Following the Fukushima accident in 2011, the Federal Council decided to phase out nuclear power: The five existing nuclear power plants (NPPs) will continue operating until the end of their lifetimes as long they meet the safety requirements of the Swiss Federal Nuclear Inspectorate (SFNI). The first NPP, Mühleberg, will be shut down by the end of December 2019, following a decision by the operator. The permit process for three new NPPs was halted. The phase-out decision stemmed from the fact that public opinion — split 50/50 before Fukushima — had become overwhelmingly anti-nuclear. Approval of new NPPs in foreseeable referendums had therefore become impossible. The phase-out decision has also been endorsed by the Swiss Parliament (National Council and Council of States).

The nuclear phase-out requires a new energy policy to be formulated to replace some 40% of the current electricity supply coming from nuclear power (assuming electricity demand growth can be eventually stabilized in the years to come). The gap is to be filled by a mix of options, including ambitious efficiency measures, accelerated promotion of new renewable energies and additional large hydro, some gas fired (gas turbine combined cycle, GTCC) and combined heat and power plants, as well as increased electricity trade. Gas fired power, a novelty for Switzerland, will be challenging for the national climate policy goal.

Public consultation on the new energy policy, the so-called Energy Strategy 2050, took place from 28 September 2012 to 31 January 2013. The Swiss Federal Office of Energy (SFOE) evaluated the statements and adjusted the project accordingly. The Federal Council presented its message to Parliament in September 2013, leading to a new Energy Act. A final vote of Parliament took place in September 2016. A public referendum in May 2017 confirmed the new Energy Act. On 1 January 2018 the new act entered into force.

TABLE 1. ESTIMATED AVAILABLE ENERGY SOURCES

* Solid, liquid: million tonnes; gas: billion m³; uranium: metric tonnes; hydro, renewable: TW.

—: data not available.

TABLE 2. ENERGY STATISTICS

** Latest available data.

*** Energy consumption = Primary energy consumption + Net import (Import–Export) of secondary energy.

*** Solid fuels include coal, lignite.

Sources: Swiss Energy Statistics 2011, Swiss Federal Office of Energy (SFOE).

The Federal Electricity Supply Act (StromVG, effective since 1 January 2008) creates the framework for a phased liberalization of the Swiss electricity market. The market was partially opened for eligible customers⁽¹⁾ in 2008. Full market liberalization will be introduced on the basis of a federal resolution, which will be subject to an optional referendum.

In order to increase the share of electricity produced from renewable energy sources, an amendment was made to the Electricity Supply Act, introducing compensatory feed-in remuneration to cover the cost of electricity from renewable energy sources.

At present, Switzerland’s electricity market is highly fragmented. The supply of electricity is assured by some 650 electricity distributors, including seven generation and transmission companies. There are also approximately 80 bigger Swiss electricity producing companies. Many tasks are undertaken by communes, which also supply water and gas. In some cantons and cities, a single vertically integrated company is responsible for the entire supply chain, while in other cantons these are provided by a variety of companies. The public sector stake in the capital stock of electricity supply companies is currently around 87.5%, while the remaining 12.5% is held by private sector companies (domestically and abroad).

Switzerland regulated grid usage in the above mentioned Electricity Supply Act. It stipulates that the high voltage transmission grid should be operated by the national grid company, Swissgrid, which guarantees non-discriminatory access to the grid for all companies. In accordance with the Federal Electricity Supply Act, the ownership of an ultra-high-voltage network was transferred to Swissgrid by 1 January 2013. The act also stipulates the unbundling of previously vertically integrated companies.⁽²⁾

ElCom is Switzerland’s independent regulatory authority in the electricity sector. It is responsible for monitoring compliance with the Swiss Federal Electricity Act, taking all necessary related decisions and pronouncing rulings where required. ElCom monitors electricity prices and rules as a judicial authority on disputes relating to network access and payment of cost-covering feed-in of electricity produced from renewable energy. It also monitors electricity security of supply and regulates issues related to international electricity transmission and trading.

In 2017, hydropower’s share of total electricity production was 59%, while nuclear power contributed 33%. The remaining 8.2% is covered by fossil and renewable sources. Tables 3 and 4 provide further information on the electricity production, consumption and capacity.

TABLE 3. ELECTRICITY PRODUCTION, CONSUMPTION AND CAPACITY

¹ Electricity transmission losses are not deducted.

* Latest available data.

Sources: Swiss Energy Statistics 2011, SFOE.

TABLE 4. ENERGY RELATED RATIOS

¹ Net import/Total energy consumption.

* Latest available data.

Sources: Swiss Energy Statistics 2011, SFOE.

Development of a nuclear programme

In November 1945, the Swiss Government established the independent Atomic Energy Committee with the mandate to advise the Government in all civilian and military matters dealing with nuclear energy. On 18 March 1957, Parliament ratified the IAEA statute, which entered into force on 29 July 1957. In 1969, Switzerland signed the Treaty on the Non-Proliferation of Nuclear Weapons, which was ratified by Parliament on 9 March 1977.

