Nuclear energy

A key part of Alpiq’s core business is power production from flexible, climate-friendly Swiss hydro power and low-carbon nuclear energy. For more information about the role nuclear energy plays in helping Alpiq meet its purpose to improve security of supply, please refer to section 7.1 ‘Security of supply’.

The nuclear power plants in which Alpiq holds shares were operated safely and reliably in 2021 and 2022. Production data for 2021 and 2022 can be found in the Alpiq Holding Ltd. Annual Report for 2021 and 2022. In addition to power production, the KKG supplies the local industry with climate-friendly process steam. The indirect CO2 emissions for 2021 and 2022 are itemized in “GRI 305: Emissions”.

Fuel preparation (front end) and power production

The uranium in the nuclear fuel used at KKG comes from Australia and Canada. When the nuclear fuel is procured, all suppliers are assessed with regard to product quality, security of supply, environmental compatibility, transparency of the supply chain and economic efficiency.

In KKG 24.8 t of fresh fuel was loaded in 2021 and also in 2022, in KKL 24.4 t in 2021 and 28.1 t in 2022.

The Swiss Federal Nuclear Safety Inspectorate (ENSI) is the Swiss oversight authority responsible for Swiss nuclear power plants. In the safety assessment published for 2021 (ENSI Oversight Report 2021, ENSI-AN-11140) and 2022 (, ENSI assessed KKG and KKL to be safe facilities. The ENSI Oversight Report 2022 will not be published until mid-2023.

Waste management, interim storage and final disposal (back end)

Power production from nuclear energy produces radioactive waste. For the nuclear power plant operators, protecting the population, employees and environment from ionising radiation takes the highest priority. This includes the safe handling of radioactive waste. As a shareholder in KKG and KKL, Alpiq pays the plants’ annual costs in proportion to its share; this includes the costs of financing decommissioning and waste disposal activities.

When handling radioactive waste in nuclear power plants, a distinction is made between operational waste and spent fuel elements and waste from reprocessing. The health and safety of employees is ensured through the consistent implementation of the appropriate guidelines: Guideline ENSI-G15 defines the radiation protection limit values that apply in Switzerland to employees and to the population in the vicinity of the nuclear power plant. These are monitored in accordance with guideline ENSI-B09 and reported to ENSI in accordance with guideline ENSI-B03.

Operational waste (IAEA classification: low and intermediate-level waste, LLW and ILW)

Radioactive operational waste (raw waste) is generated in a nuclear power plant on a regular basis from the water cleaning systems and from exhaust air cleaning. Other waste comes from replacing components during maintenance, modification or retrofitting work and the consumables used in these processes.

The radioactive waste is collected, conditioned on a campaign basis and then placed into intermediate storage. The unconditioned waste present in a nuclear power plant is stored in designated rooms in the controlled zone.

The following conditioning processes are used at a nuclear power plant: Encapsulation of resins in polystyrene, cementing of sludge or bonding in bitumen. Combustible and fusible raw waste or exhaust air filters are provided for treatment in the plasma plant at the central intermediate storage facility (Zwilag) in Würenlingen. For all conditioning processes in Switzerland, the type approvals required in accordance with the Swiss Nuclear Energy Ordinance (KEV) and guideline ENSI-B05 are available. The conditioned waste containers are routinely placed into storage at the plant’s own intermediate storage facility or at the Zwilag.

The radioactive waste from Swiss nuclear power plants is logged in an electronic accounting system used by all Swiss nuclear power plants, thus ensuring the availability of information about quantity, storage location and radiological properties at all times. A key element in the minimisation of radioactive waste is the inactive clearance measurement of materials from the controlled zone.

Fuel elements and waste from reprocessing (IAEA classification: high-level radioactive waste, HLW)

After final unloading from the reactor core, spent fuel elements are stored for several years in the plant’s own wet storage pool to cool down. During this time, the thermal output subsides significantly, so that the fuel elements can subsequently be placed under optimal storage conditions in intermediate storage containers. These storage containers are constructed according to international standards and licensed and stored in Switzerland in accordance with ENSI guidelines ENSI-B17 and ENSI-G05. The loaded containers are transported to the Zwilag where they are placed into storage. The transports from KKG and KKL to the Zwilag in the reporting year are presented in the table below.

The Swiss guidelines on the transportation of radioactive materials by road and rail are based, inter alia, on the international regulations for the carriage of dangerous goods by road (ADR) or by rail (COTIF). For all modes of transport, the IAEA recommendations for safe transport of radioactive material (IAEA SSR-6) apply.

To ensure consistency with the data in the ENSI Oversight Report 2021, the following data refers to the calendar year 2021. The data for the calendar year 2022 will not be published by ENSI until mid-2023.

The waste generated in KKG and KKL is presented in the following table. Nuclear data relating to the back end in 2021 (this data refers to the total quantity and is not scaled in proportion to the Alpiq share proportion).

Waste generated in KKG and KKLWaste generated in KKG and KKL

For KKL an additional 29 transports were made to Zwilag to transfer the replaced material from the large outage in 2021.

Since 2020, no long-lived intermediate-level waste (ILW) or high-level waste (HLW) from the reprocessing of spent fuel elements has been transported back into Switzerland. All obligations relating to the recovery of waste from reprocessing have been fulfilled.

