“You don’t get something for nothing”: Should we renounce nuclear technologies to avoid radioactive waste management issues?

 

The exploitation of radioactive properties of some materials led to substantial progress in many sectors:  low-carbon power generation, efficient cancer treatments, non-destructive industrial testing processes, archeological dating…

However, despite the rather widespread use of nuclear technologies in these sectors, many countries face a reluctant public opinion embedded in several public demonstrations and militant activities over the last decades in Europe. One of the main reasons behind this reluctance is the crucial question of radioactive waste management. Indeed, after being used, some nuclear substances remain highly radioactive for thousands of years and their management and disposal is therefore essential for our safety. Among nuclear waste producers, the power industry is one of the main contributors as it generates around 1/3 [1] of total nuclear waste. As such, reducing radioactive waste implies quitting nuclear power (although waste from past nuclear activities will have to be managed anyway…). As part of a series of articles about nuclear power [2], this one will seek to draw a clear picture of nuclear waste production and management, and enlighten the reader about the main challenges at stake with this sector.

Facts and figures: what is nuclear waste and how much is produced?

Radioactive waste includes any material that is either intrinsically radioactive or has been contaminated by radioactivity, and is deemed to have no further use. It is a by-product of any activities benefiting from nuclear technology, such as power generation, defense programs, research and medical activities. Two factors characterize nuclear waste: its radioactivity level and its lifespan.

Figure 1 – International Atomic Energy Agency, Classification of Radioactive Waste, IAEA Safety Standards Series, No. GSG-1, IAEA, Vienna, 2009 

 

The radioactivity level reflects how hazardous a certain waste is, from very low level (VLL) to high level (HL). The lifespan is characterized by the half-life (time required for it to be reduced to half its initial radioactivity) and can take few hundred days to hundreds of thousands of years. Both criteria are considered to establish the most ideal waste management process (see below). 

Inventorying radioactive waste worldwide is already tricky as it involves confidential and sensitive activities. However, even if all information about nuclear waste was seamlessly communicated by countries, counting nuclear waste is a matter of accounting and would therefore remain somehow subjective. Such as chocolates individually packed in 12 piece-boxes, nuclear waste is encapsulated in canisters (see below) surrounded by additional steel or concrete depending on its radioactivity. Some inventories count the individual packing, others consider the whole box of chocolates…

Nonetheless, the quantity of nuclear waste generated remains considerably minimal compared to “traditional” waste. As an example, France gets ¾ [3] of its power from nuclear plants and produced 56,000 tons of nuclear waste in 2015, equivalent to less than 1kg/capita [4]. During the same year, each resident generated more than 450 kg of domestic waste, and France generated 247 million tons of construction waste and 241 million tons of non-dangerous mineral waste [5]. Worldwide, the nuclear power industry represents [6] roughly 1/3 of the volume of LLW and ILW generated and half of its radioactivity.

So, what really is the problem with radioactive waste?

As described in the second article published by Greenfish about nuclear power, the scientific community agrees that the more exposed to radiation you are, the more likely you are to develop a cancer according to the Linear-No-Threshold (LNT) theory. Considering that “zero-radiation” does not exist (due to natural background radiation), the radiation protection policies commonly follow the rule of “As Low As Reasonably Achievable” (ALARA). To quantify this notion of “reasonably achievable”, each country sets maximum admissible doses (in mSv/year) based on scientific recommendations.

Therefore, nuclear waste management is basically all about preventing anyone today and in the future from being exposed to radiation over the acceptable limit.

In this regard, next section (i) reviews the principle of nuclear fuel cycle to mitigate nuclear waste production and (ii) discusses existing nuclear waste management strategies to treat and store residual waste.

Overview of waste production along the nuclear fuel cycle

The nuclear fuel cycle, shown schematically in Figure 2, consists of processes used to produce electricity from nuclear reactions (from mining uranium to the disposal of generated waste).

Figure 2 – Schematic of the nuclear fuel cycle 

 

In the “open fuel cycle” (common in the United States, Sweden and some other countries), spent fuel is generally disposed of as waste that will remain radioactive for 200,000 years. In the alternative process, known as the “partially closed fuel cycle” adopted in most European countries, spent fuel is reprocessed in order to extract the redeployable uranium and plutonium, which are then re-introduced into the fuel cycle. It improves the usage of the original uranium resource by about 20% [7]. In the closed fuel cycle, the lifetime of radioactive  waste is reduced to about 10,000 years. Fully using the material will require successive generations of fuel to be  reprocessed and recycled multiple times. The “fully closed fuel cycle” is not effective with nuclear reactors in use today, but will require the development and commercial implementation of fast neutron reactors which can enable the extraction of 50 to 100 times more energy from the originally mined uranium than reactors currently in operation. Fast neutron reactors (belonging to generation IV reactors) are, however, not yet commercially available, and the necessary development work is on-going.

