Floating nuclear power stations (FNPSs) are being constantly developed due to their potential for broad application. Meteorological parameters are an important basis for heating, ventilation and air ...conditioning (HVAC) system design and energy estimation. However, existing HVAC meteorological parameters are mostly applicable to inland buildings and are becoming obsolete due to climate change. This paper aims to determine the outdoor design temperature and relative humidity for FNPSs. Raw weather data recorded over a 30-year period from National Oceanic and Atmospheric Administration (NOAA) were used. Considering nuclear safety requirements and energy conservation goals, the HVAC meteorological parameters are classified into safety class parameters for nuclear safety-related systems and non-safety class parameters for conventional systems. In addition, the area of China Sea and its vicinity is subdivided into 18 sea regions to reflect local climate characteristics. For a typical FNPS, the outdoor design temperature proposed is compared with that provided in several standards from the perspective of cooling/heating load. It shows that cooling and heating loads with safety class design temperature are 34.0% and 26.5% less than the maximum design cooling and heating loads, respectively. This study can serve as a reference for the determination of HVAC meteorological parameters of FNPSs.
•Weather data sources from NOAA over a 30-year period from 1989 to 2018 are used.•HVAC meteorological parameters for 18 regions of the China Sea area are obtained.•Both safety class and non-safety class parameters for FNPSs are presented.•New parameters decrease 8.8%–34% of cooling load and 10.4%–26.5% of heating load.
Several countries are currently discussing whether they will rebuild their nuclear power stations in order to continue this type of energy production in the future. The public, with its own opinion ...about nuclear power stations, has an influential voice in this discussion. As a result, policy makers and nuclear scientists are interested in the public's perception of nuclear power and in what determines this perception. We therefore examined an explanatory model of the public's acceptance of nuclear power based on a telephone survey among a representative sample in Switzerland. The model included such factors as risk perception, benefit perception, affective feelings, and social trust. Moreover, we distinguished between two types of benefit perception: benefit for the climate and a secure energy supply. The model fitted very well to our data and explained acceptance very well. Acceptance was mainly influenced by perceived benefits for a secure energy supply and, to a lesser extent, both by perceived benefits for the climate and by risk perception. Affective feelings about nuclear power appeared to be a central factor in the model. Implications for communication about nuclear power stations and for further research are discussed.
► Explanatory model of determinants of nuclear power acceptance was studied in the representative survey. ► Perceived benefits for a secure energy supply had the largest influence on acceptance. ► Perceived benefits for the climate seemed less influential on acceptance. ► Affect had a central role in the explanatory model. ► Implications for communication about nuclear power plants are discussed.
The Great East Japan earthquake occurred on March 11, 2011, at 14:46, and the subsequent tsunami led Tokyo Electric Power Company's (TEPCO's) Fukushima Daiichi Nuclear Power Station (NPS) beyond a ...design-basis accident. After the accident, the Japanese government and TEPCO compiled a roadmap toward an early resolution to the accident including, among the main activities, the employment and improvement of existing severe accident (SA) computer codes. In the member countries of the Organisation for Economic Co-operation and Development/Nuclear Energy Agency (OECD/NEA), SA codes were developed after the accident at Three Mile Island Unit 2 and widely employed to assess NPS status in the postulated SA conditions. Therefore, working plans have been set up with the country members of the OECD/NEA to apply existing SA codes to analyze the accidents at the Fukushima Daiichi NPS Units 1, 2, and 3 and support the decommissioning, constituting an international program named Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF).
The objectives of the BSAF project are to analyze the accident progression of Fukushima Daiichi NPS, to raise the understanding of SA phenomena, to contribute to the improvement of the methods and models of the SA codes, and to define the status of the distribution of debris in the reactor pressure vessels and primary containment vessels for decommissioning.
The present technical paper summarizes the achievements obtained through a comparison of the results, emphasizing the portions of the accident where all the participants reached a common consensus and identifying still open questions where future work should be directed. Consensus exists on the current condition of Unit 1, where a large fraction of the fuel is assumed to have relocated ex-vessel. On the other hand, larger uncertainties exist for Units 2 and 3, where in-vessel and ex-vessel scenarios produce a reasonable prediction of the accident progression.
The primary aim of load frequency control (LFC) is to provide a good quality of electrical power to the consumers within a prescribed limit of frequency and scheduled tie-line power deviation. To ...achieve this objective, LFC needs highly efficient and intelligent control mechanism. Subsequently, here, a novel integral-tilt-derivative (I-TD) controller, fine-tuned by a powerful heuristic optimisation technique called as water cycle algorithm (WCA), is proposed for the LFC study of a two-area interconnected thermal-hydro-nuclear generating units. The studied system involves non-linearities like generation rate constraints, governor dead band, and boiler dynamics. To explore the effectiveness of the proposed controller, dynamic responses of the studied system, as obtained using I-TD controller, are compared to those yielded by other controllers such as tilt-integral-derivative and conventional proportional–integral–derivative controllers. The investigation demonstrates that the proposed I-TD controller delivers better performance in comparison to the other counterparts. Furthermore, sensitivity analysis is carried out to show robustness of the WCA tuned proposed I-TD controller by varying system parameters and loading condition. It is perceived that the proposed I-TD controller is robust and offers better transient response under varying operating conditions.
