1 Introduction

Countries are trying to establish a balance between their long-term environmental goals and their present and future energy needs. Nuclear power is quickly emerging as a key component of some countries’ energy strategies aimed to mitigate the impacts of climate change (International Energy Agency, 2022a). It is characterized by its capacity to produce large-scale, reliable, flexible, short-term, and low-emission electricity. Moreover, it has the potential to ensure a reliable baseload generation with zero carbon emissions during operation. Such reliability is crucial amidst rising concerns over energy security and the intermittent nature of renewable sources. Consequently, it becomes a compelling option for countries looking to reduce their carbon footprint while ensuring energy security and flexibility. Several European countries are reconsidering nuclear power as a stable and low-carbon energy source. Poland is planning to build its first nuclear reactor by 2033 and six more by 2043 (International Energy Agency, 2022b). The projected share of nuclear generation in the country will be 16% in 2040. This highlights the strategic aspect of nuclear energy in the future electricity mix of Poland. Meanwhile, with around 70% of its electricity from nuclear sources, France is one of the top nuclear energy producers globally. The country’s nuclear energy policy has fluctuated over the years, in attempts to balance strong support for nuclear power with efforts to integrate renewable energy and reduce greenhouse gas emissions. Notably, in 2022, the French president announced plans to add at least six new reactors to France’s nuclear fleet (International Energy Agency, 2023c). Similarly, the Romanian government decided to double the country’s nuclear power supply in a decade. Currently, Romania has two nuclear reactors generating about 20% of its electricity (World Nuclear Association, 2024). In addition, Finland’s energy policy focuses on maintaining a high share of nuclear generation, and 33% of the electricity generation came from nuclear in 2021. The country has longstanding expertise in nuclear energy, with many dedicated funds for R&D in nuclear energy and nuclear waste (International Energy Agency, 2023a).

This shift is further encouraged by the European Union’s taxonomy for sustainable activities (European Commission, 2022). The taxonomy has proposed specific safety criteria to include certain nuclear energy investments as ‘green’. This is aimed at facilitating reaching the EU’s new binding renewable target of minimum 42.5% by 2030 (The European Parliament & The Council of the European Union, 2023). Subsequently, it opens new opportunities for funding and development in the field of nuclear power.

Globally, countries are re-evaluating nuclear energy as part of their decarbonization strategies. This is evident in the U.S., China, and India (International Energy Agency, 2022a), which have shown increased interest and investments in nuclear technology. Moreover, the International Energy Agency (IEA) has recognized nuclear power as a critical component in the energy transition (International Energy Agency, 2023b) needed to meet international climate goals set forth in agreements such as the Paris Agreement. As a result, 22 countries, including the US, Canada, and many EU countries, signed a pledge to triple nuclear generation capacity by 2050 at COP28 (Henderson, 2024).

Sweden’s examination of expanding its nuclear power capability is one reflection of this global discourse. The country has a longstanding reliance on nuclear power as one of its primary sources of electricity generation, with around 30% of its electricity provided by nuclear power plants. However, the previous Swedish administration did not consider nuclear as part of its decarbonization strategy and was planning to phase it out. Nevertheless, the new administration, since September 2022, considers nuclear a pivotal component of the country’s energy mix, as it shifts the focus from 100% renewable energy to a fossil-free energy strategy. The reasons for this change in stance towards nuclear cannot be solely associated with the policy shifts. Sweden was not immune to the energy crisis that has impacted the EU since 2021 (Desideri et al., 2023). Due to its integration into the European energy market, the country experienced increases in energy and fuels prices. Nuclear energy is seen as a more economically stable option and less susceptible to market fluctuations and geopolitical tensions. In addition, unlike nuclear power, renewable sources like wind and solar are weather-dependent. Nuclear energy provides a consistent and predictable supply of electricity, which renewable sources are not capable of without efficient and reliable energy storage solutions (Andersson, 2020).

The government requested Vattenfall to conduct a feasibility study to evaluate the potential to build at least two SMRs that would be in service in the early or middle of 2030s (Vattenfall, 2023b, 2023c). The study is expected to be released by the end of 2023. Conducting feasibility studies is a common practice and is always applied for major projects to assess their viability and potential risks. While the feasibility study focuses on evaluating the financial and practical viability of a project, deploying SMRs in this case, it is equally important to conduct a sustainability assessment. A sustainability assessment evaluates how the project aligns with sustainable development goals. It ensures the project contributes to long-term sustainability targets, while meeting immediate financial and practical criteria.

However, to fully understand the implications of expanding nuclear energy, it is essential to move beyond individual project assessments and evaluate the sustainability of the entire nuclear energy system. By conducting a broad sustainability assessment of the nuclear energy system, the environmental impact, economic viability, social acceptance, and system security over the long term are considered. It is important to evaluate these factors to ensure that the Swedish nuclear energy system supports the country’s broader energy and environmental goals.

