This is the fourth article in our series on nuclear power. The first article covers the economics of nuclear. The second looks at the dangers of nuclear accidents, and the third examines the health impacts of radiation. In this article, we explore the environmental trade-offs in nuclear power plants.
Nuclear power – the largest source of carbon-free electricity
Nuclear power plants produce almost no greenhouse gases. If you want a huge amount of steady 24/7/365 electricity that has minimal impact on climate change, nuclear is your go-to option. While nuclear power plants produce negligible emissions, their fuel supply chains still require fossil-fuel intensive mining, transporting, and refining. Fortunately, when compared to the supply chain of fossil fuel power plants, the nuclear supply chain is far less greenhouse gas intensive.
But the environmental promise of minimal greenhouse gas emissions comes with an environmental cost: nuclear waste.
The industry refers to the toxic byproducts of nuclear power plants as “spent fuel.” Other people refer to it by a less glamorous name, “nuclear waste.” Regardless of what you call it, nuclear power plants across the world produce 12,000 tons of radioactive material per year. Decades of nuclear power has resulted in 250,000 tons of accumulated waste.
The world nuclear association says that, after 40 years, the radioactivity of the waste has decreased to about one-thousandth its original level. While this may be comforting in most cases, somewhat less settling is that some components of nuclear waste will remain radioactive for hundreds of thousands and even millions of years. For example, uranium-234 has a half-life of 245 thousand years and neptunium-237 has a half-life of 2.144 million years. While these materials are dangerous, they require direct contact or ingestion to cause material health impacts.
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Where does U.S. nuclear waste go?
When fresh nuclear fuel is used to create electricity, only a small part of the energy is actually extracted. Countries like France have the legislative support and the technical capabilities to “reprocess” spent fuel. By separating out still viable fuel from the nuclear waste products, the value of the original fuel is extended and the volume of waste material is reduced. The U.S. has shied away from this approach for many reasons including the increased risk that the reprocessed fuel makes it somewhat easier for use in nuclear weapons.
The U.S. policy says that all spent fuel must be disposed of in a central location. This is where things get really messy. Due to a political standoff, the U.S. government abandoned its plans for a national waste disposal site at Yucca Mountain in November 2013. Shortly after, the government stopped collecting the annual $750 million from the industry that it was stockpiling to pay for long-term storage. The $46 billion built up for that fund is, itself, contentious. Some claim it’s more than enough to clean up and consolidate all the U.S. waste. Others argue it’s not even close. And, above all that, there is a question whether all the funds are even accessible anymore.
In the absence of coherent national waste disposal policy, nuclear waste is being stored in highly secured “cooling” pools right next to the plants that created it. These pools typically store the spent fuel for five years until the radioactivity has decreased to a manageable level. There are some issues with the fixed sized pools becoming overcrowded but, so far, there have been no accidents. Once the spent fuel has “cooled down” enough, it is placed into steel and concrete containers which are stored above ground in protected lots within the nuclear plant complex. These containers will sit there for years, or even decades, until the government can once again find a workable strategy for consolidating all this waste.
Does nuclear power require water?
Coal, natural gas, and nuclear all use a similar method to generate electricity – they generate heat that turns water into steam. The industry refers to this kind of a system as a “thermal” power plant. The steam rises and turns a turbine. The turbine is attached to a generator which creates electricity.
All thermal power plants create steam within a closed system. And, they all need a way to cool the steam back to water so it can be used again. The most common way to cool water is, well… water. Cooling can take one of two approaches. The first type, “once-through” systems, are always next to a large body of water or a river. They take in cool water, heat it up, and put it back into the environment. The second type, “recirculating” systems, cools the plant by causing water to evaporate. These systems “consume” the water which removes it from the environment. Consumed water can no longer be used for agriculture or human consumption. According to data from the government, about 40% of all freshwater is withdrawn for thermal power generation (including nuclear) but less than 1/10 of that is consumed or evaporated. To put this in perspective, power plants withdraw nearly the same amount of freshwater as the U.S. uses for all agriculture. Cleary, thermal power plants play a massive role in the water ecosystems of the world. Note that because nuclear plants have only one way to dissipate heat, they tend to use more water per megawatt-hour than other fuel-based power plants.
The Freeing Energy Perspective
No other topic divides clean energy advocates like nuclear power. The last few articles cover a range of the issues but, for most debates, it comes down to the environment. Which is more important: reducing carbon dioxide emissions or avoiding more nuclear waste?
Nuclear advocates argue that reducing CO2 is paramount, that waste is effectively secured, and that fears of radioactivity are overblown. Critics argue that we may be effectively managing waste today but what about 100, or 1,000, or 10,000 years from now when the original plant owners are long gone – who will pay to keep the public safe? Critics point out that the question is not whether all nuclear waste can be effectively secured but whether a single site can be breached or blown up. They say that it only takes one security failure for dangerous radioactive material to fall into the hands of criminals or terrorists. They say that if we were suddenly building hundreds of new plants across the world, the chances of a security failure increase substantially.
For me, the question of greenhouse gas emissions versus nuclear waste is a false dilemma. While there is likely an important role for nuclear power over the next few decades, we now have a host of alternatives that have both near-zero emissions and far more less dangerous waste. Rather than trying to turn the tide on public opposition and spending hundreds of billions of dollars to safely store radioactive waste, we should redirect those efforts towards a much simpler solution: long-term electricity storage. To put it another way, what seems more feasible: to change public perception and figure out how to safely manage hundreds more nuclear plants or find a way to cost-effectively store large volumes of electricity for 3-6 months so that solar and wind can power the world 24/7 across four seasons?
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