty days you would add 60 decays per hour or 1/60 Becquerel to your radiation exposure. Becquerel is defined as decays per second.

Cesium-137 is convenient since it makes up the bulk of the radiation fallout. If the Hot Particle was Plutonium-239 with a half life of 24000 years, the decays would be 30/24,000 times 1 Becquerel. Roughly of course, since the diameters are a little different, but not much.

Based on food radiation limits, about 500 Becquerel per kilogram is safe, so to add the health impact of supposedly safe food day of meals, every sixty days you add one Becquerel so in 82 years you have accumulated 500 Becquerels of radiation from hot particles if you are unlucky enough to inhale all five hot particles per day of a Cesium-137 compound for 82 years.

Update: I used CPM instead of CPS, but you should still get the idea.

Wow! That sounds pretty dangerous to me! So if you plan on living to be 240, I would be scared shitless.

During the atmospheric nuclear testing age, there were a lot of hot particles. Chernobyl produced lots of hot particles. How much health impact have those hot particles had on cancer rates? Not a whole hellava lot since most folks don't live past 80 years. Do you think maybe that the hot particle press releases might be a little sensationalized?

Tuesday, June 21, 2011

Political Climate Change

Allegations of corruption are again making news in the Climate Change debate. A press release for a not yet published report made a claim that 80% of global energy could come from sustainable energy sources IF political will focused on that goal.

Whoop d friggin' do!

The lead author of the now published report is a bigwig with Greenpeace and the report list a variety of scenarios, one of with is a maximum possible sustainable energy percentage by 2050. So does this indicate a conflict of interest?

Of course, but what should you expect? Like it or not, the real world of politics is not all warm and fuzzy idealism. The social mores of the undeveloped nations is not the same as the developed nations which is not the same for all the developed nations. That is the way it is, has been and will continue to be. Working within the system with its imperfections is a political exercise. Science, well, would best be apolitical. It is not though. Scientists carry social baggage just like the rest of us. Intellectuals have much more baggage because their idealized views of a perfect world are unattainable because man is imperfect. There is a great deal of frustration for all to share.

Perfectionists are constantly disappointed while pessimists are often pleasantly surprised. A realist is a pessimist with hope. When it comes to policy, realists should be in charge.

The realist recognizes that good enough for now, not perfect solutions, are always required in an imperfect world. My focus in this blog changes with the general political opinions which drive transitions to hydrogen technologies. Hydrogen is not perfect, it has several issues that are challenging, but not insurmountable. I am a fan of hydrogen because it has awesome potential for not only national energy independence, but personal energy independence. That, the potential for personal energy independence, is one of hydrogen's largest obstacles. The ability to make your own fuel from less than perfect energy sources can create serious political problems for those wishing to financially control the masses.

That may sound like a paranoid conspiracy mentality, but there is plenty of basic truth in its foundation. Without sustainable profit for governments and industry, there is no political motivation for home brewed anything. For that reason, the components scaled for home production of hydrogen have taken a turn to industrial scale components. Hydrogen made from reformed natural gas is taxable because natural gas production and distribution is controllable. The US Department of Transportation research into hydrogen is focused on larger scale, taxable plant sizes. That is the way of the world.

Once you allow for the independence afforded by home brewed hydrogen from water, the cost and efficiency factors become more flexible. Fifty percent overall efficiency is more than acceptable for home brewer desiring a self directed lifestyle. For the Government, 50% is unacceptable, even though 33 percent has been more than acceptable for other energy sources in the past. This is a humorous conundrum.

Wednesday, June 15, 2011

More Biological Decay Chain

Besides the name sucking, the Radon Biological Decay Chain (RBDC), see I changed the name from Biological Half Life because that is confusing, has potential. The comparison of decay energy probability of known Radon, which we can't avoid, to other ionizing radioisotopes should be pretty easy to understand. Converting that to counts per minute is a little tricky.

Since we are comparing energy released over time for an isotope, a Radon atom will have one or two measurable counts in the decay chain, but the future counts have to be considered for biological impact. While Radon-222 has a lag of 22.3 years in the last half of the decay chain, the Pb-210 tends to stay in the body, so there is a high likelihood that the final energy in the decay chain will have a biological impact.

Since we are comparing decay energy, we compare to the probable decay energy of the other isotope, Uranium, Cesium, whatever, and few have the total biological decay chain of Radon. Radon has four alpha decays and five beta decays while most other isotopes will have one possibly two during a human life span. The RBDC ratio considers the decay energy, but the counts should be considered since that is the most common way of determining exposure. In the previous post I use the multiplier five. With one or two Radon counts out of nine probable being countable, 4.5 would be the worst case (9/2) with 9 being the best (9/1)case. Rounding to 5 should be reasonably conservative. The two multiplier just allows for normal biological tolerance and background fluctuations.

The 2 multiplier for comparing counts is most likely to be challenged. I include it because it allows for a multitude of uncertainty without pressing reasonable probability limits. One is the biological half life of the isotope. Another the the likelihood of absorption. To make the comparison more accurate, each could be considered resulting in a more complicated evaluation. The idea of the Radon Biological Decay Chain comparison is to simplify things. For the common isotopes that are likely to be fallout from a nuclear incident, it does the job.

Since Radon is naturally occurring and the leading cause of lung cancer in non-smokers, the RBDC ratio may not be all that comforting. The reality though is that life has risks and it is the magnitude of avoidable risk that is in question. Ten times the tested Radon count for most isotopes possibly causes the same risk of natural Radon exposure, remember, this is conservative. At this level other life choices cause more risk, over eating, alcohol, driving, sex you name it, all have equal or greater risk of shortening your life.

I will continue digging, but everything I have seen so far indicates that radiation risk is overly emphasized. Next I may tackle the risks in other forms of energy.

Tuesday, June 14, 2011

Biological Decay Chain - Understanding Ionizing Radiation

The Biological Decay Chain may be my own personal concept, but I doubt that. The biological damage caused by ionizing radiation should be proportional to the energy released by decay in the body. Isotopes that are likely to be active in an average lifetime less cancer growth time, about five years, have a ionizing biological impact. The isotopes may also have poisonous chemical impact, like heavy metal poisoning, but damage due to decay energy when isotopes give of alpha, beta or gamma radiation, (there are other forms, but let's stick to the basics), cause the most negative health impact.

In the photo from Wikipedia above, you can see that a lot of stuff happens after Thorium-232 decays to radium-228. In this chain, once Thorium-232 decays, the entire resulting decay process takes less than eight years to complete, resulting in stable lead-208. To simplify the biological impact, assume that each alpha decay is five and each beta decay is one. This chain has a BHL of 32 or approximately 32,000 KeV. You will notice that there is a branch near the end of the chain. There is a little difference in energy depending on the path, but not much if you consider the whole chain.

I have written about Radon-222 before and its impact. Behind smoking, Radon is the main cause of lung cancer. It is naturally occurring and it is the greatest ionizing radiation risk. Radon-224 is more harmful because the time to stable lead is much shorter.

