Spoiler alert: No! They Aren't!
You've been living in your little town for over a decade, and your favorite part about it is the crystal clean, spring-fed river that runs by just out of town. It's great for fishing, canoeing, swimming, or any combination of the three. You read the local paper one day to find out the clearing a few miles up river has been bought by a power company, and they're going to build a nuclear power plant there. You know enough about the power industry to look forward to your power bill going down, but the next time you talk to your neighbor he mentions he's worried, because the power plant plans to use the river for its runoff! Is your clean river in danger of being polluted by nuclear waste?
It really isn't. Unlike farms, chemical processing plants, metal foundries, and other man-made things that pollute local surface and groundwater [1], a nuclear power plant puts nothing back into its water source other than regular, clean water--albeit a little bit warmer.
Yes, a nuclear power plant uses water as its primary coolant, and that water is exposed to and activated by the radiation in the nuclear core. But even in a boiling water reactor (BWR) where the water across the core is turned directly into steam for turning the turbines, that water is not put into the environment. It's cooled off, chemically treated, and placed back into the core. The "cooled-off" part is accomplished through a closed secondary cycle, where "closed" means that the two never come into direct contact with each other; the water on the cold side is never exposed to the radiation from the core or held within the primary water coolant. [2] It's this secondary-cycle water that is drawn from and returned to the local river, lake, ground reservoir, or other source of water in order to maintain the temperatures of the reactor. As mentioned, due to the basic principles of thermodynamics this water is returned to its source a little warmer than it was found, but new reactors always have extensive environmental studies performed to ensure that the net temperature change in the water source will have negligible effects on the surrounding ecosystem.
If the reactor is a pressurized water reactor (PWR), the concern is even less. The primary-cycle water is never brought to a boil, the closed secondary-cycle performing steam generation and running turbines. This puts the cold cycle in a tertiary position, even more removed from the radiation of the core. Your hypothetical self can rest easy knowing that the plant will cause no effect to the river.
[1]http://floridaswater.com/waterbodies/pollutionsources.html
[2]http://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors.aspx
Feb 24, 2016
Feb 22, 2016
Man-Made Radiation in the Air: Emergency Reactor Venting
I'm pleased, because I finally get to stop talking about nuclear-related points or events that are an issue and people may or may not know that they are, to a subject that many people think is an issue but most assuredly isn't.
There have been three nuclear power accidents major enough that the average person on the street might be able to name them: most recently is Fukushima, and turning back time a little farther gets you to Chernobyl and Three Mile Island (TMI). All three accidents were the result of failures in safety systems previously thought impossible, compounded by some pretty major human error. Two of them, Fukushima and Chernobyl, deserve the titles of major accidents and both vie for a top position in "world's most expensive accidents". Chernobyl left a fifth of a country irradiated to an largely uninhabitable degree, and the full effects of Fukushima have yet to be determined, even years later.
I will likely go into detail on at least one of these in a later post, but for today we're talking about TMI.
The Accident
I'll keep this brief, as accident analysis isn't the point of the post. In 1979 A stuck valve in the non-nuclear secondary system (the part that actually makes steam and turn turbines) lead to the inability to remove heat from the reactor, even after a full shutdown via SCRAM. Secondary pumps were unable to be started due to human operator confusion over valve status and improper maintenance performed the night before. Eventually heat built up enough to cause a partial core meltdown. In order to prevent further issues the operators were forced to vent nuclear products into the air, exposing the public living near the reactor to the material.
The Aftermath
A voluntary evacuation was suggested to pregnant women in the area. Within hours of the accident, several organizations, ranging from the EPA, the national lab, college research groups, and privately funded research, began a series of extensive tests to determine the full effects of the radioactive release.