As early as 1946, Brown, Boveri & Cie. (BBC), now ABB Group, took the first steps to build up a team of physicists and to launch a development programme. BBC was later joined by Sulzer Brothers and Escher Wyss. Initial studies dealt with graphite–carbon dioxide reactor concepts, but from 1952 on, the development concentrated on heavy water moderated reactors, with subsequent planning of the research reactor DIORIT. In 1955, more than 150 private companies joined forces and formed the company Reactor Ltd to build and operate the new privately owned research centre in Würenlingen, with two reactors on the site: SAPHIR and DIORIT. In 1960, the federal government took over the research centre, known under its abbreviation EIR (Eidgenössisches Institut für Reaktorforschung). In 1988, the merger of EIR and SIN (Schweizerisches Institut für Nuklearphysik) led to the creation of the Paul Scherrer Institute (PSI).

In Switzerland, the nuclear age began on 30 April 1957, when the SAPHIR research reactor went critical under the responsibility of Swiss scientists and engineers. This pool reactor had been purchased in 1955 from the United States Government, after being exhibited in Geneva during the First International Conference on the Peaceful Uses of Atomic Energy. SAPHIR was shut down permanently at the end of 1993.

DIORIT, the first reactor designed and constructed in Switzerland, reached criticality on 15 August 1960. It was moderated and cooled by heavy water; the fuel was initially natural uranium; a special loop allowed for the testing of power reactor fuel elements. DIORIT was shut down permanently in 1977. At the end of 2003, all radioactive material was removed from the reactor building.

In 1962, construction began on the experimental nuclear power reactor in Lucens, a 30 MW(th), 6 MW(e), heavy water moderated, carbon dioxide cooled reactor located in an underground cavern. Criticality was reached in late 1966 and commissioning in early 1968. In spite of numerous difficulties, the supply consortium led by Sulzer Brothers had demonstrated that Swiss industry was capable of building nuclear plants. The goal was the development of a small to medium sized power reactor fuelled with natural uranium within a massive containment system. As enriched uranium became readily available during the mid-1960s, the unit size of commercially offered light water reactor (LWR) NPPs increased drastically and Swiss utilities started construction of such plants very early on; interest in the Lucens reactor type decreased, however, and further large expenses for such a development could not be justified. The decision was taken to operate the reactor until the end of 1969. However, on 21 January 1969, the plant was abruptly put out of service by a partial core meltdown that destroyed the integrity of the primary system and released radioactivity into the cavern. After decontamination, decommissioning and termination of intermediate storage of radioactive material, the entire site was prepared for unrestricted reuse in 2003.

Nuclear power plant projects

In August 1965, a turnkey contract was awarded by Nordostschweizerische Kraftwerke AG (NOK) to a consortium made up of Westinghouse International Atomic Power Co, Ltd. and Brown, Boveri & Cie. for the supply of a 350 MW(e) plant equipped with a pressurized water reactor and two turbo generators (Beznau). In late 1967, NOK took the option to order a duplicate of the first unit. Beznau I reached criticality by the end of June 1969, and Beznau II in October 1972.

Also in 1965, Bernische Kraftwerke AG (BKW) chose a 306 MW(e) plant equipped with a boiling water reactor (BWR) manufactured by General Electric (GE) and twin turbo generators from BBC (Mühleberg). In July 1971, full power was achieved, but on 28 July 1971 a turbine fire broke out. Sixteen months later the plant was officially handed to the owner.

In 1973, a supply contract was signed by a consortium of Swiss utilities with Kraftwerk Union (Siemens) for the delivery of a 900 MW(e) pressurized water reactor (PWR) and turbo generator (Gösgen). Construction of the plant went very smoothly until the first connection to the grid in February and an 80% power test in March 1979. However, the accident at Three Mile Island on 28 March 1979 led to an 8 month delay in commissioning.

In December 1973, a consortium of Swiss utilities and one German utility awarded a turnkey contract to General Electric Technical Services Overseas (GETSCO) and BBC for the supply of a 940 MW(e) NPP plant equipped with a BWR (Leibstadt). Construction began in 1974 and the plant was commissioned in December 1984.

Political controversy and legal framework

The nuclear controversy began in Switzerland in 1969 with the first signs of local opposition to a nuclear plant project at Kaiseraugst, near Basel. For 20 years, the Kaiseraugst project was to remain centre stage in the nuclear controversy: site permit, local referenda, legal battles, site occupation by opponents in 1975, parliamentary vote in favour of construction in 1985, and finally a parliamentary decision in 1989 to end the project definitively. The Chernobyl accident had a dramatic impact on the political climate. Although some of the necessary permits had already been issued for two planned NPPs at Kaiseraugst and Graben, their construction was subsequently abandoned, as well as other projects in Verbois, Inwil and Rüthi.

The nuclear controversy led to several anti-nuclear initiatives at the federal level:

1. An attempt to forbid all nuclear plants, both new and those already in operation — rejected by 51.2% of the vote in February 1979.

2. Aimed at forbidding future nuclear plants, leaving untouched the plants in operation, two initiatives differing only in the treatment to be applied to Leibstadt, then under construction — rejected by 55% of the vote in September 1984.

3. Nuclear phase-out — rejected by 52.9% of the vote in September 1990.

4. A 10 year moratorium on the construction of new NPPs — accepted by 54.6% of the vote in September 1990.

5. In 1999, two new initiatives were organized aiming at the ban of the construction of new NPPs until 2010 and the closure of all NPPs after a 30 year lifespan — both initiatives were rejected in May 2003 by 58.4% and 66.3%, respectively.

A new Nuclear Energy Act came into force on 1 February 2005 in addition to a new Nuclear Energy Ordinance. It allowed the possibility of building new reactors, with the possibility of a referendum against their construction. There is no time limit regarding the lifetime of existing NPPs. The general licence is still in place. It introduced a 10 year moratorium on the export of nuclear fuel for reprocessing from 2006 to 2016. It also includes provisions for decommissioning, simplifies licensing procedures and introduces the general right of appeal.