This is the Uranium-238/Radium-226 decay chain commonly called the Radium Chain. Things really start happening at Radium which is probably the reason. Starting at Radium, this chain has a BHL of 30 with alternate paths, it can increase to 32, though the time to stable is about four times longer, 22.5 years with a less likely start at Radium.

These are the two main decay chains since the Neptunium chain is considered extinct and the Uranium-235 chain start with a rare isotope. For the U-235 chain, the Radium 225 to stable lead is very close to the other more common chains.

Since Radon gas is more commonly inhaled, we can reduce the BHL radium energy by one alpha decay to give us a basic Radon BHL unit of 25 to compare to other isotopes. So the danger is greater if another isotope released more energy in a life time of say 70 years.

There is one thing that complicates things a little, Spontaneous Fission. Isotopes with an atomic weight of 230 and over have the possibility of under going fission which releases much more energy. Plutonium-240 is likely to under go fission outside of a reactor, but luckily Pu-240 is rare outside of a reactor.

Plutonium-240 is formed when Pu-239 absorbs a neutron. That is extremely improbable outside of a reactor but not impossible. Pu-239 can also spontaneous fission with little probability. The odds are pretty remote, but a spontaneous fission cannot be ruled out. Pu-240 has a half life of 6569 years and the probability of fission during a decay is 5 time 10^-8 or 1/500000000, that is a low probability which I consider negligible.

Note: For the nuclear purists, spontaneous fission is negligible as a biological factor. If you are trying to build a bomb, don't neglect it or your bomb will fizzle like North Korea's. Weapons grade Plutonium has less than 7% Pu-240 and the complex geometry of Plutonium based bombs is due to billions of Pu-240 atoms that are to expensive to remove. I may have to do a post on commercial nuclear waste and how it doesn't make good bombs.

To compare the relative dangers you have to consider two things, the energy and the probability that the energy will be released inside of the body in a normal human lifetime. The main consideration is the half life and quantity, to determine the probability of decay energy.

Plutonium-239 has a half life of about 24,000 years with one alpha decay of any significant probability since it decays to Uranium-235 with a half life of 700 million years. Since Radon WILL decay to stable in a human lifetime if ingested early in life and Pu-239 has a probability of 0.3 percent of decaying in a human lifetime (70/24,000) with 1/5 the energy (5 versus 25), Pu-239 is 0.06 percent as likely to cause biological damage as Radon.

For Strontium-90 with a half life of 29 years and two beta decays to stable Zirconium-90, compared to radon it is 2/25 or 8 percent as likely to cause biological damage.

Iodine-131 with a half life of 8 days and one beta decay to stable Xenon-131, it is also 8 percent as likely to cause biological damage as radon.

Note that in the comparisons, if the half life of the isotope is less than 70 years, average human life time, the ratio of the energy determines the comparable risk.

Just to round things off assume the comparison is ten percent instead of eight percent, then ten times more of Strontium-90 or Iodine-131 ingested than normal Radon ingested from background would give you the same cancer risk. The types of cancer would be different, Strontium-90 is likely to cause bone cancer or leukemia, Iodine-131 thyroid cancer and Radon lung cancer, but the chance of cancer would be close using the Radon BHL.

Note: Just to make this perfectly clear, ten times is on an atom to atom basis, counts is a different issue.

Plutonium-239 at 0.06 percent as likely as radon to cause harm, is barely statistically significant on an atom to atom basis. Radionuclides with half lives greater than 24,000 years would produce insignificant risk in small quantities compared to radon.

The amount of these longer lived radionuclides is then the issue. This is where the dose meters come in with a little qualification. Dose meters record what your body is exposed to not what is ingested. For this purpose ingestion would be by consumption, inhalation or direct absorption into the blood stream. Inhalation and direct absorption more directly compare. With consumption, only a percentage consumed makes it into the blood stream. Food limits then have a built in safety factor since they do not consider the percentage absorbed. Strontium-90 when consumed in food is 20 percent absorbed, Plutonium between 1 and 5 percent absorbed. Inhalation is the greatest likely danger and most directly comparable to Radon which is primarily inhaled.

Cesium-137 is a common fallout isotope with a half life of 30 years and a beta decay to stable Barium-137. There are a couple routes to stable Barium with a comparison energy of about 1.25. 1.25/25 equals 5 percent as likely as Radon at the same quantity. Cesium is more likely absorbed into the blood stream through consumption, so there is not extra safety factor.

So how well does this radon biological half life factor work? If you consider Strontium and Iodine, ten times the quantity produces equal risk, so ten times normal Radon is the cancer threshold where you would be equally likely to develop cancer. Ten times background is the prudent limit for normal safety. At this ten times limit the counts per minute or second would be roughly equal to background, so twice background would be the possible statistically significant threshold if measuring absorbed radiation.

Measuring absorbed radiation is complicated. Only some of the Radon would be measured, about a fifth because of the delay in the chain, so exposed radiation, the real counts that can be measured, would result in five times two or ten times normal background in counts to meet the threshold.

If measuring food, the normal background is approximately 100 Becquerel per kilogram. Ten times normal is 1000Bq/kg would be the implied limit by the radon BHL, which compares will with most national standards which are less than or equal to 1000 Bq/kg. For exposure limits, ten times background would be 1 Microsievert per hour in Japan or about 9 milliSieverts per year.

So the Radon biological half life standard does not change any limits, it only offers a better indication on the amounts of different radionuclides based on half life and energy required to add significant risk.

I need to double check my math, but this may give a better perspective of radiation risk than the banana dose.

For a double check, the radon decay energy to stable lead is close enough. While Radon-222 takes over 22 years to decay, the 25 is reasonable as a basic reference. To compare with another radionuclide, determine the probable decays in 70 years, that does not have to be exact. Then divide that energy (as an integer)by 25 to get a raw percentage. If the half life of the radionuclide is much greater than 70 years, divide 70 by the half life and multiply that by the probable energy in integer form divided by 25. That gives a fair conservative estimate of the relative harm of that radionuclide compared to common radon.

This may seem incorrect because of the horror stories. For example Uranium miners may have a higher cancer risk, but that is more likely due to the variety of radionuclides in the ore or pitch blend, which includes a good deal of radium. Radium alpha decays to radon so a comparison to Radium-226 with a half life of 1600 years would be (70/1600)times (30/25) yields 0.043 times 1.2 equals 0.0525 or 5.25 percent. With Radium-223, which has a very short half life, that comparison would be 30/25 or 20 percent greater chance than radon. Radium-224 would also be 20 percent greater as an estimate. Radium-228 would be 35/25 or 140 or 40 percent greater risk. Brazil nuts contain Radium-226 and are not considered a cancer risk in reasonable quantities. If they contained significant amounts of Radium-228,-224 or -223, they would be.