Now, if you ask your parents, or maybe your grandparents, you might here some ridiculous stories about babies with multiple extra limbs, or fish in the local river with three eyes, or the more believable anecdote of increased miscarriage or other pre-natal issues in the area. However, the honest truth is that there was no determinable effect. Based on soil and air samples it is estimated that the two million people living in the vicinity of the plant received an average dose above background of 1.4 millirem. By comparison, a chest x-ray is 3.2 millirem, and people receive those all the time without issue. Now, there is a big difference between the voluntary 3.2 mrem from the x-ray, and the involuntary exposure to the 1.4 mrem from the power plant. But after long, extensive study by the EPA and the other groups, it was determined that not even one additional cancer death occurred as a result of the venting at TMI. [1]
What's more, we learned a lot of important lessons from TMI. Lessons in redundancy, and how to further remove the potential for human error in an accident scenario. Thanks to those lessons, America has never had another significant reactor event, and certainly no major exposure to the public. Unfortunately, we determined all of this far too late to prevent a panic in the public and in the government, which led to a moratorium on new reactors in America that lasted until just a couple years ago. It, along with Chernobyl, instilled a fear of nuclear in the general public that had just started to die off when Fukushima occurred.
The final takeaway is this: with only a handful of exceptions, the nuclear power plant down the road from you, or in the next town over, or wherever, is not exposing you to atmospheric radiation. Even in America's most significant reactor accident, no adverse health affects occurred.
[1] http://aje.oxfordjournals.org/content/132/3/397.full.pdf+html
There have been three nuclear power accidents major enough that the average person on the street might be able to name them: most recently is Fukushima, and turning back time a little farther gets you to Chernobyl and Three Mile Island (TMI). All three accidents were the result of failures in safety systems previously thought impossible, compounded by some pretty major human error. Two of them, Fukushima and Chernobyl, deserve the titles of major accidents and both vie for a top position in "world's most expensive accidents". Chernobyl left a fifth of a country irradiated to an largely uninhabitable degree, and the full effects of Fukushima have yet to be determined, even years later.
I will likely go into detail on at least one of these in a later post, but for today we're talking about TMI.
The Accident
I'll keep this brief, as accident analysis isn't the point of the post. In 1979 A stuck valve in the non-nuclear secondary system (the part that actually makes steam and turn turbines) lead to the inability to remove heat from the reactor, even after a full shutdown via SCRAM. Secondary pumps were unable to be started due to human operator confusion over valve status and improper maintenance performed the night before. Eventually heat built up enough to cause a partial core meltdown. In order to prevent further issues the operators were forced to vent nuclear products into the air, exposing the public living near the reactor to the material.
The Aftermath
A voluntary evacuation was suggested to pregnant women in the area. Within hours of the accident, several organizations, ranging from the EPA, the national lab, college research groups, and privately funded research, began a series of extensive tests to determine the full effects of the radioactive release.
Now, if you ask your parents, or maybe your grandparents, you might here some ridiculous stories about babies with multiple extra limbs, or fish in the local river with three eyes, or the more believable anecdote of increased miscarriage or other pre-natal issues in the area. However, the honest truth is that there was no determinable effect. Based on soil and air samples it is estimated that the two million people living in the vicinity of the plant received an average dose above background of 1.4 millirem. By comparison, a chest x-ray is 3.2 millirem, and people receive those all the time without issue. Now, there is a big difference between the voluntary 3.2 mrem from the x-ray, and the involuntary exposure to the 1.4 mrem from the power plant. But after long, extensive study by the EPA and the other groups, it was determined that not even one additional cancer death occurred as a result of the venting at TMI. [1]
What's more, we learned a lot of important lessons from TMI. Lessons in redundancy, and how to further remove the potential for human error in an accident scenario. Thanks to those lessons, America has never had another significant reactor event, and certainly no major exposure to the public. Unfortunately, we determined all of this far too late to prevent a panic in the public and in the government, which led to a moratorium on new reactors in America that lasted until just a couple years ago. It, along with Chernobyl, instilled a fear of nuclear in the general public that had just started to die off when Fukushima occurred.
The final takeaway is this: with only a handful of exceptions, the nuclear power plant down the road from you, or in the next town over, or wherever, is not exposing you to atmospheric radiation. Even in America's most significant reactor accident, no adverse health affects occurred.
