Why do we offer light-water reactors to our enemies?

Answers to your questions about the news.
June 2 2006 6:36 PM

Can I Interest You in a Light-Water Reactor?

The weapons inspector's best friend.

Download the MP3 audio version of this story here, or sign up for The Explainer's free daily podcast on iTunes.

On Thursday, China and Russia signed on to the West's latest attempt to defuse the nuclear standoff with Iran. The incentive package that's now on the table includes a light-water reactor for civilian use. A similar deal had been worked out with North Korea in 1994, but the construction of that light-water reactor was officially terminated on Wednesday. Why do we like to offer this kind of power plant to nuke-hungry nations?

Because it's the most "proliferation-resistant" nuclear reactor on the market. There are two ways to make nuclear weapons. You can either take fresh reactor fuel and enrich it—as many fear the Iranians plan to do with all their centrifuges—or you can reprocess used-up reactor fuel into weapons-grade plutonium. The latter option becomes much more difficult and expensive when you're using a light-water reactor.

Daniel Engber Daniel Engber

Daniel Engber is a columnist for Slate

Advertisement

Light-water reactors are designed for commercial use and can run for years at a time on a single batch of fuel. ("Light water" refers to ordinary H2O; "heavy water" has a higher percentage of deuterium atoms, i.e. hydrogen atoms with an extra neutron.) That long burn fills out the plutonium by-product with other isotopes that make it less useful for nuclear weapons. If you shut down a light-water reactor early—after a few months, for example—you'd waste a huge amount of money.

Furthermore, it would be very easy to tell when the Iranians or North Koreans shut down their light-water reactors. To extract the fuel rods, you have to lift off a giant lid at the top of the reactor and take them out all at once. Weapons inspectors love this feature because it requires a large-scale operation that's almost impossible to conceal.

So-called "research reactors" tend to be both harder to inspect and more efficient at producing weapons-usable plutonium than the light-water variety. The North Koreans say they've already pulled some plutonium from their gas-cooled research reactor at Yongbyon. You can run a gas-cooled reactor for a few months at a time and then pull out the fuel rods for reprocessing without making a big deal of it.

We might offer Iran a Canadian-style, heavy-water reactor, which can also be used for non-military purposes. The only problem is that its design allows for the replacement of just a few fuel rods at a time. That makes reprocessing the spent fuel rods on the sly a much simpler operation.

Got a question about today's news? Ask the Explainer.

Explainer thanks Peter Hayes and David von Hippel of the Nautilus Institute.

TODAY IN SLATE

Frame Game

Hard Knocks

I was hit by a teacher in an East Texas public school. It taught me nothing.

Chief Justice John Roberts Says $1,000 Can’t Buy Influence in Congress. Looks Like He’s Wrong.

After This Merger, One Company Could Control One-Third of the Planet's Beer Sales

Hidden Messages in Corporate Logos

If You’re Outraged by the NFL, Follow This Satirical Blowhard on Twitter

Sports Nut

Giving Up on Goodell

How the NFL lost the trust of its most loyal reporters.

How Can We Investigate Potential Dangers of Fracking Without Being Alarmist?

My Year as an Abortion Doula       

  News & Politics
Weigel
Sept. 15 2014 8:56 PM The Benghazi Whistleblower Who Might Have Revealed a Massive Scandal on his Poetry Blog
  Business
Moneybox
Sept. 15 2014 7:27 PM Could IUDs Be the Next Great Weapon in the Battle Against Poverty?
  Life
Outward
Sept. 15 2014 4:38 PM What Is Straight Ice Cream?
  Double X
The XX Factor
Sept. 15 2014 3:31 PM My Year As an Abortion Doula
  Slate Plus
Tv Club
Sept. 15 2014 11:38 AM The Slate Doctor Who Podcast: Episode 4  A spoiler-filled discussion of "Listen."
  Arts
Brow Beat
Sept. 15 2014 8:58 PM Lorde Does an Excellent Cover of Kanye West’s “Flashing Lights”
  Technology
Future Tense
Sept. 15 2014 4:49 PM Cheetah Robot Is Now Wireless and Gallivanting on MIT’s Campus
  Health & Science
Bad Astronomy
Sept. 15 2014 11:00 AM The Comet and the Cosmic Beehive
  Sports
Sports Nut
Sept. 15 2014 9:05 PM Giving Up on Goodell How the NFL lost the trust of its most loyal reporters.