Shutdown Of Nuclear Power Plants Research Articles

Balancing cleaner energy and geopolitical interests in the complex transition of the European electricity mix: from Fukushima to the Ukraine war

In the modern world, electric energy plays a pivotal role in sustaining life and driving technological, scientific, and human development. Consequently, the selection and availability of the energy sources used for electricity generation have become crucial elements of strategic planning for countries and economic blocks. Moreover, the impact of these choices extends beyond the mere energy demand/supply, affecting economies, societies and the environment across geographical boundaries. This study delves into the various factors influencing the composition and the recent expansion of the European electricity mix. It explores the interplay of environmental, climatic, political, economic, and external factors that shape Europe’s energy choices. To conduct this analysis, we utilized data from the International Energy Agency on electricity generation and GHG emissions. Data mining techniques were employed to uncover patterns and trends in the monthly data from 2010 to 2022, from which political and economic milestones such as the shutdown of nuclear power plants and the European Union’s increased reliance on natural gas imports from Russia were examined. The study also discusses the impact of using natural gas for power generation on increasing GHG emissions. Ultimately, this research reveals that the European Union choices in transitioning towards a cleaner electricity mix have not yet proven efficient. In fact, these choices may have inadvertently created favorable conditions for Russia’s invasion of Ukraine, triggering, not only a humanitarian crisis, but also an economic downturn in Europe due to soaring energy prices. This crisis could potentially extend beyond Europe and impact the whole planet in 2023 and on, including developing countries that rely on stable energy prices for their sustainable growth.

Batch Deterministic and Stochastic Petri nets Modeling for Reliability Quantification for Safety Critical Systems of Nuclear Power Plants

Safety-critical systems (SCS) are essential in maintaining and controlling the nuclear power plant (NPP) facilities, providing feedback on the plant's conditions, and safeguarding it from adverse consequences i.e., SCS plays a vital role in NPP. Thus, failure of such systems can lead to massive financial losses, human resource damage, and environmental degradation. It is, therefore, important that these systems should have a high level of reliability and accuracy. This research introduces a novel method for designing and assessing the reliability of SCS by employing batch deterministic & stochastic Petri nets (BDSPNs) and Markov chain. Our method of reliability evaluation achieved 99.9905% accuracy, proving its effectiveness. This paper illustrates the proposed approach to NPP's Shutdown System (SDS).

Contrasting effects of electricity prices on retrofit and new-build installations of solar PV: Fukushima as a natural experiment

This study examines the effects of financial incentives, particularly electricity prices, on residential solar photovoltaic (PV) system installations. We highlight the importance of a factor in the adoption of low-carbon building technologies that the literature has largely overlooked: the distinction between retrofit and new-build installations. To address the endogeneity of electricity prices, we use the 2011 Fukushima nuclear accident and the subsequent shutdown of nuclear power plants in Japan as a natural experiment that caused substantial, exogenous, and regionally varying increases in electricity generation costs and prices. Electricity prices have a statistically significant, positive effect on PV system installations for existing homes (with a mean elasticity of 1.6), but a statistically insignificant, much smaller effect for new-build homes. A policy implication of these contrasting responses is that the cost-effectiveness of financial incentive schemes for low-carbon building technologies can be improved if they are targeted more at retrofits. We also find a large downward bias (40%–60%) in the estimated effect of electricity prices if they are not instrumented with exogenous cost-shifters.

Germany’s Nuclear Energy Refusal Policy: from Conflict to Compromise

The article is devoted to the analysis of the political process of Germany’s abandonment of nuclear energy. The results of a comparative analysis of government decisions taken over the course of one decade, but different in nature and having different consequences for the nuclear industry are presented in the paper. Special attention is paid to the issue of interaction between the government and energy companies in the context of the decisions of 2002 and 2011. It is shown that the abandonment of atomic energy in 2002 was a compromise solution, taking into account both the political desire of society to stop the operation of the nuclear power plant, and the economic interests of energy concerns. The author analyzes the consequences of the unilateral decision of the FRG government in 2011, infringing on the interests of the nuclear lobby, which led to many years of litigation that ended in favor of energy concerns. A review of the final compromise agreements between the companies and the government governing the issue of fair compensation for the early shutdown of nuclear power plants was carried out. Based on a comparative analysis of the two decisions on Germany’s withdrawal from nuclear energy and their consequences, it is concluded that, when entire industries are closed for political reasons, consultations with the involvement of all interested parties are necessary to work out an acceptable compromise.

