Wednesday, October 20, 2010

More on Small Modular Nuclear Fission Reactors

With six nuclear companies involved in the design of SMRs, competition could create a global market for U.S. SMRs. These companies include Westinghouse and Babcock & Wilcox, which build small reactors for the U.S. Navy, as well as start-ups like NuScale, Hyperion, and Intellectual Ventures, a Seattle firm financed by Microsoft _Standard

Small modular fission reactors can jump-start a new era in US power production. Newer technologies will require ever greater electric power generation capacities. This new power will need to be available when it is required. It must be both baseload and dispatchable. Given the modular nature of Small Modular Reactors (SMRs), and the potentially load-following nature of some of the new designs, SMRs offer incredible utility and high value for the money.
Ranging in capacity from 45 to 140 megawatts, SMRs are a fraction of the size of conventional 1000 MW nuclear plants and can be rapidly assembled at new or existing nuclear plant sites. Major SMR components such as the reactor vessel and turbine-generator are factory fabricated and transported by truck, rail or barge for prompt onsite-assembly. Some SMR designs operate continuously for over a decade before refueling.

Because factory fabrication permits greater cost savings, SMRs are expected to cost about $5,000 per kilowatt or several $100 million rather than billions for a 1000 MW plant.... _Standard
It is difficult to predict how large a boon to an economy these versatile new reactors represent. But we are beginning to learn:
A prototypical 100 megawatt (MW) SMR costing $500 million to manufacture and install onsite is estimated to create nearly 7,000 jobs and generate $1.3 billion in sales, $627 million in value-added impacts (a measure of GDP), $404 million in earnings (payroll), and $35 million in indirect business taxes;
The annual operation of each 100 MW SMR unit is estimated to create about 375 jobs and generate $107 million in sales, $68 million in value-added impacts, $27 million in earnings (payroll), and $9 million in indirect business taxes. _Heritage
Certainly US utility giant TVA is figuring SMRs into their future plans:
"In the longer term, we are just gearing up to participate in small nuclear reactors," Brinkworth said.

These are a new generation of reactor, about one-third the size of traditional reactors, that are built in a factory rather than on-site, can be transported by truck or rail, and are much less expensive than a site-built reactor.

"It is possible down the road that as we get more experience with that technology that we may see more of those units become part of our resource mix," Brinkworth said. "One of the advantages is they are smaller and you can add them in smaller increments so you can match your units to your growth (of demand)." _KnoxvilleNews
SMRs are far from being a totally-new technology. In fact they have been around for quite some time, and have accrued quite a safety record:
The United States has been operating small nuclear power plants continuously since the early 1950s. These reactors have been used for research and development, power generation, and ship propulsion. There have been tens of thousands of people associated with the design, development, manufacture and operation of these smaller reactors.

The enterprise has accumulated an admirable safety and reliability record and is the basis for some of the optimism associated with the development of small modular reactors that can produce power in volumes that would be uneconomical if produced in the far larger nuclear plants that became the standard during a period when coal, oil and natural gas were extremely cheap _RodAdams
Besides safety advantages, there are a large number of cost advantages inherent in the use of small modular reactors in place of most other power technologies:
Small reactor clustors located at recycled coal fire power plant locations potentually have greatly simplified grid connections. Not only can they be located near to the cities they are intended to serve, but grid hookup is facilitated by existing transformer farms, and grid connections. Because they can be located close to served cities new transmission lines will not cover long distances, thus lowering grid expantion costs. Large reactors may require new transmission lines that are hundreds of miles long, inorder to move surpluse electricity to market.

In addition to the above savings, and potential savings mentioned above there are other potential savings that may be avaliable with small reactors. For example, with advanced nuclear technology, for example molten salt reactors, combined Rankine (steam) and Brayton (gas) cycles are possible. A bottoming desalinization cycle could be offered to to the system, thus offering formible efficiency from small reactor packages. A high temperature reactor can provide top cycle heat for industrial processes, as well as producing middle cycle electricity generation, and bottom cycle heat for electrical generation. By adding a second generating cycle, small reactors can lower their electrical generation costs. Desalinizaion would add a further revinue stream from the reactors operation through the sale of portable water.

Thus it can be concluded that shifts to small nuclear power plants will potentially offer significant savings over current conventional nuclear costs. Shifts from conventional nuclear technology, to some advanced nuclear technologies, also offer significant potential savings. Some advanced technology savings are avaliable to both large and small nuclear power plants, but the flexibility of small NPPs may mean that at least in certain situations small advanced nuclear power plants may offer very significant potential savings in comparison to large conventional NPPs. _CharlesBarton
While many of the newer SMR designs will need to prove themselves, some of the designs are minor variants of already-proven designs with excellent safety and operating records. The NRC needs to take that into account as it begins the approval process for these designs.



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