During the 10 year moratorium on reprocessing, which began in July 2006, spent fuel was stored in Switzerland. Plutonium and uranium gained from reprocessing of spent fuel that was sent abroad before July 2006 is recycled in Swiss NPPs. The radioactive waste arising from reprocessing of spent fuel was returned to Switzerland.

Following the reactor accident in Fukushima, the head of the Federal Department of the Environment, Transport, Energy and Communications (DETEC) announced in mid-March 2011 that the pending procedures for handling applications for general licences for new NPPs had been suspended. Then, in the course of 2011, with their decision to withdraw from the use of nuclear energy on a step by step basis the Federal Council and Parliament laid the foundations for a new energy policy, the Energy Strategy 2050. The intention is to decommission Switzerland’s five NPPs when they reach the end of their service life and not to replace them with new ones. According to the Energy Strategy 2050 and the amended Nuclear Energy Act, reprocessing is forbidden indefinitely.

The public consultation on the Energy Strategy 2050 took place from 28 September 2012 to 31 January 2013. The Federal Council presented its message to Parliament in September 2013 in a new Energy Act. A final vote of Parliament took place in September 2016. A public referendum in May 2017 confirmed the new amended provisions of the Energy Act. On 1 January 2018 the new amended act entered into force.

Radioactive waste management

The safe disposal of radioactive waste is the responsibility of those parties that produce it, namely the following NPP operators: BKW FMB Energie AG (Mühleberg), KKW Gösgen–Däniken AG, KKW Leibstadt AG, Nordostschweizerische Kraftwerke Baden — now Axpo (Beznau I and II), Energie Ouest Suisse — now Alpiq. In 1972, these operators established the National Cooperative for the Disposal of Radioactive Waste (Nagra) together with the federal government, which is responsible for the disposal of radioactive waste from the health care sector, industry and research and is represented by the Federal Department of Home Affairs.

So far, there are no deep geological repositories in Switzerland. For both low/intermediate level waste (L/ILW) and high level waste (HLW) repositories, a site selection process is defined in a sectoral plan within the framework of the spatial planning legislation. The Federal Council adopted the conceptual part of the Sectoral Plan for Deep Geological Repositories in April 2008, thus initiating a three stage procedure that will result in the designation of suitable sites for deep geological repositories.

The selection — based on safety criteria — of siting regions for geological repositories for HLW and for L/ILW was the goal of the first stage. Nagra proposed six potential siting regions in October 2008. The Swiss Federal Nuclear Safety Inspectorate (ENSI), considering the input of a number of expert organizations, approved the six proposals. Following this review process, the Swiss Federal Office of Energy (SFOE) carried out a broad consultation on the first stage at the end of 2010 and submitted a report to the Federal Council. The Federal Council approved all six potential siting regions on 30 November 2011, thus concluding the first stage of the site selection process and initiating the second stage (see Section 2.7).

FIG 1. Current organizational chart.

Currently, five NPPs at four sites are currently in operation in Switzerland (see Table 5). In addition, there is one research reactor and two central disposal facilities for radioactive waste. Disposal facilities for radioactive waste are also situated in the surroundings of the NPPs. Switzerland’s five NPPs have a total capacity of 3.3 GW, and an annual availability rate of approximately 90%. Figure 2 indicates the sites of the Swiss research reactors and NPPs.

TABLE 5. STATUS AND PERFORMANCE OF NUCLEAR POWER PLANTS

* UCF (unit capability factor) for the latest available year (only applicable to reactors in operation).

** Latest available data.

+ Date, when first major placing of concrete, usually for the base mat of the reactor building, is done.++ Date of the first connection to the grid,

³ WH: Westinghouse Electric Corporation.

⁴ GETSCO: General Electric Technical Services Corporation.

⁵ KWU: Siemens Kraftwerk Union AG.

—: data not available.

Sources: PRIS database, www.iaea.org/pris

Beznau I + II: http://www.axpo.ch

Mühleberg: http://www.bkw-fmb.ch

Gösgen: http://www.kkg.ch

Leibstadt: http://www.kkl.ch

Over the past few decades, all Swiss NPPs have upgraded their power capacity. At the end of 2012, the nominal net powers were twice 365 MW(e) for Beznau NPP, 373 MW(e) for Mühleberg NPP, 985 MW(e) for Gösgen NPP and 1120 MW(e) for Leibstadt NPP.

The power plants of Beznau (Units 1 and 2), Gösgen and Leibstadt have unlimited operating licences. In December 2009, DETEC granted an unlimited operating licence for the operator of Mühleberg. This decision was appealed and subsequently approved by the Federal Supreme Court in March 2013. As a result, the operator of Mühleberg NPP and hence all Swiss NPPs have unlimited operating licences.

In 2007, the Swiss government announced a new energy policy which included renewable energies, energy efficiency, energy foreign policy and new large scale power stations, including the replacement of the existing NPPs. In 2008, the three big electricity companies, Alpiq, Axpo and BKW, submitted general licence applications for three new nuclear units at Gösgen, Beznau and Mühleberg, all three on existing nuclear sites (see Section 2.3.5 for more information on these applications).

