Nuclear Energy Ordinance (NEO) (NEO)
English is not an official language of the Swiss Confederation. This translation is provided for information purposes only and has no legal force.
Section 1 General Licence
Art. 22 Nuclear installations with low hazard potential
1 Nuclear installations do not require a general licence if the frequency of all accidents in accordance with Article 8 paragraphs 2 and 3 with a resulting dose of more than 1 mSv for members of the public does not exceed 10-6 per annum. In the case of interim storage installations and deep geological repositories, the total of activities of all nuclides to be emplaced must not exceed 1016 g LL in accordance with Annex 3 column 9 RPO. 2 ENSI shall specify the methodology and boundary conditions for the accident analysis called for in paragraph 1 in guidelines.
Para. 1 — SR 814.501 Para. 1 — Amended by Annex 11 No 4 of the Radiological Protection Ordinance of 26 April 2017, in force since 1 Jan. 2018 (AS 2017 4261). Para. 2 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 23 Application documents
Applications for a general licence must be accompanied by the following documentation: a. safety analysis report and security report that include the following information: 1. site characteristics, 2. purpose and outline of project, 3. anticipated exposure to radiation in the vicinity of the installation, 4. important information regarding organisation and personnel, 5. in the case of deep geological repositories, indication of long-term safety; b. environmental impact report; c. report on compliance with spatial planning requirements; d. concept for decommissioning, or for the monitoring period and closure; e. feasibility demonstration of the management and disposal of resulting radioactive waste.
Section 2 Construction Licence and Construction of
Art. 24 Applications
1 Applicants for a construction licence must demonstrate that: a. they are able to comply with the principles aforementioned in Articles 7 to 12; b. … c. in the case of nuclear installations with low hazard potential, the requirements aforementioned in Article 22 are met. 2 They must submit the following documentation: a. required documents for construction licence as indicated in Annex 4; b. environmental impact report; c. report on compliance with spatial planning requirements; d. quality management programme for the planning and construction phase; e. emergency preparedness concept; f. decommissioning plan or project for the monitoring period and plan for closure of the installation; g. report on compliance of the project with the general licence requirements. 2bis For activities outside construction zones, the application must in particular include plans clearly showing the boundaries of any new or removed buildings in accordance with Article 25a paragraph 1 of the Spatial Planning
Para. 1 let. b — Repealed by No I of the O of 1. Nov. 2017, with effect from 1 Jan. 2018 (AS 2017 7107). Para. 2bis — SR 700.1 Para. 2bis — Inserted by Annex No 6 of the O of 15 Oct. 2025, in force since 1 July 2026 (AS 2025 659). Para. 3 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 25 Quality management programme
1 In their quality management programme for the planning and construction phase, applicants are required to describe the organisational structure and processes, including their co-operation with contractors, and with the relevant licensing and supervisory authorities. 2 The quality management programme must take account of the state of the art of nuclear safety and security technology. 3 Applicants must have their quality management programme periodically examined by external auditors – and modified where necessary – in accordance with current industry standards. 4 ENSI shall specify the detailed requirements on quality management programmes in guidelines.
Para. 4 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 26 Permits
1 For buildings and system components that require a permit in accordance with the conditions of the construction licence, ENSI shall grant permits: a. for the construction of building structures including embedded attachment elements and the installation of reinforcement bars or the assembly of steel constructions and for the methodology applied for modifications to the original structure and subsequently installed fastening elements; b. for the manufacture of the main mechanical components; c. for the installation of mechanical and electrical systems, including their instrumentation and control and for security equipment. 2 To obtain the necessary permit, applicants must submit all the documentation necessary for the assessment as aforementioned in Annex 4. 3 ENSI shall regulate the type, content, presentation and number of required application documents in guidelines.
Para. 1 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747). Para. 3 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 27 Construction documentation
1 Licence holders must fully document the construction of buildings and the manufacture and assembly of technical equipment, as well as implemented controls and inspections in a retraceable manner at all times. 2 All documentation must be securely archived until completion of the decommissioning, or until closure or expiry of the specified monitoring period. 3 All modifications carried out on the installation, including decommissioning or closure, must be documented. 4 The licence holder must hand over all documentation to ENSI after the installation has been decommissioned, or after it has been closed or the period of observation has expired to the Department. 5 ENSI shall specify the detailed requirements on documentation and archiving in guidelines.