While there have been various studies on nuclear energy policies and sustainability assessments (as detailed in Sect. 2), our work stands out by performing a straightforward, yet thorough qualitative analysis of an energy system. Moreover, it addresses the Swedish context. To the authors’ knowledge, no previous studies have comprehensively analyzed the sustainability of Sweden’s nuclear energy system in this manner. This study seeks to explore the various aspects of nuclear power in the current Swedish context, by examining the interrelations between technology, policy, economics, and environmental impact. The analysis will consider historical trends, current practices, and future prospects, and integrate the dimensions of feasibility, viability, desirability, and openness. This is to provide insights into how Sweden’s nuclear energy system can adapt to and align with the objectives of sustainable development and climate change mitigation. Through this perspective, we aspire to contribute to the ongoing dialogue on the sustainable transition of energy systems and the strategic positioning of nuclear energy within Sweden’s environmental and energy frameworks.

2 Literature review

A range of methodologies has been proposed to assess the sustainability of nuclear energy systems. The International Atomic Energy Agency developed the INPRO method within the International Project on Innovative Nuclear Reactors and Fuel Cycles (International Atomic Energy Agency, 2008). The INPRO method is a comprehensive approach to assessing and selecting innovative nuclear energy systems. It builds on the current situation of the nuclear power system by improving its existing components and developing any missing ones. In addition, it accounts for the anticipated changes in the requirements and conditions for the future development and operation of nuclear power. The methodology assesses the system in 6 areas, including economics, environment, waste management, safety, proliferation resistance, and infrastructure. Since its launch in 2000, the INPRO method has been applied in many case studies, for the assessment of nuclear energy technologies such as molten salt reactor (MSR) (Mohsin et al., 2019), small modular reactors (SMRs) (Bikmurzin et al., n.d.; Johari et al., 2023), and pressurized water reactor in the Republic of Korea (Yoo et al., 2009).

In addition to the INPRO method, several other methodologies have been developed by researchers to provide a comprehensive and integrated sustainability assessment of nuclear or any other energy systems. These methodologies are based on a lifecycle approach, considering all relevant techno-economic, environmental and social sustainability issues from the “cradle to grave” of the energy system. Approaching from a system perspective, Azapagic et al. (2016) developed a novel decision-support framework, the DESIRES. It comprises a suite of tools, including scenario analysis, lifecycle costing (LCC), lifecycle assessment (LCA), social sustainability assessment, system optimization and multi-attribute decision analysis (MADA).

Other studies define sets of sustainability indicators across different pillars (environmental, economic, social, technical, etc.) and use methods like multi-criteria analysis to assess and compare energy scenarios based on these indicators. For instance, Stamford and Azapagic (2011) developed an indicator framework comprising 43 indicators to address concerns associated with energy technologies (Verbruggen et al., 2014) developed another indicator framework specifically for nuclear power, comprising 19 criteria. The authors introduced a fifth dimension to the traditional sustainable development framework, termed ‘risks,’ to address the catastrophic risks associated with nuclear energy and the proliferation of nuclear weapons. Building on these frameworks and many others, (Gralla et al., 2016) assessed the national energy strategies of nine countries pursuing or planning to start nuclear energy production. For each dimension of their sustainability analysis framework, adopted from (Verbruggen et al., 2014), the authors identified a series of facets or criteria to evaluate how central sustainability is in these countries policies.

Other researchers combined the lifecycle approach with the indicator-based framework concept to assess sustainability. For example, Santoyo-Castelazo and Azapagic (2014) developed an integrated sustainability assessment of energy systems. The framework consists of a LCA with 10 environmental indicators for assessing the environmental sustainability, LCC for economic sustainability, and several social indicators for the social sustainability. This assessment is followed by a multi-criteria decision analysis (MCDA) to assist in managing multiple, sometimes opposing, criteria and stakeholder views.

Another interesting framework is the Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) framework (Giampietro et al., 2022). It is a comprehensive analytical tool designed to assess the sustainability of social-ecological systems at different hierarchical levels or scales (e.g. household, municipality, region, nation) and dimensions of analysis (economic, social, demographic, ecological, etc.). It can be used for diagnostic purposes or to simulate scenarios (Giampietro et al., 2013). As diagnostic tool, the accounting system is used to capture the complex interactions and dependencies between human activities and the environment, by considering the flows or metabolic patterns of water, energy, food, and land use within a system (the water-food-energy nexus). As simulator tool, MuSIASEM framework provides feasibility, viability, desirability, and openness check of the proposed scenarios. These four sustainability pillars are used as analytical lenses to generate a quantitative analysis and evaluate a system’s sustainability (Giampietro et al., 2022):

  1. 1.

    Feasibility: This concern represents the compatibility of a system with external biophysical constraints, such as limits on resources like land, water, energy sources and minerals, as well as constraints on emissions and waste disposal.

  2. 2.

    Viability: This concern determines the compatibility of a system with internal constraints such as technological capability, availability of investments, and labor supply.

  3. 3.

    Desirability: This concern is defined as the degree to which a system aligns with prevailing institutions, norms, and living conditions, and it encompasses societal acceptance, considerations of freedom and independence, and ethical implications that may arise.

  4. 4.

    Openness or security and burden shifting: This concern revolves around understanding the dependence of a system on other systems for inputs (resource dependencies) and sink capacities (environmental burden shifting).

