Rolf Westgard: Spent nuclear fuel: More opportunity than threat

Commentary

By wide margins, the Minnesota House and Senate each have passed bills that remove the state's ban on issuing certificates of need for new nuclear power plants.

These bills now have to be reconciled into one, approved and sent to Gov. Mark Dayton for veto or signature.

The House bill contains an amendment from Rep. Phyllis Kahn, DFL-Minneapolis, that bars any new nuclear plant program that would produce "weapons grade" plutonium during reprocessing of spent nuclear fuel pellets (nuclear waste).

Dayton and many others are concerned about the long-term storage of radioactive spent fuel pellets.

The French deal with this issue for their 58 nuclear plants by reprocessing the spent fuel. Ninety-five percent of the material, including some fissionable plutonium, is recycled into new fuel, and the dangerous 5 percent is vitrified into glass cylinders for storage.

All of those cylinders from 58 reactors are stored in the floor of one large room at La Hague, France. They will eventually go to permanent geologic storage.

After five years, the pellet's percent of U235 and plutonium declines from about 5 percent to 2 percent, and no longer sustains the chain reaction, but the 2 percent is very valuable reactor fuel when recycled.

The plutonium that remains in the spent pellets is a mix of several plutonium isotopes, still useful as reactor fuel but not useful in a nuclear weapon.

A little more than half of the plutonium is Pu239, which needs to be at 93 percent for the plutonium to be weapons-grade. If there is more than 20 percent Pu240, which tends to fission spontaneously, all the plutonium is reactor grade and "entirely unsuitable for use in a bomb," per the World Nuclear Association.

The plutonium in spent fuel pellets from commercial reactors contains 24 percent Pu240, as well as other plutonium isotopes that inhibit bombmaking. That plutonium is reactor-grade, not weapons-grade.

Kahn's carefully drawn amendment (she is a physics graduate) will not limit new commercial reactors, since they don't produce weapons-grade plutonium.

Even the expensive new nuclear plants are competitive when we consider their productivity. The $5 billion, 1,200-megawatt nuclear plants being sold and installed by China and South Korea will produce 600 billion kilowatt hours over their 60-year specification lives.

That's less than a penny per kilowatt hour of capital cost, excluding interest. Fuel cost is less than a penny per kilowatt hour.

As Dale Klein, associate director of the University of Texas Energy Institute, recently told the American Association for the Advancement of Science, "Spent fuel is not waste.

The waste is our failure to tap into this valuable and abundant domestic source of clean energy in a systematic way." Klein went on to point out that "failure to reprocess spent fuel is an enormous waste of potential energy."

Reprocessing not only recovers significant energy value from spent fuel, it substantially reduces the volume and radiotoxicity of high-level nuclear waste. The French have demonstrated that it works. It is time we got on with it.

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