What will Switzerland do with its nuclear waste, and at what cost?

Since 2001, our nuclear waste has been stored in intermediate storage halls in Würenlingen (Argovia). A site for deep geological disposal is being identified in Switzerland.

Our nuclear waste comes mainly from the five nuclear reactors operating in Switzerland. To this must be added waste from the decommissioning of the plants at the end of their lives. We also have to dispose of waste resulting from the use of radioactive substances for non-energy purposes, particularly in medicine.

The hazardous nature of nuclear waste is characterised by two quantities: radioactivity and the life expectancy. There is no direct correlation between the two. Highly radioactive and long-lived waste is the most dangerous and difficult to manage, because its level of radioactivity will remain very high for thousands, even tens or hundreds of thousands of years, depending on the type of waste. They are generated in small quantities in the core of nuclear reactors.

Medium and low-level radioactive waste, or waste with a life expectancy of “only” a few tens or hundreds of years, does not require the same level of precaution. Each waste category therefore requires specific management. Worldwide, nearly 500,000 tons of highly radioactive waste has been generated to date in 436 nuclear reactors. In Switzerland, we will have to manage the waste generated since 1969. In total, by the time our last power plant closes, we will have produced about 7,000 m³ of highly radioactive waste, roughly equivalent to one litre per inhabitant. In addition, we will have produced 100,000 m³ of low- and intermediate-level radioactive waste (the equivalent of 40 Olympic swimming pools), a third of which comes from medicine, industry and research.

As required by the Swiss Federal Nuclear Energy Act, our waste is currently collected, packaged in drums and stored above ground at an interim storage facility of Zwilag in Würenlingen in the canton of Aargau. This is pending permanent burial of them in sealed geological layers, at a depth of more than 500 metres for the most radioactive waste, as soon as a suitable site has been selected and accepted, which is not yet the case.

Since 1972, the Cooperative Society for the Disposal of Radioactive Waste (NAGRA: Nationale Genossenschaft für die Lagerung radioaktiver Abfälle) has been working to identify sites with the greatest probability of long-term geological stability in order to minimise risks. NAGRA has an underground laboratory in Grimsel to study the behaviour of geological structures that could host radioactive waste. This has enabled NAGRA to demonstrate the technical feasibility of deep disposal in Switzerland, a result that was approved by the Federal Council in 2006. The depot is expected to be commissioned between 2040 and 2050. According to NAGRA, Switzerland has at least three suitable implementation areas (Jura-East, Northern Lägern, Zürich North-East) for such definitive storage. NAGRA completed its first deep drilling in Bülach (North Lägern) in 2019, began its work in the north-east Zurich region in August 2019 and will begin work in the Jura-Est domain in 2020.

Predicting the behaviour (stability, sealing, etc.) of an underground repository over periods of several tens of thousands of years or more is one of today’s scientific challenges. There is no perfect solution for waste disposal. The deep geological disposal of radioactive waste is considered by the majority of scientists to be the most reasonable solution. Most industrialised countries with nuclear power plants are aiming for underground landfill solutions similar to those developed in Switzerland.

Some experts nevertheless recommend keeping this waste accessible so that it can one day be used as fuel in new types of nuclear reactors, known as 4th generation [→ Q19]. Ideally, this would kill two birds with one stone: recovering the vast amount of nuclear energy that is still available in the waste, while significantly reducing its radioactivity, and then permanently burying it. This option is far from being unanimously accepted by the scientific community.

The costs of nuclear waste management in Switzerland – including those arising from the decommissioning of power plants – were estimated in 2018 at 24.6 billion francs, which represents an increase of 1 to 3 billion francs over previous estimates in 2011 and 2016. They include costs for decommissioning (CHF 3.8 billion) and waste management (CHF 20.8 billion). These costs are borne by the plant owners, who contribute around 1 centime per kWh of nuclear electricity produced to a joint fund. A new estimate of these costs is carried out by the Swiss Federal Energy Office every five years, and the contributions of the operators are readjusted if necessary.