Understanding the seismic response of electrical equipment subjected to high–frequency ground motions

Ground motion studies in Central and Eastern United States (CEUS) show that the ground motion response spectra exceeds design spectrum of nuclear power plants in high–frequency range. To ensure safe shutdown of nuclear power plants in events where design spectrum is exceeded, the safety–related digital control systems and electrical equipment such as relays must be seismically qualified for high–frequency ground motions. Conventionally, uncoupled linear analysis of building and electrical cabinet is conducted and then seismic demands on equipment are evaluated. The conventional analysis ignores effects of various factors such as geometric nonlinearities, mass interaction between primary (building) and secondary (electrical cabinet) systems, etc. Ignoring such factors leads to unnecessarily high seismic demands on equipment. In this study, the seismic demands on equipment are evaluated by conducting both coupled and uncoupled analysis of linear primary system and linear as well as nonlinear secondary system. Various cases are analyzed where at least one mode of primary system is tuned with one mode of secondary systems. Each case is subjected to both low–frequency and high–frequency ground motions to compare the difference in response to each ground motion. The seismic demands on equipment are compared for coupled and uncoupled analysis as well as for linear and nonlinear systems. The results show reduction in seismic demands on electrical equipment for various nonlinear coupled analysis cases. The high seismic demands evaluated from linear uncoupled analysis may lead to exclusion of some electrical equipment which can be avoided by conducting coupled nonlinear analysis of primary–secondary systems and obtaining the realistic seismic demands on equipment.

Pathways toward a Decarbonized Future—Impact on Security of Supply and System Stability in a Sustainable German Energy System

Pathways leading to a carbon neutral future for the German energy system have to deal with the expected phase-out of coal-fired power generation, in addition to the shutdown of nuclear power plants and the rapid ramp-up of photovoltaics and wind power generation. An analysis of the expected impact on electricity market, security of supply, and system stability must consider the European context because of the strong coupling—both from an economic and a system operation point of view—through the cross-border power exchange of Germany with its neighbors. This analysis, complemented by options to improve the existing development plans, is the purpose of this paper. We propose a multilevel energy system modeling, including electricity market, network congestion management, and system stability, to identify challenges for the years 2023 and 2035. Out of the results, we would like to highlight the positive role of innovative combined heat and power (CHP) solutions securing power and heat supply, the importance of a network congestion management utilizing flexibility from sector coupling, and the essential network extension plans. Network congestion and reduced security margins will become the new normal. We conclude that future energy systems require expanded flexibilities in combination with forward planning of operation.

Research on Intelligent Diagnosis Technology of Emergency Diesel Generator in Nuclear Power Plant Based on New Monitoring Method

As the emergency power source of nuclear power plant, the emergency diesel generator sets need to provide power for the safety system of nuclear power plant after all external power sources of nuclear power plant are lost, to ensure the safe shutdown of nuclear power plant and prevent the leakage of radioactive materials to the environment. In view of the critical role of emergency diesel generator sets in ensuring the safe operation of the power station, high reliability is needed. Therefore, how to accurately monitor the state of diesel engine and how to diagnose the faults has become an urgent problem to be solved. In this paper, status monitoring system for diesel engine is designed and developed based on LabVIEW and new monitoring method to realize real-time and continuous collection during the operation of the diesel engine, intensive collection during the alarm process, and data display and storage. It can provide data support for fault diagnosis. The operation results show that the system has high reliability and meets the requirements of field inspection, regular test and fault analysis.

Driving forces underlying sub-national carbon dioxide emissions within the household sector and implications for the Paris Agreement targets in Japan

This study investigated insights into reducing energy-related CO2 emissions in households by examining individual socio-economic drivers at a sub-national level. Specifically, the logarithmic mean Divisia index technique was used to decompose CO2 emission trends into six drivers in all 47 prefectures of Japan during the period from 1990 to 2015. Drivers included the change in the number of households (household effect), distribution of households (distribution effect), household size (size effect), per-capita household energy consumption (consumption effect), household energy choice (choice effect), and sectoral CO2 emission intensity (intensity effect). The results showed that, in contrast to size and the distribution effects, the number of households had a positive, significant effect on CO2 emissions, indicating that recent demographic trends are responsible for the increase in CO2 emissions observed in most of the prefectures during the study period. With regard to effects related to consumption and choice, CO2 emissions due to changes in lifestyle dropped in only seven prefectures and reductions due to changes in sectoral energy choice were seen in only two prefectures in 2015. The intensity effect boosted the emissions of these prefectures the most in 2015 because of the shutdown of nuclear power plants due to the Great East Japan Earthquake. Further, we identified those prefectures that needed to reduce their per-capita energy consumption level in order to attain the reduction targets for household CO2 emissions in 2030 from 2015, given projected changes in demographic trends and recent and projected emission intensities. In order to achieve reductions in total CO2 emissions in line with the Paris Agreement, it is important to prioritize national and local policy interventions for the transfer of new household energy technologies, upgrade household appliances, and encourage people to limit energy consumption in light of the differences in these key drivers in each prefecture.