The decay chains with half life and energy are available online in several places. For this post I used Wikipedia Decay Chain.

As far as the ten time natural background for Cesium, Strontium and Iodine radionuclides, the ingested should be reasonably conservative. The external exposure relationship may be debatable, but should be conservative because those radionuclides are beta emitters.

Another thing that makes the Radon Biological half life comparison conservative it that Cesium-137 for example has an actual biological half life of under 120 days.

I may try and make a comparison chart, but the isotopes covered should give you an idea of how to make your own rough estimate of risk.

Monday, June 13, 2011

Name That Decay Chain!

There are a lot of studies comparing different energy sources and risk. A lot of the risk is more political than real. Popular opinion means a lot to politicians. Actual risk seems to get lost in the politics.

One comment I saw today was based on a coal versus nuclear study. A large part of the study was a pole of people living near nuclear or coal power plants. That is a big part of the decision of course, what will people vote for, but education of the real risks involve is not as big a deal as I think it should be.

A coal power plant emits a lot of stuff if not scrubbed and filtered. Then if it is scrubbed and filtered, the ash and particulates contain stuff that can be nasty. Heavy metals are a big concern, with radiation a little bit of a concern that looks to be over emphasized.

Coal contains traces of Uranium and Thorium, plus other natural radioactive isotopes. Natural isotopes are generally very long lived, but a there are a few short lived isotopes in the natural decay chains.

For some odd reason, long lived isotopes have a bad reputation. Statistically, it is the short lived ones that are nasty. The short lived are more likely to decay releasing ionizing energy. Uranium-238 has a half life of 4.5 billion years. So a few atoms of Uranium-238 are essentially stable in a biological environment. You would have to ingest a fairly large amount of Uranium-238 to have any radiation harm. It would likely be more harmful as a poisonous heavy metal than a radiation hazard. Think about it. It takes 4.5 billion years for half of the ingested amount to decay. If you ingested 4.5 billion atoms of U-238, 2.25 billion would decay in 4.5 billion years, so only 2.25 would decay per year in your body. Compare 2.25 per year to 4400 per second beta decays normal for a 160 pound (about 75 kilo)person, and that ain't a lot, even if U-238 is 60 times more harmful than K-40. Plutonium-239 is only supposed to be 100 times more harmful than potassium 40, so that makes sense.

I need to build a biological decay table to make it easier for people to compare radiation risk by isotope. Then maybe people can start focusing more on the real risks. A biological decay table would b e the probability of harmful decay energy per microgram of isotope. Then everyone could compare fallout danger to the banana dose or Brazil nut dose.

Sanity in Energy Choices - Has the Time Come?

With the prospect of radical Green Energy only changing, it may be that rational decisions may finally be made. It's the economy, stupid has finally sunk in.

There are plenty of paths on the energy road to take. Affordable is the biggest road block. Natural gas while far from perfect, is affordable and offers plenty of options.

Electrical generation has gotten most of the attention. Coal fire power plants do produce a lot of pollution if not fitted with state of the art scrubbers and filters. Even then they produce more CO2 that other fuel choices. Natural gas combined cycle power plants produce much less pollution and up to 70% less CO2 than existing coal fire power plants.

A new MIT study not only promotes the future of natural gas from shale, but also points in the direction of Liquid To Gas (LTG) synthetic fuel production. Compared to Generation IV nuclear and a combination of "sustainable" energy sources, the technology of efficient natural gas and GTL technologies are a piece of cake.

As I have ranted before, Synfuel is has both economic and political advantages. While the cost of synfuels is higher than average oil based products, the swings in oil prices kill economic growth. Synfuel will help stabilize energy prices which is key to planning for the future.

Also as I have mentioned, synfuel offers a variety of green options for those so inclined. Biomass conversion to liquid fuels is limited both by feed stock and product. Synfuel expands both offering needed flexibility. Food to fuel can return to its intended role as a use for surplus or unsalable stocks instead of diverting, or at least appearing to divert, food from the starving masses.

For hydrogen fans, natural gas is both good and bad. Hydrogen from natural gas is the more cost effective method of producing hydrogen. It doesn't have the Green stamp of approval, but it can be the step needed to move into a more hydrogen based economy, buying time for fuel cells and hydrogen storage to make the next move into affordability.

Fuel cells are very close to affordability. Ballard Power and others have products that with increased production are very affordable. The Proton Exchange Membrane (PEM) technology should improve mainly with new versions of the PEM using less expensive catalysts. The basic design of the components other than the membrane may very well not change. With companies focusing on reliable and reasonable cost maintenance of the fuel cells, a fuel cell purchased now may not be obsolete in a few years. That is the big fear when investing in improving technology, the chance of your investment being replaced with something costing a fraction of the cost.

Storage of hydrogen is a bigger question. Metal hydrates offer a lot of potential but are expensive. High pressure storage can be overly expensive if a reasonable useful life cannot be expected from the expensive composite construction storage tanks. Polymer lined metal cylinders are reliable, but the volume is limited due to pressure limits. Then there are other technologies that may rise in the near future. Once storage issues are resolved, direct conversion of electricity to hydrogen will become much more attractive.

All in all, the natural gas step makes a great deal of sense.

Sunday, June 12, 2011

Fukushima Fallout Continues

The world is full of well intentioned people with not grasp of statistical probabilities. The Fukushima radiation fallout will continue because statistically misguided, but well intentioned people seem to have to repeat poorly contemplated probabilities. It is not just radiation, it is every part of our lives that statistics are involved that suffer.

On CCN, a well educated professor spoke on the risk of minute levels of radiation causing health problems. He could not say that there is zero probability of one or two cases in millions that MAY result because of Fukushima fallout, because there is always a CHANCE. How do you quantify the chance for the population to understand?

In the professor's case, Fukushima Iodine 131 fallout in the United States as of the first of April 2011 could cause a person on the west coast to absorb 3 to 5 decays or counts per day. Five counts per day is equivalent to 0.000058 Becquerel or counts per second. Compare that to an average background radiation of 12 counts per minute or 720 counts per second and you have a 0.000% chance of any health impact. What? Not enough decimal places? How about 0.00000806 percent chance of cancer risk over the normal background? If that percent risk frightens you, play the local lottery. Someone has to win right?

Even that estimate, 0.00000806 percent is high. It is only the percent increase in radiation. The radiation threshold is approximately 500 times normal background, with 100 times normal background showing no increase cancer risk. So the risk is verging on astronomically small. There is a chance though.

In Japan, the risks are much higher. Still, the risk is very low if the cause were anything but radiation. The 500 times normal background threshold is a conservative estimate. Studies for individual radioisotopes place limits in the range of 1000 times before there is any statistically significant (i.e. possible) chance of cancer. Those studies generally use linear no threshold (LNT) methods to determine risk. LNT in itself is overly conservative as it does not consider nonlinear factors and can confuse other risks with radiation levels. So the gray area can be 50 times greater. So being 20 pounds over weight has roughly 60 times more risk that having radiation levels 100 times normal and about 20 times the risk of radiation levels of 500 times normal. There is still a risk.

