How about your own neighborhood nuclear energy plant?

[RD]

Yeah, wow.  I make a couple of comments about nuclear reactors and all of a sudden I'm in negative karmic territory...    

[KBCraig]

Yeah, wow.  I make a couple of comments about nuclear reactors and all of a sudden I'm in negative karmic territory...    

Joe certainly knows how you feel. If you make comments about 9/11 truthers, you can probably join him at -50.

[Pat McCotter]

Pebble bed reactors. China and South Africa are working on these. China has a working prototype. The working fluid is helium or nitrogen or other inert gas.

The one big drawback is that the "pebbles" must be constructed to very exacting standards.

[RD]

My understanding is that pebble bed reactors still have the problem of overheating due to loss of coolant accidents.  Although the fuel supposedly won't melt, you'd need an enormous reactor vessel and containment building.  So a neighborhood-sized reactor would still require an ultimate heat sink.

They also create more radioactive waste than traditional designs, if I'm not mistaken.

[MaineShark]

My understanding is that pebble bed reactors still have the problem of overheating due to loss of coolant accidents.  Although the fuel supposedly won't melt, you'd need an enormous reactor vessel and containment building.  So a neighborhood-sized reactor would still require an ultimate heat sink.

They also create more radioactive waste than traditional designs, if I'm not mistaken.

You really need to get those calculations done.

A properly-designed reactor really cannot overheat, even without some major source of running water.  They can dump enough through conduction and radiation to handle the small amount of heat generated by decay.

You'd be amazed at the actual number of reactors around that are operating safely without "ultimate heat sinks."

Joe

[RD]

You'd be amazed at the actual number of reactors around that are operating safely without "ultimate heat sinks."

I'd love to read about them.  Do you have any references?  Thanks.

[MaineShark]

You'd be amazed at the actual number of reactors around that are operating safely without "ultimate heat sinks."

I'd love to read about them.  Do you have any references?  Thanks.

Um, every major engineering school?

Joe

[penguins4me]

I'd also like to point out that not one (not modern, anyhow) reactor design relies upon "the ultimate heatsink", a large body of water, to directly cool the core. That would be no different in practice than simply allowing the containment vessel to rupture and "release highly radioactive iodines, noble gases, and other fission products", as the "ultimate heatsink" water itself would become thoroughly contaminated with radioactive particles which would then migrate a certain distance down the water's direction of flow.

Nuclear reactors are often located next to large bodies of water because it is convenient to have access to large quantities of water to run through a heat exchanger, not as an emergency "if we have to, we can dump the core into the river!" plan.

[PattyLee loves dogs]

The pebble bed reactors really can't melt down if properly designed. It's called "doppler spectrum spreading"; the fuel is mostly U238 (like in all civilian power reactors), and if the temperature goes up the neutrons start getting absorbed into the U238 instead of the U235.

Every little kid knows this stuff in Europe, China, India... everyone but Amurricans, I guess. (Even though we still get 20% of our electricity from our ancient pre-1978 reactors  )

http://www.lewrockwell.com/walker/walker14.html

[ReverendRyan]

An easy way to put it is that Generation IV reactors are exponentially safer than Gen II. But the watermelon lobby has interfered with the construction of Gen IV's because of their fear of Gen II's, and no new reactors have been built since the Gen II's because of it.

[PattyLee loves dogs]

and no new reactors have been built

In the US... they build reactors almost everywhere else except Portugal and Zimbabwe.

Quite right about the generations, of course.

[KBCraig]

I have no idea what they mean by "10 cents a watt". Watt-hours? Watt-minutes? Watt-years? "Watts" are a rate of flow, not a unit of volume. Electricity is priced in kilowatt-hours, at least in the U.S. (this is a British article).

http://www.guardian.co.uk/environment/2008/nov/09/miniature-nuclear-reactors-los-alamos

Mini nuclear plants to power 20,000 homes
£13m shed-size reactors will be delivered by lorry

Nuclear power plants smaller than a garden shed and able to power 20,000 homes will be on sale within five years, say scientists at Los Alamos, the US government laboratory which developed the first atomic bomb.

The miniature reactors will be factory-sealed, contain no weapons-grade material, have no moving parts and will be nearly impossible to steal because they will be encased in concrete and buried underground.

The US government has licensed the technology to Hyperion, a New Mexico-based company which said last week that it has taken its first firm orders and plans to start mass production within five years. 'Our goal is to generate electricity for 10 cents a watt anywhere in the world,' said John Deal, chief executive of Hyperion. 'They will cost approximately $25m [£13m] each. For a community with 10,000 households, that is a very affordable $250 per home.'

Deal claims to have more than 100 firm orders, largely from the oil and electricity industries, but says the company is also targeting developing countries and isolated communities. 'It's leapfrog technology,' he said.

The company plans to set up three factories to produce 4,000 plants between 2013 and 2023. 'We already have a pipeline for 100 reactors, and we are taking our time to tool up to mass-produce this reactor.'

The first confirmed order came from TES, a Czech infrastructure company specialising in water plants and power plants. 'They ordered six units and optioned a further 12. We are very sure of their capability to purchase,' said Deal. The first one, he said, would be installed in Romania. 'We now have a six-year waiting list. We are in talks with developers in the Cayman Islands, Panama and the Bahamas.'

The reactors, only a few metres in diameter, will be delivered on the back of a lorry to be buried underground. They must be refuelled every 7 to 10 years. Because the reactor is based on a 50-year-old design that has proved safe for students to use, few countries are expected to object to plants on their territory. An application to build the plants will be submitted to the Nuclear Regulatory Commission next year.

'You could never have a Chernobyl-type event - there are no moving parts,' said Deal. 'You would need nation-state resources in order to enrich our uranium. Temperature-wise it's too hot to handle. It would be like stealing a barbecue with your bare hands.'

Other companies are known to be designing micro-reactors. Toshiba has been testing 200KW reactors measuring roughly six metres by two metres. Designed to fuel smaller numbers of homes for longer, they could power a single building for up to 40 years.

[Pat McCotter]

I have no idea what they mean by "10 cents a watt". Watt-hours? Watt-minutes? Watt-years? "Watts" are a rate of flow, not a unit of volume. Electricity is priced in kilowatt-hours, at least in the U.S. (this is a British article).

Construction of power plants is sometimes quoted in dollars per Watt. Looking at Hyperion's website these units are 25MWe in size so at $25,000,000.00 that comes to $0.10/W to build.