The costs for the funding of the waste disposal are listed in section “5.3. Decommissioning and dismantling of nuclear power plants”. In 2021 and 2022, all radiation protection thresholds were observed, guaranteeing the health and safety of employees. The objective of safe handling of radioactive waste was achieved. For further information please consult ENSI Radiation Safety Report (ENSI AN-11280) for 2021 and the ENSI statement for 2022. The ENSI Radiation Safety Report 2022 will not be published until mid-2023.

Decommissioning and dismantling of nuclear power plants

Guaranteeing safe operation and handling of radioactive materials includes the entire value chain and the lifecycle of nuclear energy plants, from construction through to commissioning and decommissioning of the facilities as well as their dismantling. In accordance with the conditions defined in the Nuclear Energy Act (KEG) and the Nuclear Energy Regulation (KEV), Alpiq is committed to fulfilling its obligations, nuclear energy is currently an important pillar in the Alpiq production portfolio for climate-friendly electricity.

The financing for dismantling nuclear power plants and for the safe disposal of radioactive waste is secured. To ensure the financial burden can be carried even after the end of operations at a nuclear power plant, the nuclear power plant operators pay into the STENFO on an ongoing basis. The two funds are subject to federal supervision.

The money is paid into the funds by Kernkraftwerk Gösgen-Däniken AG and Kernkraftwerk Leibstadt AG. In 2021, KKG paid CHF 43.1 million and KKL CHF 51.8 million (final determination, including back payments for 2020) and in 2022 KKG paid CHF 2.7 million and KKL CHF 7.7 million (provisional assessment) into the funds for decommissioning and waste disposal. As a shareholder in KKG and KKL, Alpiq pays that part of the annual costs in proportion to its share, including the costs of financing decommissioning and waste disposal activities.

The payments made into the funds are calculated on the basis of cost estimates prepared every five years for decommissioning and dismantling nuclear power plants and for disposing of nuclear waste in accordance with the Swiss Ordinance on the Decommissioning and Disposal Funds for Nuclear Power Plants (Verordnung über den Stilllegungs- und den Entsorgungsfonds für Kernanlagen – SEFV).

The most recent cost study is from 2021. At the end of 2021, this updated cost study was submitted in the form of Cost Study 21 and is now being reviewed and assessed by STENFO. This cost study is updated every five years. The next update of the cost study will therefore be 2026. For further information, please see the Annual Reports of KKG AG and KKL AG.

The status of the two funds is on track and, as described above, is continuously monitored independently (for further information see

Environmental safety and monitoring

The nuclear power plants in which Alpiq holds shares are required to comply with safety aspects in a comprehensive, consistent and efficient way as well as to take measures to ensure that they are implemented. This must be done while taking into account ethical, economic and social principles as well as legal provisions. Both Alpiq and the operators of the nuclear power plants consider responsibility for people and the environment a central task. The focus is firmly on the health and safety of the public, employees and third-party companies.

The nuclear power plants in Switzerland are subject to the most stringent safety standards. Reportable events at nuclear power plants do not mean that measurable quantities of radioactive substances have been released. They simply indicate that there were irregularities in operation that needed to be observed and reported in accordance with guideline ENSI-B03. Guideline ENSI-G15 defines the radiation protection limit values that apply in Switzerland to employees and to the population in the vicinity of a nuclear power plant. These are monitored in accordance with guideline ENSI-B09 and reported to ENSI in accordance with guideline ENSI-B03.

Since 2010, the nuclear energy key performance indicators (reportable events, energy availability, dose values) have been communicated by the operators of the nuclear power plants exclusively by calendar year to ensure comparison with the official reports from ENSI and World Association of Nuclear Operators (WANO). There is no additional conversion or communication for other periods of time (water year) in order to avoid any contradictory data and misinterpretations when compared with the reports sent to ENSI and WANO. The data for the calendar year 2022 will be published by ENSI in the Oversight Report 2022 in mid-2023.

In the nuclear power plants in which Alpiq holds shares, there were no accidents with a measurable release of radioactive material in the reporting year.

The number of events that were reported in 2021 in accordance with guideline ENSI-B03 by KKG and KKL, respectively, are listed in the following table.

Number of reportable events in 2021 in accordance with guideline ENSI-B03

The International Nuclear and Radiological Event Scale (INES) is a tool for communicating the safety significance of nuclear and radiological events to the public. 0 is the lowest level and 7 is the highest. For more information, please visit the website of the International Atomic Energy Agency ( For further information about these events, please see the ENSI Oversight Report 2021 (ENSI AN-11140).

Handling water and waste water is defined in specific terms for each nuclear power plant in rules of delivery that are checked and approved by ENSI. The delivery data for 2021 and 2022 is publicly available from ENSI (ANPA-EMI data).

No Swiss nuclear power plant in which Alpiq holds a share causes significant heating of a body of water. Both KKG and KKL are cooled by a cooling tower and not by an adjacent river. The water in the cooling towers comes from the rivers; the reinjection of cooling water introduces some heat, but not in a significant way. In hot summer weather with very high river temperatures, nuclear power plants reduce their output to stay below the legal limits.

The data above show that none of the values exceeded the legal limits in the reporting year and the number of reportable events presented in the table above is lower than the year before, thus demonstrating the effectiveness of measures implemented and control measures taken to mitigate any release of radioactive material into the environment.