Pretty cool idea. Well, hot really but, you know what I mean.
Posted on 02/25/2009 3:45:37 PM PST by Reaganesque
A new way of fueling reactors could make nuclear power safer and less expensive, says John Gilleland. By Matt Wald
Enriching the uranium for reactor fuel and opening the reactor periodically to refuel it are among the most cumbersome and expensive steps in running a nuclear plant. And after spent fuel is removed from the reactor, reprocessing it to recover usable materials has the same drawbacks, plus two more: the risks of nuclear-weapons proliferation and environmental pollution.
These problems are mostly accepted as a given, but not by a group of researchers at Intellectual Ventures, an invention and investment company in Bellevue, WA. The scientists there have come up with a preliminary design for a reactor that requires only a small amount of enriched fuel--that is, the kind whose atoms can easily be split in a chain reaction. It's called a traveling-wave reactor. And while government researchers intermittently bring out new reactor designs, the traveling-wave reactor is noteworthy for having come from something that barely exists in the nuclear industry: a privately funded research company.
As it runs, the core in a traveling-wave reactor gradually converts nonfissile material into the fuel it needs. Nuclear reactors based on such designs "theoretically could run for a couple of hundred years" without refueling, says John Gilleland, manager of nuclear programs at Intellectual Ventures.
Gilleland's aim is to run a nuclear reactor on what is now waste. Conventional reactors use uranium-235, which splits easily to carry on a chain reaction but is scarce and expensive; it must be separated from the more common, nonfissile uranium-238 in special enrichment plants. Every 18 to 24 months, the reactor must be opened, hundreds of fuel bundles removed, hundreds added, and the remainder reshuffled to supply all the fissile uranium needed for the next run. This raises proliferation concerns, since an enrichment plant designed to make low-enriched uranium for a power reactor differs trivially from one that makes highly enriched material for a bomb.
But the traveling-wave reactor needs only a thin layer of enriched U-235. Most of the core is U-238, millions of pounds of which are stockpiled around the world as leftovers from natural uranium after the U-235 has been scavenged. The design provides "the simplest possible fuel cycle," says Charles W. Forsberg, executive director of the Nuclear Fuel Cycle Project at MIT, "and it requires only one uranium enrichment plant per planet."
The trick is that the reactor itself will convert the uranium-238 into a usable fuel, plutonium-239. Conventional reactors also produce P-239, but using it requires removing the spent fuel, chopping it up, and chemically extracting the plutonium--a dirty, expensive process that is also a major step toward building an atomic bomb. The traveling-wave reactor produces plutonium and uses it at once, eliminating the possibility of its being diverted for weapons. An active region less than a meter thick moves along the reactor core, breeding new plutonium in front of it.
The traveling-wave idea dates to the early 1990s. However, Gilleland's team is the first to develop a practical design. Intellectual Ventures has patented the technology; the company says it is in licensing discussions with reactor manufacturers but won't name them. Although there are still some basic design issues to be worked out--for instance, precise models of how the reactor would behave under accident conditions--Gilleland thinks a commercial unit could be running by the early 2020s.
While Intellectual Ventures has caught the attention of academics, the commercial industry--hoping to stimulate interest in an energy source that doesn't contribute to global warming--is focused on selling its first reactors in the U.S. in 30 years. The designs it's proposing, however, are essentially updates on the models operating today. Intellectual Ventures thinks that the traveling-wave design will have more appeal a bit further down the road, when a nuclear renaissance is fully under way and fuel supplies look tight.
"We need a little excitement in the nuclear field," says Forsberg. "We have too many people working on 1/10th of 1 percent change."
Pretty cool idea. Well, hot really but, you know what I mean.
Pingin’ me.
Neat idea. I picture the nuclear pile being “burned” thru like a slow burning match. It is especially cleaver in creating and then using plutonium on-the-fly.
Barbara Streisand, who exactly is going to build these nuclear weapons??? The U.S. Government, who already has reactors designed to produce weapons grade plutonium??? Anyone hear of Hanford??? Why would reprocessing spent fuel rods proliferate something that the government already does????
I still think the pebble bed reactor design is the coolest, but this certainly should be researched further.
Curious what the waste products are, and what will be done with them.
Also curious how long it takes to burn through the fuel block and how the reaction is stopped once it starts - maybe the hex-shaped rods can be pulled up to cut the reaction?
For those interested:
http://en.wikipedia.org/wiki/Nuclear_fuel_cycle
http://en.wikipedia.org/wiki/Breeder_reactor
“Enrichment” is the key. It takes 5% U235 to make nuclear reactor fuel; to make nuclear bombs, it takes at least 20% U235 to be weapons-useable, 85% is better. This is not an easy task, especially when you’re talking about converting depleted nuclear fuel into a weapon.
A “Mr. Fusion”, perhaps?
Well, if those come out anytime soon, I’ll be out of a job...but if they’re affordable, I guess I won’t need one!
Don’t know what your job is. But if you could see yourself installing these babies, don’t worry about your job.
This is amazing! We have a half million tons of potential nuke fuel and all we have to do is pull it out of storage and burn it. We are so close to energy independence, it hurts.
A lot of “spent” fuel can be recycled several times. It gets more expensive, but it can be done.
Nuclear chemistry? Isn’t that just another name for nuclear physics? :)
Analytical chemistry in the nuclear industry. NOT the same, I’m afraid.
Though to answer your question, I don’t know if there are chemists who go sub-atomic.
They call me a radiochemist. I work for the Navy. We're a pretty rare breed of chemist since the Chernobyl and TMI years.
I wonder what the delta T is on these reactors. I'm thinking not nearly as high as a PWR, and if so, they won't be very useful for propulsion plants.
Besides, by the time these come on line, I will either have drool dripping from my chin or I'll be worm food.
2020? Oh, you're an OLD chemist. I thought old chemists didn't die, their reaction rates just slowed down?
They call me a radiochemist.
My friends like to call me a "nuclear chemist" because it sounds like they have a really smart friend.
I wonder what the delta T is on these reactors. I'm thinking not nearly as high as a PWR, and if so, they won't be very useful for propulsion plants.
I suppose we'll have to wait until they do some real peer-reviewed publishing to see their numbers. What's typical for a PWR?
Damn straight and I still have all my hair too. It's just that it's growing out of my ears now.
My friends like to call me a "nuclear chemist" because it sounds like they have a really smart friend.
Yeah, that's probably better. I always get questions about when my show on the radio is on.
What's typical for a PWR?
Well that, they say in navy circles, is not for general discussion. However, a PWR is a PWR is a PWR. One quick google and all the Navy's secrets are the talk of the town.
Nice technology, mayve, because you don’t have the technological/financial overhead and physical space requirements of changing rods, it may be worthwhile considering to built compact TWRs in salt caverns, so that you don’t even have to dismantle and have to move waste after finally decommishioning them after 100 years or so.
Yah, ditto!
Speaking of nuke designs — anyone have any idea why GE BWRS have a dry sump, what purpose does it serve?
Pretty Wide Rabbit?
Purple/White Roads?
People With Radishes?
;-)
What? You mean everybody doesn’t eat my brand of alphabet soup?
PWR = Pressurized Water Reactor, that is, a big ole pressure cooker, as opposed to a
BWR = Boiling Water Reactor, a teapot sitting on the stove.
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