Japan To Create a Nuclear Meltdown

Taco Cowboy writes "Japanese researchers are planning an experiment to better understand what transpires during a nuclear meltdown by attempting to create a controlled nuclear meltdown. Using a scaled down version of a nuclear reactor — essentially a meter long stainless steel container — the experiment will involve the insertion of a foot long (30 cm) nuclear fuel rod, starting the fission process, and then draining the coolant. The experiment is scheduled to take place later this year."

Comments

Great

[StripedCow]

What could possibly go wrong?

By the way, didn't they have to hand in their license to do nuclear stuff already?

Re:Great

[Stargoat]

What could possibly go wrong?

I believe that's what they want to find out.

Re:Great

[Sarten-X]

And, it should be noted, they want to find out in controlled conditions with sufficient protective equipment in a facility explicitly configured for this kind of situation. This is science.

Re:Great

[ebno-10db]

This is science.

The problem is that it should have been done decades ago. You're supposed to test failure modes before you declare something safe. That's doubly true of something as potentially dangerous as nuclear meltdowns.

Re:Great

[Sarten-X]

Fukushima's containment vessel could (and did) contain the molten core... but not the hydrogen explosions that also occurred inside the reactor chamber because of the total coolant loss.

My language should imply that nuclear reactors are safe against the foreseen failure modes. At Fukushima Daiichi, it was not expected that all of the coolant systems would fail at once and that repairs would be hampered by the tsunami damage.

Re:Great

[amorsen]

Good luck with that. IDB Reference Characteristics of LWR Nuclear Fuel Assemblies from the 1996 Integrated Database Report (copied from Nuclear Tourist) mentions a fuel rod assembly containing 185 kg uranium. In contrast, Little Boy which destroyed Hiroshima contained 64 kg uranium, and that was certainly not a 100% efficient fission reaction.

It is not realistic to design nuclear power plants to withstand the maximum energy you could get out of the reaction. That would kill off the nuclear industry.

Feel free to start discussing whether it is realistic to get all the energy out of the 185 kg uranium. You can argue that it is less highly enriched than bombs, and that it is entirely unlikely that uranium which is mostly U-238 is going to suddenly decide to fission. I completely agree, but then we are no longer protecting against the maximum energy that could get released.

Good Idea

[Anonymous Coward]

It seems so obvious to me now, having seen the idea in print. This is not the sort of thing that is easy to analyze. A test is really a good way to understand the phenomenon. The paradigm where engineers attempt to make sure it never happens has its limits. Looking at what happens during the failure will allow engineers to develop meaningful "defense in depth" measures.

Regards,
Jason C. Wells

Re:Good Idea

[ebno-10db]

The paradigm where engineers attempt to make sure it never happens has its limits. Looking at what happens during the failure will allow engineers to develop meaningful "defense in depth" measures.

That was understood decades ago, and has been SOP for that long in other safety critical applications like aircraft. The fact that it wasn't done before this is extreme negligence.

Redundant?

[TheBilgeRat]

Don't they have an open-air experiment going on already? Just take a day trip to Fukushima.