Para. 4 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747). Para. 5 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 27a Reporting obligations
1 The SFOE shall inform the Federal Office of Topography (swisstopo) that a construction licence procedure has been completed by forwarding the construction licence and the required plans. 2 In the case of buildings and installations that require an update to the official cadastral survey or national survey, the licence holder shall provide swisstopo with the following information within 20 days and enclose the required plans: a. the start of construction; and b. the completion of construction. 3 Where activities are situated wholly or partly outside construction zones, the licence holder shall, at the same time as informing swisstopo that construction has been completed, submit the legally binding plans referred to in Article 24 paragraph 2bis to the cantonal authority responsible in accordance with Article 25 paragraph 2 of the Spatial Planning Act of 22 June 1979. The plans shall be submitted in the form of geodata.
Art. 27a — Inserted by Annex No 6 of the O of 15 Oct. 2025, in force since 1 July 2026 (AS 2025 659). Para. 3 — SR 700
Section 3 Operating Licence
Art. 28 Application documents
1 Applications for an operating licence must be accompanied by the following documentation: a. the required organisational and technical documentation as indicated in Annex 3; b. the required documents for an operating licence as indicated in Annex 4; c. evidence of insurance cover; d. the report on compliance of the installation with the requirements of the general licence and the construction licence. 2 ENSI shall regulate the type, content, presentation and number of required application documents in guidelines.
Para. 2 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 29 Permits
1 The operating licence shall require permits for the following stages of the commissioning procedure: a. the first delivery of nuclear fuel; b. the first fuel load; c. the first criticality; d. the next stages in accordance with the commissioning programme; e. continuous operation in the first operating cycle; f. the first storage of waste packages of a given type; g. the storage of transport and storage casks with spent fuel elements or high level waste. 2 To obtain the necessary permit, applicants must submit the documentation necessary for the assessment as aforementioned in Annex 4. 3 ENSI shall regulate the type, content, presentation and number of required application documents in guidelines.
Para. 3 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 30 Requirements concerning organisation
1 The organisation of the installation must be structured in such a manner that it ensures internal responsibility for at least the following activities and areas: a. operation of the installation in all operating modes; b. maintenance, material technology and testing methods, technical support; c. design and surveillance of the reactor core; d. radiation protection and radioactive waste; e. water chemistry and use of chemical additives. f. emergency planning and preparedness; g. supervision and assessment of nuclear safety; h. security; i. quality assurance for services provided by contractors; j. initial and continuing training of personnel; k. fostering of safety awareness. 2 The licence holder must organise the personnel into a manageable number of organisational units which are headed by a designated manager. Deputies must also be appointed for all managers. 3 The licence holder must appoint a committee that analyses events and findings that are attributable to human factors, and
Para. 5 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 31 Quality management system for operation
The quality management system for operation must meet the following requirements in particular: a. Responsibilities and competencies for processes in the organisation must be described clearly and in detail. b. Tasks of relevance to safety and security must be defined in a management cycle and must be systematically planned, executed, controlled, documented, internally and externally audited on a periodical basis, and adjusted as necessary. c. The quality management system must correspond to the state of the art of nuclear safety and security technology.
Section 4 Operation
Art. 32 Maintenance, in-service inspection and functional testing
1 The licence holder must define systematic programmes for the maintenance of safety and security equipment and must implement the measures specified therein, in particular relating to: a. maintenance; b. non-destructive in-service inspections; c. periodic functional tests. 2 Any deviations from the target state must be rectified by taking the appropriate repair measures. 3 Qualified procedures and equipment must be used for maintenance, inspection and repair tasks, and these must be carried out by qualified personnel. 4 All maintenance and repair work must be documented and the outcome periodically evaluated. Programmes must be supplemented as necessary.
