Some Basic Information Useful for Understanding Nuclear Power Safety

When people talk about nuclear power safety they often don't explain certain basic information that you need to know in order to really understand the the subject.  This is probably for the best because repeating the same information over and over again would grow old really fast, but unfortunately this leaves people new to the subject unable to fully understand the arguments.  The goal of this article is to hopefully be helpful to anyone who doesn't understand the basics. Basically I tried to write something that I think would have been helpful to me when I was starting out. 

The Very Basic

Lithium atom model

Lets start with the very basic, all the stuff on earth is made up of tiny building blocks called atoms (you can see all types on the periodic table of the elements).  Atoms are made up of three things.  Those three things are electrons, protons and neutrons.  Protons and neutron exist in the middle of the atom clumped together in what is called the nucleus.  The electrons exist around that. Atoms can form molecules (i.e. groups of atoms) by sharing electrons. 

The type of atom (i.e. the element) is determined by the number of protons in it's nucleus.  For example atoms that have one proton are hydrogen atoms, and atoms that have 92 protons are uranium atoms.

Unlike protons and neutrons, the number of electrons an atom has can change fairly easily.  The default position for atoms is having the same number of electrons as protons.  When atoms don't have an equal numbers of protons and electrons they are called ions.  Knowing what ion you're dealing is important because different ions (even of the same element) behave very differently chemically which is why they came up with Equivalent notations for writing it down.

Example of Equivalent Notations

Every proton is +1, and every electron is -1, simple subtraction tells you what ion you've got.  For example iron (Symbol Fe) has 26 protons.  If an atom of Iron has 24 electrons then its ionic state is 2+ (26 - 24 = +2), and if it has 28 electrons its ionic state 2- (26 - 28 = -2).

The number of neutrons an atom has determines what type of isotope it is.  All atoms are some type of isotope even though it's not usually that important because different isotopes of the same element (i.e. type of atom) behave the same chemically for most intents purposes and thus it is often not mentioned or thought about.

Isotopes are identified by their atomic mass.  The atomic mass includes both protons and neutrons (electrons are very light so they don't count).  So for example there are three naturally occurring isotopes of carbon on earth.  They are called carbon-12, carbon-13 and Carbon-14.  Carbon has 6 protons so Carbon-12 has 6 neutrons (12 - 6 = 6), Carbon-13 has 7 neutrons (13 - 6 = 7) and Carbon-14 has has 8 neutrons (14 - 6 = 8).


Ionizing Radiation and Radioisotopes


Not all isotopes are stable.  Unstable isotopes eventually decay into different types of atoms releasing radiation in the process.  For example Carbon-12 and Carbon-13 are stable while Cabron-14 eventually decays into Nitrogen-14 (which is stable).

The unstable isotopes are called radioisotopes (also known as radionuclide, radioactive nuclide, or radioactive isotopes), and the radiation released is know as ionizing radiation although most people just call it radiation.

When an unstable isotope decays is random while the probability of it decaying over any period time is fixed.  This probability is understood through something called a half-life.  A half-life is the time it takes for half of a given amount of a radioisotope to transmute (i.e. decay) into something else

It's a bit like rolling a dice. Every time you roll a dice the chance of getting a one is the same.  If you replace "time you roll a dice" with "fixed period of time" and "getting a one" with "a type radioisotope decaying" it's exactly the same. 

You can also use the dice analogy to understand half-lives.  Picture that you were rolling a group of six sided dice.  Every time you rolled them you remove any dice that lands on a one.  The half life of these dice would be three rolls because after three rolls half the dice should be gone.  You might be thinking to yourself that half lives aren't very precise because of the random element, but you have to remember that atoms come in large numbers.   There are something like 78,000,000,000,000,000,000 atoms in a grain of sand.  If you rolled six dice then at the end maybe half would be gone or maybe not, but if you are rolling trillions of dice pretty darn close to half of them would be gone. 

In fact half lives are so precise that people use it for dating stuff.   There is something called Radiocarbon dating that uses the half life of Carbon-14 in order to tell how old things are.  Carbon-14 is constantly being created in the earth's atmosphere by nitrogen being bombarded by cosmic radiation.  Because it's being created at a constant rate it's also being absorbed by plants at a constant rate and from plants it moves to animals.  When something dies it stop taking in Carbon-14 so by using it's half life researches can tell how long ago something died based off the amount of carbon-14 left in it's remains.   