However, whatever the fuel cycle adopted and whether the waste lifetime is ten thousand years or over hundreds of thousands of years, the nuclear power industry still generates some kind of unavoidable nuclear waste radioactive enough to radiate over the accepted limit according to the LNT theory. Thus, regarding waste management, a high level of safety should be applied to treat and dispose of nuclear waste.

Radioactive waste management: what does it consist of?

Whether it comes from the nuclear power industry or other industries, any radioactive waste is handled in different ways according to its properties (where it appears in figure 1). However, radioactive waste management relies on the 4-step process [8] described below:

  • Treatment involves operations intended to change waste streams’ characteristics to improve safety.
  • Conditioning is undertaken to change waste into a form that is suitable for safe handling, transportation, storage, and disposal. This step typically involves the immobilisation of waste in containers.
  • Storage of waste may take place at any stage during the management process. Storage involves maintaining the waste in a manner such that it is retrievable, while ensuring that it is isolated from the external environment. Waste may be stored to make the next stage of management easier (for example, by allowing its natural radioactivity to decay). Storage facilities are commonly onsite at the power plant, in ponds first and in dry storage afterwards.
  • Disposal of waste takes place when there is no further foreseeable use for it, and in the case of HLW, when radioactivity has decayed to relatively low levels after about 40-50 years. The commonly-accepted disposal options are near-surface disposal for LLW and ILW and deep geological disposal for HLW and long-lived ILW.

Today, most of global LLW (85%) found long-term storage solutions. However, only 20% of ILW and none of HLW are actually disposed of [9]; as they are being mostly stored in nuclear ponds. Regarding this high level waste, although it represents a small part of the total volume, it involves most radioactivity and constitutes a major security challenge. Indeed, (i) surface storage is not meant to be a long-term solution and therefore does not check long-term safety requirements while (ii) geological disposal solutions remain controversial regarding long-term reliability. The next section aims to illustrate this debate from 2 opposing perspectives.

Surface storage

Since the early 2000’s and 9/11, most threats concerning nuclear waste management rely on the assumed weakness of nuclear infrastructure’s protection against malicious acts. In particular, a report by several international independent experts commissioned by Greenpeace France [10] in 2017 highlights a certain type of facility at nuclear plants: the spent fuel storage pools. Based on safety analysis at the time of their construction, the risk of a runaway nuclear reaction in the pools was neglected and they were not equipped with a robust confinement building similar to those found in reactors. Yet, the five pools at The Hague (the main storage facility in France) for instance contain the equivalent of nearly one hundred-fifty 900 MWe reactor cores in total. Now that terrorist and malicious attacks seem to have no limit regarding their modus operandi, such vulnerability could undoubtedly represent a high risk.

Geological disposal

In the past decades, the debate around deep geological disposals has been particularly lively. Most countries using nuclear power have been developing projects of deep waste burying (see technical frame). Although none of these geological disposals is actively used today, many of them are about to start receiving ILW and HLW. One specific concern opposed by those who are “anti” is the long-term functioning of the copper canisters in which the spent fuel would be encapsulated. Although they are designed to contain waste for tens of thousands of years, some fear the canisters’ premature wear and tear. Considering the timescale at stake with nuclear storage, no full-scale experiment can properly validate these technologies and the decision to adopt geological disposal would rely “only” on strong scientific studies and modeling.

Among the articles on risks associated with geological disposals, the one by J. M. Korhonen [11] which is based on an analysis published by the Finnish Radiation Safety Authority (STUK) [12] tends to wipe out all risks in an intentionally provocative graphic (see figure 3). Indeed, the article, whose content was widely relayed to defend deep burying applications, suggests that even in the worst-case scenario of a canister leaking 500 m underground, no actual risks of irradiation would exist even after 10, 000 years’ time.

Figure 3 – What does research say about the safety of nuclear power? [11]

 

Whether we discuss Greenpeace studies or some national nuclear associations’, the point of views are transparently biased to defend their cause. Nonetheless, scientific conclusions rely on clear methodologies and supposedly analysis in good faith. Thus, the debate should not oppose dogmatic and irrational opinions. We think that everyone can streamline his or her opinion on this topic by reading scientific articles and confronting arguments.

Technical glimpse on deep geological disposals for HLW
HLW accounts for just 3% of the volume, but 95% of the total radioactivity of produced waste. Considering the long timelines over which this waste remains radioactive, the idea of deep disposal in underground depositories in stable geological formations is being tested in several countries. The objective is to build safe underground depositories where HLW can be successively stored and eventually potentially retrieved if the new generations decide on new waste management strategies.
In Sweden, KBS-3 is the name of the deep geological repository being built 500 m underground to store HLW. It is based on three protective barriers: copper canisters, Bentonite clay and the Swedish bedrock. Figure 4 -Description KBS-3 method, www.skb.com
Each copper canister is 5 meters long and weighs 25 tons, full of spent fuel. The copper canisters are embedded in Bentonite clay acting as a buffer that protect the canister from corrosion and minor movements in the bedrock. It chemically and physically isolates the waste from the environment for theoretically tens of thousands of years.
Many countries on all continents producing HLW are working on deep geological depositories similar to KBS-3 with different levels of progress. The first ones are expected to be operational by 2025-2030.