What is acceptable risk? That is the question of the millennium. There will never be zero.

Saturday, June 11, 2011

For the Tokyo Radiation Levels Gang

Citizens testing radiation levels is both good and bad. It is good because more people will become familiar with the normal radiation everyone in the world lives with daily. Bad because some will jump to conclusions that may frighten others.

Setting basic standards for testing will help increase the good and decrease the bad. The various detectors that are purchased by private citizens vary greatly. The main differences between detectors will be the biological impact readings. These are generally given in MicroSieverts or Roetgens Equivalent Man (REM). Biological impact depends on the type of radio isotope, whether its radiation is internal or external, how easily the isotope is inhaled or ingest. For example, Uranium 238 is pretty common, is an alpha particle emitter and is not very harmful unless ingested or inhaled. Alpha particles have high energy, but they can be stopped by a sheet of paper, the human skin, even air restricts the distance it can travel significantly. A dose meter would assign a fairly high microSievert reading to a sample of Uranium, but really it would have virtually no biological impact.

Iodine 131 is a beta/gamma emitter with a short half life that can be very harmful, so a microsievert setting for Uranium would underestimate the biological impact. Since radio Iodine is so harmful, dose meters may be calibrated for that harm, so they would over estimate the harm of uranium. Most dose meters are calibrated for Cesium 137 as a compromise, but may have settings for other isotopes like Iodine 131. Without knowing the calibration and calculations used, the microsievert reading is nearly useless. If calibration and calculation are known, it can be invaluable for determining the potential harm of known isotopes.

For the amateur, The counts per minutes is much more useful. To get the most use, you should have a standard method for testing and recording your data. For instance a common natural radiation in the background is Radon gas. Radon has a half life of four days. It can react in rain to form compounds that are solids, so it can be rinsed out of the air and collect in drainage ditch, culverts, and soil. With a half life of only four days, a Citizen Radiation Patrol (CRP) participant can measure a level after a rain at actually determine if the radiation is due to Radon by measuring the same spot over a number of days the same way. This would be a reasonably scientific method of testing.

To make it better, record the type of meter, background level of the area, time of day, weather conditions and an average of more than one test per day of the site in question. Three five minute tests should be enough to determine a reasonable average in counts per minute or second. Recording the microsievert reading as well could provide more information on how conservative you detector is. It should be conservative, read higher, because it is a safety device. Repeating the tests in the same manner over a number of days may give you an indication of the types of radioisotopes present. Radon222 and Iodine131 should be the easiest to isolate since they have half lives of 4 and 8 days respectively. Other isotopes with longer half lives would require more complex test equipment, but the CRP can gather pretty good information if they use a standardized test method.

Food testing can also be done with reasonable accuracy, provided natural levels in food are considered. I found a couple of good references for natural radiation in foods, but to simplify, 125 Becquerel per kilogram is good average to expect. Since the average radiation detector cannot test the whole one kilogram mass, a small amount, approximate 1 gram can be tested which should produce 125/1000 (0.125)becquerel or counts per second. Since there is normal background radiation in the air, your meter may measure virtually nothing in the food sample. Then again it may show a few counts above background for perfectly normal food. A much higher reading is what to expect if the food is contaminated. Since 10 to 15 counts per minute is a typical background level, food with more than 30 counts per minute (0.5 counts per second)may be suspect, but over 60 counts per minute ( 1 counts per second)would indicate significant contamination. That does not mean the food would exceed safe limits, only that it has more than just natural radiation. It takes a very strict method to produce repeatable results. Considering the numbers and limitations, four times normal background is a good indication of other than natural radiation, anything less is a maybe.

With high quality equipment and proper test procedure, one gram of a food item with the 500 Becquerel per kilogram upper limit would measure 0.5 counts per second or 30 counts per minute. Natural radiation levels would produce about 7.5 counts per minute. With normal background which should be subtracted, 17.5 to 20 counts per minute may be perfectly normal.

With background measurement the same should apply. Twice normal background is not unusual, four time normal background is an indication of significant contamination.

Even with readings that indicate significant contamination, that does not mean unsafe conditions. Japan like most countries has areas with higher natural radiation. There are natural springs high in radiation. So there may be other areas with higher than normal background levels. This leads to a good deal of confusion. Man made radioisotopes are assumed to be more dangerous. Some are and some are not. Radon, which is a decay product of radium is the prime example.

"222Rn belongs to the radium and uranium-238 decay chain, and has a half-life of 3.8235 days. Its four first products (excluding marginal decay schemes) are very short-lived, meaning that the corresponding disintegrations are indicative of the initial radon distribution. Its decay goes through the following sequence:[20]

218Po, 3.10 minutes, alpha decaying to...
214Pb, 26.8 minutes, beta decaying to...
214Bi, 19.9 minutes, beta decaying to...
214Po, 0.1643 ms, alpha decaying to...

At the next step, 214Po decays to 210Pb, which has a much longer half-life of 22.3 years. Its progenies are:

210Bi, 5.013 days, beta decaying to...
210Po, 138.376 days, alpha decaying to...
206Pb, stable."

From Wikipedia, Radon has a 50% chance of decaying to 210Pb (unstable lead) in the sequence above in 4 days. Then alpha decays, where the atomic weight drops by 4, have an average energy of 5,000 KeV (thousand electron Volts) and the beta decays (elemental change with the same weight) release an average energy of roughly 1,000 KeV. So the total energy from 222Radon is about 8,000 KeV. From Radium the total energy would be about 13,000 KeV, (I had a typo in the Plutonium post). With a possibility of another 11,000 KeV to stable 206Pb from 214Pb with a 22.3 year half life.

Plutonium 239 for example, considered the most dangerous man made isotope, has about a 24,000 year have life and alpha decays to Uranium 235 which has a half life of 700 million years. Energy wise, radon 222 is just as harmful if not more so.

Do double check my numbers, but I think you will find radiation deserves respect but not fear. Everything I have read supports the limits imposed by different countries for safety with a few overly conservation limits that could be relaxed.

Friday, June 10, 2011

Japan's Citizen Radiation Patrol - The Geiger Counter Explosion

With all the purchases of Geiger counters and dose meters I wrote a post a while back about testing your food. It is not all that easy to take an off the shelf Geiger counter and accurately test stuff on your own. You can get an initial range or baseline to compare things, but accurate readings that can compare to another reading with another counter is difficult. There can be a wide range of counts per minute or second. The REM or Sievert readings are even more difficult to compare from one unit to another. So I recommended sticking to counts per second which is the same as Becquerels.

There are now radiation clubs posting results online. I found one group on Facebook thanks to Japan Probe. In the video, one Citizen Radiation Patrol member, measures a fairly high Sievert level in a street drain. Street drains should be higher than normal because radiation in the air can be rinsed out by rain and collect in the water run off. Remember that there is often natural Radon 222 that adds to the counts for a few days following rain.