[1] http://aje.oxfordjournals.org/content/132/3/397.full.pdf+html
Man-Made Radiation in the Air: Weapon Fallout
As a soon-to-be nuclear engineer, I feel the need to defend my field as much as possible from undue criticism about the danger of nuclear power and the aspects surrounding it. I feel like a broken record stating that this defense is the original idea of this blog, but I have to seeing how the last couple posts have been about legitimate nuclear dangers, and this post is no different. Today we're talking about nuclear weapons.
Now, I'm not an idiot, and I don't assume anyone reading this blog is an idiot. Obviously, nuclear weapons are bad. I'm not going to even attempt to defend their existence (outside of their creation leading to the first development of nuclear power). I also don't think I need to explain how dangerous to human life they are; I feel that most people have at least some idea of their local destructive power as well as their lasting radiation. Most importantly, this series of posts is supposed to be on atmospheric dispersion of radionuclides in the air, and so that's what we'll discuss: the morbidly fascinating reach of a nuclear weapon.
Basics of Fallout
A nuclear weapon unleashes a large amount of energy when it detonates. This energy vaporizes most things around it, organic or not, within instants of the detonation. A large amount of this energy also throws nuclear material far and wide, whether it's produced directly by the fission reaction in the bomb, or indirectly by making the dirt and ash thrown into the air radioactive or at least ionized by the energy and radioactive processes of the detonation. This dirt and ash are pushed and pulled by the charged air currents, resulting in the iconic "mushroom cloud" of a nuclear weapon. This cloud of radioactive ash is thrown into the atmosphere where it is free to spread far and wide, and settle wherever the winds and rains take it.
Nuclear Weapons Testing
Fortunately, only two nuclear weapons have ever been used in anger: the bombings of Hiroshima and Nagasaki that ended WWII. Unfortunately, that was followed by the Cold War, and from the period of 1945-1980 at least 500 nuclear weapons tests were performed by various world powers underground, underwater, and--most importantly--in the air. [1]
Any particle in our atmosphere has the ability to travel anywhere in the world. So, given enough sources, the nuclear material from a nuclear weapon can appear anywhere. If you analyzed a cup of soil anywhere in the world, you would almost certainly find cesium-137 in small quantities. But if you somehow had a soil sample preserved from before 1945, you would not find this isotope of cesium in it, as it is a non-naturally occurring isotope; it's created by nuclear processes, either in a reactor or in a bomb.
Now, this isn't always a bad thing. Nuclear materials like cesium are used for some cool applications, like atomic clocks. And cesium has even been used to detect wine fraud [2]. Because if it's in the soil, that means it can make it into our crops, like grapes. But if it's in our crops, that means it's in us! Similar to cesium-137, iodine-131 is a non-natural isotope that exists from the fallout of nuclear weapon tests. The CDC estimates that due to those 500+ tests mentioned earlier, at least 11,000 excess deaths have occurred due to thyroid cancer caused by exposure to ingested iodine-131. [1]
Thankfully, nuclear testing has been banned through the Comprehensive Nuclear-Test-Ban Treaty, which has been signed by all nuclear powers except the craziest (looking at you Pakistan and India) [3]. Still though, the world has been changed, potentially permanently, through exposure to non-natural isotopes caused by nuclear weapons, and spread through natural atmospheric dispersion. Thankfully, the average increase in background exposure is tiny, and 11,000 excess deaths in 35 years is not that bad from a cold, utilitarian standpoint. But the global effect of nuclear weapons and their release of nuclear material to the atmosphere, even when not used in anger, is intimidating. Hopefully, in time, humanity can finally phase them out of existence.