Art. 32a Reliability assessments
1 The regular reliability assessments on persons who carry out functions that are essential for nuclear safety and the security of the nuclear installation are governed by the Ordinance of 8 November 2023 on Personnel Security Screening (PSSO). 2 The costs of the assessments are borne by the instigating body in accordance with Article 15 paragraph 4 letter a PSSO.
Art. 32a — Originally Art. 33a. Inserted by Annex 8 No II 7 of the O of 8 Nov. 2023 on Personnel Security Screening, in force since 1 Jan. 2024 (AS 2023 736). Para. 1 — SR 128.31
Art. 33 Systematic safety and security assessments
1 The licence holder must carry out systematic safety assessments for the following areas: a. impacts of modifications to the installation, and of events and findings, on the safety of the installation, and in particular on risk; each risk assessment must incorporate an up-to-date, plant-specific probabilistic safety analysis ( PSA ); b. operational experience feedback from electrical and mechanical equipment important to safety, fuel elements, structures important to safety and water chemistry; c. radiation protection and radioactive waste; d. organisation and personnel; e. emergency planning; f. criteria in accordance with Article 44 paragraph 1. 2 The licence holder must carry out systematic security assessments for the following areas: a. security concept; b. physical protection measures. 3 ENSI shall specify the detailed requirements on systematic safety and security assessments in guidelines.
Para. 3 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 33a Comprehensive systematic safety assessments for nuclear installations other than nuclear power plants
1 The holder of an operating licence for a nuclear installation other than a nuclear power plant must carry out a comprehensive systematic safety assessment every ten years in addition to the systematic safety assessments in accordance with Article 33 paragraph 1. 2 ENSI shall specify the detailed requirements on the comprehensive systematic safety assessment in guidelines.
Art. 33a — Inserted by No I of the O of 21 May 2025, in force since 1 July 2025 (AS 2025 384).
Art. 34 Comprehensive safety reviews for nuclear power plants
1 The holder of an operating licence for a nuclear power plant must carry out a comprehensive safety review every 10 years (Periodic Safety Review, PSR). 2 For this purpose it must: a. explain and evaluate the safety concept; b. conduct a deterministic analysis of the safety status and a PSR; c. explain and evaluate the overall safety status; d. explain and evaluate whether the organisation of the plant and its personnel satisfy safety requirements. 3 The PSR documents must be submitted to ENSI two years at the latest before the end of any operating decade. 4 For the period following the fourth operating decade, proof of safety for long-term operations in accordance with Article 34a must also be submitted as part of the PSR. 5 ENSI shall specify the detailed requirements on periodical safety reviews in guidelines. It may provide relief for nuclear power plants for the period following their being definitively taken out of service or exempt them entirely from the obligation to submit a
Art. 34 — Amended by No I of the O of 26 April 2017, in force since 1 June 2017 (AS 2017 2829).
Art. 34a Proof of safety for long-term operations
1 Proof of safety for long-term operations shall comprise the following information in particular: a. the relevant period of operation; b. proof that the design limits for the parts of the plant with technical safety relevance will not be reached during the planned period of operation; c. the backfitting and technical or organisational improvements planned for the following operating decade; d. the measures intended to guarantee sufficient numbers of staff with the required expertise for the planned period of operation. 2 ENSI shall specify the detailed requirements on proof of safety for long-term operations in guidelines.
Art. 34a — Inserted by No I of the O of 26 April 2017, in force since 1 June 2017 (AS 2017 2829).
Art. 35 Ageing management
1 With the aid of a programme for managing ageing, the licence holder must systematically monitor the ageing of all systems, structures and components, the functions and integrity of which are of importance with regard to safety and security. 2 The results must be evaluated, and any necessary measures must be defined and duly implemented. 3 With the aid of the said programme for managing ageing, the licence holder must document the inspection of the installation from the point of view of the effects of ageing, and the programme must be periodically updated in accordance with the current status of the installation. 4 ENSI shall specify the methods and scope of the ageing management programme in guidelines.
