Heavy Water vs. Light Water

The reactors at Bruce Power use light water, compared to the heavy water used in the United States. So what's the difference?

If water is heavy water, it means the water is enriched with the hydrogen isotope deuterium, which is a natural abundance in all the Earth's oceans.

It it useful in nuclear reactors because of the large reaction rate and high energy yield. The only downside is that it is needed in large quantities to be effective.

The photo here is of Bruce A, which has eight reactors.

Deuterium was used during WWII to produce plutonium and help develop the atomic bomb.

Light water is used in the United States and is a better reactor with enriched uranium.

There are only about 2,000 tonnes of enriched uranium in the world and most of that is concentrated on nuclear weapons and naval propulsion.

When used in nuclear reactors, enriched uranium can be used in much more concentrated quantities.

While a power plant in Canada might have eight reactors per unit, a plant in the U.S. would have two total reactors.

Photo courtesy Bruce Power.