Following the nuclear accident at the Fukushima NPP in Japan, the head of DETEC suspended the licensing procedure for the new Swiss NPPs. The decision was taken only three days after the nuclear accident in Japan, on 14 March 2011.

As a consequence of the events in Japan, ENSI immediately started carrying out a safety review of the existing NPPs. According to an ENSI ordinance, the Swiss NPPs had to participate in the European Union stress tests. The European Nuclear Safety Regulators Group (ENSREG) in charge of this peer review process stated in the final report for Switzerland: “In general, the design and further development of the plants are based on the ‘defence in depth’ concept and in consequence results in good robustness of the plants against severe accidents”. ENSREG recommended “that the regulator assesses the opportunity of requiring more reliance on passive systems for hydrogen management for severe accident conditions. It is also recommended that the regulator considers further studies on the hydrogen management for the venting systems”. Based on the reviews carried out so far, several measures have been taken to optimize safety and security. They are included in the post-Fukushima action plan. This plan foresees that 45 open points will be dealt with through 2015. The Fukushima measures were implemented to the greatest extent possible and the post-Fukushima action plan is now complete.

On 25 May 2011, the Federal Council decided to phase out nuclear power. The Swiss Parliament (National Council and Council of States) subsequently confirmed the Federal Council’s decision by approving a stepwise phase-out of nuclear power: Existing NPPs should be decommissioned at the end of their operational lifespan and not be replaced by new NPPs, as originally foreseen. The Federal Council presented its message to Parliament in September 2013 in a new Energy Act. A final vote of Parliament took place in September 2016. A public referendum in May 2017 confirmed the new Energy Act. On 1 January 2018, the new Energy Act entered into force (Swiss Federal Office of Energy SFOE - Energy Strategy 2050).

The owners and operators of NPPs are responsible for fuel cycle planning and decision making. They make contracts in accordance with national legislation and international agreements. The strategy chosen by the NPP operators included the reprocessing and storage of spent fuel, the latter with a view to later reprocessing or direct disposal. The reprocessing took place abroad (France and United Kingdom). Plutonium and uranium gained from reprocessing was used for fuel fabrication and was reused in Swiss NPPs. The radioactive waste arising from reprocessing has completely been returned to Switzerland. With the new Energy Strategy 2050, spent fuel must be disposed of as radioactive waste and may not reprocessed.

In accordance with the polluter pays principle, producers of radioactive waste in Switzerland are responsible for ensuring its safe disposal at their own cost. The various ongoing costs (e.g. studies carried out by Nagra, construction of interim storage sites, site selection procedures for deep geological repositories) have to be paid as they arise. Decommissioning costs and expenditures associated with the management (including disposal) of radioactive waste after an NPP has been closed down, are secured through contributions paid into two independent funds by the operator:

• Decommissioning fund;

• Waste disposal fund.

The Nuclear Energy Act and the Ordinance on the Decommissioning Fund and the Waste Disposal Fund (SR 732.17, 7 December 2007) form the legal basis for these two funds.

Licensing procedures are divided in three stages: i) the general licence procedure, ii) the construction licence procedure, and iii) the operating licence procedure.

The Federal Council is the executive branch of the Swiss Government, consisting of seven members elected by the United Federal Assembly for a four year term. It is responsible for decision making regarding the application for a general licence. Any decision of the Federal Council will be brought before Parliament. Resolutions by the Federal Assembly concerning the approval of general licences are subject to an optional national referendum.

DETEC is responsible for decision making regarding applications for construction and operating licences. Its decisions can be appealed to the Federal Administrative Court, and at a later stage to the Federal Supreme Court.

SFOE has the lead on all three authorization procedures. SFOE employs almost 250 staff members. As of the beginning of March 2018, SFOE comprises six divisions and two operational sections.

ENSI is the national regulatory body with responsibility for the nuclear safety and security of Swiss nuclear facilities. In the licensing procedures it is also responsible for safety related examination and assessment of nuclear facilities. Most of ENSI’s expenses are covered by fees, which licence holders have to pay to the federal government. ENSI currently employs around 140 staff members: physicists, mechanical, electrical and civil engineers, geologists, chemists, biologists and psychologists, in addition to technical and administrative personnel.

Other public entities involved in the above mentioned authorization procedures are the Swiss Federal Nuclear Safety Commission (NSC), the Federal Office for the Environment (FOEN), the Federal Office for Spatial Development (ARE) and the cantons.

No Government financial support is granted for the construction of new NPPs. Some public entities such as the cantons nevertheless have considerable shares of some of the relevant companies.

The transmission and distribution networks for electricity need to be modernized and expanded. To cope with the increasing fluctuations in electricity production (e.g. wind and photovoltaic), electricity systems must become more flexible. The continuous balance between production and consumption needs to be guaranteed under increasingly dynamic conditions and grids need to become more automated; smart grids offer one possible solution to these challenges.

Switzerland is closely integrated into the European electricity system. A close integration of markets is of mutual benefit for Switzerland and its neighbouring countries with respect to security of supply. In addition to the Energy Strategy 2050 there is a further national strategy for energy networks in place, including aspects of the international integration, that will be defined to this end. This strategy will also include measures to accelerate the approval process and address aspects concerning the costs of grid expansion and renovation as well as the development of electricity grids towards smart grids.

On 9 June 2008, Kernkraftwerk Niederamt AG, a subsidiary of Atel Holding AG (now known as Alpiq Holding AG), submitted an application to the SFOE for a general licence for an NPP with a maximum output of 1600 MW. The plan for the new facility was to be constructed in Niederamt (canton of Solothurn), near the existing Gösgen NPP.