The reading obtain is a little humorous. The little dp802i dosemeter sounds the alarm for high radiation. The Sievert reading hits 5.77 microsieverts per hour compared to the initial background reading of 0.11 Microsieverts per hour. So is this a danger signal that should be heeded?

First, isolated patches of higher levels are not uncommon. A 25% increase following rain is not uncommon, but should drop in four days if the extra radiation is due to Radon 222 washing out of the air. If you plan on living in the drain, that may be a indication that that is not a great idea.

Second, the Sievert readings on most dosemeters are very sensitive. It is after all suppose to warn you of potential danger. The counts per second readings are what the overall dose is based on, or at least that should be the plan.

In the video, the Sievert reading is in the middle of the display in the largest font. Below that is the counts in what appears to be per minute (could be counts per hour, hard to see the decimal placement). The 11.4 Counts per minute is pretty normal as I stated in my previous post.

A second video linked by the Japan Probe post shows a variety of counters or dose meters being compared when using a slightly radioactive lantern mantle or a test sample. One of those happens to be a model dp802i.

The dp802i is on the left.

In the test, you can see the Sievert reading fluctuate wildly and the counts gradually change up dating every 15 seconds or so.

The Japan Probe poster believes that the dp80i is either wildly inaccurate or requires a longer time to obtain a reliable reading. He(she) is right that it does take a longer time. As far as accuracy, the dp801i appears to be pretty good, it is just the sievert readings sensitivity is very sensitive. This is not a sign of inaccuracy, more of a safety feature. It warns of a increase, but it takes time to determine the energy which is needed to determine the actual potential harm. So I would say that the dp802i is not a bad dose meter, just that it is not the final word on radiation evaluation, which it is not designed to be.

The Tokyo Radiation Levels Facebook page is dedicated to locals learning about radiation detection. If you are interested, you can follow their efforts a learn along with them. There are and will be plenty of high sievert readings that seem scary, but once you learn that Sieverts are very inaccurate until properly calculated, you will be amused. Dose meters should read well on the high side for safety. Then the high quality equipment can be brought in to provide the needed accuracy. It is not a conspiracy, just the nature of the beast. The dp802I is on the overly sensitive side, but if you consider the counts, not too bad of an inexpensive dose meter.

Tuesday, June 7, 2011

Radiation: So Many Experts - So Much Controversy

I spend much more time than I should trying to understand why there is so much disagreement among experts over the subject of radiation. We are bathed in radiation every day of our lives. Some is harmful, some beneficial and some we cannot agree upon. The Three Mile Island incident started my first inquiries into ionizing radiation. The sudden interest in Radon gas prompted another inquiry. Chernobyl brought it to mind again. Now Fukushima has piqued my interest again.

Before Fukushima I just assumed that Plutonium was extremely dangerous. It was the terrorist dream material. It was used to make the big bombs. It was supposed to be the most poisonous of the radioactive elements made by man.

Trying to sort out which experts to believe, I have spent more time studying Plutonium and Radium this time around. It is hard to find an expert opinion that makes sense.

Radium 226 is the most stable of the radium isotopes and is naturally occurring. It is a decay product of Uranium 238, the most common form of Uranium. Radium 226 has a fairly short half life at 1601 years. It decays by releasing an alpha particle into Radon 222 giving off 4871 KeV of energy. Radon 222 has a half life of only 3.8 day and decays by releasing an alpha particle into Polonium 218 with a half life of 3.1 minutes, giving off approximately 5500 KeV of energy, which decays to Lead 214 with a half life of 3.1 minutes giving off an energy of approximately 5000 KeV, which decays by Beta emission to Bismuth 214 which beta decays with a half life of 27 minutes to Polonium 214 with a half life of 20 minutes to Lead 210 with a half life of 160 milliseconds. I'll stop there since Lead 210 has a half life of a full 22 years.

Plutonium 239 decays has a half life of about 24,000 years which decays to Uranium 235 releasing 5245 KeV. Uranium 235 has a half life of 700 million years.

Energy wise, if you consume Radium 226, there is a lot of radiation released within a day or so on the order of 23,000 KeV, after one Radium 226 atom pops. Radium has a pretty significant decay chain with a large biological impact. Still, since it is common in Brazil nuts, it does not seem to be that harmful with tests indicating it is safe in levels up to 1000 times normal background.

Plutonium 239 with about of the quarter of the energy and 15 times less likely to pop than Radium 226 is considered 100 times more dangerous. That does not make sense.

In a reactor, Plutonium 239 produces 207,100 KeV during fission. There should not be a great likelihood of fission in the body, but perhaps this is where the 100 times more dangerous comes from, an unlikely situation. During fallout following a nuclear incident, it is pretty unlikely that large concentrations of Plutonium 239 would end up in an area far from the power plant. That is the case at Fukushima, a few traces were found and only one appears to be confirmed from power plant. The rest appear to be due to atmospheric testing in the fifties and sixties.

The danger from ionizing radiation is the decay frequency and energy per decay. There is some danger from the chemical properties of the heavy metals, but that is unlikely to be the case in food contamination. So Radium 226 should be 4 times more dangerous than Plutonium 239 if ingested.

So this has me really suspicious of some of the anti-nuke experts warning of the dangers of fallout from Fukushima in the US and Canada. That fallout may possibly increase radiation levels by 5 pops per day versus about 25 pops per second from a good thick steak or 15 pops per second from a tofu burger. The source of the ionizing radiation may be different, but it is the energy that counts.

Sunday, June 5, 2011

Natural Radiation in Foods: Where is all the Information?

It would seem with all the health conscious organic food affectionados, there would be more information on foods high in natural ionizing radiation. Really, the organic food guys are trying to avoid part per billions of pesticides, hormones and inorganic fertilizer elements. It would seem that they would have stepped up to the plate to warn the world of all the radiation in certain foods. The best list I have found so far is at this site at Idaho State University.

This list is pretty basic as far as individual foods. With the exception of Brazil Nuts, the list may be useful for types of food stuffs. At least it gives a little bit of insight.

The propagation part of plants seem to be highest in radiation, so the root vegetables and seed portions should be the highest source of radiation in the plant. That is not a definite, but it makes some sense. Leafy vegetables should have radiation levels proportional to their potassium content. Since cesium 137 is chemically similar to potassium, it is likely that vegetables high in potassium would also tend to be higher in cesium if grown in an area with radiation fallout. Since the first atomic bomb tests, wine has traces of cesium 137, which seems to support that thought.

It would seem reasonable that farmers and gardeners that want to reduce the Cesium uptake of their crops would increase the potassium in their soils. The plants would fill their potassium needs more easily with the abundant potassium instead of scrounging around for traces of Cesium. Since the potassium content of the vegetables is lower in Becquerel/kilogram than the limits set by governments, it is unlikely that plants would shift gears to absorb more Cesium than potassium. To me that would indicate that most of the excess radiation contained in food stuffs would be external to the plants. Rinsing vegetables well before serving should then significantly reduce the exposure to radiation fallout.

