You’ve probably heard of iodine pills as ‘radiation pills’ and its somewhat commonly known to take iodine to protect your thyroids from radioactive fallout. However it only protects you from the relatively short lived iodine 131.
In theory, many harmful late-cancer effects of nuclear fallout might be prevented in this way, since an excess of thyroid cancers, presumably due to radioiodine uptake, is the only proven radioisotope contamination effect after a fission accident, or from contamination by fallout from an atomic bomb (prompt radiation from the bomb also causes other cancers, such as leukemias, directly).
Taking large amounts of iodide saturates thyroid receptors and prevents uptake of most radioactive iodine-131 that may be present from fission product exposure (although it does not protect from other radioisotopes, nor from any other form of direct radiation).
The protective effect of KI lasts approximately 24 hours, so must be dosed daily until a risk of significant exposure to radioiodines from fission products no longer exists. Iodine-131 (the most common radioiodine contaminant in fallout) also decays relatively rapidly with a half-life of eight days, so that 99.95% of the original radioiodine has vanished after three months. -Wikipedia
The iodine supplement must be taken every 24 hours however. And it doesn’t protect you from other radioactive isotopes like strontium-90. Strontium-90 mimics calcium and is taken up into the bones. It has a much longer half life than 8 days! So you should take calcium supplements too.
New fission products are continually being produced and dumped into the ocean and probably the air as well. Reports of 300 tons of contaminated water are flowing into the pacific ocean. And there are reports of steam coming out of some of the burned out reactors from the still molten and cores down in the ground underneath the reactors. They melted through containment 6 years ago in 2011 and continue to melt deeper into the their corium boreholes. It is hypothesized that they are now in the ground water, sitting there, still fissioning and hot as hell no doubt. Attempts to send robots in result in failure of the electronics inside of two hours. No one knows where the cores are to date. And Tepco has even said that the technology to re-mediate and decommission the plants by retrieval of the corium and spent fuel in a pool in reactor 4. The technology doesnt exist yet! In other words they havent a clue what they are doing.
This is a global problem, and an effectively ‘forever’ one as well. Its time something is done about it, no doubt the entire global community should be involved.