The science behind shrinking the EPZ

My colleague Richard January wrote about the safety of Vermont Yankee's used fuel, saying it is safe in the fuel pool. He is right.

Here's why.

In operation a reactor gets 93 percent of its heat from atom splitting and 7 percent from the decay of the radioactive atom splitting pieces (fission products or other atoms).

When the atom splitting stops (reactor shutdown), that heat stops immediately. The heat from the fission products continues. The fission products are radioactive, which means the radiation and heat decrease continually over time.

Once an atom gives off its radiation, it is no longer the same. It may be another form of the same atom, or it may be another radioactive atom. Eventually, all the radiation will stop.

The question is not how long will there be any radiation, but how long until it is safe enough. The answer: it will be safe before the radiation in the Statehouse, from the uranium in the granite building blocks, stops.

This is proven by the used fuel having to be water cooled until the heat generation is low enough for it to be air cooled-in dry casks.

The source of danger to the public is the possible release of the radioactive fission products at any time. At any time, accidents are possible, even though the odds against one are very high that one might happen.

After the last shutdown, the amount of fission products that are available to get out continuously decreases.

This is the scientific basis for shrinking - not eliminating - the Emergency Planning Zone. It will shrink to the fence line. There will still be an emergency plan. The public will still be notified.

Over time, the danger is less, the heat being generated is less, so the time it takes for a release is longer. This longer time means more time for operators and first responders to take action to prevent the release. It also means that there will be more time to notify the public.

Subscribe to the newsletter for weekly updates