The recently published Radiation Protection Report 2024 provides an in-depth look at the inspection system – one of ENSI’s main monitoring instruments. ENSI’s inspectors carried out 156 inspections in the areas of radiation protection and emergency preparedness during 2024. These confirm that nuclear installation operators have implemented legally compliant and appropriate radiation protection during all operating phases in the year under review.
ENSI also did not detect any increase in local dose rates in the vicinity that could be traced back to emissions from the nuclear installations. This was notably illustrated by the evaluation of the 57 measuring probes that make up the measurement network for automatic dose rate monitoring in the vicinity of the nuclear power plants (MADUK). The data from these probes, collected at ten-minute intervals, is used for the early detection of malfunctions and accidents, and serves as documented evidence for the authorities and the public. The probe measurements can be viewed on the ENSI website.
Personal dose limit comfortably met
In 2024, optimisation measures were implemented at the nuclear installations to reduce both collective and individual doses. The evaluation of personal dosimeters shows that the individual dose limit set out in the Radiation Protection Ordinance was met by a considerable margin. ENSI identified that the nuclear installation operators are fulfilling their responsibility to keep both individual and collective doses for personnel as low as possible and to continue optimising them.
Cooperation for greater safety
In the year under review, a notable area of focus was the interface between occupational radiation protection and occupational health and safety. This prompted ENSI to conduct joint inspections of various nuclear installations with the Swiss National Accident Insurance Fund (Suva).
In the case of nuclear installations undergoing decommissioning, ENSI monitored compliance with the work procedures to verify that adequate protection was being provided for people and the environment.
Significant increase in clearance measurements
As the decommissioning of the Mühleberg Nuclear Power Plant (KKM) and the dismantling projects at the Paul Scherrer Institute (PSI) progress, ENSI has seen a significant increase in notifications regarding the clearance of materials. Specialists use clearance measurements to ensure that materials from controlled areas of nuclear installations can be released from ENSI oversight following decontamination. In 2024, ENSI inspectors conducted a campaign to take a closer look at the use of clearance measurement systems for small items. They found that users were highly competent in operating and handling these systems in the nuclear installations.
Emergency response organisation performs an emergency drill
In November 2024, a full-scale emergency drill was held over two days, simulating a major nuclear accident at the Gösgen nuclear power plant. The drill involved Switzerland’s national emergency response organisations and provided the first opportunity for ENSI to deploy its newly operational digital user interface (DANFO). This platform allows the two task forces – radiation protection and reactor safety – to perform and document the majority of their routine tasks digitally. The new interface has proven effective, and ENSI is developing it further to make full use of the potential identified during the emergency drill as part of an ongoing improvement cycle.
ENSI guidelines aligned with international standards
In 2024, as part of the continued development of its regulatory framework, ENSI definitively issued the new Guideline ENSI-B09 on the measurement and recording of doses for individuals exposed to radiation. The revised version of Guideline ENSI-G14, which covers the calculation of environmental doses caused by emissions from radioactive substances and direct radiation from nuclear installations, was close to being finalised at the end of 2024.
With these two updated guidelines, ENSI is following recommendations by the International Atomic Energy Agency (IAEA) and addressing gaps in its regulatory framework.