Some radioisotopes decay into other radioisotopes.  When that happens you have what is called a decay chain.  The decay chain is used to describe how radioisotopes decay until they eventually reach a stable state.  Here is the decay chain for Thorium a common naturally occurring radioisotope. 

You may be wondering at this point where all the radioisotopes on earth come from.   Well some (34 types) are primordial (i.e. they came about before the earth was formed).  This includes Uranium, Thorium and Potassium-40.  Some of them are caused by cosmic radiation such as Carbon-14.  A small minority are created as a result of human activity, the most common of these activities involves the breaking down of larger radioisotopes into smaller radioisotopes in order to produce energy.  Here is a really good link about radioactivity in the environment if you're interested in learning more about it.


Types of Radiation 


The types of radiation produced by radioisotopes include both Electromagnetic radiation and Particle radiation.  Electromagnetic radiation plays a big part in our lives.  Depending on the frequency it has many different applications and also names.  The most familiar form is the visitable spectrum, or more commonly just called light.  It's also useful for microwaves ovens, cell phones, radio, x-rays etc.

But for our purposes we are only interested in electromagnetic radiation that is ionizing radiation. Ionizing radiation is radiation that has enough energy to knock electrons off atoms (or molecules) thus ionizing them.   This is important because as we talked about before different ions behave much differently chemically.  This can cause problems.  In most cases a few atoms (or molecules) being ionized doesn't matter much, but in some cases it does.  For example ionizing radiation can cause harm to living tissue.  You've probably noticed such harm yourself if you've ever spent too much time in the sun and got sunburned.  

Some atoms (and molecules) hold their electrons better than others so what types of radiation are ionizing isn't so clear cut, but really what we care most about is the effect of ionizing on human beings so I would say ultraviolet (sun burn) rang and higher (higher frequency that is, the higher the frequency the more energetic the more able to knock of electrons) is ionizing radiation.

Usually when we are talking about radioisotopes decaying we are talking about gamma rays (i.e. y-rays), not X-rays or ultraviolet. Lower wave length ionizing radiation can be created as secondary radiation (i.e. ionizing radiation created by other ionizing radiation) though. 

Particle radiation is simply particles that are moving very quickly.  The two types of particles that matter for what we are talking about are Alpha particles and Beta particles.

Alpha particles are helium-4 atoms without any electron.  The ones created by radioactive decay have a strong ability to ionize things, but they have little ability to penetrate shielding and can be stopped by a piece of paper or the thin layer of dead skin all of us have. 

Beta particles are electrons or sometimes positrons.  Positrons are the antimatter equivalent of electrons.  When electrons and positrons meat they destroy each other releasing some gamma rays in the process.


Metric Prefixes


Now that we've covered what radiation is and where it comes from lets talk about how it's measured.  Well before that we have to talk about something call metric prefixes.  If you spend time reading about this subject you're going to encounter these things a lot.

For Micro it's usually abbreviated μ or mc

Metric prefixes are used for writing really large or really small numbers without having to write all the zeros.  It's very similar to scientific notations in that regards.  The prefix goes before the unit abbreviation.  For example with 10 cm the c is the metric prefix (centi) and the m is the abbreviated unit types (meter). 

It's fairly easy to convert a number to a different prefix or know the number in it's entirety (i.e. what the number is without prefixes). Look at the table above to the left of prefix you want to convert from.  The number to the right of the 10 is the one we're interested in.  Take that number and subtract the number next to the 10 of the prefix you want to convert to.  If you want to convert to no prefixes then subtract zero.    If the number you get is negative move the decimal point that many spaces to left, if it's positive move the decimal point that many places to the right. 

For example 1,000 nm (-9 - (-6) = -3) = 1 µm ,  1,000 µm (-6 - (-3) = -3) = 1 mm, 1,000 mm (-3 - 0 = -3) = 1 m, and 1,000 m (0 - 3 = -3 ) = 1 km.  Where m stands for meters.


Measuring Radiation


There are a lot of different ways of measuring radiation.  I'll try and go over the most common ones.

Activity (A)

Activity measures the number of nucleus decays.  It's calculated using amounts of radioisotopes and knowledge of there half lives.  The two main units for this are Becquerel, and Curie. 

The becquerel (symbol Bq) it is the SI derived unit of radioactivity.  One Bq is defined as the activity of a quantity of radioactive material (i.e. radioisotopes) in which one nucleus decays per second. Basically it's a unit used to describe the amount of radiation produced by some amount of radioisotopes.

