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Next-Generation Nuclear Energy Reactors: A Primer

Gen IV plants will be safer and less water intensive, but they won't be commercially viable until 2030 at the earliest. Will there still be market demand?

By Lisa Song, SolveClimate News

May 9, 2011
Boiling water nuclear reactor

The next generation of nuclear power reactors promises to be safer, more fuel efficient and less water intensive — but the world must wait at least 20 years to see them in action.

Known as Generation IV reactors, the models are "revolutionary" in design, said David Lochbaum, director of the Nuclear Safety Project at the . Ironically, though, the reactors' leading-edge features could end up being the greatest impediment to their initial adoption, he said.

Utilities are likely to be leery to shell out billions and billions without proof of operational success, Lochbaum told SolveClimate News, and that could "slow down the market" for the new designs.

The goal is to make the Gen IV fleet "competitive" on price with today's plants, said Robert Hill, a senior nuclear engineer at the Department of Energy's , though it's too early to tell if that's possible. A large nuclear reactor today costs between $4 and $10 billion.

For the moment, at least, the point is immaterial. Gen IV reactors still need a great deal of research and development, and the U.S. Department of Energy estimates they won't be commercially viable until 2030 at the earliest.

Development of the reactors is led by the , a collaboration of 13 member nations, including the United States, Canada, Japan, China and the European Atomic Energy Community (Euratom). Each country contributes its own share of funding. In total, the forum's research and development work costs a year.

Since its establishment in 2001, members have selected six basic designs of Gen IV technology.

Safety Improvements

Most of the world's existing reactors are Generation II plants designed in the 1970s. Over the past ten years, several countries have built Generation III reactors that are safer and , supposedly reducing upfront capital costs.

Many Gen III reactors include "passive safety" mechanisms that get triggered by gravity or other natural forces in the event of trouble, said Hill. A reactor vessel, for instance, might have circulation systems that kick in even when electricity goes out to cool the facility through convection, making the plant less vulnerable to meltdown.

There's also a subset of reactors called Gen III-plus that can be hard to distinguish from Gen III designs, though generally they have safety enhancements.

Ted Quinn, former president of the , an industry group, said one of the Gen III-plus designs includes a "swimming pool," a reservoir of water positioned high up in the reactor. Since the water can be released through gravity there's no need to find power for water pumps during emergency situations, he said.

If Japan's Fukushima Daiichi reactor, a Gen II design, had such safety features, "we could have prevented some of the core damage," Quinn added.

The Gen III-plus plants also have backup batteries with a 72-hour lifespan, which gives emergency responders three days to restore power. It's an improvement over older reactors like Fukushima, whose batteries only last four to eight hours, he said.

Four Gen III-plus units are being licensed in the United States. Two are proposed for the Vogtle plant in Burke County, Georgia, and the other two for the V.C. Summer station near Jenkinsville, South Carolina.

Water as Coolant

Despite variations in age and design, most of the pre-Gen IV plants have one thing in common: They all use water as a coolant.

A coolant is the fluid that brings heat from the reactor core to other parts of the plant. The heat boils water into steam, which spins turbines to generate electricity. Then the steam is either condensed by pumping in cold water, or cooled through cooling towers.

What about Thorium Gen IV reactors???

You are forgetting another Gen IV reactor that both the French and Chinese are working on, the Molten Salt Reactor, where the fuel is suspended IN the liquid hot salt which makes onsite, inline, reprocessing a simple matter of chemistry and plumbing.

The most sophisticated and beneficial version of this is the Liquid Flourdie Thorium Rector which doesn't use any input of uranium at all but breeds it's own from Thorium, a fertile substance that is 4 times as plentiful as uranium and doesn't need any form of enrichment at all.

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