[1]National Research Council. Exposure of the American Population to Radioactive Fallout from Nuclear Weapons Tests: A Review of the CDC-NCI Draft Report on a Feasibility Study of the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations. Washington, DC: The National Academies Press, 2003. doi:10.17226/10621
Available: http://www.nap.edu/catalog/10621/exposure-of-the-american-population-to-radioactive-fallout-from-nuclear-weapons-tests
[2]http://www.npr.org/sections/thesalt/2014/06/03/318241738/how-atomic-particles-became-the-smoking-gun-in-wine-fraud-mystery
[3] https://fas.org/sgp/crs/nuke/RL34394.pdf
Now, I'm not an idiot, and I don't assume anyone reading this blog is an idiot. Obviously, nuclear weapons are bad. I'm not going to even attempt to defend their existence (outside of their creation leading to the first development of nuclear power). I also don't think I need to explain how dangerous to human life they are; I feel that most people have at least some idea of their local destructive power as well as their lasting radiation. Most importantly, this series of posts is supposed to be on atmospheric dispersion of radionuclides in the air, and so that's what we'll discuss: the morbidly fascinating reach of a nuclear weapon.
Basics of Fallout
A nuclear weapon unleashes a large amount of energy when it detonates. This energy vaporizes most things around it, organic or not, within instants of the detonation. A large amount of this energy also throws nuclear material far and wide, whether it's produced directly by the fission reaction in the bomb, or indirectly by making the dirt and ash thrown into the air radioactive or at least ionized by the energy and radioactive processes of the detonation. This dirt and ash are pushed and pulled by the charged air currents, resulting in the iconic "mushroom cloud" of a nuclear weapon. This cloud of radioactive ash is thrown into the atmosphere where it is free to spread far and wide, and settle wherever the winds and rains take it.
Nuclear Weapons Testing
Fortunately, only two nuclear weapons have ever been used in anger: the bombings of Hiroshima and Nagasaki that ended WWII. Unfortunately, that was followed by the Cold War, and from the period of 1945-1980 at least 500 nuclear weapons tests were performed by various world powers underground, underwater, and--most importantly--in the air. [1]
Any particle in our atmosphere has the ability to travel anywhere in the world. So, given enough sources, the nuclear material from a nuclear weapon can appear anywhere. If you analyzed a cup of soil anywhere in the world, you would almost certainly find cesium-137 in small quantities. But if you somehow had a soil sample preserved from before 1945, you would not find this isotope of cesium in it, as it is a non-naturally occurring isotope; it's created by nuclear processes, either in a reactor or in a bomb.
Now, this isn't always a bad thing. Nuclear materials like cesium are used for some cool applications, like atomic clocks. And cesium has even been used to detect wine fraud [2]. Because if it's in the soil, that means it can make it into our crops, like grapes. But if it's in our crops, that means it's in us! Similar to cesium-137, iodine-131 is a non-natural isotope that exists from the fallout of nuclear weapon tests. The CDC estimates that due to those 500+ tests mentioned earlier, at least 11,000 excess deaths have occurred due to thyroid cancer caused by exposure to ingested iodine-131. [1]
Thankfully, nuclear testing has been banned through the Comprehensive Nuclear-Test-Ban Treaty, which has been signed by all nuclear powers except the craziest (looking at you Pakistan and India) [3]. Still though, the world has been changed, potentially permanently, through exposure to non-natural isotopes caused by nuclear weapons, and spread through natural atmospheric dispersion. Thankfully, the average increase in background exposure is tiny, and 11,000 excess deaths in 35 years is not that bad from a cold, utilitarian standpoint. But the global effect of nuclear weapons and their release of nuclear material to the atmosphere, even when not used in anger, is intimidating. Hopefully, in time, humanity can finally phase them out of existence.
[1]National Research Council. Exposure of the American Population to Radioactive Fallout from Nuclear Weapons Tests: A Review of the CDC-NCI Draft Report on a Feasibility Study of the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations. Washington, DC: The National Academies Press, 2003. doi:10.17226/10621
Available: http://www.nap.edu/catalog/10621/exposure-of-the-american-population-to-radioactive-fallout-from-nuclear-weapons-tests
[2]http://www.npr.org/sections/thesalt/2014/06/03/318241738/how-atomic-particles-became-the-smoking-gun-in-wine-fraud-mystery
[3] https://fas.org/sgp/crs/nuke/RL34394.pdf
Feb 19, 2016
Man-Made Radiation in the Air: Primer
This post is going to be the first of a three-part series on "atmospheric dispersion of radionuclides". The intention is to give some basic information on the topic that would otherwise clutter the other two topics, weapon fallout and power plant release.
