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Report: Nuclear Plants Should Focus On Risks Posed By External Events
mdsolar (1045926) writes "Engineers at American nuclear plants have been much better at calculating the risk of an internal problem that would lead to an accident than they have at figuring the probability and consequences of accidents caused by events outside a plant, a report released Thursday by the National Academy of Science said. Accidents that American reactors are designed to withstand, like a major pipe break, are "stylized" and do not reflect the bigger source of risk, which is external, according to the study. That conclusion is one of the major lessons from the Fukushima Daiichi nuclear accident in Japan in 2011, which began after an earthquake at sea caused a tsunami.
If the 1 in 10.000 years is per reactor, 18 years between accidents is "reasonable". With 400 reactors worldwide, that would mean approximately 25 years (~10000/400) between accidents.* Accounting for older designs, improving risk estimation, worse safety/quality standards in some parts of the world, etc. 18 years is close and not "far outside the claimed safety envelope".
Also, one "near miss" per year suggests luck, ten or more per year implies that there are enough safeties and checks in the systems to catch trouble before a catastrophe happens.
* I know this is not exact. It should be close enough. Fanatics can do the 1/(1 - ((10k-1)/10k)^400) stuff with a calculator.
Natural radioactivity is mainly something that hits you from the 'outside'... it hits your skin
Except for the ~5kBq of K-40 in your nerves. And the C-14 in all of your tissues. Also, cosmic radiation doesn't stop on your skin - it's comprised of extremely high energy particles at 1 GeV or more. Those sort of energies make the radiation from nuclear reactors seem like child's play. That is not to say that you'd rather be inside of a nuclear reactor - most definitely not, the flux there is many orders of magnitude larger - but it does show that cosmic rays don't just "hit your skin", but instead fire right through you and irradiate your internals quite easily.
First of all a healthy person has no Uranium or Thorium in his body.
I'd be careful with throwing around superlatives like "none", but it's probably fair to say that the abundance of actinides in most humans would be classed as "trace" at best.
you are again mixing up external radiation by natural sources with radioactive elements incorporated into the body
Except that both K-40 and C-14 are both natural and inside your body. In fact, we use C-14 abundance in tissues to date when organisms died. Whether something is or isn't natural has no bearing on where it is harmful.
The fallout is measurable every where in north Japan.
This statement, while true, is misleading, or at the very least oversimplified. We have extremely sensitive measurement equipment, but the mere detection of the presence of a radionuclide does not in itself imply any danger from it. What needs to be assessed is the particular type of radionuclide, its abundance and sample distribution, in order to be able to at least roughly assess the potential biological impacts. In pretty much any scoop e.g. topsoil you'd be able to find all manner of toxic stuff, from mercury through arsenic, lead and even to uranium - this is simply a consequence of the magnitude of Avogadro's number.
I'll leave you with just one tiny factiod: long-haul flights are associated with elevated exposure to cosmic rays, easily 20-30x sea-level background and comparable to some of the hotter parts of the Fukushima exclusion zone. This has been repeatedly assessed and demonstrated. As such, one would expect to find radiation-related cancer clusters among airline crew, who spend a sizable amount of their lives in this elevated radiation environment. And yet, no reliable evidence for this has been found so far.