The curie (symbol Ci) is a non-SI unit of radioactivity, named after Marie and Pierre Curie. It is defined as 1 Ci = 3.7 × 10¹⁰ decays per second.

Conversion factors:

1 GBq = 0.027 Ci

Absorbed dose (D)

Absorbed dose measures the energy (from ionizing radiation) absorbed by a mass.  This is important because it takes energy to ionize things so knowing how much energy is going towards ionizing things help you know how much stuff is getting ionized.  This in turn can help give you some idea of the effect.  Most Geiger counters measure this. The two main unit types for this are Rad and Grey.

The SI unit for absorbed dose is the gray (Gy).  One gray is the absorption of one joule of energy, in the form of ionizing radiation, per kilogram of matter.

The other unit is called the Rad.  The rad is a non-SI CGS unit that is sometimes also used, predominantly in the USA.

Conversion factor:

1 rad = 0.01 Gy 

Dose equivalent (H)

Dose equivalent is a measure of the health effect of low levels of ionizing radiation on the human body.   The two main unit types for this are Roentgen and Sievert.  Quantities that are measured in roentgens or sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic damage.  There is no way to directly measure equivalent dose.  Instead other measurements are used to arrive at equivalent dose using various conventions.  For example with X-rays and gamma rays the gray is numerically the same value when expressed as the sievert (Sv), but for alpha particles one gray is equivalent to twenty sieverts because of the radiation weighting factor that is applied.

Conversion factor:

1 rem = 0.01 Sv

Radiation Inside the Body


Internal doses can be worse than external one's (depends on amounts and other factors).   For example alpha particles can be stopped by a thin layer of dead skin making them fairly harmless outside the body, but more dangerous than other types of radiation inside it.  In fact a large part of people's average annual doses comes from alpha particles produced by the decay of Radon (symbol Rn).  Radon is an odourless, colourless, gas that exists in small amounts all around us.  Radon is constantly being created as part of the decay chain of all the naturally occurring isotopes of uranium and thorium.

At any rate predicting internal doses is important.  An important thing to remember when internal doses are concerned is that different isotopes behave the same chemically.  This can be both a good thing and a bad thing.  For example Iodine-131 is a radioactive isotope of iodine that is produced a lot in nuclear reactors.  It has a half life of about 8 days.   Like all iodine it's utilized by the thyroid which means if it gets released into the environment it can be a problem.   Luckily by taking potassium-iodide pill you can flood your body with non radioactive iodine so Iodine-131 wont get absorbed, and because it's half life is so short it will be gone in short order.  Because they behave the same chemically radioisotopes also have many beneficial uses such as Radiopharmacology a branch of medicine which uses radioisotopes for medical imaging and in therapy for many diseases (for example, brachytherapy).  Ironically Iodine-131 is also one of the radioisotope used in medicine.

Internal Dosimetry 

Internal dosimetry is the science and art of internal ionizing radiation dose assessment due to radioisotopes incorporated inside the human body.  Radioisotopes deposited within a body will irradiate tissues and organs and give rise to committed dose until they are excreted from the body or the radionuclide is completely decayed.  The internal doses for workers or members of the public exposed to the intake of radioactive particulates can be estimated using bioassay data such as lung and body counter measurements, urine or faecal radioisotope concentration, etc.


Man-Made Radiation Exposure Breakdown 

This kind of depends on what you think of as man made exposure.  For example is Radon pumped into people's houses along with natural gas man made or natural exposure?  At any rate, not counting stuff like Radon most man made radiation exposure is a result of various medical procedures (such as x-ray).  This accounts for around 20% of exposure worldwide and up to 50% of exposure in  industrialized countries.  Here is a pie chart.

Harm

Linear no threshold model

The most widely accepted model for determining harm for low doses is known as the Linear no threshold model  (LNT).  For this model it doesn't matter how much radiation you receive.  All radiation can cause harm, all radiation has an equal chance of causing harm.  Here is a nifty online calculator for it applying it. 

Organizations That Support LNT

 United States National Research Council

"The assumption that any stimulatory hormetic effects from low doses of ionizing radiation will have a significant health benefit to humans that exceeds potential detrimental effects from the radiation exposure is unwarranted at this time."

United States National Academies

"The scientific research base shows that there is no threshold of exposure below which low levels of ionizing radiation can be demonstrated to be harmless or beneficial."