Why do we care?
Man-made radiation releases to the atmosphere are a top priority for many nuclear regulatory and research organizations around the world. [1] The primary reason being that the air provides both the fastest and widest-reaching medium for radioactive particles and their radiation to spread to and around an area. Though radiation can and will travel through water, soil, and underground, none of it beats the speed or area coverage of radiation in the air. Plus, humans have a tendency to breathe the atmosphere; as we discussed with radon, radioactive material in your lungs is something you should avoid whenever possible.
The ability to avoid it is another reason why it's so important--or more accurately, the lack of an ability to avoid it. Depending on the source event, radiation in the atmosphere can travel very quickly over a very large area. If that area happens to include where you live, unless you evacuated a while ago chances are you're going to be exposed to something.
What's in the air?
That "something" depends on the source event. Many radioactive nuclear byproducts exist naturally in a gaseous state. We've already discussed radon, but alongside it can be krypton, xenon, radioactive isotopes of oxygen or nitrogen, and a few others, none of which are going to be very good for you if you breathe them in. Depending on the energy behind the release (e.g. a bomb versus a reactor venting, which we'll get into in the other parts of this series) there may be heavy elements flying through the atmosphere as well. These elements, which can be decaying with all kinds of nasty radiation from high-energy gammas that can do damage no matter where they hit you, to alpha particles that can really hurt the interior of your lungs when you inhale them. They also tend to be part of long decay chains, which means they and their "daughter" elements can still be highly radioactive even after a large amount of time has passed (we'll discuss this further in the subsequent posts).
To be continued
I know the stated idea of this blog is to try and assuage some fears about nuclear, but it sure sounds like I've done some fear mongering here. I just wanted to build a bit of a teaser for the more in-depth posts to come, on the atmospheric radiation from nuclear weapons and non-weapons. I will say that thankfully, the number of man-made events resulting in the release of radionuclides to the atmosphere are quite few; unfortunately, most of them have been very serious.
Up next will be a discussion of nuclear fallout from weapons, and its lasting effects.
[1] https://rem.jrc.ec.europa.eu/RemWeb/activities/AtmosphericDispersion.aspx
Why do we care?
Man-made radiation releases to the atmosphere are a top priority for many nuclear regulatory and research organizations around the world. [1] The primary reason being that the air provides both the fastest and widest-reaching medium for radioactive particles and their radiation to spread to and around an area. Though radiation can and will travel through water, soil, and underground, none of it beats the speed or area coverage of radiation in the air. Plus, humans have a tendency to breathe the atmosphere; as we discussed with radon, radioactive material in your lungs is something you should avoid whenever possible.
The ability to avoid it is another reason why it's so important--or more accurately, the lack of an ability to avoid it. Depending on the source event, radiation in the atmosphere can travel very quickly over a very large area. If that area happens to include where you live, unless you evacuated a while ago chances are you're going to be exposed to something.
What's in the air?
That "something" depends on the source event. Many radioactive nuclear byproducts exist naturally in a gaseous state. We've already discussed radon, but alongside it can be krypton, xenon, radioactive isotopes of oxygen or nitrogen, and a few others, none of which are going to be very good for you if you breathe them in. Depending on the energy behind the release (e.g. a bomb versus a reactor venting, which we'll get into in the other parts of this series) there may be heavy elements flying through the atmosphere as well. These elements, which can be decaying with all kinds of nasty radiation from high-energy gammas that can do damage no matter where they hit you, to alpha particles that can really hurt the interior of your lungs when you inhale them. They also tend to be part of long decay chains, which means they and their "daughter" elements can still be highly radioactive even after a large amount of time has passed (we'll discuss this further in the subsequent posts).
To be continued
I know the stated idea of this blog is to try and assuage some fears about nuclear, but it sure sounds like I've done some fear mongering here. I just wanted to build a bit of a teaser for the more in-depth posts to come, on the atmospheric radiation from nuclear weapons and non-weapons. I will say that thankfully, the number of man-made events resulting in the release of radionuclides to the atmosphere are quite few; unfortunately, most of them have been very serious.