Para. 4 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 36 Monitoring the state of the art in science and technology and the operating experience in comparable installations
1 The licence holder must monitor field-related scientific developments, especially findings obtained from research activities, and must examine the extent to which conclusions may be drawn therefrom concerning safety and security of the licence holder’s installation. 2 The licence holder must monitor technological developments, including those relating to organisation and personnel, and must examine the extent to which conclusions may be drawn therefrom concerning the safety and security of the licence holder’s installation. The following are of particular relevance: a. recognised domestic and foreign technical standards; b. regulations of the country supplying the nuclear installation, as well as of other countries, relating to nuclear technology; c. recommendations of international bodies; d. state of the art in nuclear installations of a similar nature and in other relevant installations. 3 The licence holder must monitor operating experiences and findings of similar installations
Art. 37 Periodical reporting
1 In accordance with Annex 5, the licence holder must submit reports to ENSI for the purpose of assessing the status and operation of the installation. 2 ENSI shall regulate the type, content, presentation and number of required reports in guidelines.
Para. 1 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747). Para. 2 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 38 Reporting obligations in the area of nuclear safety
1 Holders of an operating licence must report the following activities in particular to ENSI before they are carried out: a. planned shutdown of a reactor; b. restart of a reactor following shutdown due to an accident; c. work with an anticipated collective dose exceeding 50 mSv; d. planned non-routine discharge of radioactivity into the environment; e. change of activated carbon in emergency filters of ventilation systems; f. planning and execution of emergency exercises; g. experiments on systems or components important to safety. 2 They must report the following activities to ENSI: a. modifications of systems that are not subject to licence or permit; b. changes in the content of documentation within the meaning of Articles 27 and 41. 3 They must report the following events and findings to ENSI: a. any events that impair or may impair safety; b. any other events of public interest; c. findings that may impair safety but have not given rise to an event. 4 They must submit to ENSI all
Art. 38 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 39 Reporting obligations in the area of security
1 The holder of an operating licence must in particular report the following activities to ENSI before they are carried out: a. … b. security-related exercises with the involvement of military, cantonal or municipal authorities; c. extraordinary security-related activities. 2 The holder of an operating licence must report the following malicious acts and findings to ENSI without delay: a. use of violence against personnel; b. sabotage and attempted sabotage; c. bomb threats; d. extortion and hostage-taking; e. accidents, damage to or failure of security equipment and systems that last longer than 24 hours; f. malicious acts in and in the vicinity of the nuclear installation that are attributable to, or indicate, unauthorised interference; g. any other malicious acts and findings that impair or may impair security. 3 The holder of an operating licence must submit a report on every malicious act or finding to ENSI within 30 days. The report must be classified.
Art. 39 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747). Para. 1 let. a — Repealed by No I of the O of 31 May 2024, with effect from 1 July 2024 (AS 2024 280).
Art. 40 Modifications that require a permit
1 The following modifications are generally regarded as modifications that do not deviate significantly from the respective licence but which require a permit in accordance with Article 65, paragraph 3 of the Nuclear Energy Act: a. modifications to structures, systems and components subject to safety or security classification and to equipment relevant to safety or security, providing the existing safety or security functions are maintained or improved; b. the following modifications to the reactor core: 1. modifications to the loading of the reactor core with fuel elements as part of the refuelling procedure, 2. modifications to and repair of fuel elements and control rods, 3. increase of permissible burn-up, 4. modification to safety assessment methods, 5. modification of safety criteria, 6. increase of the proportion of uranium-plutonium-mixed-oxide fuel elements in reactor core up to a maximum of 50 percent; c. changes in the content of the following documents: 1. the power plant o
Para. 5 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 41 Documentation
1 The licence holder must update the organisational and technical documents in accordance with Annex 3 throughout the entire period of operation of the nuclear installation, up to its decommissioning or closure, and must adapt them to the current status of the installation. 2 The licence holder must at all times traceably document the operation of the installation on the basis of records in accordance with Annex 3 and documents describing function tests and maintenance operations. 3 All documentation must be securely archived until completion of the decommissioning, or until closure of the installation or expiry of the specified monitoring period. 4 The licence holder must hand over all documentation to ENSI after the installation has been decommissioned, or to the Department after closure of the installation or expiry of the monitoring period. 5 ENSI shall specify the detailed requirements on documentation and its archiving in guidelines.