The MuSIASEM framework can and has been applied to various contexts, such as agriculture (Cadillo-Benalcazar et al., 2020, 2022), water management (Rodríguez Huerta, 2020), and urban development (Acevedo-De-los-Ríos et al., 2024; Wang et al., 2017). In the energy context, the MuSIASEM was applied to analyze the potential of producing biofuel from sugarcane in Mauritius and assess alternative energy sources for electricity production in South Africa (Giampietro et al., 2013). In other study, the framework was applied to characterize the urban system metabolic patterns by analyzing the energy flows and land use associated with Barcelona’s socioeconomic activities (Pérez-Sánchez et al., 2019).

3 Methodological approach

In this study, we apply a qualitative assessment of the nuclear energy system in Sweden, inspired from the MuSIASEM framework. By exploring the historical trends, current practices, and prospects, we provide a narrative description of how these elements interact within the Swedish nuclear energy context. The analysis is structured around the four key sustainability lenses: feasibility, viability, desirability, and openness. Each lens is explored as follows:

  1. 1.

    Feasibility: We evaluate the external biophysical constraints of the Swedish nuclear system. This involves examining the limits on uranium and the impact of climate change. In addition, we evaluate the system’s interactions with the ecological system and determine the environmental pressure exerted by the nuclear energy system in terms of nuclear waste.

  2. 2.

    Viability: We evaluate the internal technical and economic constraints of the nuclear energy system. This includes assessing the technological capabilities and economic viability in reactors development and uranium exploration and extraction.

  3. 3.

    Desirability: We assess the public perceptions of nuclear energy in terms of safety, environmental impact among relevant stakeholders, including citizens in general, residents living near mining sites, policymakers, and environmental groups.

  4. 4.

    Openness: We analyze the degree of openness of the Swedish nuclear energy system by considering its dependence on external inputs, such as uranium from other countries. In addition, we assess the implications of such dependency internally and in terms of externalization of environmental impacts.

The basis of this study consists of an extensive review of academic literature, policy documents, industry and institutions’ reports, and recent news to gather relevant qualitative data. News published after November 2023 were not included in this study.

4 Nuclear power in Sweden: a historical overview (1960s-2023)

Sweden’s journey with nuclear power began in the 1960s and 1970s, marking a significant step in its energy sector. The country had initially set up 12 reactors that were strategically spread across different locations. These reactors supplied a substantial portion of the nation’s electricity. However, by the early 21st century, only half of these reactors remained operational, with the remaining six reactors providing almost a third of the country’s electricity needs.

As the years progressed, Sweden’s policy landscape regarding nuclear energy underwent significant transformations. The shutdown of the two reactors at the Barsebäck power plant in 1999 and 2003 was influenced by a combination of longstanding concerns, public sentiment, and international pressures. This decision reflected the political unpredictability of the sector, shaped by the 1980 referendum and the resulting non-binding decision to phase out the nuclear power system by 2010 (Roßegger & Ramin, 2013), public reaction following the Chernobyl disaster in 1986 (Biel, 1989), and pressures from neighboring Denmark (Kaijser & Meyer, 2018).

However, based on a decision taken in the Swedish Parliament in 2010, Sweden reversed its nuclear power phase-out (Roßegger & Ramin, 2013). Yet, between 2014 and 2022, Sweden phased out several reactors: Oskarshamn 1 and 2, along with Ringhals 1 and 2, were decommissioned due to economic and safety upgrade requirements. These shutdowns signaled a significant shift in the energy mix heading towards completely renewable energy production by 2040. They also raised questions about long-term energy security and supply. This period witnessed a few notable policy changes, one of which was the increase of the nuclear power impact tax in 2015 (World Nuclear Association, 2023). The decision, however, was short-lived, and the government was forced to repeal it just 1.5 years later, with the complete removal of the tax in 2017 to avoid serious implications. The decision decreased profitability for plants already struggling with low market prices. Moreover, these plants faced the burden of costly upgrades to comply with stricter safety standards following Japan’s Fukushima nuclear disaster.

In 2018, the left bloc government introduced a ban on uranium mining across the country (Nuclear Energy Agency & International Atomic Energy Agency, 2023). This decision was influenced by both the government’s stance on nuclear power and the nation’s commitment to environmental protection and renewable energy sources. The ban aimed to phase out the extraction of uranium and ensure that any future mining activities would be consistent with Sweden’s ambitious climate goals and the welfare of its citizens. The ban was on the extraction of uranium, meaning the actual mining and processing of uranium ore was prohibited. Exploration, which involves searching for potential deposits of uranium, was not banned. However, since the possibility of mining these deposits was prohibited, the interest in exploration diminished. It is important to highlight that, before the ban on uranium extraction, uranium was not produced as a primary product in Sweden; instead, it was recovered as a by-product of other mining operations. Sweden has known uranium deposits, but the country has not had any active uranium mines specifically for the extraction of uranium ore. Historically, the Ranstad mine, which operated from 1965 to 1969 (Laxvik, 2009), was a notable facility in Sweden where uranium was extracted as a by-product from alum shale. The focus of the mine was on alum shale for other minerals and the extraction of uranium was secondary. The closure of the Ranstad mine was due to the fact that the extracted minerals, including uranium, were economically unviable under prevailing market conditions. After this, Sweden did not have any commercial uranium mining operations, and the country has since relied on the import of uranium to fuel its nuclear reactors. The 2018 ban on uranium extraction was therefore more about preventing future mining activities rather than stopping current operations.