On 4 December 2008, on behalf of Axpo Holding AG and BKW FMB Energie AG, respectively, Ersatz Kernkraftwerk Beznau AG and Ersatz Kernkraftwerk Mühleberg AG each submitted an application to the SFOE for a general licence for the construction of new NPPs to replace the existing Beznau I, Beznau II and Mühleberg facilities. The plan was for these new NPPs, each with a maximum output of 1,600 MW, to be constructed at the locations of the existing facilities, namely in Beznau (canton of Aargau) and Mühleberg (canton of Bern).

All three applications have been examined in detail by ENSI. The NSC stated that ENSI delivered an in-depth safety review. The NSC has also made a number of recommendations.

All three applications were suspended in March 2011 as a consequence of the nuclear accident in Fukushima, Japan. In October 2016, the applicants withdrew their applications and on 14 November 2016 DETEC dismissed the general licence procedures.

The Paul Scherrer Institute (PSI) is the largest research centre for natural and engineering sciences within Switzerland. Approximately 1150 scientists, including 160 postdocs and 200 PhD students (2017 data) at the institute perform high level research in a large variety of scientific questions that can be grouped into three main fields: matter and material, human health, and energy and environment. By conducting fundamental and applied research, PSI works on long term solutions for major challenges facing society, industry and science.

PSI operates several large scale facilities that allow experiments to be performed that would be impossible in smaller laboratories. The facilities are unique in Switzerland, and some of them are the only ones of their type or scale in the world. The institute provides access to the facilities within the framework of a user service to researchers from universities, other research centres and industrial companies. Each year, about 2300 researchers in these categories perform experiments at the facilities.

Energy and environment

The goal of PSI’s energy research is the development of technologies for a sustainable use of energy. This includes environmentally friendly energy production, the application of renewable energy sources, and low-loss energy storage. In addition, technologies are investigated which will contribute to the safe use of nuclear energy. Environmental research is concentrated on the study of processes taking place in the atmosphere. Comprehensive assessment of the economic, ecological and environmental performance of current and future energy supply technologies provides support for decision making.

To cope with the increasing fluctuating energy production (solar, wind), development of new energy storage methods is critical. In order to test, further develop and optimize different energy storage methods, PSI operates the Energy System Integration (ESI) Platform. This facility offers research and industry an experimental platform where promising approaches can be tested in all their complex connections and interrelations. New ideas for energy conversion can be tested on a small scale, and their potential for industrial use can be realistically evaluated.

Nuclear energy research

About 8% of PSI’s annual government funding of CHF 280 million is dedicated to nuclear energy research (budget 2017 data). PSI’s government funded nuclear energy research activities have been strongly reduced over the past two decades. This reduction was partly compensated by increasing external funding. The current staffing quota per year of about 155 person-years (plus about 25 postdocs and 40 PhD students). More than 57% of the overall direct costs of nuclear energy research are externally funded by Swiss NPP operators, Nagra, ENSI, SNF and other national and, in particular, international agencies (inter alia the EU and OECD/Overview Committee on the Safety of Nuclear Installations, CSNI). A large part of this support is for long term research contracts.

About 50% of the nuclear energy research at PSI concentrates on reactor safety and safety related operational aspects of Swiss NPPs and on nuclear waste disposal. Nearly 15% of the resources are dedicated to future reactor concepts and their safety features, which rely on inherent safety mechanisms and on passive system layouts which are investigated (to a limited extent through an active partnership of PSI in the Generation IV International Forum (GIF)).

The main objectives of nuclear energy research carried out in the Nuclear Energy and Safety (NES) research division at PSI are as follows:

1. To foster nuclear education by substantially contributing to the Swiss Nuclear Master Programme and other programmes (PSI/EPFL/ETHZ);

2. To contribute to the safe and economic operation of the existing NPPs in Switzerland and to the safe geological storage of radioactive waste by reinforcing the scientific bases of the technologies in the appropriate areas;

3. To secure standby functionality in key areas, particularly those requiring the services of a Hot Lab;

4. To provide inputs to ‘stakeholders’ for decision making purposes;

5. To look for opportunities to apply NES expertise in sectors other than nuclear, and in its role as an international technical safety organization;

6. To train young nuclear specialists over a broad spectrum of disciplines, including those with experience of other energy systems.

The NES department is structured into six research laboratories according to their specific scientific and technical areas of competence; an additional department operates the only Hot Lab in the country.

In addition, the PSI academy, which includes the Reactor School and the Radioprotection School offers education and training programmes for present and future reactor operators as well as for radioprotection experts or scientists and technicians working with radioisotopes.

The following provides a brief description of the programmes currently carried out within the NES department:

Reactor technology

The STARS programme is a long-standing project aimed at the development, maintenance and application of a complex code and database system to be used for investigations into the behaviour of the Swiss nuclear reactors. Focus areas include combined system transient and uncertainty analysis, fuel modelling and neutronics.

The main focus in the HRA (risk and human reliability) concerns resolution of current and emerging issues associated with the treatment of human factors in the context of a probabilistic safety assessment (PSA). Examples of currently investigated topics include: development of HRA methods, quantification of errors of commission, application of simulator data and a technical basis for seismic HRA.

