Friday, December 21, 2007

Toshiba's Neighborhood Nuke

Westinghouse AP1000 Nuclear Plant (Jan 25, 2006) drawing The News and Observer.
Click to Enlarge.

Micro-Nuke in Blogs; Not in Paper of Record.

All you have to do is google Toshiba micro nuclear and up come a bunch of links. Slashdot went freaking nuts on this, although the paper of record remains silent. (On this. Much to say on other issues. For example, it likes Sweeney Todd and Charlie Wilson's War. I may go see one of these myself this weekend. But I digress.)


Examining further, it certainly isn't the AP1000 I have the diagram of up top. That's massively too big. (Toshiba purchased Westinghouse last year.)


It does seem like the company is well on its way to commercializing the design.

Toshiba's Micro Nuclear reactors are designed to power a single apartment building or city block, and measure a mere 20-feet by 6-feet. The 200 kilowatt reactor is fully automatic and fail-safe, and is completely self-sustaining. It uses special liquid lithium-6 reservoirs instead of traditional control rods, and can last up to 40 years, making energy for about 5 cents per kilowatt hour.
One of these with their ability to power just -- as Engadget points out -- an apartment building or a city block, would be perfect for a small data center, a call center, or a few of them for communities off the grid.

The key is regulatory approval.

Let me give you that again...

The key is regulatory approval AND dealing with NIMBY -- Not In My Back Yard.

I know this isn't the great progressive position to take, but I'm not reactionary about these things. I'd want to see the science, before rejecting it out of hand. Energy is the issue these days, and I'm interested in any solution which doesn't include a one-third to two-thirds die-off of the human race back to our normal pre-petroleum planet-wide carrying capacity. If nuclear is part of that solution, even for a hundred years, well, so be it.

Or shall we line up your family and have you watch one or two out of three die of starvation or worse as you sit there while we run out of oil? In the next fifteen to thirty years? Okay then. Moving on... (And yes, of course I'm open to rebuttals in comments. Please be polite, provide evidence to support your positions, and use a name, even if it's pseudonymous.)

I did a bunch of digging around and I think -- key word think -- that what they're talking about is a kind of Liquid Metal cooled Fast Reactor called the Rapid-L. This is not the 4S design (also talked about below.)
Encyclopedia of Earth

Liquid Metal cooled Fast Reactors

Fast neutron reactors have no moderator, a higher neutron flux and are normally cooled by liquid metal such as sodium, lead, or lead-bismuth, with high conductivity and boiling point. They operate at or near atmospheric pressure and have passive safety features (most have convection circulating the primary coolant). Automatic load following is achieved due to the reactivity feedback—constrained coolant flow leads to higher core temperature which slows the reaction. Primary coolant flow is by convection. They typically use boron carbide control rods.

A small-scale design developed by Toshiba Corporation in cooperation with Japan's Central Research Institute of Electric Power Industry (CRIEPI) and funded by the Japan Atomic Energy Research Institute (JAERI) is the 5 MWt, 200 kWe Rapid-L, using lithium-6 (a liquid neutron poison) as a control medium. It would have 2700 fuel pins of 40-50% enriched uranium nitride with 2600°C melting point integrated into a disposable cartridge. The reactivity control system is passive, using lithium expansion modules (LEM) which give burnup compensation, partial load operation as well as negative reactivity feedback. As the reactor temperature rises, the lithium expands into the core, displacing an inert gas. Other kinds of lithium modules, also integrated into the fuel cartridge, shut down and start up the nuclear reactor. Cooling is by molten sodium, and with the LEM control system, reactor power is proportional to primary coolant flow rate. Refuelling would be every 10 years in an inert gas environment. Operation would require no skill, due to the inherent safety design features. The whole plant would be about 6.5 meters high and 2 meters in diameter.

The Super-Safe, Small & Simple (4S) 'nuclear battery' system is being developed by Toshiba and CRIEPI in Japan in collaboration with STAR work in USA. It uses sodium as coolant (with electromagnetic pumps) and has passive safety features, notably negative temperature and void reactivity. The whole unit would be factory-built, transported to site, installed below ground level, and would drive a steam cycle. It is capable of three decades of continuous operation without refuelling. Metallic fuel (169 pins 10mm in diameter) is uranium-zirconium or uranium-plutonium-zirconium alloy enriched to less than 20%. Steady power output over the core lifetime is achieved by progressively moving upwards an annular reflector around the slender core (0.68m diameter, 2m high). After 14 years, a neutron absorber at the center of the core is removed and the reflector repeats its slow movement up the core for 16 more years. In the event of power loss, the reflector falls to the bottom of the reactor vessel, slowing the reaction, and external air circulation gives decay heat removal.

Both 10 MWe and 50 MWe versions of 4S are designed to automatically maintain an outlet coolant temperature of 510°C—suitable for power generation with high temperature electrolytic hydrogen production. Plant cost is projected at US$2500/kW and power cost 5-7 cents/kWh for the small unit—very competitive with diesel in many locations. The design has gained considerable support in Alaska and toward the end of 2004 the town of Galena granted initial approval for Toshiba to build a 4S reactor in the remote location. A pre-application review by the Nuclear Regulatory Commission (NRC) is being sought with a view to a demonstration unit operating by 2012. Its design is sufficiently similar to PRISM—GE's modular 150 MWe liquid metal-cooled inherently-safe reactor that went part-way through US NRC approval process, giving it favorable prospects for licensing.

There's more...
Well the thing looks real.

I wonder why all the sudden drama? Who is pushing to get this hyped?

We just got a significantly more friendly nuclear regulatory environment *waves to Vice President Cheney* so I wonder...

What the hell is going on?