Following the 2022 elections, there was a shift in the political landscape, leading to a leadership with a rejuvenated approach to nuclear energy. Through the Tidö Agreement announced one month after the elections (Ruderstam et al., 2022), the new administration, which is made up of right-wing parties, is determined to restore Sweden’s nuclear potential. Their initiative is part of their vision for fossil-free electricity production by 2045. This agreement detailed several aspects related to the future of nuclear energy in the country. Among the key components of the agreement were legislative adjustments that would allow the construction of new nuclear power plants in various locations. These adjustments move beyond the existing restriction of building only near current nuclear sites. The agreement also proposed an increase in the number of reactors beyond the ten previously permitted. The parties outlined in the Tidö Agreement a safeguard of nuclear power plants from arbitrary political decisions that might lead to shutdowns. If such an event occurred, the owners would be entitled to compensation. The government’s commitment to nuclear power is further emphasized with the directive given to Vattenfall, a significant partly state-owned energy company, to initiate the procurement of new nuclear power plants in Ringhal (Vattenfall, 2023c). To further support the country’s nuclear ambitions, the Tidö Agreement proposed state credit guarantees of up to SEK 400 billion. This guarantee aims to reduce investment risks and, in turn, bring down energy costs. It represents roughly 7% of Sweden’s GDP, which stood at approximately $635.7 billion (in 2021). Such a commitment is a strong signal of the government’s determination to secure a robust nuclear infrastructure by providing a more favorable environment for nuclear investments in Sweden.

This commitment was fulfilled in September 2023 with the release of the government’s proposal 2023/24:19 titled “Regeringens proposition 2023/24:19 Ny kärnkraft i Sverige – ett första steg” (New nuclear power in Sweden – a first step) (Sveriges Riksdag, 2023). The proposal suggested pivotal changes, including the removal of the condition from the Environmental Code that limited the construction of nuclear reactors to areas with pre-existing nuclear power. This requirement primarily seeks to allow the construction of Small Modular Reactors (SMRs), which are more efficient if placed near end-users, or in proximity to hydrogen and district heating industries. It also allows for a reduction in investment costs for transmission networks. This was complemented by the recommendation to eliminate the cap on the number of operational reactors, allowing for more than ten to be functional. This adjustment is also in favor of SMRs technology. The changes are expected to become effective by the beginning of 2024.

Shifting their stance, the Social Democrats, a major political entity in Sweden from the left-wing bloc, also appears to support the idea of lifting the reactor count restriction. This party was in power when 6 reactors were closed between 2014 and 2022. This new position was announced in a press conference in October 2023 (Gasslander, 2023). This suggests that nuclear power is no longer a left-right issue as it was for decades and during the last elections (Holmberg, 2023). A growing agreement among major stakeholders regarding the country’s nuclear direction has possibly emerged.

5 Sweden’s nuclear energy landscape: prospects, challenges, and dependencies

5.1 Feasibility

From a feasibility standpoint, Sweden’s legacy in nuclear expertise and infrastructure certainly provides a robust foundation. However, with aging reactors and the dynamic landscape of nuclear technologies, there are tangible challenges ahead. One notable concern is the consistent availability of Uranium, both as a resource and a traded commodity (Muellner et al., 2021). Uranium, as a finite resource, faces uncertainties regarding its availability in required quantities, due to the long periods of low prices and reliance on secondary supplies. This resulted in a reduction in primary resources’ production and investments (Nuclear Energy Agency & International Atomic Energy Agency, 2023). Recently, the demand for nuclear energy has risen globally, driven by countries seeking to diversify their energy mix and meet carbon reduction targets. As a result, the pressures on the global uranium market are anticipated to intensify. Several forecasts have projected an increase in uranium requirements over the coming years, potentially outpacing the current identified uranium resources. This could lead to a shortage, causing price hikes and making nuclear energy less economically competitive. This is already happening, as the uranium price is increasing (Fig. 1), reaching its peak in 12 years in October 2023. This is due to an increase in demand and potential supply challenges. Such a scenario would especially affect countries like Sweden that rely heavily on nuclear power but do not have economically competitive uranium resources. However, if these elevated prices persist and remain high in the foreseeable future, the exploration and extraction of uranium from primary resources could stimulate investments. This would be further supported by the successful intensification of nuclear energy plans.