Para. 4 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747). Para. 5 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 42 Updating of plan or project concerning decommissioning and closure
1 Every ten years, the holder of an operating licence must review and update the plan for the decommissioning of a nuclear installation or, in the case of a deep geological repository, the project for the monitoring period and the plan for closure. 2 Updating is also required if: a. significant changes have been made to the installation; b. significant requirements have been changed that relate to decommissioning, or the monitoring period and closure of the installation; c. significant technological developments make updating necessary.
Art. 43 Shutdown of a nuclear power plant
1 The holder of an operating licence for a nuclear power plant must shut down the installation if one of the shutdown criteria in the technical specifications or power plant regulations should be fulfilled. 2 The licence holder may only resume operation with a reactor output of more than 5 percent after the necessary measures have been taken.
Art. 44 Criteria for provisional taking out of service and backfitting of nuclear power plants
1 The holder of an operating licence must take the nuclear power plant out of service and backfit it if one or more of the following technical criteria are fulfilled: a. accident analyses indicate that core cooling in the event of an accident in accordance with Article 8 paragraphs 2 and 3 can no longer be assured and a dose of 100 mSv will be exceeded as a consequence; b. the integrity of the primary coolant system can no longer be assured; c. the integrity of the containment can no longer be assured. 2 In the analysis under paragraph 1 letter a, accidents with a frequency of more than 10-6 per year that are not triggered by natural events and natural events with a frequency of 10-4 per year must be taken into account. 3 The Department specifies the methodology and boundary conditions governing the review of criteria in an ordinance.
Art. 44 — Amended by No I of the O of 7 Dec. 2018, in force since 1 Feb. 2019 (AS 2019 183).
Section 5 Decommissioning
Art. 45 Project documentation
The organisation required to carry out decommissioning must submit the following documents concerning the decommissioning project: a. comparison of variants for the different stages, timetable for the decommissioning operations and expected end status, including the reason for choice of variant; b. description of each step and required funding, i.e. determination of radiological status of the installation, disassembly, dismantling and decontamination of installations, decontamination and demolition of buildings; c. procedure for separating radioactive from non-radioactive waste and management of the radioactive waste; d. measures to protect personnel against radiation and to prevent the release of radioactive substances into the environment; e. security measures; f. accident analysis, specifically the identification of potential accidents during decommissioning, assessment of their frequency and radiological impacts, as well as counter-measures and any necessary emergency preparedness
Art. 46 Decommissioning order
The decommissioning order specifies the following details: a. scope of decommissioning activities; b. the various decommissioning stages, in particular the duration of any safe enclosure of the nuclear installation; c. limits for the discharge of radioactive substances into the environment; d. monitoring of immissions of radioactive substances and of direct radiation; e. organisation.
Art. 47 Permits
The decommissioning order sets forth the need for a permit especially for the following activities: a. procedure for the clearance measurement of resulting materials; b. conditioning of resulting radioactive waste; c. demolition of buildings after their decontamination and clearance measurement; d. non-nuclear use of installations after completion of the decommissioning process; e. repeal of security measures; f. in the case of decommissioning of nuclear power plants, disassembly of the reactor vessel and its surrounding building elements.
let. a — Amended by No I of the O of 7 Dec. 2018, in force since 1 Feb. 2019 (AS 2019 183). let. c — Amended by No I of the O of 7 Dec. 2018, in force since 1 Feb. 2019 (AS 2019 183).
Art. 48 Reporting procedure for decommissioning
The organisation required to carry out decommissioning must report to ENSI once a year on the status of decommissioning of the installation, and must also submit a final report after completion of the process.
Art. 48 — Amended by Annex No 12 of the O of 12 Nov. 2008 on the Swiss Federal Nuclear Safety Inspectorate, in force since 1 Jan. 2009 (AS 2008 5747).
Art. 49 Reporting obligations
Articles 38 and 39 apply by analogy to reporting obligations relating to decommissioning.