Dynamic linear modeling of monthly electricity demand in Japan: Time variation of electricity conservation effect.

After the severe nuclear disaster in Fukushima, which was triggered by the Great East Japan earthquake in March 2011, nuclear power plants in Japan were temporarily shut down for mandatory inspections. To prevent large-scale blackouts, the Japanese government requested companies and households to reduce electricity consumption in summer and winter. It is reported that the domestic electricity demand had a structural decrease because of the electricity conservation effect (ECE). However, quantitative analysis of the ECE is not sufficient, and especially time variation of the ECE remains unclear. Understanding the ECE is important because Japan’s NDC (nationally determined contribution) assumes the reduction of CO2 emissions through aggressive energy conservation. In this study, we develop a time series model of monthly electricity demand in Japan and estimate time variation of the ECE. Moreover, we evaluate the impact of electricity conservation on CO2 emissions from power plants. The dynamic linear model is used to separate the ECE from the effects of other irrelevant factors (e.g. air temperature, economic production, and electricity price). Our result clearly shows that consumers’ electricity conservation behavior after the earthquake was not temporary but became established as a habit. Between March 2011 and March 2016, the ECE on industrial electricity demand ranged from 3.9% to 5.4%, and the ECE on residential electricity demand ranged from 1.6% to 7.6%. The ECE on the total electricity demand was estimated at 3.2%–6.0%. We found a seasonal pattern that the residential ECE in summer is higher than that in winter. The emissions increase from the shutdown of nuclear power plants was mitigated by electricity conservation. The emissions reduction effect was estimated at 0.82 MtCO2–2.26 MtCO2 (−4.5% on average compared to the zero-ECE case). The time-varying ECE is necessary for predicting Japan’s electricity demand and CO2 emissions after the earthquake.

Fiscal and social costs of recovery programs for an earthquake disaster in northern Taiwan

We investigate the long-run disaster impact of an earthquake hitting northern Taiwan with a nuclear power plant shutdown and the costs and effectiveness of recovery programs using a dynamic computable general equilibrium model. We simulate the losses of capital and labor from the disaster with a nuclear power plant shutdown and then conduct policy experiments of the recovery of Taiwan’s three major industries by subsidizing their output or capital use. We find that the semiconductor and electronic equipment sectors could recover with the aid of subsidies. In contrast, the recovery of the chemical sector would be crucially dependent on the availability of nuclear power. This is because the chemical sector is heavily dependent on petroleum products as inputs and thus susceptible to fuel price rises, induced by a fuel demand increase following the shutdown of a nuclear power plant. The fiscal and welfare costs differ by type of subsidy and program duration. Capital-use subsidies would cost less than output subsidies. A longer recovery program duration would cost less by reducing the distortionary effects of the policy interventions.

Parameter analysis of neutron point kinetics for nuclear reactors

There is no one model can describe the neutron point kinetic formulation of reactor behaviors. This is due to that nuclear reactor operates in different time regions under different conditions. Therefore, we investigated in this paper several models to explain the performance of neutron point kinetic reactors according to time region of operation. These regions of operation represent the prompt neutron analysis, the delayed supercritical assessment and the transient behavior analysis. The first region of operation is described by neutron jump approximation model. The delayed supercritical one is evaluated by substitution model and combinational analysis model. The transient behavior includes prompt and delayed temperature feedback models. The obtained results are compared with published numerical models and validated using block diagram programming technique. The effects of initial power on the reactor performance are evaluated. Moreover, the influences of inserted positive and negative reactivity on the generated neutron flux density are introduced. The steady state operation of nuclear reactor is improved after step reactivity of ρ0>1β. It is observed that the behavior of delayed neutron precursor increases after 40s from cold start-up mode. Furthermore, optimum reactivity with step reactivity of ρ=2β is accomplished that introduces efficient handling of control rod within reactor core. Hence, the neutron dynamic behaviors under variation of control rod positions can be estimated. Thus, safety analysis and transient behaviors during start-up and shutdown of nuclear power plants can be optimized. Consequently, efficient nuclear protection level of nuclear power plant can be fulfilled.

