Friday, June 12, 2009

mPower Modular Nuclear Reactor for TVA

Modular nuclear reactors provide a much more versatile load matching for utility and grid designers. Babcock and Wilcox of Lynchburg, Virginia, build a modular 125 MW nuclear reactor called the mPower. The US TVA is lining up to be the lead client for the mPower, possibly siting the first modular reactor in the Oak Ridge area.
Here is a bullet list of the key features of the mPowerTM as I see them:

* Pressurized water reactor (PWR) 17 x 17 fuel bundles
(Shorter than normal, but otherwise standard)
* Five year refueling schedule
* Fuel storage pool large enough for 60 years worth of fuel
* Adaptable to advances in LWR fuel
(MOX or thorium)
* Below grade construction in most locations
* Air cooled condensers
* Tall, thin pressure vessel
* Passive cooling
* Manufactured system with rail delivery to site
* American engineering and manufacturing (avoids queue at Japan Steel Works)
* 125 MWe of electrical power output
(I admit, I was wrong yesterday with my prediction of an even smaller system, but 125 MW is about 10th the size of the AP-1000.)

Knowing what I know about the company's performance for a very demanding customer, I feel reasonably confident that the timelines announced yesterday (design certification application in 2011, COL application in 2012, full license in 2015 and commercial operation in 2018) are not "stretch goals", but are reasonably achievable with some margin for the inevitable obstacles. _AtomicInsights
Medium sized nuclear reactors of this type can be "ganged" to achieve the power production of a full-sized 1 GW reactor, or can be distributed at strategic locations along the grid to provide critical baseload power for a region if adjacent grid regions shut down for some reason.

Like any nuclear reactor, it takes time to start up and shut down safely, so it would not serve as backup for unreliable wind power installations.

Small scale nuclear reactors -- smaller than the mPower -- would be ideal as local and regional baseload power in case of a large scale power shut down caused by EMP or excessive solar electromagnetic activity. In such a situation, available power components such as transformers and power electronics would be relatively scarce, and insufficient to support full scale power grid re-start. The grid would have to re-start in sections, as the components could be repaired, rebuilt, or replaced -- which could take years in some circumstances.



Anonymous Anonymous said...

Assuming this small reactor has the same thermal efficiency of larger reactors then it could help the US have a more efficient electrical distribution system.

Right now electricity is generated 100 miles or more away from the consumer at large megastations, and then this electricity is distributed over long power lines that often have *relatively* high transmission losses. If this reactor was mass produced it could be sited close to the consumer, and could allow us to break up the current hub-and-spoke grid into a patchwork of isolated grids. Having relatively small local grids would also keep major grid failures contained to one state or region.

Also, smaller reactors can be mass produced eliminating the bane of the American reactor inductry: custom, one of a kind parts of dubious quality. Instead the parts can be produced by the thousands in an ISO-9001 facility.

2:55 PM  

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