Tennessee Valley Authority Expecting Nuctuplets


Small enough to hide from the durned Revenoors? Image credit:Flickr, Mushy's Captures

TVA and reactor-maker Babcock and Wilcox have agreed to work together to see if they can build up to 6 "small reactors." Nuctuplets, then? They can knock these babys off on a production line and install them one after the other, linking to the power grid in sequence of commissioning. The combined capacity will add up to that of a traditional Daddy Nuc and avert the extended review typically needed for licensing and building just one of those. (This approach parallels the advantages of a wind farm: each wind turbine you put up helps pay for the overall wind farm while construction is still underway.)Sourcing advantage.
So large in diameter are the pipes needed to move water and steam for a traditional 1000+ MW Daddy Nuc, such pipes are only made a few places and require much lead time to order. Importing such pipes from Asia when other nations are rushing to expand their nuclear fleets could be a drag on an American project. (Sourcing anything from Japan, presently, is likely to be problematic, given that the Japanese nuc-tuplets melted down, crippling the massive export machine that had been Japan, Inc.)

Regulatory advantage?
Each baby nuc being perhaps 100 MW in capacity, it would be in the size range of a merchant power gas-fired plant. This explanation lays out the regulatory and financial implications.

A merchant power plant is funded by investors and sells electricity in the competitive wholesale power market. Since a merchant plant is not required to serve any specific retail consumers, consumers are not obligated to pay for the construction, operations or maintenance of the plant.

A traditional rate-based power plant, on the other hand, is built and operated by a regulated electric utility specifically to serve that utility's retail customers. In return, the customers are obligated to pay for the plant's construction, operations and maintenance.
The merchant power plants are not tied up with long-term power purchase agreements (PPA).

How then would these Tennessee baby nucs be regulated and their power priced? As a cluster, or as individual merchant units? This is for politicians and Public Utility Commissions to determine. It will be controversial, I bet.

For you engineers and aquatic biologists.
By segmenting the project into six baby nucs, could it be more feasible to use air to water heat exchangers for management of each reactor cooling loop? That would be a huge advantage, cutting back the permitting and construction schedule. We shall see.

In the event that six separate single-pass cooling water systems are needed: should the water intake pipes be as large in diameter as has been traditional - a factor which helps cope with the flow drag caused by Zebra muscles - the reduced velocity needed to meet the lessened flow requirements of a baby nuc reactor would mean they won't be sucking so many big fishes into bar screens. Smaller aquatic life forms which are able to sense and avoid the slower intake also would be more likely to be spared. This too will be interesting to watch.

Evacuation paradox.
Separate the baby nuc cluster members far enough from each other and it will be reasonable to argue that no more than one will be subject to a any single catastrophic event, such as an aircraft crash or a flood.

Keeping them clustered tightly enough to share a single set of management systems and other administrative support infrastructure, however, risks the catastrophic risk buffer argument being negated. The devil will be in these details and He will debut at the public hearings.

For you environmental purists.
This is not-coal. This is not Japan-like. Take a breather.

Technology Review has the details.

Tags: Nuclear Power | Tennessee

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