Proposed as the energy market’s silver bullet, nuclear power would meet all the worlds needs for increased energy demands with little pollution or fear of accidents, right? Actually, we know that this isn’t true. Light water reactors, which provide the bulk of our nuclear capacity, are notoriously inefficient. Couple this with concerns about waste and nuclear safety, the present day problems loom large. So, what does the future bring for nuclear power? As Robert Kennedy told us, “The future is not a gift. It is an achievement.”
Nuclear Power: In the Beginning?
It all started about 60 years ago in Idaho. The military was anxious to get up and running with a new power source for their submarine fleet, and the light water reactor (LWR) was obvious for the next step in power generation. At the time, it was easier to take an already-existing military design and scale it up for commercial use. Since then, nuclear power plant design has evolved through four distinct design generations.
The First Generation (1950 -1970) included prototypes and first designs.
The Second Generation (1970 – 2030) included currently operating plants.
The Third Generation (2000 – on) includes improvements and retrofits to current plants.
The Fourth Generation (2030 – on) will include new and advanced nuclear plant designs.
Today, operating reactors are typically LWR’s of the second or third generation. The fourth generation or Generation IV nuclear reactors are now on the drawing board and in a testing phase. Gen IV reactors are not your garden variety, everyday LWR.
Light Water Reactors
There are two types of LWR: boiling water reactors (BWR) and pressurized water reactors (PWR). Both use water passed through the core, where it is heated. In the BWR, the water turns to steam that drives the turbines and produces electricity. In the PWR, the water is heated by the core and is kept under pressure so it remains liquid. The heated water is then passed through a heat exchanger which produces steam and drives the turbines.