The Nuclear Fuels programme involves micro-structural/micro-mechanical examination of the ageing of core internals (fuel rods, structural materials), and the development of associated theoretical models. In particular, fuel rod behaviour under service but also under long dry storage conditions are investigated and possible causes of failure are evaluated. Novel methods for production of Gen IV fuels, and their associated fuel cycles, are also under consideration.

The Component Safety programme (INTEGER) involves the experimental characterization of important ageing mechanisms (stress corrosion cracking, thermal fatigue and irradiation embrittlement) in primary pressure boundary components, the development and validation of advanced mechanistic material ageing models and probabilistic methods for improved integrity assessments and lifetime predictions, as well as the evaluation of advanced non-destructive techniques for the early detection of fatigue and stress corrosion crack initiation and for the characterization of the actual degree of embrittlement in components.

The containment phenomenology during postulated severe accidents is further carried out by participation in the project HYMERES (Hydrogen Mitigation Experiments for Reactor Safety Project Phase) 2 (OECD/NEA). Its main objective is to improve basic understanding of the complex thermohydraulic processes and to extend the experimental database to phenomenology not investigated previously. The experiments are carried out at PSI in the PANDA facility (a large scale, multicompartmental thermal hydraulic facility suited for investigations related to the safety of current and advanced LWRs).

The Source-Term Evaluation programme activities are centred on the ARTIST (AeRosol Trapping in the Steam generator) test facility which reproduces (at reduced scale), aerosol deposition behaviour during a severe accident following a postulated steam generator tube rupture. General considerations of iodine chemistry are being investigated, with specific application to NPPs. The experimental programme is balanced by the development and validation of numerical models, the overall theme being aimed at replacing the existing empirical models by mechanistic modelling using computational fluid dynamics (CFD). All activities are directed towards source term evaluation relevant to the Swiss NPPs.

Waste management

The programme is an ongoing commitment, overseen by the Federal Government, to ensure the safe disposal of radioactive waste from the medical and nuclear industries and also various research facilities. The activities cover fundamental waste disposal chemistry, the physics and chemistry of radio nuclides, and investigation of the geological barriers for radionuclide transport. Results will ultimately find use in the comprehensive application of safety criteria. This R&D programme is carried out in close cooperation with Nagra.

Energy systems analysis

These activities are carried out within the Laboratory for Energy System Analysis (LEA) which is an interdisciplinary laboratory supporting both NES and the Energy and Environment Division (ENE). The laboratory aims to contribute to effective decision making on long term technology strategies in energy supply and demand by ensuring the full integration of major environmental, economic and social factors. LEA also develops methodologies, and carries out the associated risk analyses, with a focus on HRA.

The Technology Assessment programme involves comprehensive analyses of environmental, economic and risk performance of fossil, nuclear and renewable energy technologies as well as of a wide spectrum of mobility options. It is based on an interdisciplinary framework, thus enabling consistent comparisons to be made between current and future options for the electricity, heating and transport sectors.

In the Energy Economics programme, energy system models are developed and quantitative analyses are carried out on the Swiss, European and global levels to improve the understanding of the interactions among energy, economics, the environment and technology. The generated long term scenarios of energy systems enable examination of the associated energy-technology strategies and the impact of related policy instruments

Hot Laboratory

The Hot Laboratory (Hot Lab) is the largest nuclear research facility in Switzerland, under the supervision of ENSI, and the only Swiss research facility capable of examining large quantities of radioactive materials. The two main tasks of the department Hot Laboratory (AHL), the operating organization unit, are to ensure the safe and efficient operation of the Hot Lab infrastructure and to conduct state of the art service work for the Swiss nuclear industry. Accordingly, AHL offers Hot Lab users (i.e. research groups from other units) modern analytical tools for the manipulation and investigation of radioactive materials. In particular, the laboratory is well equipped for structural and chemical analyses of the materials used in NPPs and accelerator facilities.

Research on future reactors (Generation III and IV) at PSI

The ALPHA programme provides confirmation of the characteristics of passive safety systems for advanced LWRs, and is centred on the large scale, integral test facility PANDA. More recently, the experimental base was broadened to incorporate investigations of fundamental phenomena in both the primary circuit and containment, and include the study of two-phase flow phenomena (such as bubbly flows), the prediction of critical heat flux, and mixture/stratification phenomena. A number of additional small and medium scale, single effect test facilities are now also included under the project heading. At all three scales, experimentation is accompanied by the development and application of novel instrumentation techniques able to measure the distributed parameters characteristic of 3-D flow fields. In parallel, there is an ongoing development and validation programme for the accompanying numerical tools, particularly CFD, but also including multiscale modelling approaches to basic phenomena, such as boiling.

In the appropriately named FAST programme (fast spectrum core and safety analysis with emphasis on generic developments and Generation IV systems), activities are aimed at the development and implementation of a code system representing state of the art safety analyses of nuclear systems incorporating fast neutron spectra.

The High-Temperature Materials programme activities involve characterization of materials to be used in future Generation IV reactors (particularly gas cooled reactors), which will operate at significantly higher temperatures, and are subject to a more intense radiation environment than current Gen II reactors. Mechanistic models are being developed for the prediction of material behaviour, from the atomic level up to the scale of the continuum. Experimental validation of the models is also undertaken using advanced spectroscopic methods and, in particular, synchrotron radiation.