Meats are a little different. Pork and sheep that are mainly feed in pastures would tend to absorb more fallout. Pork especially since they are rooting feeders. They would ingest more soil with the fallout. Sheep feed close to the ground so they also would tend to be higher as well as free range poultry. So to reduce the amount of radiation farm animals absorb, their feed should be limited to the least amount of radiation possible. Milk producing cattle are pasture feed primarily. Milk is susceptible to higher radioactive iodine levels early in a nuclear event which reduces quickly with the decay of the iodine 131 and rain rinsing the radiation off the grass leaves into the soil. Cattle generally consume less soil when grazing.

Radioactive cesium is the primary isotope of concern after the first month of an incident. With its half life of 30 years versus many millions of years for potassium 40, it only takes a small percentage of cesium replacing potassium to make a large increase in radiation activity. Cesium and potassium have similar biological half lives of 70 to 100 days, so it is quite possible that animals fed high potassium feeds would reduce Cesium levels in the meat and other products.

How effective is blocking with potassium? That is kind of hard to say. The Becquerel reading is decays per second or pops per second. It takes a tiny fraction of Cesium to produce the equivalent counts per second of the huge amount of potassium. A single Cesium 137 atom is about a billion times more likely to pop in its biological half than a potassium atom. On the other hand, only a very small amount of Cesium would need to be replaced to prevent a lot of pops. So reducing the likelihood of absorbing Cesium is much better than trying to get rid of it.

The banana dose, while not perfect, does give a pretty good indication of risk. White potatoes have a natural Becquerel reading of 126 per kilogram. That is close to the 130 Bq/kilogram for bananas, 126 for carrots, 111 for red meat, and 172 for raw lima beans. Brazil Nuts which seem to not be harmful, have an average around 350 Bq/kg with a high of about 465 Bq/kg. Most of the Brazil nut radiation is from Radium 226 which has a half life of 1600 years. Radium 226 is an alpha particle emitter with energy of about 5000 KeV per decay. While alpha particles travel less than Beta particles or gamma rays, the energy is significant. Brazil nuts by the way have radium levels nearly 1000 times higher than most foods. That just gives you an indication of how flexible the radiation level can be in the body without significant damage. So the 500 Bq/kg limit in Japan is quite safe as are the 600 Bq/kg in the EU and the 1000 Bq/kg in the UK for sheep meat, unless the body absorbs more than a normal percentage of the more active isotopes.

The main concern should be good nutrition and healthy lifestyle. Good nutrition with normal electrolyte levels and regularity, helps the body prevent absorption of excess amount of the stronger radiation. Normal body weight would also reduce absorbed radiation. Active lifestyles burn more calories which would reduce the biological half life of radiation in the body. Home remedies and special diets may be of some help, but good health is the best defense.

While I was researching to provide a more comprehensive list a natural radiation levels in foods, I could not help but notice the similarity of radium 226 decay energy and plutonium 239 decay energy. Pu239 is also an alpha particle emitter with just a little higher energy than radium 226. A very small amount of Pu239 was released at Fukushima. Since Ra226 has a half life of 1600 years and Pu239 a half life of 24,000 years, milligram per milligram, naturally occurring radium is more dangerous than plutonium. While both are dangerous, it seems that plutonium fears may be a bit overstated. The Radium Girls were workers employed to paint watch dials with radium for glow in the dark operation. The workers ingested radium from licking their paint brushes to smooth the tips. Research on the dial painters determined a threshold of 0.1 microcurries (3700 Becquerel) of radium which was established as the tolerance level for radium. The Argonne National Laboratory performed further research finding that 1000 times normal radium 226 levels is a suggested threshold for radium induced malignancies. Interesting that threshold is verified by Brazil nuts.

Inhalation of radium or plutonium is much more hazardous than ingestion. Approximately 20% of the radium and one percent of the plutonium ingested with be absorbed in the blood stream. Once in the bloodstream, both radium and plutonium are likely to treated as calcium in the body. This is not to say we should add plutonium to our diets, just that naturally occurring isotopes are so similar to the nasty man made ones, that natural dietary radioisotopes give a better clue of what to expect.

There is no way anything I write will calm many fears, but if some of the health food guru's look at the facts, they may be able to have more influence. Everything I have read so far indicates there is no governmental or nuclear industry conspiracy to force us to accept dangers. If the health food gurus devoted a little more time to natural radioactivity and how it compares to the unnatural radioactivity things would be more understandable for the general public. One thing they should more greatly research is natural iodine in various foods such as sea foods and kelps. Natural iodine does help block radioactive iodine, but daily doses need to be on the order of 120 milligrams to make a difference early in an event. Most that I have seen do responsibly recommend stable iodine tables, but a few are misleading. Another thing they may wish to research is the odd radiation paradox. Relatively low levels of radiation in addition to normal background seem to have produce a vaccine effect helping to reduce cancer risk.

Added resources: This is a pretty in depth study that generally confirms the other one.

I found another US study that generally confirms the 1000 Bq/kg limit for most accidental release isotopes except Plutionium 239
. That study lists that Pu239 is 100 times more dangerous, but did not include Radium 226. It did list the biological impact of Pu239 at 1.7 e-5 Sv/Bq. Since only an extremely small amount of plutonium has been released and radium 226 is much more abundant, it would be interesting to see a more direct comparison.

Friday, June 3, 2011

Natural Cures for Radiation?

Whenever there is a nuclear, biological or chemical (NBC) scare people break out the natural or holistic treatments to protect themselves and loved ones. Some of the natural treatments have some scientific basis which may produce statistically significant results, most don't. From a total lay point of view, I want to look at the logic.

With Fukushima, I have only really looked at the most common radioactive isotopes in the fallout. Since I am not there, I look at things rather coldly. I am more concerned with the increased real risk and economic damage. Nuclear energy so far have proven to be pretty safe, but situations like Fukushima have a low probability of happening and the degree of damage has various level of probabilities. Following Fukushima, there have been plenty of inaccurate reports, most appear to be due to poor translations and inaccurate conversion of the confusing units of radiation levels. One was a report that spinach in one area of Japan tested over the limit of 2000 Becquerel per kilogram. The actual limit on foods like spinach is 500 becquerel per kilogram. That sounded odd, so I did some checking and 2000 Bq/kg is not really that far fetched compared to the UK limit of 1000 Bq/kg for meat.

When food contamination or fallout exposure is at or below the limits set by a government they should be safe, i.e. no probable statistically significant health risk. 2000 Bq/kg meets that assumption depending on manner or methods used. It is getting pretty close to the gray area when competing methods begin to diverge.

Statistically significant isn't all that well understood by the public. Any risk from accidental radiation fallout is significant in their opinion despite the fact that being 10% over weight has a greater probability of harm than 2000 Bq/kg of radiation in your hamburger may have.