 National Council on Radiation Protection and Measurements

United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)

Until the [...] uncertainties on low-dose response are resolved, the Committee believes that an increase in the risk of tumour induction proportionate to the radiation dose is consistent with developing knowledge and that it remains, accordingly, the most scientifically defensible approximation of low-dose response. However, a strictly linear dose response should not be expected in all circumstances

The Controversy

Radiation can be harmful. Everyone seems to agree with that.  What people can't always agree about is the effect of very small doses of radiation.  Anyway Here is a page that does a good job of describing the controversy.  If you want to understand this subject better this is worth reading. 

Living things evolved in a world full of radiation.  Various biological defence mechanisms have come about in order to protect organisms from it and other sources of harm.  Here is a list of some of our bodies defences. 

1. Defences against the metabolically induced reactive oxygen species (i.e. defence against things that have been ionized),  
2. DNA repair, and  
3. Elimination of damaged cells. 

The big disagreement is low levels of radiation, where it is difficult to show statistically what is going on.  There are several different models that describe the effects of radiation at low doses. 

Another model is the threshold model

This model says that only radiation over a certain dose is harmful.

Organizations that support this model

French Academy of Sciences (Académie des Sciences) and the National Academy of Medicine (Académie nationale de Médecine).

In conclusion, this report raises doubts on the validity of using LNT for evaluating the carcinogenic risk of low doses (< 100 mSv) and even more for very low doses (< 10 mSv). The LNT concept can be a useful pragmatic tool for assessing rules in radioprotection for doses above 10 mSv; however since it is not based on biological concepts of our current knowledge, it should not be used without precaution for assessing by extrapolation the risks associated with low and even more so, with very low doses (< 10 mSv), especially for benefit-risk assessments imposed on radiologists by the European directive 97-43.

Hormesis Model

Another model is the  is the hormesis model which postulates that a certain amount of radiation actually decreases your chance of getting cancer a little because it stimulates your body's natural defences.

What People agree About

At any rate pretty much everyone agree about larger doses so Here are a few facts I think anyone would agree with. 

• 100 rem received in a short time can cause observable health effects from which your body will likely recover, and will increase your chances of getting cancer.
• 1,000 rem in a short or long period of time will cause immediately observable health effects and is likely to cause death.

Conclusion 


As for conclusions there isn't one really.  Hope this was helpful to someone.

Update:  I've made a lot of changes in order to make it more complete.  Also, changes some things to make it more balanced.

Random Idea Number One

Disclaimer:  Occasionally I get ideas about random things.  I love thinking about how to solve problems.  Even though not all my ideas are good ones, or things that I think should be done, it's still fun to share.  So I thought about it and decided it might be fun make blog posts about them.

Recently I've been reading people complaining about the low oil price, and I was thinking about why the US government doesn't buy and store it in order to keep the price at some set level.   Then I started thinking about how they might store it.  I figured the EPA might make this difficult and expensive.  Thinking about it some more what I finally came up with was abandon open pit mines.
 

They are already environmental problem spots so maybe people would be less against it.  Then I started thinking about how to seal them so the oil doesn't leak into the ground, and I remembered that because of China's recent policies recycled plastic prices are down.  Maybe they could be sealed with Polly Propylene or HDPE.  Then I started thinking about how to apply the plastic, and what I came up with was something like a giant heat gun that would both blow plastic chips onto the surface and melt them.   Maybe a converted jet engine would do the job.

Then I started thinking this might be useful for storing other things then oil (Such as fresh water).  Then I thought that this could be a good investment for people.  Oil went down because of a small oversupply but it's bound to come up again eventually.  People could maybe double their money in a few years.  Well that's all my thought on it. 

Comparing Aviation and Nuclear Power's Safety Record for 2014

It often seems like people zero in on the dangers of certain things while largely ignoring the dangers of others.  For example commercial airlines.  People are often more afraid of flying then they are of driving, and if they've been watching the news this year they would probably feel justified in their fears as this year has seen news story after news story about downed and missing airliners, but things are not always as they appear to be.   In 2014 761 people died on commercial airlines world wide while a staggering 33,783 people died in automotive accidents in the US alone.  Things can look a lot different when you compare statistic than they do when you just go by gut feeling, or what makes the news more often.  Often people consider nuclear power to be dangerous.  Far more dangerous then flying, but I wonder if that's really the case.  That's why I'd like to try and compare Aviation and Nuclear Power safety record for 2014.

Accidental Deaths 

The first comparison is talking about the number of people directly killed as a result of the different activities.  This comparison doesn't deal with radiation.  That's up next. 

Aviation
Well we got 761 death for commercial aviation.