Switzerland has participated in international projects in the field of plasma physics and controlled nuclear fusion for the past 25 years, primarily in a European context. In participating in the research programmes of the European Atomic Energy Community (Euratom), Swiss research on fusion has focused on its primary skills and is seen as an important partner at the European level. Switzerland participates indirectly in the international organization, ITER (“The Way” in Latin), which has been tasked with conducting a decisive experiment for determining the viability of nuclear fusion as a clean and safe source of energy. Switzerland is a member of Fusion for Energy, the common European company established to provide Europe’s contribution to the ITER project.

Radio chemistry

The Laboratory of Radiochemistry (LRC) focuses on fundamental research and on education in the field of radiochemistry. The topics studied within LRC cover a wide and diverse range of radiochemical research, including studies on the chemistry of heavy elements, harvesting exotic radionuclides from irradiated accelerator components for use in fundamental research, developing innovative radiopharmaceuticals and the chemical behaviour of radionuclides in liquid metals proposed as target material or coolant in future nuclear facilities.

Scientific computing and modelling

A new laboratory concentrating different groups that are active in the modelling of complex, multiscale processes was created in the NES division. The main goal of this laboratory is to offer a centre of competence for the development of high-end tools for numerical simulations and visualization of complex physical phenomena using the High Performance Computers (HPC) available in Switzerland. In particular, the further development of computational fluid dynamics and the simulation of advanced nuclear systems will ideally be realized in this lab.

The Swiss Federal Nuclear Safety Inspectorate (ENSI) operates its Regulatory Safety Research programme in order to support its supervisory activities. The programme covers reactor safety, radiation protection and waste disposal. It comprises around 40 projects and a budget of about CHF 6 million per year. The projects are conducted by Swiss Partners (mainly the Paul Scherrer Institute, the Swiss Federal Institute of Technology (ETH), and universities), by international organizations and research institutions abroad, and, to a smaller degree, by ENSI itself.

Projects in the ENSI Research Programme contribute towards clarifying outstanding issues, establishing fundamentals and developing the tools that ENSI requires to discharge its responsibilities. The projects also foster the skills needed for regulatory activities and help develop independent expertise. Finally, international projects deliver results that Switzerland could not achieve on its own and at the same time encourage cross-border networking. These are the main objectives of ENSI’s research strategy.

The Regulatory Safety Research programme is divided into seven subject areas:

1. The fuels and materials area covers the reactor core and the multiple successive barriers used for the containment of radioactive materials. Research into fuels is particularly concerned with high burnup rates and safety criteria for accidents.

2. Projects conducted under the auspices of the Nuclear Energy Agency (NEA) of the Organisation for Economic Co-operation and Development (OECD) and relating to internal events and damage encourage the international exchange of information on incidents, accidents and component damage that can trigger accidents or affect them adversely. Subject-specific databases (e.g. on incidents involving fires or damage to passive metal components) are created for this purpose. These databases facilitate the collation and systematic analysis of operating experience from many countries.

3. ENSI supports research projects addressing external events such as earthquakes, flooding, aircraft crashes and explosions.

4. The impact of operator actions on incidents and accidents in nuclear power plants is the most important human factor under consideration. Identifying and assessing operating errors that adversely affect the course of an accident are key aspects of reducing uncertainty in probabilistic safety analyses. The design of interfaces between humans and technical systems is also of paramount importance.

5. System behaviour and accident sequences in nuclear power plants are analysed in various conditions ranging from normal operation to accidents involving core meltdown. This entails creating computer models and validating them by carrying out experiments. These are also used as a basis for quantitative identification of plant risk in probabilistic safety analyses.

6. PSI’s applications based research activities in the field of radiological protection range from radiation measurement techniques, through aerial radiometrics (measuring airborne radioactivity), to developing new radionuclide analysis methods. In addition, involvement in the development of international standards contributes to cross-border harmonization of radiological protection methods. It is particularly important that expertise is maintained in this field.

7. The field of waste management covers not only deep geological disposal, but also preceding processes such as transport and interim storage of radioactive waste.

The European Atomic Energy Community (EURATOM) was established in 1957 by the Treaty of Rome. In 1978, Switzerland and EURATOM signed a cooperation agreement in the field of controlled thermonuclear fusion and plasma physics. Based on this agreement, Switzerland participates in the European effort to develop sustained fusion power. This effort includes participation in the operation of the Joint European Torus JET, the ITER project and other international activities related to plasma and material research.

Since 2004, Switzerland has been fully associated with the sixth and seventh framework programmes of EURATOM. This has enabled Switzerland to extend its cooperation with EURATOM to the fields of general research in the fission domain and the nuclear activities of the European Joint Research Centre (JRC).

ENSI supports research into nuclear safety and is represented on more than 70 international commissions and specialist groups working in the field of nuclear safety. It therefore makes an active contribution to new international safety guidelines. Through its network of contacts, ENSI is in touch with current developments in science and technology and discharges its regulatory remit on the basis of global experience in nuclear energy. Since 2011, ENSI has chaired the Western European Nuclear Regulators’ Association (WENRA). In 2013, ENSI submitted a proposal to amend the Convention on Nuclear Safety (CNS) to the International Atomic Energy Agency (IAEA) in Vienna. The proposal aimed to make the backfitting of existing nuclear installations a legally binding obligation within the CNS. The endeavor proved successful and the Vienna Declaration on Nuclear Safety (VDNS) was adopted at a CNS diplomatic conference in 2015. With this declaration, CNS contracting parties are committed to implementing the principles enshrined in the VDNS and regularly reporting on their implementation at CNS review meetings.

