I couldn’t see a link to an English translation of the site.

I am not a scientist & whilst I get the gist of what you say, I haven’t gained any idea of the implications of your worst case scenarios for people living in Japan.

For example, if “the spent fuel rods in the storage pool at Reactor Number 4 undergo a renewed chain reaction” AND there is unstoppable radiation from reactors 1 & 3 – including plutonium from 3 – what could the dangers be for people living 100, 200, 300 etc kilometers from the site, assuming the wind is blowing their way?

(I have friends in Japan whom I am trying to advise as to the potential dangers.)

Thanking you.

You raise the right questions, for which there are no good answers; certainly, there are no answers that support the view that ‘there is no reason for most people to worry’ (except, perhaps, for the heroic technicians and emergency responders working at Daiichi).

This is a pretty nice summary of what we need to be looking at:

(from: http://www.saiea.com/uranium/Chapter712Radiation.pdf)

“7.12.1.3 Health impacts of exposure to ionising radiation

Damage to living organisms as a result of exposure to ionising radiation mainly occurs at the cellular level, and manifests itself in a variety of ways depending on the type of radiation, the radiation dose and the duration of exposure. The effects of being exposed to ionising radiation in humans range from:

â?¢ Skin burn, which occasionally manifests itself as a result of intense radiotherapy
treatment;
â?¢ Cancer, which includes skin cancer and leukaemia;
â?¢ Teratogenic effects, i.e. the impairment of an embryo in utero; and
â?¢ Blood destruction and death within days, for example when directly exposed to high doses of radiation as would be associated with the explosion of a nuclear weapon.

An important distinction when considering exposure to ionising radiation is between â??promptâ?? or â??acuteâ?? effects, and â??delayedâ?? effects. Prompt effects are usually due to large exposures delivered over a short period of time, as would be the case in an explosion and fallout of a nuclear bomb, or a major accident in a nuclear reactor, and usually occur within hours or days following such exposure. Prompt effects are dose dependent or, more accurately, dependent on the total amount of energy transferred between the source of radiation and the receptor. Below a certain dose there is no discernible effect, but as the dose increases â?? all other things being equal â?? the magnitude and
manifestation of the effects also increase. As there is a direct relationship between the applied dose and the resulting effects, chance is not playing a part here; dose dependent effects are therefore also called â??deterministicâ?? or â??non-stochasticâ??.

Non-stochastic effects have exposure thresholds below which no health effects are observable, while increasing exposures to above such thresholds gives rise to physical effects which are reasonably predictable.

On the other hand, certain kinds of cancer are induced through the prolonged exposure to ionising radiation. Such effects may not occur immediately, or even within a short period following the exposure, or they may not occur at all. Because of the probabilistic nature of such delayed effects, they are also termed â??stochasticâ??. No threshold exists for stochastic effects â?? an increase in radiation dose results in an increase of the likelihood of such effects occurring, but not of the severity of impacts.

Therefore, when considering the effects of prolonged exposures to low levels of ionising radiation, as would for example occur in a population living near uranium mining and milling operations, the possibility of having delayed stochastic effects constitutes the main health concern.

In contrast to non-stochastic effects, it is far more difficult to quantify low level exposure risks and identify exposure thresholds for stochastic effects. This is partly because of the â??all or nothingâ?? nature of such effects, and because it is difficult to separate out the effects of low
level but prolonged radiation exposure from prevailing levels of natural background radiation. In addition, a variety of environmental effects, personal behaviour patterns (such as smoking and air travel) as well as the personal genetic predisposition all have an influence and
determine whether and how substantially a person is affected by low level exposure to ionising radiation.

The actual estimation of the health risk associated with exposures to low levels of ionising radiation is a complex process, which involves determining the type of radiation, duration of exposure and amount of energy actually deposited into particular organs. When exposed to
radionuclides it is important to determine the (radio)-activity of the radionuclides in question, the rate at which the body deals with and eliminates such radionuclides, and identify the target organ, i.e. the particular organ in which the radionuclides are preferentially deposited.

Another consideration when determining the health risk associated with ionising radiation is whether the exposure to such radiation is external, i.e. from the outside of the body as is the case for cosmic and terrestrial gamma radiation, or is internal, which occurs by way of ingesting radioactively contaminated food or water, or as a result of inhaling radioactive dust or gas. Occupationally exposed groups (e.g. workers in the uranium mining sector, or some hospital staff and airline personnel) tend to receive higher exposure doses over time than members of the general public.

When considering a total populationâ??s health risks from radiation, human factors also assume importance. Effects due to the exposure to radiation are generally more serious in unborn babies and children.”

As radioactive materials disseminate through the environment (water, soil, plants, animals, air, etc.), greater numbers of individuals will face indeterminate exposure– some external, some ingested (as the residents of Tokyo, whose tap water is now shown to have increased levels of radioactivity).

What the ‘don’t worry’ crowd seems to downplay, is the cumulative nature of exposure, coupled with the idiosyncratic vulnerabilities of different individuals and cohorts (e.g., young children). The risks can be made to look trivial when washed across the whole population, and when each risk factor is considered in isolation.

I have a suspicion (maybe completely false, but I’ll gladly accept correction from a nuclear advocate), that when someone believes strongly that nuclear reactors are ‘generally safe’, there is a tendency to equate ‘low level exposure’ to ‘can be discounted from future consideration’. Stated differently– ‘this instance of exposure on this day with this person’ (they only ate half an ounce of contaminated spinach, and eight ounces of contaminated water), then those exposures don’t need to be counted towards the total.

The risks of exposure are cumulative, not discrete. It is somewhat misleading to make a statement ‘the dose was less than you might get from a dental X-ray’, with the implication that expressing concern is tantamount to an admission of ignorance, and unwarranted concern (mature, informed people, apparently, wouldn’t worry).

Since I’ve already gotten the dental X-rays, and my exposure from sunlight, and radon, and so forth, I’d rather not keep adding more exposures. Especially since this latest round of exposures for the people of Japan was entirely preventable. No reactor, no increased risk of exposure.

The inevitability of health effects among individuals is what makes the risks of nuclear power unacceptable. The myth of its basic safety relies on considering the risks in isolation, diluting the estimate of risks across populations, and ingnoring the cumulative nature of the risks. Oh, and highly favorable assumtions about likelihood of adverse events.

Back in the days of atomic surface tests fallout was traveling across the US and was rained out across the country. On 4/27/53 a small group of university radiochemistry students at Rensselaer Polytechnic Institute noticed above background levels in their lab, when they surveyed outside they found the ground was very active in some places thousands of times above normal. Downspouts and puddles were especially active samples of puddle water showed a radioactive level of 270,000 micromicrocuries per liter the maximum level permitted by the AEC at the time was 100 mmc/l normal drinking water has 1 mmc/l. Professor Herbert Clark quickly guessed where the high readings had come from it had rained the evening before and an atomic bomb(Operation Upshot-Knothole shot Simon) had been set off two days earlier this was “rainout” a concentrated form of fallout.

Another problem with all the talk of “safe” levels of radiation is not all man made decay products are as benign as natural materials Uranium passes through the body radioactive Iodine and Cesium are incorporated into the tissues of all animals and plants

I guess dropping in some industrial generators or large pumps that have their own motors like those used to pump out flooded dikes or in hazardous liquid removable (often used in mills) are readily available and pump huge amounts of liquid through long lengths of hose. I guess I not there but I vote these guys are idiots and expect it to get worse.

Core catchers were used in the very first nuclear plants. The first meltdown in a plant with core catcher warped the core catcher and it ended up concentrating the material and making it worse.

But you are correct, the Japanese plants don’t have one.