Up next will be a discussion of nuclear fallout from weapons, and its lasting effects.
[1] https://rem.jrc.ec.europa.eu/RemWeb/activities/AtmosphericDispersion.aspx
Feb 17, 2016
Radiation Protection Standards: What stands between you and radiation
Last post, we talked about a source of radiation over which you have some control of your exposure: radon, through keeping good ventilation in your homes and letting the air change out now and again (and if you're really concerned, buying a radon test kit). You can control your exposure to a lot of potentially dangerous sources of radiation: don't seal your house/basement if you want to avoid radon, don't be out in the sun all day every day if you want to avoid skin cancer, don't let your doctor give you a dozen chest x-rays in short order unless you want an easy malpractice lawsuit, etc.
But what about radiation exposure that you can't control? Say you live next to a nuclear power plant: what guarantees do you have that they aren't venting radioactive gasses into your local atmosphere, or leaking radiation out of the trains and trucks that deliver nuclear material and take away nuclear waste, or even the workers in and around the plant being irradiated and then spreading that radiation into the community spaces that you share with them? Are any of these things a danger to you?
Spoiler alert: they aren't. Not even a little bit. In fact, a nuclear plants net effect on your personal exposure level, even if you live right next door, is low enough to be entirely negligible. But how? What rules are in place to ensure that you and everyone associated with the plant are safe?
Well if you didn't know, the American government has a big book of rules called the "Code of Federal Regulations" or CFR. And when I say big, I mean big. Relevant to us out of its 50 titles is title 10: Energy. Within the energy title (denoted in shorthand as 10CFR) are many, many more rules, regulations, and standards, with one in particular being of great interest to us for this post. CFR title 10, part 20 (or 10CFR20) is titled "Standards for Protection Against Radiation", and it's quite the daunting read. But hey, at least we know it exists. I won't list it all out here, because as you can see in the link even when its simplified into its subparts and subheadings it looks like more than you want to read through. But if you do read through it, you'll find that it denotes everything you could possibly think of in terms of radiation exposure and safety: how much radiation a nuclear facility can expose a worker to (very low), how much it can expose the public to (even lower!), even so far as denoting special radiation levels for pregnant women. If it somehow doesn't cover something of importance, then the slack is probably picked up somewhere else by the US Nuclear Regulatory Commission (NRC), who are also the guys who get people in serious trouble when they don't follow the standards set by 10CFR20.
So rest easy if you live near a licensed nuclear facility of any kind. It's not a crapshoot, the nuclear engineers, scientists, and technicians aren't just making it up as they go along. They've got an honestly frustrating number of rules to adhere to to keep you and the rest of the public safe.
But what about radiation exposure that you can't control? Say you live next to a nuclear power plant: what guarantees do you have that they aren't venting radioactive gasses into your local atmosphere, or leaking radiation out of the trains and trucks that deliver nuclear material and take away nuclear waste, or even the workers in and around the plant being irradiated and then spreading that radiation into the community spaces that you share with them? Are any of these things a danger to you?
Spoiler alert: they aren't. Not even a little bit. In fact, a nuclear plants net effect on your personal exposure level, even if you live right next door, is low enough to be entirely negligible. But how? What rules are in place to ensure that you and everyone associated with the plant are safe?
Well if you didn't know, the American government has a big book of rules called the "Code of Federal Regulations" or CFR. And when I say big, I mean big. Relevant to us out of its 50 titles is title 10: Energy. Within the energy title (denoted in shorthand as 10CFR) are many, many more rules, regulations, and standards, with one in particular being of great interest to us for this post. CFR title 10, part 20 (or 10CFR20) is titled "Standards for Protection Against Radiation", and it's quite the daunting read. But hey, at least we know it exists. I won't list it all out here, because as you can see in the link even when its simplified into its subparts and subheadings it looks like more than you want to read through. But if you do read through it, you'll find that it denotes everything you could possibly think of in terms of radiation exposure and safety: how much radiation a nuclear facility can expose a worker to (very low), how much it can expose the public to (even lower!), even so far as denoting special radiation levels for pregnant women. If it somehow doesn't cover something of importance, then the slack is probably picked up somewhere else by the US Nuclear Regulatory Commission (NRC), who are also the guys who get people in serious trouble when they don't follow the standards set by 10CFR20.
