Tuesday, March 11, 2008

INL Reached a Milestone on Nuclear Fuel Performance

From ScienceDaily:

The research to improve the performance of coated-particle nuclear fuel met an important milestone by reaching a burnup of 9 percent without any fuel failure. Raising the burnup level of fuel in a nuclear reactor reduces the amount of fuel required to produce a given amount of energy while reducing the volume of the used fuel generated, and improves the overall economics of the reactor system.

The [Idaho National Lab] team studied the very successful technology developed by the Germans for this fuel in the 1980s and decided to make the carbon and silicon carbide layers of the U.S. particle coatings more closely resemble the German model. The changes resulted in success that has matched the historical German level.

INL's Advanced Test Reactor was a key enabler of the successful research. The ATR was used to provide the heating of the fuel to watch the fuel's response. The fuel kernel is coated with layers of carbon and silicon compounds. These microspheres are then placed in compacts one-half-inch wide by two inches long and then placed in graphite inside the reactor for testing. The fuel element is closely monitored while inside the test reactor to track its behavior.

...

The team has now set its sights on reaching its next major milestone -- achievement of a 12-14 percent burnup* expected later this calendar year.

...

*A burnup is a measure of the neutron irradiation of the fuel. Higher burnup allows more of the fissile 235U and of the plutonium bred from the 238U to be utilised, reducing the uranium requirements of the fuel cycle.
Pretty exciting stuff.

4 comments:

Kirk Sorensen said...

Thank you for posting this, David, but to me it just points out the inherent limitations of solid nuclear fuel forms. They are inherently compromised by their covalent bonds.

Liquid-fluoride forms of nuclear fuel have ionic bonding that is impervious to radiation damage, and can achieve essentially unlimited radiation exposure. Which means fuels in fluoride form (like UF4 or ThF4) can achieve essentially 100% burnup. All of this was demonstrated in ORNL test reactors back in the 50s and 60s, but has been almost entirely forgotten by today's nuclear engineering community.

Rod Adams said...

Kirk:

Keep reminding us. In the meantime, the high temperature solid fuel does have some useful advantages over conventionally available light water reactor fuel in zircalloy cladding.

As you know, I really like the idea of using that fuel in simple gas turbine machines that can make the "high capital" cost disadvantage of nuclear power an obsolete concept in certain markets.

Rod Adams
Adams Atomic Engines, Inc.

Pete said...

Has anyone run the numbers to convert this 9% burnup to megawatt-days per metric tonne? Since plutonium is being produced at the same time, is it 9% of initial fissile material or 9% of total uranium?

Alessandro said...

Pete,

It' s 9% of burn-up of all heavy metals. If you consider that the fission of one gram of HM produces about 1 MWday of thermal enenrgy, that 9% means about 85-90 MWd per kg of strarting low enriched uranium