Monday, March 28, 2011

CETA Professor Thomas Filburn published in Hartford Courant

Nuclear Safety: An Ongoing Imperative

On-Site Spent Fuel Is A Pressing Problem

The Fukushima nuclear accident is a tragedy for the Japanese people, but it should not signal the end of nuclear power in this country. What it should do is to spur us to resolve what is potentially the most serious safety issue with nuclear power — on-site storage of spent fuel.

Ending the use of nuclear power would drive Connecticut's already high energy costs off the charts. The state generates 50 percent of its electricity from the two operating units at the Millstone Nuclear Power Station in Waterford. The country gets 20 percent of its electric power from nuclear sources. These plants should continue to be one of the country's sources of electricity.

Look closely at what happened in Japan. The nuclear plants and their coolant systems essentially survived a 9.0 earthquake, one of the most powerful ever recorded. The enormous tsunami following the quake, however, was more than the plants' backup electric power system was designed to withstand. The emergency power is required for cooling the reactor and spent fuel if the normal, off-site electric power is disabled. Spent fuel is still radioactive and must be stored somewhere outside the plants for years while its energy diminishes.

  Japan needed the backup electricity to pump water into the fuel containment areas. Without the cooling water, the nuclear fuel overheats dangerously. Designs from Westinghouse and General Electric for the latest nuclear power plants licensed by the U.S. Nuclear Regulatory Commission rely on large water supplies within the containment structure and the natural circulation of steam and water to cool the reactor after an accident. These designs can maintain the reactor in a cool, safe manner for at least three days without the need for emergency power.

But that doesn't solve the problem of storing spent fuel. The Fukushima nuclear complex disaster has shown that the spent fuel stored at the plant site does not get the same level of protection as the fuel inside the reactor core. Fuel in the reactor core is housed in a very strong pressure vessel and further enclosed in a thick, reinforced concrete containment bunker. The spent fuel is in deep pools of water that are nowhere near as well protected.

The U.S. stores all of its spent nuclear fuel at each plant site, including plants such as Connecticut Yankee in the Haddam Neck section of Haddam, which has long been closed and demolished.

A federal blue ribbon commission is now evaluating how to handle spent nuclear fuel. One possibility is to reprocess it. The U.S. has for decades operated on a once-through fuel cycle, which fails to use the residual energy in spent fuel. This policy stemmed from a Carter-era concern about nuclear weapons proliferation, and the fuzzy thought that not reusing plutonium would somehow set a good example for the rest of the world.

Reprocessing offers the opportunity to reduce, by as much as 85 percent, the volume of spent fuel that needs to be sequestered in a high-level waste repository. France reprocesses its own nuclear fuel and that of several other countries. The downside is that the U.S. does not have a reprocessing facility. Most economic studies indicate that reprocessing is more expensive than just storing the spent fuel and creating new fuel. But adding the long-term costs of storage may tilt the cost-benefit analysis toward reprocessing.

The other option would be the development of one or more federal interim storage facilities for spent fuel.

Such facilities, not at reactor sites, could hold spent fuel prior to the creation of a long-term, high-level waste repository. Though there are none now, such facilities are easy to build and not dangerous. Fuel that has been out of the core for long periods of time can be stored in dry canisters, which can be placed in concrete casks and cooled passively with natural air circulation, as has been done at many reactor sites (including Millstone and Connecticut Yankee).

The political difficulty of creating a long-term facility — witness the long-running controversy over Yucca Mountain in Nevada — may also argue for cutting the volume of spent fuel by reprocessing it. However accomplished, storing all of the spent fuel at the operating plants should not continue. It is too dangerous, too susceptible to natural or man-made disasters. That's the lesson from Fukushima.

Thomas Filburn, an associate professor of mechanical engineering at the University of Hartford, formerly worked in the commercial and naval nuclear industries.


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