Swedish nuclear researchers have discovered that natural processes in deep shaft nuclear waste storage can prevent waste from leaking into the surrounding soil and water table, significantly reducing the risk of nuclear pollution from waste storage.
Nuclear Power has suffered a maligned history in this country resulting in significant increases in atmospheric pollution by the growth in coal and gas power generating plants. Understanding that CO2 emissions are rising significantly and will result in catastrophic climate change if unchecked, it is clear we need to rebalance our energy generating mix.
Now, although many other countries have well developed nuclear power generation, including France and Japan, and have operated safely for decades, there is still significant trepidation here to going down that path. We've had this discussion back and forth for decades and the discussion always comes back to two things - renewables and nuclear waste.
On the renewables front, anyone that has researched renewable power understands that it is an unpredictable source of energy. Sunny days come and go, windy days come and go, oceans can generate waves one day and be calm the next. Hence, solar, wind and wave power have their uses and are part of the mix, but cannot provide a guaranteed baseline power level to keep the grid running smoothly.
Currently baseline power continues to be provided largely by coal power plants in the US. Replacing this baseline power will require that we seriously invest in nuclear power generation. Which brings us to concern #2, nuclear waste and its storage.
Currently nuclear waste in the US is largely stored in-situ, on site at the nuclear plant. How anyone thinks this is safer than say burying the waste in a million tons of concrete under Yucca Mountain beats me. Some of these nuclear plants are located on or near active fault lines. So, assuming above ground storage is not ideal, what can be done to solve the problem of making below ground storage safe and clean ? Assuming we are looking for a rational solution here, lets look at the research.
In what is now termed the Hydrogen Effect, scientists believe that 100% safe nuclear storage sites are within reach of existing technology. Scientists at the University of Technology in Sweden have published a research paper indicating that due to natural processes, a compromised underground storage sarcophagus would not leak radioactive elements into the water table.
When Sweden's spent nuclear fuel is to be permanently stored, it will be protected by three different barriers. Even if all three barriers are damaged, the nuclear fuel will not dissolve into the groundwater, according to a new doctoral dissertation from Chalmers University of Technology in Sweden.
By Midsummer it will be announced where Sweden's spent nuclear fuel will be permanently stored. Ahead of the decision a debate is underway regarding how safe the method for final storage is, primarily in terms of the three barriers that are intended to keep radioactive material from leaking into the surrounding groundwater.
But according to the new doctoral dissertation, uranium would not be dissolved by the water even if all three barriers were compromised.
"This is a result of what we call the hydrogen effect," says Patrik Fors, who will defend his thesis in nuclear chemistry at Chalmers on Friday. "The hydrogen effect was discovered in 2000. It's a powerful effect that was not factored in when plans for permanent storage began to be forged, and now I have shown that it's even more powerful than was previously thought."
The hydrogen effect is predicated on the existence of large amounts of iron in connection with the nuclear fuel. In the Swedish method for final storage, the first barrier consists of a copper capsule that is reinforced with iron. The second barrier is a buffer of bentonite clay, and the third is 500 meters of granite bedrock. Some other countries have chosen to make the first barrier entirely of iron.
It is known that microorganisms and fissure minerals in the rock will consume all the oxygen in the groundwater. If all three barriers were to be damaged, the iron in the capsule would therefore be anaerobically corroded by the water, producing large amounts of hydrogen. In final storage at a depth of 500 meters, a pressure of at least 5 megapascals of hydrogen would be created.
Patrik Fors has now created these conditions in the laboratory and examined three different types of spent nuclear fuel. All of the trials showed that the hydrogen protects the fuel from being dissolved in the water, even though the highly radioactive fuels create a corrosive environment in the water as a result of their radiation. The reason for the protective effect is that the hydrogen prevents the uranium from oxidizing and converting to liquid form.
Furthermore, the hydrogen makes the oxidized uranium that already exists as a liquid in the water shift to a solid state. The outcome was that the amount of uranium found dissolved in the water, after experiments lasting several years, was lower than the natural levels in Swedish groundwater.
"The hydrogen effect will prevent the dissolution of nuclear fuel until the fuel's radioactivity is so low that it need no longer be considered a hazard," says Patrik Fors. The amount of iron in the capsules is so great that it would produce sufficient hydrogen to protect the fuel for tens of thousands of years.
The dissertation "The effect of dissolved hydrogen on spent nuclear fuel corrosion" will be publicly defended on April 24 at 10 a.m. Place: Hall KE, Chemistry Building, Kemigården 4, Chalmers University of Technology, Gothenburg, Sweden.
For more information, please contact: Patrik Fors, Nuclear Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Sweden
Tel: +46707-696 334 patrik.fors@chalmers.se
In defense of optimism
I understand many will react flinchingly at the mere thought of safe nuclear waste storage and I posted this diary fully expecting the wrath of the anti-nuclear crowd. Fair enough, this is an open forum, however let me make a few points.
I am not in any way affiliated with the nuclear energy industry, I am interested in balancing risk / reward and consider greenhouse gas emissions (and other water table pollutants from coal) a significant global risk. As such, the relative merits and abilities of each source of energy must be weighed together. I believe nuclear must play a role in our replacement of coal and to a lesser extent, gas powered plants.
Second - yes this piece is based upon a research paper and yes research can be faulty. However, I believe we can solve these problems via science and I remain optimistic that we are making progress. As such, I think we should invest in this kind of research and start making progress tackling the issue of nuclear waste storage NOW.