Besides, the impact of climate change on nuclear power cannot be ignored. Production loss and reduced efficiency are anticipated with climate change hazards, such as water shortages, extreme heat, flooding, among others (Ahmad et al., 2023). An insightful study (Ahmad, 2021) has shown that the frequency of weather-related outages at nuclear power plants in the last decade (2010–2019) has increased to eight times that of the 1990s. By the end of the century, climate-induced outages could reduce global nuclear power generation by about 1.4 to 2.4%. One associated vulnerability to climate change hazards is water temperature increase (Linnerud et al., 2011). In the summer of 2018, the reactor Ringhals 2 in Sweden (which was permanently closed in 2019) had to cease operations because the seawater temperature, used for cooling, exceeded its maximum permissible limit of 25 °C. This led to the loss of 117 h of operations (International Atomic Energy Agency, 2019). Moreover, climate models project an increase in the frequency of extreme marine temperatures in the future (IPCC, 2023). Such incidents could become more common, necessitating advanced planning and adaptation measures for the continued operation of coastal nuclear power plants. Another emerging concern related to climate change is the rise in sea levels (SMHI, 2022). While the land in Sweden is experiencing an upward shift at varied rates across different regions—outpacing the sea level rise in certain areas—the south and southwest coasts of the country are notably impacted by the rising sea levels. These coastal areas are where two reactors are currently operational and potential sites for SMRs are being examined. While sea rise may not necessitate additional preventative actions until the end of this century (Unger et al., 2021), such trend underscores the importance of incorporating these considerations into planning and site selection for new power plants. It will ensure long-term safety and operability amidst evolving environmental conditions.

Another pivotal concern within the nuclear energy discourse and from a feasibility aspect is the management of spent nuclear fuel and the complexities associated with nuclear waste disposal (Hilding-Rydevik, 2023). Currently, Sweden has approximately 7,500 tons of spent nuclear fuel, which is reserved for secure storage in a new final repository. The construction and operationalization of this repository, which is a novel and unprecedented initiative in its field, are anticipated to take place in the mid-2030s (Vattenfall Media Relations, 2023). The Swedish government and the Radiation Safety Authority accepted the proposal from nuclear energy implementer body SKB in January 2022. Five decades of extensive planning and research went into it. Yet, the method of fuel storage has not been without criticism from certain researchers and environmental entities. Their concern centers on the possibility that, under extreme conditions, the radiation from the uranium might induce cracking in the copper capsules over time. This might potentially allow groundwater to interact with the spent uranium (Hilding-Rydevik, 2023). On the other hand, and in just 20 years, 2,400 additional tons of spent nuclear fuel will be generated from the current 6 operational reactors only, and there is no clear plan on how to secure these (Johan Zachrisson Winberg, 2023). In this context, it is imperative to highlight the ongoing efforts in R&D to develop techniques for recycling spent nuclear fuel and use it as a new fuel for the nuclear power plants (Rodríguez-Penalonga & Yolanda Moratilla Soria, 2017). Reprocessing has the potential to reduce the repositories’ sizes and lessens the time frame during which the nuclear waste should be left intact. From an economic viability point of view, it has the potential to be more cost-effective than using new nuclear fuel (Nash & Nilsson, 2015). Sweden might consider incorporating closed nuclear fuel innovations in its energy strategies in the future. However, reprocessing technologies are still not mature and require more time to be commercialized.

Fig. 1
figure 1

Uranium spot prices trend since 2013. https://tradingeconomics.com/commodity/uranium

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5.2 Viability

Besides external constraints, any system is subject to internal constraints such as technological capability and availability of investments (Giampietro et al., 2022), and its compatibility with these constraints determines its viability. This is often where fossil-free initiatives stumble. Nuclear plants demand vast capital investments, with returns projected far into the future. In addition, the lead-time required for delivering nuclear power plants is extensive. With the increased interest and advancement in technology in Small Modular Reactors (SMRs), these small reactors could lessen the huge investment costs and financial risks compared to larger, conventional reactors. SMRs have capacities typically between 30 and 300 MWe and are suitable for regions with smaller electrical grids or remote areas (Nuclear Energy Agency & International Atomic Energy Agency, 2023). However, the technology behind SMRs is still under development and has not yet reached a fully matured or universally adopted status in the nuclear energy sector. This focus might lead to delays as market players wait for more predictable nuclear power costs, as highlighted by Göransson and Johnsson (2023). This could lead to a neglect of other promising power sources’ investment, such as wind power which currently attracts significant interest. In extreme cases, this imbalance might result in costly and uncertain investments in underdeveloped nuclear power (Göransson & Johnsson, 2023). Moreover, due to the current economic crisis in Sweden and globally, securing a long-term investment environment faces uncertainty. Investigation of its impact on the viability of nuclear energy, including SMRs, is required. The current government is acknowledging the associated long-term risks, thus has proposed introducing credit guarantees to support nuclear power. Moreover, it recognizes that these guarantees alone may not suffice to stimulate new production and is considering a risk-sharing and financing model where the state would also share in the risks (Regeringskansliet, 2023).

Additionally, Sweden imports its uranium needs. While the country has its own resources shown in Fig. 2, uranium resources are mainly available in alum shales, crystalline bedrocks, and seawater – the extraction of which still face technical challenges (Chen et al., 2022; Yuan et al., 2021). All deposits, including the high-grade uranium, are not economically viable even with the current uranium prices. However, if other strategic or critical minerals can be extracted from the mines (such as copper, nickel, tellurium, vanadium, among others), previously non-economical uranium resources in Sweden might become viable for extraction. This approach could enhance Sweden’s ability to secure self-reliance in uranium supply for the foreseeable future, based on the country’s estimated uranium resources and its needs as of 2016 (Sveriges geologiska undersökning, 2016). Nonetheless, it should be noted that detailed studies and assessments are necessary to substantiate such claims.