Nuclear Power
Three people died in and industrial accident while constructing a nuclear reactor.  They most likely died of asphyxiation from breath pure nitrogen gas.  Nitrogen gas is sometimes used in construction. 

Conclusion 
761 is much larger then 3.  Point 1 goes to nuclear.

Radiation Exposure 

This section is for comparing radiation exposures between the two activities.  Some useful information: 1,000 nSv = 1 µSv,  1,000 µSv = 1 mSv, and 1,000 mSv = 1Sv.  Sv stands for Sievert which is a unit used to measure the effect of low levels of ionizing radiation on the human body

Aviation
Lets start with commercial aviation.  On commercial airlines people are exposed to higher the normal levels of ionizing radiation because of their altitude.  Basically there's ionizing radiation coming from space (i.e. cosmic radiation).  A lot of it gets blocked by our atmosphere, but not all of it, and when you higher you receive large doses (also being closer to the equator gets you higher dosages).  So lets try and calculating how much radiation exposure results from air traffic.

According to the FAA Revenue Passenger Miles (An RPM represents one paying passenger travelling one mile) where 815 billion in 2011 and expected to be 1.57 trillion in 2032.  That's as close as I could get to 2014 with my Google skills, but It probably hasn't changed that much in three years so I'll just go with it. I couldn’t find information on total hours passenger spent travelled so but a commercial jet travels between 500 to 900 km/hr.  With that and a little math we get 1.46 to 2.62 billion total hours flown by paying customers in 2011, and a projected 2.81 to 5.05 billion total hours flown by paying customers in 2032. 

That is a lot of hours. Next lets look at what people are exposed to during those hours. The amount of radiation people are exposed to during flight depends on both altitude and latitude, so in order to get a better idea of the rate of exposure people can reasonably expect during commercial flights lets look at some data taken from Xinjiang Airlines.

Feng YJ, Chen WR, Sun TP, Duan SY, Jia BS, Zhang HL. Estimated cosmic radiation doses for flight personnel. Space Med Med Eng 15(4):265–269; 2002.

• The average effective dose rate of all flights of Xinjiang Airlines from 1997 to 1999 was 2.38 µSv h^-1.
• The average annual cosmic radiation dose for flight personnel was 2.19 mSv.
• Annual individual doses of all monitored flight personnel are well below the limit of 20 mSv y^-1 recommended by the International Commission on Radiological Protection (ICRP).

Now we need to know the average world wide natural background radiation so we know how much more people get while flying.  Using Wikipedia I got this 0.27 µSv/h (Derived from 2.4 mSv a year) So with a bit of subtraction I get 2.11µSv/h (2.38 - 0.27 = 2.11) more radiation from flying.  Using this we have 1.46 Gh to 2.62 Gh times 2.11 µSv which equals 3,100 Sv (3,080,600,000 µSv) to 5,500 Sv (5,528,200,000 µSv).  If you applied Linear No-Threshold Model to that it would equal 155 to 275 extra cases of cancer for one year of commercial flight, projected to almost double by 2032.  To put that number in perspective this study estimates a total of 130 fatal cancers as a result of the Fukushima nuclear accident.  Though some people contest the validity of applying the Linear No-Threshold Model to low levels of exposure. 

I looked for information about military aviation exposure, but couldn't find anything so I'll leave that out.  I'm also leaving out commercial pilots.  They fly aircraft for other reasons, such as charter flights, rescue operations, firefighting, aerial photography, and aerial application, also known as crop dusting.  I have no clue what kinds of does they get.  For things like crop dusting I'm guessing not a lot. 

For information about flight attendants and pilot.  I was able to get some employment numbers.  There were  84,800 jobs for flight attendants, and for airline pilots there were  66,760 (104,100 - 37,340 = 66,760) job.  From the study quoted above we get 2.19 mSv does for flight personnel each year so that adds another 330 Sv (331916.4 mSv = 2.19 mSv (66760+84800)). 

Next lets talk about space.  Do to the lack of atmosphere astronauts get higher dosage than most professions do.  So lets try and calculate that.  The international space station has six crew spots and they've been filled all year round.  I've found this information about their doses.

The green line is the one that matters to us.

The number on the left are for annual mSv.  The number one the bottoms describe aluminium shielding with 0 being zero shielding and 100 being the most shielding.  Looking at the green line, at solar minimum it looks like they get up to 225 mSv  unshielded, and down to around 75 mSv shielded by aluminium.  I'm just going to assume they're shielded most of the time and call it 100 mSv a year.  There are 6 people on the station all year round so we end up with 600 mSv.