In the field of radioactive waste management, international research programmes are carried out in the Mont Terri rock laboratory (near St. Ursane in the canton of Jura; investigation of the Opalinus clay; an indurated claystone of lower Jurassic age; operator: swisstopo) and the Grimsel Test Site (canton of Bern; investigation of crystalline rocks; operator: Nagra).

The Mont Terri rock laboratory provides a platform for international collaboration and the exchange of know-how among researchers, technicians, engineers and scientists. The Federal Office of Topography (swisstopo) operates the rock laboratory and runs the Mont Terri Project. Today, 16 organizations from Belgium, Canada, France, Germany, Japan, Spain, Switzerland and the USA are involved in the underground research project. Other countries are also considering argillaceous rocks like Opalinus clay as possible host rocks for deep geological disposal. From 1996 to 2017, the allocated investments in the Mont Terri rock laboratory amounted to CHF 84.3 million. Swiss partners Nagra, ENSI and swisstopo contributed 45% and the other partners 55%.

The Mont Terri rock laboratory serves research purposes only. There is no question of disposing of radioactive waste there, on the one hand, for geological reasons (folded Jura Mountains, where the Opalinus clay is tectonized), and, on the other hand, because the disposal of any such waste is excluded by the contractual agreement with the canton of Jura.

The Grimsel Test Site (GTS) was established in 1984 as a centre for underground R&D supporting a wide range of research projects on the disposal of radioactive waste. It is located at an altitude of 1730 metres above sea level in the granitic formations of the Aar Massif. Twenty-one partner organizations from 12 countries (from Europe, Asia and North America) and the EU as well as universities, research institutes and consulting companies from various countries, are involved in the projects at the test site (2018 data).

Similar to Mont Terri, GTS is a research facility and not a potential repository site; although investigations may utilize a wide range of radioactive tracers, no radioactive waste will be disposed of at the GTS. Therefore, a unique characteristic of the GTS among existing rock laboratories worldwide is the existence of a radiation controlled zone (IAEA Level B/C) in one of the investigation tunnels, which allows experiments to be carried out with radioactive tracers in the geosphere under realistic conditions. The GTS, as an open underground research facility, also offers its services and infrastructure to non-radioactive waste related research activities such as geothermal or fundamental geoscientific/engineering disciplines.

Licensing

The Federal Council is the authority that grants general licences. DETEC grants construction licences and operating licences for nuclear facilities. SFOE is responsible for coordinating the licensing procedures and issuing licences for the handling of nuclear materials and radioactive waste.

Supervision

ENSI is the national regulatory authority in Switzerland with responsibility for nuclear energy. It is supervised by an independent board, which is elected by the Swiss Federal Council and reports directly to it.

ENSI is responsible for the supervision of Swiss nuclear facilities (i.e. the NPPs, the interim storage facility for radioactive waste, the nuclear research facilities at PSI in Villigen, the EPF Lausanne and the University of Basel). Its regulatory remit covers the entire life of a facility (i.e. from initial planning through operation to final decommissioning, including the disposal of radioactive waste). It also includes the safety of staff and the public and their protection from radiation, sabotage and terrorism. In addition, ENSI is involved in the transport of radioactive materials to and from nuclear facilities and in the continuing geoscientific investigations to identify a suitable location for the deep geological disposal of radioactive waste.

ENSI monitors the operation of nuclear facilities:

• ENSI reviews reporting by the operators, holds regular supervisory discussions and monitors the nuclear facilities (including their organization and operation) by means of more than 400 on-site inspections each year.

• Each summer, every NPP carries out an inspection, lasting several weeks, during which maintenance work and repairs are undertaken in the plant.

• In order to protect staff, the population and the environment, ENSI monitors compliance with the radiation protection regulations and dose limits.

• ENSI collates all the data obtained during the year into one comprehensive safety assessment, from which it derives any measures that may be required as well as its future supervision plans.

ENSI assesses nuclear facilities:

• The assessment and monitoring of nuclear facilities are based on laws, guidelines and underlying technical and scientific documentation, which transparently set out the safety requirements and criteria that ENSI applies for its assessments. ENSI continues to develop the underlying documentation and guidelines in accordance with the latest status of science and technology.

• ENSI draws up safety assessments when operators of nuclear facilities submit applications which go beyond the scope of their existing operation.

• Applications for modifications to nuclear facilities that are covered by existing operating licences are dealt with by ENSI, which issues a permit if the decision is positive.

Advisory committee

The NSC is designated as an advisory committee to the Federal Council and DETEC. It is involved in the licensing process as it reviews and comments on the safety evaluation reports prepared by the supervisory authorities.

Others

In the nuclear field, the supervisory authority with respect to nuclear safety and radiation protection is ENSI. In the non-nuclear field, the supervisory authorities are the Federal Office of Public Health (FOPH) and the public sector insurer SUVA (formerly Swiss National Accident Insurance Fund). FOPH manages the licensing procedures in the non-nuclear field according to the radiological protection legislation. It is responsible for waste produced from the health care sector, industry and research.

The National Emergency Operations Centre — part of the Federal Office of Civil Protection in the Federal Department of Defence, Civil Protection and Sport — is in charge of all emergency situations, including those arising from events at NPPs and relating to the protection of the public and the environment.

Several advisory committees to the government or governmental departments covering aspects of radiological protection, emergency planning and waste disposal have responsibilities associated with the operation of NPPs. However, they are not involved in the licensing process and have no authority over the plants.