Money wise, how much does waste management weigh on the scale?

It is internationally accepted [13] that all nuclear industries are responsible for the management of the waste they generate and therefore should be financially responsible for the waste treatment cycle. As such, power companies are meant to secure funds for waste management and decommissioning operations. However, neither long-term waste management (in particular deep geological depositories) or plant dismantling are mature enough activities to allow for slack in the costs associated. Estimates of these costs highly fluctuate from one country to another, and sometimes are even missing. These projects are meant to run over a hundred years and therefore the cost estimates rely on many volatile factors (future cost of manpower, stock markets, the cost of raw materials, etc…). Nonetheless, a lot of analyses intend to evaluate the cost of “nuclear power” and to forecast it. These assessments rely on several assumptions in terms of accounting methodology and life cycle analysis. In order to be able to compare cost analysis, origins of costs must be identified and distinguished: spent fuel management, nuclear plants dismantling, deep geological storage, accident risk costs.

As an example, the disposal of LLW reportedly costs around £2,000/m³ in the UK. HLW costs somewhere between £67,000/m³ and £201,000/m³ [14]. In France, LLW disposal costs were estimated around €2500/m3 [15] in 2002.

Regarding deep geological depositories, costs are even more arbitrary because they are highly dependent on the discounted value. For the sake of illustrating the magnitude of costs, the French agency for nuclear waste management evaluated the deep geological depository project (around 40,000 m3 of HLW and 350,000 m3 of ILW) at 35 M€ [16].

In Sweden, KBS-3 project (see technical frame) is estimated at 9,5 M€.

In the framework of its series of articles about nuclear power, Greenfish will publish another article fully dedicated to the financial aspect of nuclear power industry.

Conclusion

Whether you are “pro” or “anti” for good or bad reasons, all countries with a nuclear power industry have nuclear waste on their lands. As such, it is up to our governments, representing us, to decide and implement the best strategy to manage nuclear waste for now and in the future.

Whatever the type of waste, waste management strategies are always constrained by financial factors, technical solutions and strategic planning. The nuclear industry, as any chemical or heavy industry, involves a fourth dimension : security and safety.  Although not all countries have the same budget, the same technological resources or the same soil, all countries have to give as much importance to the safety issue to safeguard human health and the environment.

Today, most nuclear waste is properly managed with safe, long-term solutions. However, regarding HLW, accounting for only a small percent of production but concentrating mostly on radioactivity, there is still no long-term operational disposal solution yet. Although many projects are being tested and highly supervised, the lack of perspective and experience on the behavior of HLW disposed of underground does not allow us to have a clear view and opinion on the future of nuclear waste management. Assessing the benefits offered by radioactivity for power generation, evaluating the actual risks associated and comparing it to what alternatives to nuclear fission we have, remains a favored way of deliberating on the use of nuclear power.

 

Pierre Marneffe, Consultant at Greenfish
Nassim Daoudi – Chief Executive Officer at Greenfish

 

[1] Estimation of Global Inventories of Radioactive Waste and Other Radioactive Materials, IAEA, June 201
[2] www.greenfish.eu/blog
[3] RTE, 2016
[4] Inventaire, Agence Nationale pour la gestion des Déchets Radioactifs (ANDRA)
[5] Agence de l’Environnement et de la Maîtrise de l’Energie (ADEME), Déchets Chiffres-clés, Edition 2016
[6] Estimation of global inventories of radioactive waste and other radioactive materials, IAEA, 2008
[7] Management of spent nuclear fuel and its waste a Joint Research Centre and EASAC Report
[8] World Nuclear Association, www.world-nuclear.org
[9] IAEA, estimates of nuclear waste, 2018
[10] “Security of nuclear reactors and spent fuel pools in France and Belgium and related reinforcement measures”, October 2017
[11] https://jmkorhonen.net/2013/08/15/graph-of-the-week-what-happens-if-nuclear-waste-repository-leaks/
[12] Posiva Biosphere Assesment Report, 2009, http://www.posiva.fi/files/1230/POSIVA_2010-03web.pdf
[13] Policies and Strategies for Radioactive Waste Management, No. NW-G-1.1, IAEA
[14] Nukenomics: The commercialization of Britain’s nuclear industry, Ian Jackson, April 2008
[15] Le démantèlement des installations nucléaires et la gestion des déchets radioactifs, Cour des comptes, January 2005
[16] ANDRA, https://www.andra.fr/sites/default/files/2018-02/note-de-synthese.pdf