Waste management, interim storage and final disposal

Management approach

GRI 103
(103-1, 103-2, 103-3)


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 obviously includes the costs of financing decommissioning and waste disposal activities.

Management approach

When handling radioactive waste in nuclear power plants, a distinction is made between operational waste and spent fuel elements and waste from reprocessing. The safety and health 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 surrounding 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 specified 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, so that information about quantity, storage location and radiological properties is available at all times. A key element in the minimization 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. In the reporting year, the following transportation took place from KKG and KKL to the Zwilag, see Table below.

The Swiss guidelines on the transportation of radioactive materials on road and rail are based, inter alia, on the international regulations on 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.

The financing for safe disposal of the radioactive waste is secured. To ensure the financial burden can be carried after the end of operations at a nuclear power plant, the nuclear power plant operators pay into the Decommissioning Fund for Nuclear Facilities and Waste Disposal Fund for Nuclear Power Plants (Stilllegungsfonds für Kernanlagen und Entsorgungsfonds für Kernkraftwerke – STENFO) on a continuous basis. The two funds are subject to federal supervision.


To ensure consistency with the data in the ENSI Oversight Report 2020, the following data refers to the calendar year 2020. The data for the calendar year 2021 will not be published by ENSI until mid-2022.

In 2020 and 2021, all radiation protection limit values were observed, guaranteeing the safety and health of employees. The objective of safe handling of radioactive waste was achieved.

The waste generated in KKG and KKL is listed in the following table. Nuclear data relating to the back end in 2020 (this data refers to the total quantity and is not scaled according to the Alpiq share proportion).


LLW / ILW containers to Zwilag

LLW / ILW unconditioned in m3

LLW / ILW conditioned in m3

ILW in m3

HLW in m3

Unloaded fuel in t

Fuel transported to Zwilag in t

Gösgen nuclear power plant (KKG)








Leibstadt nuclear power plant (KKL)








Since 2020, no long-lived intermediate-level waste (ILW) or high-level waste (HLW) from the reprocessing of spent fuel elements was 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 ”Decommissioning and dismantling of nuclear power plants”.