All together for aviation 2014 we get between 3,430.6 Sv to 5,830.6 Sv.  There are a lot of things I've left out like solar particle events, but given my limited resources and waning patience this will have to do.

Nuclear Power  
When you think nuclear and radiation the first thing on a lot of people's minds these days seems to be Fukushima.   So I did some searching and found one map that shows up to date radiation readings, and the other map shows the current evacuated areas.  Here are the two maps side by side at roughly the same scale (I think).

I find these maps rather interesting in light of what I've learned about aviation.   Consider 2.38 µSv/h the the average does for airlines that I used above.   If I wrote this like the radiation readings map it would be 2,380 nSv/h, and would be accompanied by an ominous red dot.  It becomes even more interesting when you consider that 2.38 is just an average. Depending on the type of flight exposure can be much higher.  From an earlier link. 

Friedberg W, Copeland K, Duke FE, O'Brien K 3^rd, Darden EB Jr. Radiation exposure during air travel: Guidance provided by the FAA for air carrier crews. Health Phys 79(5):591–595; 2000.

• Seattle to Portland: 0.03 mSv per 100 block hours
• New York to Chicago: 0.39 mSv per 100 block hours
• Los Angeles to Honolulu: 0.26 mSv per 100 block hours
• London to New York: 0.51 mSv per 100 block hours
• Athens to New York: 0.63 mSv per 100 block hours
• Tokyo to New York: 0.55 mSv per 100 block hours

On the first map a flight from Athens to New York would be listed as 6,300 nSv/h. Furthermore the space station data from Nasa would get purple dots with the heights level of shielding getting 8,560 nSv/h, and no shielding getting 25,700(much higher than anything on the Fukushima map). I find it ironic that people can get on a plane and travel halfway around the world, or even go to space, while thousands of Japanese people aren't even allowed to travel the handful of miles needed to see their own homes.

Unfortunately while this investigation was interesting to me it didn't really give me an idea of what doses people are getting because of Fukushima. I was starting to worry that I would ever get the information I need but luckily Wikipedia came to my rescue again (The same page even). From that article I got an average of 0.0002 mSv a year exposure worldwide. Knowing that there are around 7.3 billion people on earth we can do a little math and get 1,460 Sv ((7,300,000,000 * .0002)/1000 = 1,460) a year exposure from nuclear power.

Conclusion

With between between 3,430.6 Sv to 5,830.6 Sv. from aviation  and 1,460 Sv from nuclear power.  Point 2 goes to nuclear. What an upset victory! 

Terrorist Threat

Terrorist threats are on a lot of people minds these day.  People keep worrying about what they might be up to next. So the question this time is what is more vulnerable to terrorist attacks.  Nuclear power plants or aviation.  Something like this is really hard to put a number on.  Luckily Wikipedia came to my rescue again with the List of terrorist incidents in 2014.  I'm just going to add up all the ones that had to do with nuclear power or aviation.  The one that gets the least wins.

Aviation
Aviation has a bit of history of terrorism with the whole Twin Towers thing.  Lets see how it fared this year. 

Date	Type	Dead	Injured	Location	Details	Perpetrator
Feb. 13	Car bomb	7	19	Mogadishu, Somalia	A remote control car bomb exploded near the international airport in Mogadishu as a convoy of U.N vehicles traveled by, damaging one of the U.N vehicles, killing seven Somali civilians and injuring 15 civilians and four security guards. No U.N. Somali or International staff were injured or killed in the terrorist attack.[68][69]	Al Shabab
June 8	Attack	14 (+10 terrorists)	14	Karachi, Pakistan	Gunmen stormed Jinnah International Airport, killing 24 people and injuring 14 others.[160]	Tehrik-i-Taliban Pakistan
June 21	Attack	0	0	Jalalabad, Afghanistan	Taliban fighters fired eight rockets at a Jalalabad NATO air base. No casualties or property damage were reported.[181]	Taliban
June 26	Suicide bombing, shootout, raid	13	n/a	Seiyun, Yemen	Assailants conducted a series of attacks in the Seiyun, Yemen. In one attack a suicide bomber drove an explosive-laden vehicle into the entrance of an army base, killing four soldiers. In another attack, non-state militants attempted to raid Seiyun's airport, killing two soldiers. The government killed four militants in order to regain control of the airport. In another attack, a civilian woman was killed by an agricultural plant.[19	Al-Qaeda in the Arabian Peninsula

Nuclear Power

There wasn't any.

