How-To: Manage nuclear waste
The benefits and risks of nuclear power generation and usage are an ongoing topic of discussion – and often disagreement – with radioactive waste continuing to occupy one of the top spots on the “risk” list.
And while it goes without saying that this form of power has always brought with it a certain amount of concern – previous power plant accidents and the threat of nuclear war are enough to scare any human being – the issue of radioactive waste may stand-out even more to industry leaders than the memory of Hiroshima.
So just how risky is this top-of-mind risk?
According to the World Nuclear Association, it is not as extreme as many believe. As recently as August 2015, the Association stated the following:
• The amount of radioactive wastes is very small relative to wastes produced by fossil fuel electricity generation.
• Used nuclear fuel may be treated as a resource or simply as a waste.
• Nuclear wastes are neither particularly hazardous nor hard to manage relative to other toxic industrial wastes.
• Safe methods for the final disposal of high-level radioactive waste are technically proven; the international consensus is that this should be geological disposal.
As of 2013, it was reported that there were 437 operational nuclear reactors creating electricity, and all of the 437 reactors were located in 31 countries. In 2015 there are 67 civil fission electric reactors under construction. These new facilities are in 15 countries, including some in Gulf States, Asia, and 28 in the Peoples Republic of China. Regardless of how “risky” the risk, we still need solutions.
Options for storage and disposal of nuclear waste
Some of the radioactive waste from nuclear power plants is considered low-level radioactive waste (LLW). Most of the LLW is sent to land-based disposal sites where it is expected to be kept of long-term management. This is how around 90 percent of all nuclear waste is managed around the world.
When intermediate level waste (ILW) and high level waste (HLW) is considered, there have been different management options for this waste investigated. The goal is to find safe and environmental solutions to the storage of this waste that is acceptable to the public. Some countries have just begun to do the research, while other countries, such as Finland and Sweden have advanced with their investigations and in gaining public support for places to keep this waste. In the United States, there is a site below ground in salt formations in the state of New Mexico where waste from defense related sites is currently stored.
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Many countries, such as the Czech Republic, Finland, France, Japan, the United Kingdom and the United States, use near surface disposal. This means the LLW is stored at ground level, or at depths of 10 meters for these countries. Sweden and Finland also store ILW materials for short periods of time at these disposal sites.
The International Atomic Energy Agency (IAEA) recommends that near surface disposal can be used in near-surface facilities at ground level. These facilities can be set up with engineered barriers, or without the engineered barriers. When nuclear waste (LLW) is stored at surface level, there is a protective covering placed over the materials that is a few meters thick. The wasted containers are put in vaults, and after the vaults are filled, and then they are backfilled. Eventually they will be covered and capped with an impermeable membrane. Then the membrane is covered with topsoil. Often these facilities will be built with some sort of drainage system added, and sometimes there are also gas venting systems added.
Near surface disposal facilities can also be built in caverns that are below ground level. When near surface disposal sites are begun at ground level, access is from the surface. When the surface disposal site is in a cavern, access to the nuclear waste site is tens of meters below the surface of the Earth, and the material is accessed through a drift.
Another way to store nuclear waste that is being investigated is deep borehole disposal. This method has been indicated to have a high potential for “robust” isolation of waste, and could present a way to dispose of some wastes that might be able to go into storage faster than current methods, according to the U.S. Department of Energy.
When sites are chosen for these facilities, the long-term expectations for changes in climate must be taken into consideration. The waste associated with LLW and ILW generally has a half-life of about 30 years so stability must be taken into consideration for at least that length of time.
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Another form of radiation comes from uranium mining. While the uranium is being mined, “fine sandy tailings” are left behind. These remains of the mining process have almost all of the radioactive elements that are naturally occurring in uranium ore. Companies make dams that collect the tailings, then they are covered with clay and rock which is intended to stop the leaking of radon gas and made the radioactive materials stabile in the long-term. In the short-term, these materials are often covered with water for a few months, after which it will have about 75 percent of the original radioactivity.
The global approach
French radioactive waste disposal agency Andra is in the process of designing a deep geological nuclear repository in Bure in Eastern France. This site has clay which they believe will be a good way to keep the nuclear waste from leaking and causing other difficulties. They believe this repository will be able to operate at up to 90 degrees C, which they think will be reached about 20 years after the nuclear waste has been stored.
Belgium is considering a similar process for storing spent fuel and HLW. Their investigation into a disposal process involves placing the waste in high integrity steel containers, then in excavated tunnels with the clay, which is self-sealing. This clay is self-sealing and has low permeability so that almost no groundwater can get into the nuclear waste. The Netherlands is considering a similar method.
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The UK uses Nirex Phased Disposal Concept which is intended to store fairly large volumes of ILW and LLW. The nuclear waste is sealed into cemented stainless steel containers. These containers are then stored in a repository that is below the water table. Eventually, the waste will be backfilled with special cement which is intended to prevent waste from reaching the groundwater. Similar forms of storage of nuclear waste are considered in France, Japan, Sweden and Switzerland.
Transporting nuclear waste
The most important safety guarantee in transporting nuclear waste and many other hazardous materials is found the way it is packaged. There have been recommendations by the International Atomic Energy Agency that have been implemented around world as part of the legal provisions for transporting these materials. These standards and recommendations make it relatively safe to transport the waste no matter what method is being used.