Despite that, the country’s nuclear power plants have managed to maintain economic competitiveness when compared to other forms of electricity generation. Though, this competitiveness is less pronounced when compared to regions with direct access to inexpensive fossil fuels (World Nuclear Association, 2022). However, recent observations by Tomas Kåberger (Kåberger, 2023), a professor at Chalmers University, indicate that Swedish nuclear facilities may not be operating to their full potential. He suggests that the companies’ efforts to maximize their profitability through cost reduction, including minimized maintenance, could be harmfully impacting the efficiency and safety of nuclear production. This situation could lead to an increased number of outages, thereby challenging the current status of nuclear energy as an economically viable competitor in Sweden’s energy market.

It is noteworthy to highlight the enhanced expertise in nuclear power across Europe. This proficiency surge aligns with the growing trend towards the adoption of nuclear energy in many European countries, like Poland (Kancelaria Prezesa Rady Ministrów, 2023), especially after the crisis with Russia and the urgent need to shift away from fossil-fuel based energy due to climate change. Sharing learned lessons from recent projects, such as the Olkiluoto 3 power plant in Finland (Linus Olin, 2023) and all the problems the project encounters during its 18 years of delayed construction, can provide invaluable insights for Sweden as it navigates the challenges of modern nuclear plant construction and regulatory compliance.

5.3 Desirability

Another sustainability dimension to be considered is desirability. After the pandemic had subsided in 2021, Swedish citizens’ desire and support for nuclear energy increased (Holmberg, 2023). This is mainly attributed to the successful political campaign led by the Right bloc. In addition, the energy crisis in Europe that started at the end of 2021 and reached its peak just before the elections, shifted the climate debates. The focus moved towards providing cheaper energy and counteracting growing inflation, instead of focusing primarily on climate change as a pressing global concern (Betty Wehtje, 2022).

Despite this growing support, disastrous events associated with nuclear power can replace this enthusiasm with public opinion or even pressure to phase out nuclear power. This was the case in Sweden and throughout the world after the reactor accident in Fukushima in 2011 (Holmberg, 2015). Furthermore, those in Sweden who oppose nuclear power often have strong environmental concerns (Holmberg, 2023). The escalating number of disasters attributed to climate change, coupled with potential terrorist threats and attacks on nuclear facilities (Sweden nuclear facilities are not well protected against such attacks (Lundell & Crona, 2018), could once again shift public sentiment. This concern is heightened by the fact that the terrorist threat level in Sweden was raised from “Elevated” (level 3) to “High” (level 4 on a 5-level scale) in August 2023.

Another influencing factor is a change in government, which could shift priorities and potentially alter the direction of nuclear energy policies. It is essential to consider the political landscape, as different administrations might have varying views on nuclear energy, influencing its expansion or reduction (and ultimately those of other technologies, such as renewable energy). The present government has already initiated measures, setting forth compensation for nuclear firms in case Sweden alters its nuclear strategy. This is a significant step in creating stability and confidence for the industry. However, the country’s endeavors are influenced by European politics as well. Uniper, a German firm with substantial ownership in Sweden’s operational reactors, has declined to fund new reactors due to Germany’s policy decision. This decision led Germany to decommission all its nuclear power plants by April 2023, despite the ongoing energy challenges in the country and in Europe (Desideri et al., 2023).

With the plans to allow uranium mining again, it is worthy to note that many deposits are within populated areas. This would complicate the acquisition of environmental permits (Olofsson, 2023), and also face local resistance. As long as municipalities have veto rights, uranium mining might not be as straightforward as it seems. Therefore, it is important to allow and encourage the participation of citizens and concerned stakeholders in the nuclear energy discourse. This will ensure a transparent, democratic, and inclusive process (Hilding-Rydevik, 2023), and contain any local resistance by addressing any concerns through communication.

Fig. 2
figure 2

Known uranium resources in Sweden. Green parts show the extent of black shales (including alum shales) in Sweden. The large deposits in blue are of low-grade uranium, while the smallest deposits in red are of high-grade uranium. Adopted from (Sveriges geologiska undersökning, 2016)

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5.4 Openness

When discussing openness, we are delving into the system’s dependency on other systems (Giampietro et al., 2022). The fact that Sweden imports uranium (Vattenfall, 2023a) underscores its nuclear program’s vulnerability and makes it particularly sensitive to geopolitical events, trade disputes, and logistical challenges that might impact the availability or cost of uranium. This high degree of openness introduces a cascade of challenges. Sweden, through the Euratom Supply Agency (ESA), sources its uranium from three locations, one of which is Kazakhstan, a Russian ally. The main shipping route for Kazatomprom, Kazakhstan’s national atomic company, goes through Russia, but they also use an alternative path called the Trans-Caspian International Transport Route (TITR). If tensions with Russia intensify, it could jeopardize a portion of these imports. Additionally, the alternative route passes through multiple countries, heightening the dependence of uranium imports on the region’s geopolitical stability. Additionally, uranium enrichment, another key step in the supply chain, takes place abroad.

