Friday, 27 September 2013

Gas from US fracking increases radioactive pollution in Europe

It’s true and the logic goes like this.

In the USA gas obtained by fracking schist, together with an increase in energy from renewables, has reduced wholesale gas prices per unit of thermal energy to less than the formerly much cheaper coal.  This has in turn lowered coal prices and stimulated US coal exports.

Gas prices in Europe have increased as a result of the Libyan conflict, and after Fukushima, the Japanese decision to shut down its nuclear power stations and rely on imported gas.

These market adjustments have coincided with a dramatic drop in the cost of European carbon credits since 2008 due to the recession.  So it’s much cheaper to burn an inefficient fuel like coal, and produce more carbon dioxide, than it was earlier this century.

There is therefore now an economic incentive to burn coal instead of gas in Europe.

Photo credit: Reuters/Staff Photographer (Southern Company’s Plant Bowen in Cartersville, Georgia, one of the biggest coal-fired plants in the United States)

But each year a typical coal fired power station discharges to the environment 100 times as much radioactivity as a nuclear power plant emits.  This radioactivity comes from the uranium, thorium and other radioactive decay products naturally present in coal, which is discharged as ash and particulates.  Coal fired power stations, unlike nuclear, are not subject to the controls on radioactive emissions which make building and operating nuclear power stations expensive.

This comprehensive and well researched article by Alex Gabbard from ORNL written in 1993 gives the details.  It also points out that ash from coal is a source of fissionable fuels and fertile materials, which is likely to be overlooked by authorities attempting to control the proliferation of nuclear weapons.

Additionally he calculates that, both in the US and globally, the waste ash from burning coal contains far more potential nuclear fuels than the entire nuclear industry consumes each year!

So thanks to fracking in the US, and market forces, Europeans are being exposed to more radiation than before.  

Monday, 23 September 2013

13 Million Bananas per day

0.01mrem is equal to 10-7Sv  
(Picture from
Last week, at an “Echange Linguistique” with two of our friends, the subject of nuclear power came up very briefly. As far as these two French ladies were concerned 
There were no intermediate steps in the conversation and for them these two things were equivalent and inevitable.

It was very revealing, and I was appalled by their ignorance, but I couldn't immediately enter into an argument which would rapidly have become very heated and found me at the limits of my command of French.

The fundamental problem is that the public lacks any understanding concerning radiation and also lacks any ability to appreciate that the numbers are important when it comes to all environmental challenges to living organisms, including radiation.  Since we are all surrounded by radiation from natural sources it's a very good thing that the body has repair mechanisms and it's only when these can no longer cope, or when the exposure to radiation is too intense over too long a period, that cancers result.

Even radiation units are difficult to understand. Firstly, there are many different ways to measure the intensity of radiation emissions  and then there are the concepts of an absorbed dose of radiation (measured in Grays) and the biological effects of a committed dose of radiation on a human body (measured in Sieverts ). This is dependent on the type of radiation and the tissues which are irradiated.

The Banana Equivalent Dose
Since bananas contain potassium, which has a small percentage of radioactive Potassium-40 they emit radiation. 

One somewhat whimsical attempt to make all of this more relevant to ordinary people is the Banana Equivalent Dose BED, which is usually rounded up to 0.1 ┬ÁSieverts. 

So I decided to calculate how many bananas were equivalent to the average radiation dose of 2.7mSv per year received by a typical UK citizen, which works out to 74 bananas/day. 

The exposure limit for a worker in a nuclear power station is 0.18mSv/year or 5 bananas /day.

Back in the late eighties I had radiation treatment for cancer and received 5,400 rads across my abdomen over a six week period.  This is equivalent to 54Sv or 12,857,143 bananas/day and I'm still here!

So, if they ever find this post, as well as equating nuclear power with cancer, I expect that these two French ladies will also stop eating bananas!