So rest easy if you live near a licensed nuclear facility of any kind. It's not a crapshoot, the nuclear engineers, scientists, and technicians aren't just making it up as they go along. They've got an honestly frustrating number of rules to adhere to to keep you and the rest of the public safe.
Feb 15, 2016
Radon: An Actual Danger?
Continuing the cancer discussion from last week, we're shifting to a more specific topic: radon.
What is radon?
Radon is a very heavy noble gas with 86 protons. It's a part of the "decay chain" (series of elements made from the decays of multiple radioactive elements in a row) of uranium, thorium, radium, and probably some other elements, all of which are found naturally in the earth's soil and rock. It's tasteless, odorless, and radioactive. [1]
Why is it dangerous?
Yeah, I said it was radioactive. But just because something's radioactive, doesn't make it a guarantee for cancer (see last week's discussion). Radon decays quickly with alpha decay, or an energized helium nucleus. Alphas can be stopped by a "shield" of a few sheets of paper, and are almost completely ineffective a getting through human skin. But here's the catch: radon is a gas, and that means it can be inhaled. Alpha particles might be mostly harmless outside of you, but when they're allowed to bounce around in your very sensitive lung tissue, things can get very bad very fast.
Humans developed with radon being a natural occurrence in the air, so we can take it in normal doses. Inhaled in a larger-than-normal concentration, however, and your cancer risks can skyrocket. An estimated 15,000-22,000 cancer deaths in America per year are believed to be caused by over-exposure to radon. [2]
How does over-exposure occur?
Time for an anecdote:
My mother is an appraiser in Florida, and a few years ago she shared with me a story about radon. In warm, sunny places like Florida, it was a growing trend in the late '90s and early 2000's to build houses with windows that don't open; fully sealed windows in houses designed to be fully dependent on AC, never outside air. So what happened? The radon concentration built up in these houses, being emitted from their foundations, and people started dying from, as she put it, "radon poisoning". Whether it was straight poisoning or cancer I'm not sure, but studies seem to support her claim. [3]
Conclusion
So this has been a little different than the usual idea: this is something you might not have known about, but is actually a radiation-related danger. So what can you do about it? It's actually really easy: open your windows. Just pop your windows open every now and again and the air in your house will change around and keep your local radon concentrations down in healthy, expected levels. Stay safe!
[1] http://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet
[2] Field RW, Steck DJ, Smith BJ, et al. Residential radon gas exposure and lung cancer: the Iowa Radon Lung Cancer Study. American Journal of Epidemiology 2000; 151(11):1091–1102.
[3] Field RW. A review of residential radon case-control epidemiologic studies performed in the United States. Reviews on Environmental Health 2001; 16(3):151–167.
What is radon?
Radon is a very heavy noble gas with 86 protons. It's a part of the "decay chain" (series of elements made from the decays of multiple radioactive elements in a row) of uranium, thorium, radium, and probably some other elements, all of which are found naturally in the earth's soil and rock. It's tasteless, odorless, and radioactive. [1]
Why is it dangerous?
Yeah, I said it was radioactive. But just because something's radioactive, doesn't make it a guarantee for cancer (see last week's discussion). Radon decays quickly with alpha decay, or an energized helium nucleus. Alphas can be stopped by a "shield" of a few sheets of paper, and are almost completely ineffective a getting through human skin. But here's the catch: radon is a gas, and that means it can be inhaled. Alpha particles might be mostly harmless outside of you, but when they're allowed to bounce around in your very sensitive lung tissue, things can get very bad very fast.
Humans developed with radon being a natural occurrence in the air, so we can take it in normal doses. Inhaled in a larger-than-normal concentration, however, and your cancer risks can skyrocket. An estimated 15,000-22,000 cancer deaths in America per year are believed to be caused by over-exposure to radon. [2]
How does over-exposure occur?
