There is a good deal of misinformation being circulated about the potential harm to people in Japan from plutonium present in mixed oxide (MOX) fuel in the unit 3 reactor at Fukushima Daiichi.  The real story comes from an independent group of scientists who make up the American Nuclear Society Special Committee on Nuclear Non-Proliferation .  Their conclusion?

Mixed Oxide (MOX) fuel has been used safely in nuclear power reactors for decades.  The presence of a limited number of MOX fuel assemblies at Fukushima Daiichi Unit 3 has not had a significant impact on the ability to cool the reactor or on any radioactive releases from the site due to damage from the earthquake and tsunami.

Here’s a link to their full report.  It’s a short read and provides an excellent explanation of the current situation and risks associated with MOX fuel.

Back in TWiN Episode #77 I covered the topic of MOX fuel, where it comes from, and where it is used.  Here are some important facts about MOX nuclear fuel:

  • MOX present in nuclear plant fuel changes some aspects of the fuel’s performance in accident conditions, but these changes are relatively minor (see the ANS letter for details on this).
  • MOX fuel comes from two main sources; recycling former weapons material into nuclear fuel, and recycling used nuclear power plant fuel for reuse.
  • Creating MOX for power reactors is a safe way to dispose of weapons grade plutonium.
  • MOX fuel can not be used to make nuclear weapons.  The NRC states “Using the plutonium in the reactor as MOX fuel makes using it for any other purposes difficult.”
  • Plutonium in nuclear fuel is not unique to MOX fueled reactors.  All nuclear reactors contain plutonium after the reactor has been in operation for any period of time.  In fact, at the end of life of a typical low enriched uranium core up to about 20% of the heat being generated is from the fission of plutonium atoms.
  • Plutonium in MOX fueled reactors can not cause the reactor to explode.