The Effect of Electricity Prices on Residential Solar Photovoltaic Panel Adoption: Fukushima as a Natural Experiment

There are a range of private financial benefits of residential solar photovoltaic (PV) installation, such as a reduced electricity bill, tax incentives and a feed-in tariff for generated electricity. To empirically analyze how rising electricity prices affect household adoption decisions, we use the 2011 Fukushima nuclear disaster as a natural experiment. The shutdown of nuclear power plants across Japan led to a sizable increase in electricity prices that varied by region, allowing us to identify the effect of electricity prices on household PV system adoption. We find that higher electricity prices are significantly more influential on PV adoption on existing homes than on newly-built homes. Our estimated electricity price elasticity of PV systems ranges from 0.9 to 1.2 for existing homes and is much smaller and statistically insignificant for newly-built homes. We discuss behavioral mechanisms explaining this difference and implications for policies stimulating residential adoption of renewables.

Strategies and dismantling solutions for RPV internals of Trino NPP

The last step of nuclear power plants’ life is the decommissioning phase. Many strategies have been developed in the last decades; the main options consists in: immediate dismantling, safe storage and entombment.In Italy, due to the premature shutdown of nuclear power plants (NPP) as a consequence of the 1986 referendum following the Chernobyl accident, all the NPPs were shut down. Therefore, currently decommissioning activities are under way. In this work specifically the dismantling procedures of the “Enrico Fermi” NPP reactor pressure vessel (RPV) are dealt with. The attention is so focused on the optimization of number, position and length of the Internals cuts, optimization of volume and number of waste containers, and of the dose rates, according to the imposed site and the transport requirements.The systematic approach developed to identify the optimum dismantling solution is presented and discussed. To the intent three solutions have been identified as more advantageous. In addition, the evaluation of dose rate outside the container has been performed by means of VISIPLAN software, in order to guarantee the respect of the limits imposed by National and International regulations. The obtained results suggest that the cutting of Zircalloy elements in correspondence of the gap between two non-consecutive central stumps, with the possibility to re-arrange the element, led to a significant reduction of the number of containers, with consequent decrease of the stowed RWs volume and overall supplying costs of the activity.

Effects of nuclear power plant shutdowns on electricity consumption and greenhouse gas emissions after the Tohoku Earthquake

This study analyzes how the substitution of fossil fuels for nuclear power due to the shutdown of nuclear power plants after the Tohoku Earthquake affects electricity consumption and greenhouse gas emissions in Japan. Results indicate that Japan generated 4.3 million metric tons (or 0.3%, with a 95% confidence interval) of additional CO2 emissions in 2011 following the earthquake. The increase in CO2 emissions stemmed from the combined effects of decreased electricity consumption due to energy conservation efforts and the substitution of fossil fuels for nuclear power following the Tohoku Earthquake. Results also show considerable spatial variation in the impacts of the earthquake on net CO2 emissions. A majority of the prefectures (40 of 47 prefectures, or 85%) were predicted to experience higher CO2 emissions after the Tohoku Earthquake while the remaining (7 prefectures) were predicted to experience lower CO2 emissions. Our findings suggest that Japan and countries under similar risks may want to reformulate energy policy by emphasizing utilization of diverse power and energy sources, including more renewable energy production and electricity conservation. The policy reform should also consider spatial variation in the combined effects of reduced reliance on nuclear power and increased CO2 conversion factors.

Impact of environmental regulation and the 2011 earthquake on the Japanese electricity industry

Environmental regulations may erode competition owing to additional costs of compliance. To investigate the impact of such regulations in the Japanese electricity market, we analyze the effects of the environmental quality threshold set for public sector procurement. Using data on electricity procurement auctions from 2005 to 2012, we employ an endogenous switching regression model. We show that the environmental quality threshold lowers the participation of new power suppliers in auctions but does not increase their winning bids as long as competition is maintained. In fact, compliance with the quality threshold has made new power suppliers competitive in green auctions. By contrast, electricity utilities have suffered increased compliance costs since the Great East Japan Earthquake in 2011 owing to the shutdown of nuclear power plants and increased reliance on fossil fuels.