Time for an anecdote:
My mother is an appraiser in Florida, and a few years ago she shared with me a story about radon. In warm, sunny places like Florida, it was a growing trend in the late '90s and early 2000's to build houses with windows that don't open; fully sealed windows in houses designed to be fully dependent on AC, never outside air. So what happened? The radon concentration built up in these houses, being emitted from their foundations, and people started dying from, as she put it, "radon poisoning". Whether it was straight poisoning or cancer I'm not sure, but studies seem to support her claim. [3]
Conclusion
So this has been a little different than the usual idea: this is something you might not have known about, but is actually a radiation-related danger. So what can you do about it? It's actually really easy: open your windows. Just pop your windows open every now and again and the air in your house will change around and keep your local radon concentrations down in healthy, expected levels. Stay safe!
[1] http://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet
[2] Field RW, Steck DJ, Smith BJ, et al. Residential radon gas exposure and lung cancer: the Iowa Radon Lung Cancer Study. American Journal of Epidemiology 2000; 151(11):1091–1102.
[3] Field RW. A review of residential radon case-control epidemiologic studies performed in the United States. Reviews on Environmental Health 2001; 16(3):151–167.
Feb 12, 2016
Class Changes and Guaranteed Updates
Due to class changes deemed necessary for the professor, blog posts now have mandatory time frames and mandatory topics. I won't get in to my opinions of it, but I will say that the fact that I have yet to update this blog until now means that I was part of the issue and abused the more relaxed approach the professor was previously taking.
The mandatory topics may make it difficult, but I would still like to focus this blog on the common fears and misconceptions the general population has about nuclear sciences and radiation. I've liked the idea of this blog from the beginning, I just left it by the wayside. The first topic is on cancer risks; so, here we go.
A lot of things have evidence showing that they cause cancer [1]. However, more importantly for this blog, a lot of things don't cause cancer. [2]
Here's some things that I have personally heard people express cancer concerns over,
[1] http://www.cancer.gov/about-cancer/causes-prevention/risk
[2] http://www.cancer.gov/about-cancer/causes-prevention/risk/myths
[3] http://www.physicscentral.com/explore/action/radiationandhumans.cfm
The mandatory topics may make it difficult, but I would still like to focus this blog on the common fears and misconceptions the general population has about nuclear sciences and radiation. I've liked the idea of this blog from the beginning, I just left it by the wayside. The first topic is on cancer risks; so, here we go.
A lot of things have evidence showing that they cause cancer [1]. However, more importantly for this blog, a lot of things don't cause cancer. [2]
Here's some things that I have personally heard people express cancer concerns over,
- Cell phones
- Power lines
- Computers
- Stereos
- Bananas
- Microwaves
This last one, microwaves, is especially important to me, because I love microwaves. As a busy college student, a microwave is just about the most important component to my diet. I'll cook a couple huge meals over the weekend, and then bam, microwavable leftovers for the weekend.
Anyway, as for what they have to do with cancer--or rather, what they don't. Let me be clear, a microwave--just like an oven, stove, or toaster--can be a dangerous implement. It can burn you (more specifically, boil you) if you manage to operate it with the door open, or with a severely damaged Faraday cage (the little black grid pattern across the glass viewing window in the door). But what it won't do is give you cancer.
Yes, a microwave uses radiation to vibrate water molecules in food, increasing their kinetic energy which results in an increase in temperature (which is really cool). But as it turns out, there are two kinds of radiation: ionizing and non-ionizing. Ionizing radiation is radiation that is above the energy threshold to cause damage to human DNA, damage that is believed to have a direct link to cancer in humans and other animals. [3] What a microwave uses is non-ionizing radiation, or radiation below this energy threshold. Enough to energize your water molecules (again, that is dangerous and should not be toyed with) but not enough to give you cancer. Or your food cancer, for that matter.
[1] http://www.cancer.gov/about-cancer/causes-prevention/risk
[2] http://www.cancer.gov/about-cancer/causes-prevention/risk/myths
[3] http://www.physicscentral.com/explore/action/radiationandhumans.cfm