[LINK] Nuke station radiation

[Kim Holburn]

On 2011/Apr/02, at 2:55 PM, stephen at melbpc.org.au wrote:

> Regards there being NO safe level for radiation and cancer, it appears
> perhaps I must clarify emails by noting the type of radiation exposure.
> 
> For example, regarding general UV radiation, Jan writes,
> 
>>> It's not irrational to fear and doubt something if it's clearly poison
>> 
>> What sort of radiation?

Ionising radiation.

>> Sunlight is radiation. 

In general sunlight is not ionising radiation except possibly for some short UV.

> Yes, and so that's why, "Australia has one of the highest rates of skin 
> cancer in the world. At least two in three Australians will be diagnosed 
> with skin cancer by the age of 70. Over 1,000 Australians are treated for 
> skin cancer every day (and) the major cause of skin cancer is exposure to 
> ultraviolet (UV) radiation from the sun" <www.sunsmart.com.au/skin_cancer>

It's a bit more complicated than that.  I've lived in Italy.  In Italy we could go to the beach in summer and be in the sun all day without getting burnt.  As an Australian who knows how quickly I get burnt here, I wondered about that ever since.  I even asked an upper atmosphere physicist why it is so and got a surprising answer.  

>> Nearly every object on the planet emits radiation. I think that is what 
>> is going on here -- blanket generalisations to a public that doesn't
>> have a basic science understanding. Homework .. 
>> http://people.reed.edu/~emcmanis/radiation.html
> 
> True Jan, and when you read this website you have quoted, you will note:
> 
> "I separated these doses received on a short timescale (in a day) and 
> doses received over a longer timescale (a year) for a reason.  *A dose 
> which is acute, that is, received over a short period of time, has a much 
> greater biological effect than one received over longer periods of time* 
> This is because radiation acts by depositing energy in tissue, damaging 
> your cells. Very minor damage, repeated often, will be better repaired 
> than a major assault ..  Both the timing and absolute dose determine the 
> effect -- for eg, 1 Sv over the course of 20 years (a US radiation worker 
> receiving his or her limit for the year 20 years in a row) will not cause 
> radiation poisoning, but a dose of 1 Sv over 5 minutes certainly will."
> 
> So, see the point? By saying under 100 Sv is 'safe' is simply a nonsense.
> 
> According to your website just 1 Sv exposure can certainly mean a cancer.
> 
> Now see what I mean? To quote background radiation is irrelevant, because
> it's over years, and even for sunlight, is not all that concentrated. But
> *any* damaged nuclear power station emission radiation is quick and dirty
> and, can possibly result in a cancer over a very short time period indeed.

Exposure to ionising radiation is cumulative.  You reach a certain amount you have a much higher probability of being damaged.  It's not so much the concentration but the total and the type and energy of the particles. Also most people forget chemical toxicity of the waste and the problem when you ingest either heavy isotopes of normal atoms and they become part of you (and subsequently decay releasing large amounts of energy, particles and breaking up whatever molecule they were part of) or particles of dangerous things like plutonium.

> So i say yet again, it is shameful that Tokyo Power Co is still so silent.

I don't know it is (maybe it's working hard just trying to fix things) but nuclear engineers are discussing it:
http://spectrum.ieee.org/tech-talk/energy/nuclear/nuclear-risk-expert-fukushimas-fuel-could-still-seep-out

> Whatever, as Tom also writes, it's about time we moved on from this topic?

Just because it's a contentious issue doesn't mean we should shy from it.

-- 
Kim Holburn
IT Network & Security Consultant
T: +61 2 61402408  M: +61 404072753
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