Combating Radiation Poisoning is one of many websites that have tips to reduce your radiation damage with natural means. Some of the treatments produce desired results, but do they by combating radiation or reducing other risk factors?

The Macrobiotic diet is a big one. The story behind this one starts with a doctor at a hospital one mile away from ground zero of the WWII Nagasaki blast saving all his patients from radiation poisoning. One mile is very close to the blast. But the terrain of Nagasaki protected some areas from the initial blast, so that part is believable. The items in the diet are very unique to the Western world, but probably not all that unusual for the area. The combination of items in the diet are given credit for the survival of the patients. One of the interesting foods was Hokkaido pumpkin, which is a winter squash as best as I can determine.

Winter squashes are good, nutritional foods. They are high in vitamin C and potassium as well as other stuff good for you. Potassium should be a very good nutrient to reduce absorption by the body of various radioactive "salts". Most of the more dangerous radioactive isotopes react with moisture to produce salts which the body thinks are normal salts that it incorporates to maintain electrolyte levels. Cesium 137 forms an ion similar to potassium for example. If your body has a normal potassium level or more that it needs, it is less likely that it will use the Cesium. Another dietary item is sea salt. Sea salt would balance the body's need for sodium as an electrolyte, doing the same thing. So far so good.

Sea salt contains traces of iodine. Stable iodine is used to prevent the absorption of radioactive iodine in the thyroid, so it has to help right? Not so much. Stable iodine is given in very high dosages to protect the thyroid. There is just not enough iodine in sea salt or iodized salt to have much impact.

Without going into all the other food items, the overall diet is healthy but not high enough in calories to promote obesity. Sugar was not a part of the diet which would be normal for a restricted war time diet. The lack of refined sugar and rather high in fiber diet would promote regularity which would help reduce the time radioactive isotopes spent in the body before flushing. That is basically reducing the metabolic half life of the isotopes in the body. So overall the diet is a good preventative method to reduce risk of radiation harm to the body. It is not the particular dietary items, but the diet in general. So a healthy diet with plenty of electrolytes, vitamins, fiber and fluids is a good thing.

Baking soda and sea salt baths are also touted as being good for releasing radioactive energy from the body. I am not particularly a fan of the logic behind this idea. It does have benefits that are real. Cleanliness is next to Godliness is a clique for a reason. It has health benefits, especially when radiation is involved. Cleating, detoxifying or neutralizing the radioactive isotopes may have a minor impact on the radiation, but cleaning is the most important part. About equally important is the relaxation that you could get from a twenty minute bath and laying naked in the sun afterwards. The naked in the sun afterward may be inconvenient and potentially harmful if you are not a normal naked in the sun layer. If you are on a good healthy diet and in good physical shape, the laying naked in the sun may benefit others, always something to consider.

Baking soda gargling with or without exotic salts is excellent within reason. Too much of anything is bad and too much baking soda can cause gastrointestinal issues. Gargling though is cleaning so it has a benefit depending on how dirty your mouth and throat are.

Clays and rare earths are highly touted by some "experts". Radioactive isotopes often form ions because they react in moisture to become salts. Ions easily react to form other compounds some of which are more stable that others. This is the cleating angle assumed to detoxify, but some of the compounds formed may be toxic negating the "detoxifying". Clays and/or rare earths may form less toxic compounds when they react with radioactive ions or they may not. Outside of the body, you can control the reaction to decontaminate different isotopes. Inside the body it is a little more of a crap shoot. All things in moderation, but as with stable iodine, it normally takes much higher quantities to be therapeutic which pushes other health concerns.

Teas and beverages are good because they promote flushing, can improve electrolyte levels and provide vitamins, minerals and simple sugars. I would be skeptical of detoxifying beverages, but anti-oxidants are beneficial. There are various food items high in anti-oxidants, chocolate is one of my favorites, red wines, dark beers, darker beans, about anything with darker natural color has decent anti-oxidant properties. While some elaborate teas may be more beneficial a dark beer with some potassium chloride salt to kill the head is similar. Teas and beverages are going to be beneficial as long as they don't overly act as a diuretic. Maintaining proper hydration and electrolyte levels is more important.

One of the biggest things to remember are the other risk factors. Twenty times normal background radiation may increase cancer risk by a fraction of a percent. 100 times normal background may increase risk between 1 and 5 percent. Being 20 pounds over weight increases your other risks by about 15 percent. Smoking increases your risk about 50 percent. Improper hydration increases your risk proportionally to how dehydrated you are. Being overly stressed increases risk. It is normally better to relax and weigh your options. Have a beer, wine or some tea and think over the situation.

Thursday, June 2, 2011

Radiation and Health - The Gray Areas

Linear no threshold modeling is a commonly used and commonly criticized method for determining the effect of something on something else. Radiation's impact on health is commonly calculated by the linear no threshold method. There is nothing particularly wrong with using this method as a part of an analysis. It provides a reasonable upper bound for the relationship of radiation to health.

With radiation, the main concern is long term cancer risk. Does exposure to x amount of radiation at y age produce z more cancers. There are more interesting parts of the puzzle.

Medicine has made a lot of advances in the past couple of hundred years. The average life expectancy at birth has increased from say 40 years to nearly 80 years since the late 1800's. Small pox, polio, measles, influenza, malaria and many other maladies have been eliminated or more easily controlled in most regions. In comparison only a few other new maladies have been cropped up but some older maladies have increased.

Cancer was virtually unknown in the 1800's. Between all the other causes of death, cancer took too long to become apparent and medical science was not up to speed in determining the exact cause of death. Autopsies were pretty uncommon due to religious belief and limits on preserving the dead long enough to do autopsies.

I know this is pretty macabre, but people only live so long. Average life expectancy doubled, but a constant doubling is unlikely. 120 years appears to be about the maximum life expectancy. Getting the average to approach the maximum is going to be harder and harder as science advances.

Since 1950, the average live expectancy has increased greatly and the percentage of death due to cancer has as well. Some of the cancer increase is due to man made radiation but realistically, the majority of the cancer increases is due to medical advances decreasing deaths by other causes.

How the other causes of cancer rate increase is dealt with greatly impacts the results of linear no threshold modeling. To be honest, it is only in the past 20 years or so that we have developed the tools to even begin to determine the different causes with human genome mapping (DNA testing).

Recent studies have found that cellular telephone use may possibly be linked to brain cancer. The media picked up part of the studies that indicate people that have used cell phones for 10 years or more have twice the occurrence of a pre-cancerous brain condition. Twice what and when will it be cancer? Dunno. Will technology increase the risk of other types of cancer and diseases? Of course. But if we eliminate the technologies that lead to the increased risk we increase the risk of something else. For example, without cellular phones, the risks due to inadequate warning of sever weather, fire and a variety of other things could more than offset the health gains of not having cell phones that may possibly cause brain cancer. There is no need to eliminate cell phones, just be aware of the possibilities and adjust your use responsibly. Manufacturers will probably add a little extra radiation barrier between the microwave source and the speaker or more people will get ear pieces which have a different potential health impact. It is a learning curve thing.