The dynamics of Sweden’s nuclear energy system encapsulate not only a question of energy security and independence but also the inherent complexity of global environmental management. The import of uranium effectively shifts a portion of the environmental impact of the country’s nuclear energy program to the exporting countries. Mining activities are associated with environmental degradation, including habitat destruction, water contamination, and increased carbon emissions from mining operations, and health issues, such as respiratory diseases and lung cancer, to name a few (Srivastava et al., 2020). This dependency implicates the country in the environmental and ethical implications of uranium mining in other nations. Moreover, with people becoming more aware of the human rights violations and ethical implications of uranium mining in other countries, resistance to such projects might be greater, which can create a desirability issue. As Sweden navigates the balance between national energy requirements and international environmental responsibilities, the export of environmental problems associated with uranium extraction becomes a critical and complex facet of its openness. This aspect should not be overlooked.

The Swedish government’s strategic response to mitigate these vulnerabilities involves the pivotal decision to overturn the 2018 uranium mining ban. This move is intended to strengthen Sweden’s nuclear infrastructure. Simultaneously, it aims to diminish the openness of the system and provide Sweden with a more fortified position in the global energy landscape. Importantly, revoking the ban is pivotal in facilitating the extraction of other valuable minerals. With the ban in place, mining operations were hampered, as they were not permitted to extract or manage uranium even incidentally. This was particularly problematic given that uranium often coexists with rare and critical minerals, which are crucial for Sweden’s technological and energy sectors (Nyman, 2023). For example, the Oviken uranium deposit, situated in central Sweden, could offer economic advantages due to its significant size. Additionally, the presence of vanadium, a valuable metal known for its applications in steel alloys and advanced energy storage solutions, adds to its potential benefits. How quickly the uranium will reach the market is still unclear since the timeline for companies to start selling uranium hinges on multiple factors. Firstly, exploration is required to identify viable deposits (compared to the market prices), which can span several years. Following this, regulatory processes, including environmental assessments and securing permits, might extend the waiting period by a few more years, especially since many deposits are within populated areas. The next step would be the development of infrastructure for mining facilities, which adds to the timeline. Once these prerequisites are met, the actual mining, processing, and decision to sell based on market conditions finalize the timeline. When these steps are accumulated, there may be a delay of several years to more than a decade before uranium reaches the market.

6 Discussion

6.1 Strengths of the assessment

The results of this study highlight the complex structure of Sweden’s nuclear energy sector, emphasizing the cruciality of integrating various dimensions in its sustainability assessment. A major strength of the presented evaluation lies in its comprehensive approach. By considering the four sustainability aspects of feasibility, viability, desirability, and openness, it was possible to identify the main challenges associated with maintaining a long-term sustainable nuclear system, as well as the potential opportunities. This dual insight is critical for the country’s energy policy discourse.

Another notable strength of this study is its reliance on qualitative data to assess the system. This approach can be advantageous compared to assessments that rely heavily on quantitative analysis, such as MuSIASEM and LCA, which can be time-consuming and require extensive data collection. The presented qualitative assessment allowed for a flexible and holistic evaluation and provided useful and important insights into the examined nuclear energy system.

The analysis also emphasizes the nexus among sustainability criteria and the importance of avoiding isolated analysis. As put by Cadillo-Benalcazar et al. (2020), “it allows to contrast between what is desired and what can be done”. For instance, the availability of uranium is one significant feasibility concern. The global uranium market faces potential shortages due to increased demand and decreased primary production. This could lead to price hikes and impact the economic viability of nuclear energy in Sweden. While persistent high prices might stimulate investment in domestic uranium extraction, such developments require substantial time and capital, which is another viability concern. Additionally, social acceptance from communities near mining facilities remains a significant obstacle, posing a desirability concern. Another example would be the global political decision to increase the share of nuclear generation (Henderson, 2024). While this international “desirability” will assist in achieving the global and national decarbonization targets, it initiates a cascade of concerns. Uranium is a finite source. By performing a rough estimation of the lifespan of current reserves (of ∼ 6 million tons) (Nuclear Energy Agency & International Atomic Energy Agency, 2023) and given the current consumption rate (of ∼ 67,500tons) (Donovan, 2023), the existing uranium reserves could last for approximately 88 years. This estimation assumes no increase in the number of reactors and stable consumption rates. With triple nuclear generation, a sustainability uncertainty is looming. Countries, including Sweden, may face supply risks, potentially leading to geopolitical tensions and trade disruptions, jeopardizing their energy security (openness concern). Moreover, increased local mining activities (assuming the reserves become economically viable) could result in ecological degradation, including habitat destruction and water contamination (feasibility concern), which can also intensify the social resistance (desirability concern). Additionally, as uranium reserves deplete globally, the price of uranium is likely to increase due to scarcity. This can make nuclear energy more expensive and less competitive compared to other energy sources (viability concern).

Given these complex and interrelated challenges, it becomes significant the need to include experts from different backgrounds when drafting the country’s nuclear energy strategy. For example, experts in environmental science can evaluate ecological impacts from both the supply and sink sides, economists can assess market dynamics, and sociologists can estimate social acceptance. In addition, transparent communication with citizens and their inclusion in the decision-making process should be considered. Furthermore, political experts from different ministries should be included to provide insights into policy implications, regulatory frameworks, and the potential political ramifications of energy strategies.