There are different levels of packages depending on the danger of the product being shipped. There are different designations, for example Type B or Type C. The larger the letter, the more care needs to be given to the package. When examined, prior to the transportation, things such as radiation shielding, mechanical thermal characteristics and tightness and quality assurances are examined.
It can be difficult to find the cost of transporting and storing nuclear waste, but in 2012-2013, the UK spent about £1.6 billion. In Germany, the reported costs were from USD$50 million to USD$70 million a year, just to transport the nuclear waste.
With the hundreds of nuclear facilities around the world, and dozens more being built, it is apparent that nuclear energy is not going away soon. It is incumbent on countries and citizens to find safe places to store the waste from these facilities.
Carbon dioxide removal revenues worth £2bn a year by 2030
Carbon dioxide removal revenues could reach £2bn a year by 2030 in the UK with costs per megatonne totalling up to £400 million, according to the National Infrastructure Commission.
Engineered greenhouse gas removals will become "a major new infrastructure sector" in the coming decades - although costs are uncertain given removal technologies are in their infancy - and revenues could match that of the UK’s water sector by 2050. The Commission’s analysis suggests engineered removals technologies need to have capacity to remove five to ten megatonnes of carbon dioxide no later than 2030, and between 40 and 100 megatonnes by 2050.
The Commission states technologies fit into two categories: extracting carbon dioxide directly out of the air; and bioenergy with carbon capture technology – processing biomass to recapture carbon dioxide absorbed as the fuel grew. In both cases, the captured CO2 is then stored permanently out of the atmosphere, typically under the seabed.
The report sets out how the engineered removal and storage of carbon dioxide offers the most realistic way to mitigate the final slice of emissions expected to remain by the 2040s from sources that don’t currently have a decarbonisation solution, like aviation and agriculture.
It stresses that the potential of these technologies is “not an excuse to delay necessary action elsewhere” and cannot replace efforts to reduce emissions from sectors like road transport or power, where removals would be a more expensive alternative.
The critical role these technologies will play in meeting climate targets means government must rapidly kick start the sector so that it becomes viable by the 2030s, according to the report, which was commissioned by government in November 2020.
Early movement by the UK to develop the expertise and capacity in greenhouse gas removal technologies could create a comparative advantage, with the prospect of other countries needing to procure the knowledge and skills the UK develops.
The Commission recommends that government should support the development of this new sector in the short term with policies that drive delivery of these technologies and create demand through obligations on polluting industries, which will over time enable a competitive market to develop. Robust independent regulation must also be put in place from the start to help build public and investor confidence.
While the burden of these costs could be shared by different parts of industries required to pay for removals or in part shared with government, the report acknowledges that, over the longer term, the aim should be to have polluting sectors pay for removals they need to reach carbon targets.
Polluting industries are likely to pass a proportion of the costs onto consumers. While those with bigger household expenditures will pay more than those on lower incomes, the report underlines that government will need to identify ways of protecting vulnerable consumers and to decide where in relevant industry supply chains the costs should fall.
Chair of the National Infrastructure Commission, Sir John Armitt, said taking steps to clean our air is something we’re going to have to get used to, just as we already manage our wastewater and household refuse.
"While engineered removals will not be everyone’s favourite device in the toolkit, they are there for the hardest jobs. And in the overall project of mitigating our impact on the planet for the sake of generations to come, we need every tool we can find," he said.
“But to get close to having the sector operating where and when we need it to, the government needs to get ahead of the game now. The adaptive approach to market building we recommend will create the best environment for emerging technologies to develop quickly and show their worth, avoiding the need for government to pick winners. We know from the dramatic fall in the cost of renewables that this approach works and we must apply the lessons learned to this novel, but necessary, technology.”
The Intergovernmental Panel on Climate Change and International Energy Agency estimate a global capacity for engineered removals of 2,000 to 16,000 megatonnes of carbon dioxide each year by 2050 will be needed in order to meet global reduction targets.
Yesterday Summit Carbon Solutions received "a strategic investment" from John Deere to advance a major CCUS project (click here). The project will accelerate decarbonisation efforts across the agriculture industry by enabling the production of low carbon ethanol, resulting in the production of more sustainable food, feed, and fuel. Summit Carbon Solutions has partnered with 31 biorefineries across the Midwest United States to capture and permanently sequester their CO2 emissions.
Cory Reed, President, Agriculture & Turf Division of John Deere, said: "Carbon neutral ethanol would have a positive impact on the environment and bolster the long-term sustainability of the agriculture industry. The work Summit Carbon Solutions is doing will be critical in delivering on these goals."
McKinsey highlights a number of CCUS methods which can drive CO2 to net zero:
- Today’s leader: Enhanced oil recovery Among CO2 uses by industry, enhanced oil recovery leads the field. It accounts for around 90 percent of all CO2 usage today
- Cementing in CO2 for the ages New processes could lock up CO2 permanently in concrete, “storing” CO2 in buildings, sidewalks, or anywhere else concrete is used
- Carbon neutral fuel for jets Technically, CO2 could be used to create virtually any type of fuel. Through a chemical reaction, CO2 captured from industry can be combined with hydrogen to create synthetic gasoline, jet fuel, and diesel
- Capturing CO2 from ambient air - anywhere Direct air capture (DAC) could push CO2 emissions into negative territory in a big way
- The biomass-energy cycle: CO2 neutral or even negative Bioenergy with carbon capture and storage relies on nature to remove CO2 from the atmosphere for use elsewhere