Too much sun leads to skin cancers which can evolve into other cancers. Stay out of the sun or use more sunscreen. But a certain amount of sun is good for other health reasons and gradual increases in sun exposure seems to reduce the potential of skin cancer, the radiation paradox.

Some where there is an optimum balance that increases life expectancy. I am a proponent of nuclear energy because there is an optimum balance were some increase in risk of radiation hazard offsets other risks. Life is full of trade offs.

This brings me back to linear no threshold modeling. While it is a valid statistical method, it tends to over emphasize the risks of one aspect while not illustrating the big picture. Studies by Green Peace and other non-governmental agencies tend to overly emphasize their cause, muddying the overall picture. Not that there is no validity to their work, just that their lack of objectivity biases their results.

It is frustratingly similar in climate science. Man does appear to have an impact on climate. That impact is due to a variety of activities, some of which are more easily modified and others that require a shift of risk factors. Increasing nuclear energy use has its risks, changing economic conditions has risks and changing political power structure has risks.

The change in climate may improve overall conditions. We are adapted to current conditions, so we accept current risks. A changed climate may include rewards, but also may include new risks. To determine a best plan of action or inaction, we need to better understand the possibilities and basically chose the preferred type of life and death for us and future generations. Scary thought.

Some groups are confident that their plan for the future will produce the near optimum future world. Personally, I am not arrogant enough to believe my vision is better. I am fairly confident that actions that blend risks wisely are a good way to hedge against stupidity. So when I look at future energy options, I lean toward what I envision are responsible compromises.

Nuclear energy is a large part of my vision. Smaller, more widely dispersed nuclear power plants tend to reduce risk and increase availability and increase shared risk. Alternate energies like wind, wave and solar also are best dispersed to allow for shared risk.

Yes, even "clean" energies have risks. After manufacture, solar photovoltaic panels are pretty low risk, but the chemicals used in their manufacture are not without risk. Wind power is clean, but you have the risk involved with the chemicals and pollutants during manufacture, some environmental risks where the wind turbines are installed and the risk of no power at critical times.

The no power at critical times is a risk I believe is under emphasized. Over reliance on any one form of energy increases that risk. Huge mega power plants increase risks not only locally, like Fukushima, but nation wide. Distribution infrastructure is overly taxed when a large power plant goes off line increasing the risk of black outs or brown outs which are risks because our societies are dependent on the near uninterpretable sources of energy. A relatively short blackout of a few days in a large metropolitan areas causes deaths.

Over reliance on petroleum products also is a great risk as many societies depend on that source of easily available energy. Societies that have less dependence on fossil fuels also have shorter average life spans.

Secure energy and energy security sound the same but are different. Energy security reduces risks by reducing dependence on other societies which may have different visions. Secure energy reduces self inflicted risks. So instead of thinking about your favorite energy options as being sustainable, cheap or profitable you should add secure. That would make you more inclined to accept a mix of options instead of arrogantly assuming your vision is perfect. While there may be a perfect energy source, it is pretty unlikely. If you feel that all energy is evil, maybe you should try to realize that is also pretty unlikely.

If you can objectively look at energy sources, you may find that linear no threshold evaluation of nuclear energy is properly criticized because it discounts the overall benefits for the sake of minimal increased risk.

Wednesday, June 1, 2011

More Radiation Stuff - Playing with Lightning

I have been looking for neat things online by people using various radiation detectors for all the new radiation detector owners. This link to Whats Hot and Whats Not is a great source for guys getting freaked out with the readings they find on their new radiation detectors.

The first video you can see the sparks cause by alpha particles. One of the sources used is a smoke detector ionizer.

This video is a pretty neat demonstration of x-rays. While they are created differently, x-rays are produced by free electrons like the beta particles and similar to gamma rays.

Geiger counters are designed to test for alpha particles and gamma rays. So if you are looking for Cesium 137 or iodine 131, the Geiger counter will pick up the gamma part of the decay. Strontium 90 though has very high beta radiation and very small gamma radiation. When I posted More on Radiation - When to be Worried I gave some numbers that many may think are way too high. They really are not, but radiation testing requires a lot of practice and formulas to get solid results. The natural radiation in your body from Potassium 40 will produce the 60 counts per kilogram per second if you can properly test and calculate. Beta particles don't travel very far and most detectors you are liable to purchase will be the Geiger counters. So you will only be testing a fairly small amount of gamma radiation that can travel to the detector and be measured. So instead of 60 cps you may only register 10 to 20 counts per minute.

I was very specific about sticking to counts or pops and not the energy, Sieverts, because that is pretty tricky to measure accurately. You can establish a baseline which can be of some use, but other than some counts versus a bunch more counts, not a lot without specialized equipment. If you are into testing your food for safety, it is pretty easy to compare something you know is safe against something suspect. But you are looking for something often with the wrong glasses.

Iodine 131 and Cesium 137 should be pretty easy with any counter. Both have enough average gamma energy to be detectable, but it is the difference that gives you the clue.

The limit per kilogram in food for Japan is 500 cps or Becquerel. If you are measuring meat, which is pretty dense, you would have a higher reading than measure say dried tea which is very light in comparison. That is when measuring gamma radiation which can travel through the denser meat. If you have a beta detector, like in the second video, you are more likely to measure more radiation in the tea than the meat because the tea is more likely to block less beta particles. So it will be pretty easy to think something good or bad and be totally wrong.

That is why I wrote the last post and this post, to get you to think. While I have been looking for good links from people that know what they are doing, I have been finding several by people that are getting pretty lost. One was by a pretty smart guy that noticed that when it rained his radiation readings went up. That can happen for several reasons that have nothing to do with Fukushima fallout.

First, there are many areas where the main source of background radiation is radon gas. In the rain the radon get a little more concentrated. The difference is tiny though. It may be 15 counts per minute before the rain and 17 while it is raining. That is perfectly normal

Second, if it was dry and dusty before the rain, it is likely that the dust will increase the readings a little as the rain washes it out of the air. Unless you see a pretty big jump in the count, three or more times higher, there is no big deal. Particulates like smoke or smog can increase the readings as well.

After the rain you will probably see a slight decrease in the background radiation. Small changes are perfectly normal. After you get familiar with your counter you will get a better feel for how much is a lot. Even then you are limited to counts, which could amount to very little harm and not energy which is what you want.

In the first video with the sparks, that was alpha particles. Alpha particle are pretty much harmless unless you eat them. Hardly any of the Fukushima fallout was alpha particle emitters, so your smoke detector is about the best source you can find to testing your counter for alpha particles.

This video is just for fun. Neutrons are around us too in small amounts but not a problem. But this shows in a small way what makes a nuclear power plant work.