Nuclear Power and Renewables

[EDIT 9 May 2017]
 I haven't read this for AGES, but I know the flavour of my opinion piece below, and I know in hindsight that I was totally wrong. A huge geographic area was affected, and a huge population were displaced in this substantial man-made disaster. Out of interest, (though no-one will ever read this) I leave it published and untouched.
[/EDIT]



Japan's Fukushima Daiichi issues seem to be stabilising in the worlds eye over the last day or so, that is unless you read articles like this (dailymail.co.uk) from Sunday just gone.

Ostensibly the author seems to be railing against irresponsible reporting, stating that she swam in the ocean near a North Sea nuclear plant as a kid because of the warm water, and it didn't have any influence on her health at all. In the next breath she comes out with the statement;

the Fukushima 50 [vigilant plant workers].

They will almost certainly receive fatal doses of radiation as they work around the clock.

This is the most irresponsible of all journos, because not a single person has died due to radiation related causes, and none are likely to have exceeded levels of radiation exposure with long term health implications.

I came across the above article by way of Lewis Page, a Journo for the on-line tech news site TheRegister.co.uk. In his series of articles about Fukushima, he was talking to the fact that no plant worker has been exposed to a dose of more than a 400 millisievierts/hour, and that exposure was for minutes not for a sustained hour or more. 

With a current allowable dosage of 250 millisieverts, and with the plant workers being exposed to a usual dosage of less than 3-4 millisieverts per hour the workers are not at risk of sustained health implications - which start after dosages in the order of 1000 millisieverts. For perspective, a chest x-ray exposes you to a 7 millisievert dosage.

Yes the workers have to manage their time near the damaged reactors and spent fuel pools and they have to be withdrawn during planned venting of the primary containment or the undamaged secondary containment buildings, but their dosages are tolerable.

When we step outside the nuclear complex's boundary, these levels have been measured at between 0.8 and 9 millisieverts per hour. Now lets worst-case this. You would have to sit outside, in the one place that had a reliable 9 millisievert per hour dosage, for more than a full day before you exceeded the allowable dosage for the plant workers. You would still have no long term health implications from doing so, and taking steps such as sitting indoors would reduce or remove this risk.

Are the workers or local residents being exposed to iodine or casaeum radioisotopes which have half lives between 8 days and 20 years, and are if occurring, is the exposure at a truly hazardous level? This isn't likely. 

These isotopes are produced in the reactor cores themselves and the primary containment vessels for each of Fukushima's buildings are in tact. Primary containment is intended to firstly avoid unnecessary generation of radioisotopes that are superfluous to design intent, but to also capture such material and give it time to decay before disposing of it. Secondary containment in fact - the buildings outside the reactor cores containing the spent fuel pools - are similarly designed to capture and hold radioisotopes whose half-lives are measured in seconds, before releasing harmless steam to the atmosphere. 

There is evidence through TEPCO testing, of iodine and other longer lived radioisotopes registering small quantities in the southern discharge canal at the plant, and in reducing quantities in air, but in each case the dosages are so small as to have negligible influence on human well being as attested to by the March 21 TEPCO testing (pdf) showing just .04245 radon measurement, compared with the normal 'healthy' limit of 0.0400 - a difference of only 0.2% or 2/1000 over the tolerable target.

To put that in perspective, in the USA 2.4 million people will die this year. Of these 570k or 23.75%, will die from Cancer. 

It may be a trite correllation to draw, but we are talking about a 0.2% increase in your radon exposure beyond what has deemed to be acceptable exposure health-wise. This kind of exposure is unlikely to be the thing to tip us over the cancer edge. We are already 25% likely to die from cancer, and sure we don't want to do anything to worsen that rate, but would stress and related issues, arising out of worrying about invisible nasties, have just as much influence on your health as a fifth of 1 percent increase in your radon exposure? I'm thinking the two risks are comparable. 

Having already stated that our risks are only minimally increased by exposure, the difference that I DO see, is that with radon exposure we can take mitigating steps if we feel compelled, in order to reduce or remove the risk of isotopes such as iodine-131 from entering your thyroid. Steps such as avoiding dairy for a week. As iodine-131 has a half life of 8 days, if it measures at 0.042 radons per cm3 of sea water this week, it will measure 0.021 in 8 days time - well below tolerable levels.

Page took some care to point out aspects of this 'nuclear disaster' such as there being zero radiation-related deaths and zero high dosages received, and only death on the Daiichi site being caused by a crane operator falling during the actual quake. 

So we have a death toll of only 1, despite the quake at its epicentre (0.34g of ground movement) exceeding Daiichi's design spec (0.18g of ground movement) by a factor of almost 2. 

While the ground movement measure actually at Daiichi is not known, the quake itself has been recorded as a magnitude 9 on the Richter scale, which exceeds Daiichi's design spec by something in the order of 22.3 times, not just 2. That is 1410 Petajoules worth of energy experienced compared with the 63 Petajoules Daiichi was designed for. 

In explanation, I suppose we are talking at first about linear motion in the initial 'g' measurement, but about actual energy expended in the joule comparisons (Richter is a logarithmic scale, so an 8 is not 1/9 less severe than a 9 but is 22 times less severe), so the greater energy discrepancy between design and actual might be a more pertinent measure of the severity.

The tsunami itself was 14m high, and with a tsunami design spec of 5.7m, the wave inundated the compound. The reactors themselves and the backup power sources were at an elevation of 10 to 13 metres so were able to weather the wave comparatively well, however due to the significantly greater than spec event, the primary power and cooling went off line. 

 

The high-ground battery backups recovered for a time to ensure cooling was maintained. Portable generators were deployed in short order and the emergency fire system was fired up to continue cooling for the reactors. After build up of hydrogen in the spent fuel pools in buildings 1 and 3 resulted in their secondary containment being blown up, helicopter drops, fire truck pumps and concrete truck pumps were deployed at various times to continue pumping sea water into the spent fuel to maintain cool shutdown and to prevent damaging their containment vessels (a meltdown in spent fuel being unlikely).

So in summary, we have reactors that experienced a natural disaster significantly stronger than their design specs. The reactors immediately went into a cold shutdown emergency state, and the area was evacuated in preparation for the incoming tsunami. No deaths arose out of the tsunami. No deaths have occurred due to radiation exposure. No deaths are going to happen amongst plant workers let alone local residents who are far removed from the nuclear exposure. There is no credible reason to believe that radioisotopes are entering the biosphere (water, milk, fresh produce) in quantities that are going to cause long-term health implications. 

It truly seems to be a nothing-bad-going-on situation, and the media has been coming out with taglines such as "Fukushima: the danger of going critical" all the while cause that is news.

And people wonder why I have Bill Hicks spewing bile about mass media idiocy tattooed on me.