Do We Need Lynas-A Twist Of Mindset

I have always been a fan of people who are willing to acknowledge changes. For me, a person who apologizes for his mistakes is more honorable than someone who stands his ground in the face of contradicting evidence.

Image: sodahead.com

In December last year I blogged about the issue of LYNAS in Kuantan, and I questioned whether were we ready for the sudden uplift of lifestyle. I totally disregarded the aspect of science in my previous post, which was suicidal. Suspecting a problem last night, I took to the table and started doing some math, which I should have done when I wrote the previous post. (so right now I'm giving myself some spanking, to be fair)

Image: resourceinvestor.com

*Behold math/science haters, you might want to skip the following section.
Thorium exists almost exclusively as Thorium-232 (more than 99%), and so I will omit the calculation for Thorium-230 and Thorium-229.
The radioactivity for a gram of Thorium-232 can be calculated via the following formula:

Activity, A = (M/Mo)*NA*λ

where
λ = (ln 2/t1/2)

So the formula becomes
A = (M/Mo)*NA*(ln 2/t1/2)

t1/2 = half-life of Thorium-232
M = mass of thorium (in grams)
Mo = molecular mass of Thorium-232
NA = Avogadro's number

If we have a gram of Thorium-232,
A = (1/232)*6.022 x 10E23*(ln 2/14000000000)
    = 4070 Becquerel

That's not a huge number to be honest. Bananas are radioactive too. The unstable radioisotope Potassium-40 in bananas has a half-life of 1.25 billion years, but it only makes up 0.0117% of the total Potassium content in a banana. So a typical 120gram banana has roughly 15 Becqueral, and 273 bananas produce the same amount of activity as a gram of pure Thorium-232.

Image: hobbiesteller.com

I sent an email to LYNAS a couple of days ago and got some very helpful information.

The figure you quote for the specific activity of Th-232 of 4070 Bq/g is correct. However this relates to PURE Thorium-232. The Lynas rare earths concentrate contains only 0.16% Thorium-232: 4070 x 0.16% = ~6 Bq/g. 
Which means every gram of soil mined by LYNAS produces 6 disintegrations per second. That's less than half the radioactivity of a banana.

Does it mean if we could afford to stand by the fruit stall selling several bunches of bananas for hours on end and expose ourselves to plenty of banana-radiation, then perhaps we're ready for thorium?

Image: worldofstock.com

Well, not exactly. Radioactivity is directly proportional to the mass of sample i.e. more Thorium-232 means more radioactivity. Pound for pound, Thorium-232 still gives off more radiation than bananas. So importing a tonne of Thorium-232 into Kuantan everyday will definitely impose some severe environmental hazards.

And according to LYNAS,
The LAMP is completely different to the Bukit Merah rare earths plant. The Bukit Merah plant processed "monazite" from the waste of tin mines, which is very different to the rare earths we are processing. There are now much higher standards in place which mean Bukit Merah could never be repeated.
"Monazite" typically contains 6~7% thorium i.e. 40 times more than the thorium contained in the soil mined by LYNAS. Hence it is much safer than the Bukit Merah rare earths plant.

Monazite sand. Image: geology.com

Statistically, the radiation given off by LAMP is really minute. What worries me still, is the safety of the plant itself. As I'd suggested in previous post, no one can predict when the next flood/landslide is going to happen. Fukushima was a safe plant, until tsunami left it in a state of derelict in 2010. But again, I shouldn't ignore the fact that radiation-wise, the LAMP's hazard has been vastly exaggerated.

Image: mynewshub.my

A bit of self-reflection is certainly good once in a while.



Malcolm
info: http://www.lynasandmalaysia.com/#faq-section
http://nuclearfissionary.com/2010/03/28/safe-levels-of-radiation/
http://www.ccohs.ca/oshanswers/phys_agents/ionizing.html
http://www.chiquitabananas.com/Worlds-Favorite-Fruit/bananas-and-potassium.aspx
http://www.evs.anl.gov/pub/doc/Thorium.pdf