Conclusion

Nuclear wins again.  There are a lot of things about airports that make them good targets.  For example lots of people going in and out leaving holes in security.  Also, they often exist in places that have a lot of terrorists making them conveniently located targets for them to lash out at the 'evil' foreigners.  

The Dangers of War   

I'm not really sure that this is comparison is really needed, but people often argue that nuclear power is a nuclear weapons proliferation threat so I figured I better at least mention it.  My own view is that technical advancement of any kind is a nuclear proliferation threat.  If you want to keep someone from getting nuclear weapons you have to basically keep them down so that they can not make anything that can threaten you.  Such a practice is unethical in my opinion, and counter productive because poor miserable people are more likely to be violent.  Really instead of holding some people down I think we should bring everyone up so that we can all enjoy the fruits of technological progress together.  Then I think the world would be a much safer friendlier place.  In the end I declare this category a tie because I can not quantify this in any way that I find meaningful.

Final Conclusion

 
Nuclear wins!

Whether or not this article changes your mind about anything I hope you enjoyed it, and it at least made you think. 

 



 
 

The Hidden Costs of Wind and Solar: Part II intermittency (i.e. variability)

Wind and solar are intermittent (i.e. The wind isn't always blowing and the sun isn’t always shining).  This creates costs that need to be accounted for properly.

Lets start by talking about the electric grid sense understand it is important for understanding the issues with intermittency.  With the electric grids the amount of electric power produced always needs to equal the amount used.  Matching production and use with uncontrollable and difficult to predict sources like wind and solar can be tricky. Things like clouds and changes in wind speed can cause problems.  One way of understanding this problem is to think of the electric like a giant bucket.

"The Western Grid is like a giant bucket," said Mark Avery, SRP's grid manager "with a bunch of spouts running in and out, and you have to keep the water level constant." The Denver Post

Picturing the electric grid as a giant bucket. Some people are taking cups of water (electric power) and pouring them into the bucket while others are taking cups of water out of the bucket. If the bucket become empty it’s bad because people can’t get their water, and it’s also bad if the bucket gets too much water and starts overflowing. The water in the bucket isn't very deep (just enough for someone to get a cup full) so the rate of the water going into the bucket has to precisely match the rate of the water coming out of the bucket. If there is only one person drawing water from the bucket this can be difficult to do. One person is fairly unpredictable. What if he all the sudden decides he wants a lot of water, or what if he all the sudden decides he doesn't need any for a while. This makes load following (i.e. making sure the right level of water is always present) more difficult and less efficient.  Lucky the actions of a lot of people average out into something much easier to predict. So in order to deal with the problem they made the buck wider (but still just as deep) so many people can draw out their cups of water at once.

This system worked well enough (most of the time). Then one day some new people (i.e. wind and solar advocates) decided that they wanted to put their cups of water into the bucket as well, but other people didn't want them to because they couldn't control when they put the water into the bucket, and because they also couldn't predict it with perfect accuracy. The new people said it would be fine, and that just like with people taking water out of the bucket things would become more predictable if they just made the buck wider so more people could put their cups of water into the bucket at once. Then once things became predictable the people that could control the rate they put water into the bucket would help match everything up.

So how well does this new way work?  Opinions vary, but personally I am very sceptical that adding different types of unpredictability together will somehow make things more manageable. One thing’s for certain, the electric grid is not really a bucket. It is an expensive complex machine, and making it do what the renewable energy advocates want makes it even more complex and expensive. I think that’s why they are always saying things like “we need to upgrade our archaic electric grid” or “we need a smart grid”. Sure the electric grid (just like roads) needs maintenance, occasion expansions and even upgrades; but I believe that the biggest reason they are pushing so hard is because they want the money needed to integrate more solar pv and wind without having to included that money in the costs of those technologies.

So what happens when things don't match up?  Well larger difference cause Power outages while smaller differences cause other power quality issues.  Both of these things have costs.   A Berkeley Lab Study estimates that power interruptions cost the US $80 Billion annually.

Lets talk a little bit more about power quality.   What is power quality?  Opinions vary but here is one definition I found useful.

"Power quality is simply the interaction of electrical power with electrical equipment. If electrical equipment operates correctly and reliably without being damaged or stressed, we would say that the electrical power is of good quality. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, we would suspect that the power quality is poor."