6.2 Limitations and future work

While flexible and time-efficient, the qualitative assessment presented in this paper paves the road for a future quantitative assessment. It is an initial analysis that provides an overview and understanding of the key factors and interrelations within the Swedish nuclear energy system. Therefore, it informs and guides the subsequent application of a quantitative framework, such as MuSIASEM or LCA, for a more detailed and robust evaluation of the system’s sustainability.

Transitioning from one component-level assessment to a national energy system assessment, the principles of sustainability become even more critical. Nuclear energy is one part of a broader mix of energy sources in Sweden. While this study intentionally focused on nuclear, considering other resources, especially renewables, is important. Sweden is planning to increase its wind power generation from 30 TWh to at least 120 TWh in 2040 (Swedish Wind Energy Association, 2021). Moreover, solar energy was the only renewable energy to see a significant increase of 58% in 2023 compared to 2022. With the increase share of these renewable sources, the electricity grid will require significant adaptations due to their variability, intermittency and location constraints. For instance, most of the current wind power generation is concentrated in the northern regions of Sweden, while most of the electricity consumption occurs in the southern parts of the country. The challenges of integrating high shares of renewable to the grid include maintaining grid stability, addressing overloading and voltage rise issues, and expanding transmission capacity to balance supply and demand effectively (Steen et al., 2014). Moreover, replacing a remarkable share of stable base load electricity with intermittent energy sources presents significant challenges for maintaining grid stability, ensuring reliability, and preserving supply levels. Therefore, conducting a sustainability assessment of an energy mix across various scenarios is essential due to the interactions among different energy sources within Sweden’s energy market. Different energy mixes have diverse implications for the economy, society, climate, and energy security, as shown by (Andersson, 2020), which in turn influence policy decisions. Given the changing energy landscape in Sweden, such integrated assessment of the entire system and its individual components is essential for gaining holistic insight.

7 Conclusion

In this paper, we present a simple, yet comprehensive sustainability assessment framework based on a qualitative analysis of the Swedish nuclear energy system. Such analysis has not been previously performed for the Swedish nuclear sector. We showcase that, even without quantitative assessment, it is possible to explore challenges and opportunities associated with the sustainability of a nuclear energy system. In addition, the complexities of the system can be captured. Such assessment is indeed complementary to quantitative assessments, and the two methods should be combined for policy and decision-making.

For Sweden’s nuclear policy, its potential re-emergence must be viewed as part of a larger trend where energy security, environmental concerns, and climate commitments intersect. The Swedish government has taken a variety of actions, such as removing the banning on uranium mining and supporting the development of new nuclear technologies, in an attempt to achieve a balance between national objectives and the broader global shift towards sustainable energy sources.

For Sweden, expanding nuclear power offers appealing prospects for a fossil-free future. Still, it is not without challenges. From a feasibility perspective, the country still must deal with the dual challenges of ensuring a consistent uranium supply and managing the long-term implications of spent nuclear fuel. On one hand, the upward trajectory of uranium prices reflects market twists and forecasts a future where previously non-economic Swedish resources could become viable. Such outlook can transform Sweden’s nuclear energy economics. On the other hand, this trend might lead to increased nuclear energy prices. This could reduce its competitiveness among progressively popular renewable energy sources, such as wind. Moreover, the climate crisis’s accompanying threats, such as increased temperatures and sea-level rise, add layers of complexity to the nuclear feasibility challenge. This would require advanced planning and adaptation measures for current and future nuclear facilities.

In this context, the potential of Small Modular Reactors (SMRs) promises a more affordable and flexible nuclear infrastructure. However, it is still uncertain when SMRs’ techniques will be fully developed. In addition, the Sweden’s current economic situation poses a threat to securing the investments needed for such nuclear advancements.

In addition, the sustainability of Sweden’s nuclear energy program relies not only on technological feasibility and economic viability, but also on the social dimension of desirability. Swedish public opinion towards nuclear energy has shown resilience and adaptability, supporting it in the face of energy crises and political campaigning. However, this support is not unconditional; it is susceptible to the impact of environmental concerns related to nuclear waste, and impact on local communities who have shown resistance towards mining activities in some areas. Additionally, political shifts and European influences play critical roles in the direction of Sweden’s nuclear policies.

The openness of Sweden’s nuclear energy program, largely due to its reliance on imported uranium, exposes it to geopolitical risks, trade uncertainties and ethical implications. By recognizing these vulnerabilities, Sweden can strategically fortify its position against such geopolitical dynamics and uncertainties in trade, ensuring a more reliable and sustainable energy infrastructure.

By conducting the presented sustainability analysis, it is possible to analyze the state of the nuclear energy system across different dimensions, and explore the possible consequences of various policies. However, the complicated nature of climate policy necessitates inputs from various fields of expertise. As the Swedish government prepares to introduce a new energy policy framework, the benefits of engaging a team with diverse disciplinary backgrounds are particularly noteworthy. Such a team, with their collective expertise in social science, technology advancement, environmental research, and political strategy, can deliver a comprehensible and actionable policy. This inclusive approach is key to ensuring that the country’s energy strategies, including nuclear energy, are resilient and pioneering in the face of global environmental changes.