How can we prep for the possibility of radioactive fallout from a nuclear power plant disaster, dirty bomb, or, worst of all, a nuclear explosion

I’ll try to keep this post focused on the prepping and survival aspects of the topic, as opposed to the politics of the situation.

Why should preppers focus some time and effort on preparing for the possibility of nuclear fallout? I would say there are three reasons.

One is the possibility of another nuclear power plant disaster, like that of Fukushima or Chernobyl. A second possibility, hopefully remote, is that some terrorist group might get their hands on enough radioactive material for a dirty bomb. And then there is the ever-increasing possibility of a third scenario, where a rogue nation obtains and decides to use nuclear bombs.

North Korea is of particular concern, since they have already successfully tested a nuclear bomb. And they have an active medium- and long-range missile program. They cannot reach the U.S. yet (as far as we know). But they show no signs of abandoning their research and development of long-range missiles. (General Joseph Dunford warned that North Korea was the most dangerous threat the US faced: “North Korea will develop nuclear weapons capable of reaching the US within a “very short time”, a top US general Joseph Dunford has warned.”)

Many preppers store potassium iodide or potassium iodate for protection from the uptake of radioactive iodine into the thyroid gland. This protection is most useful for children and young adults; the thyroid gland of adults over 40 is much less active. The pills flood the body with non-radioactive iodine, lessening the chance that radioactive iodine will be taken up and stored by the thyroid.

But radioactive fallout also contains radioactive strontium. The radioactive iodine decays quickly, and is gone within 80 days or so. The radioactive strontium has a much longer half-life, and it tends to be taken up by the bones and teeth. That is not what you want. So is there a pill we can use to protect ourselves from radioactive strontium? Yes, it turns out that a number of different over-the-counter antacids are recommended by the National Council on Radiation Protection and Measurement (NCRP) to protect against radioactive strontium.

There are 3 Countermeasures against Radioactive Fallout:

1. Potassium Iodide tablets (KI)

This one, you knew already. KI tablets block the thyroid from storing radioactive iodine, one of the most common radioactive isotopes in nuclear fallout. Essentially, you flood the body with non-radioactive iodine, from the KI tablets, and then any radioactive iodine is much less likely to be taken up and stored in the body. Radioactive iodine has a half-life of 8.1 days, and after 10 half-lives or 81 days, only traces of the radioactive iodine would be left. So it is a short-term countermeasure.

KIO3 tablets work in the same way. But KI is preferred, since KIO3 has a greater likelihood of causing intestinal irritation. According to the World Health Organization: “Tablets packed in a hermetic alufoil and kept in a dry and cool place preserve fully their iodine content for 5 years” [Guidelines for Iodine Prophylaxis following Nuclear Accidents, WHO/SDE/PHE/99.6]

2. Gaviscon

Gaviscon is an over-the-counter antacid. It contains aluminum hydroxide, which blocks the absorption, by your GI tract, of both radium and strontium, two radioactive compounds in nuclear fallout. The HHS site says: “Give one dose within 24 hr of radionuclide intake to block intestinal absorption; administer before absorption occurs.” So it is a one-time dose, to prevent absorption.

Aluminum hydroxide is also available, OTC, as a gel. But Gaviscon contains a second ingredient, sodium alginate (alginic acid), which the HHS site also lists as a blocking agent for radium and strontium. So Gaviscon is preferable.

What happens if radium or strontium gets into your body? Both strontium and radium will be mistaken by the body for calcium and deposited in the bones and teeth. That is not what you want. Strontium and radium remain radioactive for, well, the rest of your life.

3. TUMS (or generic calcium carbonate)

Gaviscon only blocks the absorption of radium and strontium. You need another countermeasure in case some of the radium or strontium is absorbed.

Since both of those radioactive elements are mistaken by the body for calcium, flooding the body with calcium makes it much less likely that the radium and strontium will be taken up and stored in the bones or teeth. The mechanism of action here is much the same as with the KI tablets. If you have enough calcium in your system from the TUMS (or generic calcium carbonate), then the strontium and radium are diluted and are less likely to be stored in the body. Your system takes up the ordinary calcium instead of the radioactive strontium or radium.

The HHS site says: “Use as directed on label” and “Begin therapy within 12 hr of radionuclide intake if possible”.

But while the aluminum hydroxide countermeasure (Gavison) is a one-time dose to prevent absorption, the Calcium Carbonate should be taken daily, during the time that exposure to the radioactive elements is likely.


The above 3 countermeasures are widely available, inexpensive, and are suggested by the HHS and other government authorities to treat internal contamination with radioactive elements. A nuclear power plant disaster is probably the most likely scenario. But we can’t rule out a terrorist dirty bomb, or a nuclear bomb from a rogue nation. In any case, it would be prudent to have the above countermeasures, stored in advance. Once an event occurs, people will buy up all the available OTC countermeasures.

Use Caution

Consult a physician before using any of the above countermeasures. Do not use when there is no radioactive fallout, as use of any of the above compounds is not without health risks.