We have standard for voltage, frequency and phase.  Then we make devices that run off those standards.  If the power difference to much from the standard then devices won't work properly or they can even be damaged.  Both Solar pv and wind can cause power quality issues (e.g. can deregulate line voltages and sometimes in extreme circumstances even shifting the line phase ).  Google the words wind and solar along with power quality and you can learn about the various issues and proposed solutions, or you can watch this video (I highly recommended it).  There are sighs Germany is already having problems  with it’s level of penetration.

"short interruptions in the grid has increased by 29 per cent in the past three years – resulting in some firms on the grid reporting damage running into hundreds of thousands of euros as a result of unexpected stoppages."

Manufacturing requires good power quality which solar/wind can have trouble supplying. This is especially true for manufacturing high tech things like solar panels. There have been attempts to deal with the problem with things like battery back up at the source, but there are still signs that large amounts of wind and solar can cause problems.  In order to cope with these problems  manufactures need to spend money on special systems (for example system that use battery backup), but such things have costs.  However the problem is dealt with (e.g. at the source, smart grids and/or making the end users deal with it) there are costs that should be included in the price of wind and solar.

The variability of wind and solar means that other types of energy generation have to ramp up and down more often in order to match electric production with use.   This creates inefficiencies which have costs that should be attributed to wind and solar.

A good way to understand these inefficiencies is to compare electric generation to something  most people are familiar with.   Cars are more efficient when they are driven a certain way.  For example.

"While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 50 mph."

Power plants also have an optimal fuel economy when operated at a certain continuous output.   They call plants made to operate at their optimal fuel economy Base load Power Plants and anything that causes them to very from their continuous optimal output  creates inefficiencies that have costs.  Some of that cost should be attributed to wind and solar (The rest of it should be attributed to things like changing demand).

It's important to note that power plant not operating at their optimal output because they are being used for load following(i.e. being used to help match electric production with use) are performing a service for the gird.  This service is called spinning reserve and studies have been conducted to try and estimate how much it costs.  One such study is quoted below.

"An expected finding from case studies made to date is that the specific cost of power generated in spinning reserve mode is quite high compared to the optimum cost of power from the same unit. This is, of course, due to the poor heat rate of most thermal power units at low load. If the unit could have operated at high load instead of spinning reserve, there is a lost opportunity cost which may double the cost of the spinning reserve service."

Next is another comparison between cars and power plants.

"Idling can use a quarter to a half gallon of fuel per hour, depending on engine size and air conditioner (AC) use. Turn off your engine when your vehicle is parked. It only takes a few seconds worth of fuel to restart your vehicle. Turning your engine on and off excessively, however, may increase starter wear."

Unlike internal combustion engines base load power plants can't start up that easily (Some can take more than 12 hours to reach full load).  How long it takes to start a base load power plant varies based on numerous factors.  One such factor is how hot it is.  Cold starts take the longest while warm and hot starts take less time.  Trying to get the plant online too fast can result in unnecessary plant failure or wear.  This bring us to another cost that is increased by intermittency.    Intermittency increases Power Plant Cycling Costs.   Power Plant Cycling Costs are the increased costs of maintenance and forced outages caused by things like turning the plant on/off, load following, and minimum load operation, in response to changes in system load requirements.  There are ways to reduce these costs like keeping the plants hot, but such things also have costs.

Another costs of intermittency is as the cost of underutilized capital assets.  A good example of an underutilized capital asset would be a power plant that only runs a few month out of the year when its too cloudy for solar pv, or a transmission line going to a wind farm that has to be build to handle that wind farm’s maximum capacity even though on average the wind farm only delivers 30 percent of that.  Here is a good example of the problem from Germany.

As you can see there are days in January with almost no wind or solar production.   The question you might be asking yourself is how do they get power when wind and solar aren't there for them.  What happens is that people end up having to have two power systems.  The conventional power system (mostly coal in Germany) which is able to meat all of the countries needs plus an extra wind and solar system which can't be relied upon.   Both of these systems have to be paid for which as you can imagination is quit costly.   A lot of people seem to think that some costs don’t count, but if people want to continue to enjoy electricity on demand 24/7/365 then they do count and they need to get paid.

In conclusion there are reasons why electric prices are higher in places that embrace solar and wind.  The sticker price they show you isn't even close to all that you'll have to fork out.  This shouldn't be allowed to go on.  There need to be a better accounting of the true costs of producing electricity with different methods.  Some people have already started on it, but a lot more work need to be done.

Update Mar 4 2015:  Made some changes on things I didn't like.