Mini-FAQ About Japan’s Nuclear Power Plant Crisis

How Bad is Japan’s Nuclear Problem?

There is a lot that is being said and written about Japan’s earthquake-damaged nuclear power plants right now. Sadly, unless there’s a big catastrophe, few people care to learn about nuclear power, so when things go wrong, people aren’t sure what is going on and this can lead to panic. I’m no nuclear expert myself, but in this post I will share what I’ve learned about this situation and answer the most pressing questions that people might have (“Can it blow up? Is it another Chernobyl”) to the best of my knowledge.

Can Japan’s nuclear power plants explode like a nuclear bomb?

Thankfully, it is physically impossible for a nuclear power plant to explode like a nuclear bomb. It simply doesn’t have the right kinds of materials: A fission bomb uses highly enriched uranium or plutonium (90%+ of U-235 or Pu-239), while a nuclear power station generally uses Uranium that is only enriched to around 5% (sometimes up to 20% in smaller research reactors). A nuclear power station also lacks all the other mechanisms that are necessary to create a nuclear explosion (like for example the implosion or gun-type assembly configurations that allow supercritical mass to be reached).

What is a ‘meltdown’?

When you get right down to it, a nuclear power plant is very sophisticated way to boil water. Controlled fission in the core generates heat, which creates steam that spins turbines.

When a big earthquake hits, nuclear power plants are programmed to automatically shut down. But even after the fission reaction in the core is stopped, it takes a certain time for the radioactive byproducts to decay and cool down. If something – in this case a huge earthquake and tsunami double hit – prevents the cooling system from pumping water to the core and the emergency cooling system is prevented from kicking in, it can get hot enough to melt. In the very worst cases, part of the containment building, which envelops the reactor vessel which itself contains the fuel rods (it’s like a russian doll of buildings), can partially melt, but containment buildings are designed to withstand the high pressures and high temperatures that occur in a meltdown, so in principle they should hold and allow the fuel rods to cool down safely over the next days.

Is a repeat of what happened at Chernobyl likely?

It appears extremely unlikely because the Japanese nuclear power plants, as well as all nuclear power plants now in operation around the world, are designed very differently from the plant that exploded in Ukraine in 1986. The crucial difference is that the soviet reactor was not inside any kind of hard containment vessel. This means that when it failed, the high pressure couldn’t be contained, which caused steam explosions that destroyed the reactor building and caused fires that sent a plume of radioactive fallout into the atmosphere. Chernobyl didn’t explode like a nuclear bomb, it was closer to a “dirty bomb”, which is a conventional bomb that spreads radioactive material around. The Japanese nukes have containment buildings and some seem to already have been vented to reduce the pressure inside.

What kind of radiation exposure can be expected, and what are the potential health effects?

Treehugger just did a post about this very thing, so I suggest you go check it out. The good news is that potential exposure seems extremely low even for people who are close and likely to remain so.

This post originally appears on Treehugger.

For more Care2 coverage on the Japanese tsunami and earthquake, click here.


Photo courtesy of Beacon Radio via flickr
Written by Michael Graham Richard, a Treehugger blogger


Walter G.
Walter G5 years ago

too bad for them, and for us who now share in their pollution, that they caved in to internal politics instead of insisting ion green energy sources isn't it? Fortunately the USA is too intelligent to let taht happen within its borders. OK, if you all don't stop laughing so loud it will drown out the rest of my speech.

Jane R.
Jane R5 years ago

It's worse than any of you might expect. Radioactive fallout will reach the U.S., no doubt about that. It's already reached California. What will this do to our food supply? Many veggies and fruit are grown there. Will they be safe to eat? This accident of nature will harm people for decades. Don't let anyone tell you differently.

ana p.
ana p5 years ago


Susan S.
Susan S5 years ago

Thanks for the overview.

Marilyn L.
Marilyn L5 years ago

Thanks Lindsey for a well thought out article.

pam wilkerson
pam wilkerson5 years ago

I agree it is not nice to fool mothernature!!

Jonathan B.
Jonathan B5 years ago

The events in Japan triggered by the earthquake and tsunami have triggered a much more serious situation than the press has been letting on.

First, there was a three thousand foot explosion at a MOX reactor in Japan, as well as two other explosions in conventional uranium powered reactors.

MOX reactors have a 6% Plutonium element in the fuel rods as well as 94% uranium, so this is a much more dangerous reactor in an accident.

Plutonium can kill an adult dog with one single molecule of material.

The trade winds blow from Japan to the continental United States, and in a couple of days, we will face a variety of radioactive isotopes blowing from Japan.

It is VITAL that the public consume kelp, sea vagetables, and other nutrietive iodine sources to protect the thyroid, since the biggest risk of fallout is the absorption of isotopes into the thyroid, which can occur of the public is not consuming enough kelp and sea vegetable, dulse or other iodine sources.

Lynnette Bower
Lynnette Bower5 years ago

It's not nice to fool Mother Nature.

Kay L.
KayL NOFORWARDS5 years ago

Good, clear explanation. Thank you.

Annahlah C.
Avalon C5 years ago

Thank you for taking the time to clear things up for people who have no information of nuclear power generation.