Challenges and Approaches for a Continuous Cable Production

The shut-down of nuclear power plants and the general shift from fossil to regenerative energies lead to an increase of disparity between energy production and energy consumption in Germany. Because of the immense acceptance problems among the public against overhead lines and underground cables new solutions are needed. After considering various options the idea of a tunnel along the highway for the electricity transmission was selected within a VDE study as a promising option. Since joints are expensive and a source of failure and the transportation of cables that are longer than one kilometer is barely possible on land, on-site production is considered as an alternative. To make a production on-site economically more attractive, challenges and first approaches towards a continuous HVDC cable production are described.

Responding to electricity shortfalls: Electricity-saving activities of households and firms in Japan after Fukushima

Japan has experienced a severe electricity shortfall since the Great East Japan Earthquake in March 2011 and the subsequent shutdown of nuclear power plants. Disruption to the supply-demand balance was especially severe in Tokyo and Tohoku in summer 2011, forcing the government to introduce mandatory rationing for large customers. Following intensive efforts, a reduction in demand of more than 15% compared with the 2010 level was achieved in these two regions. Surprisingly, most of the savings achieved in 2011 have persisted for almost four years. This paper examines the Japanese experience of saving electricity, based primarily on a detailed review of surveys of households and commercial and industrial customers we conducted each fall from 2011 to 2014. The paper analyzes major electricity-saving measures, energy users' perceptions and motivations, and trends from 2011 to 2014. The results show that the implementation rates of various electricity-saving measures are declining from the 2011 or 2012 levels, while the actual reduction in demand has remained at almost the same level. This seemingly paradoxical finding can be explained by the cumulative effect of replacing old equipment with newer, more efficient models and adopting new technology such as LED lighting.

Activists in Politics: The Influence of Embedded Activists on the Success of Social Movements

Social movements strive for policy changes that will realize their conception of the “perfect world.” To achieve their aims as rapidly as possible, movements attempt to identify the most effective ways of influencing decision makers. In parliamentary democracies, the central decision makers are political parties. Much of the existing literature emphasizes the use of public pressure and lobbying. To complement this literature, I argue that the intersection between political parties and social movements is also a strong and stable means for activists to influence policy. Using novel microdata on the German antinuclear movement, and particularly its success in influencing the shutdown of nuclear power plants, I demonstrate that movements realize their goals significantly more rapidly when their intersection with political parties increases. My results also suggest that there is a tipping point beyond which the effect of this intersection declines.

Oil price fluctuations and oil consuming sectors: An empirical analysis of Japan

Since the oil price shocks of the 1970s, several studies have found significant impacts of oil prices on macro variables. However, it is particularly crucial to know how each micro sector in an economy, such as the residential, transport, industrial and non-energy sectors, respond to oil price impulses. In this research, we try to shed light on the impact of crude oil price volatility on each sector in Japan, the world’s third-largest crude oil consumer. In order to do so, we apply a vector auto regression model and perform impulse response analysis by using quarterly data from Q1 1990 to Q1 2014. The findings indicate that some economic sectors, such as the residential sector, did not have significant sensitivity to the sharp oil price fluctuations. In contrast, some other sectors, like the commercial, industrial, and transport sectors, were strongly sensitive to the drastic oil price fluctuations. Moreover, our findings show that after the Fukushima disaster in 2011, which led to the shutdown of nuclear power plants in Japan, because of greater reliance on oil imports, the sensitivity of most sectors to oil price volatility declined.

Nuclear power plant shutdown and alternative power plant installation scenarios – A nine-region spatial equilibrium analysis of the electric power market in Japan

After the Great East Japan Earthquake and the subsequent nuclear accident, nuclear power stations cannot be presumed perfectly safe any longer and can be hardly allowed to restart in Japan. We develop a nine-region spatial equilibrium model for Japan's power market and simulate two-part situations: (a) none of the nuclear power plants can operate any longer and (b) gas turbine combined cycle (GTCC) power plants are installed to cover the lost nuclear capacity. When all the nuclear power plants are shut down, the average power prices would rise by 1.5–3yen/kWh. By replacing that lost capacity with GTCC power plants, we could compress the average price rise as high as 0.5–1.5yen/kWh compared with the status quo. Their impact would differ by region on the basis of the share of nuclear power in their plant portfolios. After the nuclear power plant shutdown, regions with abundant nuclear capacity would not be able to afford to sell their power to other regions, which would cause less serious congestion at the inter-regional transmission links. The installation of GTCC power plants would make the plant portfolios more similar among regions and, thus, reduce inter-regional transmission further, which would very rarely cause congestion.