A new swarm optimisation algorithm, that is, fruit fly optimisation algorithm is proposed to tuned several classical controllers for multi-area multi-source interconnected power system under ...deregulated environment. In deregulated environment, for multi-source combination of reheat thermal, hydro and nuclear generating units in each control area with appropriate generation rate constraint and AC/DC link. The performance of several controller such as integral (I), proportional-integral, proportional-integral-derivative, integral-double derivative (IDD) and proportional-integral-double derivative (PIDD) are compared under different power system scenario and it is found that PIDD controller performs better than other controllers. Then sensitivity analysis is performed with system parameter variation from their nominal values. Sensitivity analysis reveals that optimum gains of PIDD controller need not be reset for wide variation in system parameters.
Comprehensively considering the operation cost and safety constraints of nuclear power, an optimal operation scheme of large-scale nuclear power plant participating in peak load regulation of power ...system is proposed. After quantitatively analysing the peak load regulation cost of nuclear power, the optimal objective is set to minimise the total operation cost including the fuel cost, the start–stop cost, and the peak load regulation cost. On the basis of the normal constraints of power scheduling, safety constraints of the nuclear power unit's daily output performance and power characteristic constraints of the pumped storage unit are considered. The mixed integer programming method is used to achieve the solution of the optimal operation scheme. Simulation results from a regional power system show that the proposed optimal operation scheme can effectively reflect the real characteristic of nuclear power and apply to power dispatching analysis under the background of the large-scale access of nuclear power. In comparison to other two typical schemes of peak load regulation, the proposed optimal operation scheme of peak load regulation is more economic and efficient.
This Safety Guide provides recommendations on the structure and content of the safety analysis report to be submitted by the operating organization to the regulatory body for authorization of the ...siting, construction, commissioning, operation and decommissioning of a nuclear power plant. It is intended to facilitate both the development of the safety analysis report by the operating organization and the checking of its completeness and adequacy by the regulatory body. The publication is a revision of IAEA Safety Standards Series No. GS-G-4.1, Format and Content of the Safety Analysis Report for Nuclear Power Plants, which it supersedes. The revision reflects feedback experience from the Fukushima Daiichi accident and the subsequent stress tests performed. It also describes good practices and experience from the use of safety analysis reports for newly built nuclear power plants in different States and informs on recent progress made in approaches to safety assessment.
This study examined whether participation in a role play on the socio-scientific issue of the use of nuclear power had an impact on pre-service primary teachers’ ideas regarding the process of ...obtaining electricity in a nuclear power station. Before and after the role play, 78 pre-service primary teachers were asked to describe this process to analyze the ideas they displayed about the stages involved in it. The results showed, overall, an increased presence of more scientifically informed ideas in some of these stages following the role play, although a number of non-scientifically informed ideas persisted, for example, regarding the way in which heat is obtained or the final transformation of energy into electricity. These results support the potential value of role play for developing more scientifically informed ideas, although some modifications of the role play are recommended for further development of them.
To mitigate the consequence of severe accident involving core meltdown, many advanced reactors employ ex-vessel core catchers which stabilize and cool the corium for prolonged period by strategically ...flooding it. The cooling system for the core catcher is one of the key components in designing the core catcher. To understand the coolability of melt pool including the effects of decay heat, a simulated experiment was performed in a scaled down ex-vessel core catcher model (CCM) employing electrical heaters to simulate decay heat of 1 MW/m
3
. The experiment was carried out by melting about 25 liters of sodium borosilicate glass, as a mixture of corium and sacrificial material simulant, using cold crucible induction furnace at about 1200°C. The electrical heaters were turned on as the molten corium was poured in the CCM test vessel. K-type thermocouples were used to monitor melt pool temperature as well as the bulk water temperature at different locations with time. The results show that in presence of water outside of the CCM test vessel for the present geometry, coolability of melt pool including removal of decay heat is achievable with outside vessel temperatures not exceeding 100°C. A stable crust was observed at the top surface of the melt pool, which prevented water ingression into the molten corium.
This publication provides practical guidance and information to Member States on how to manage nuclear safety knowledge at the national level, beyond the boundaries of individual organizations. It ...describes the underlying concepts, challenges and available approaches and tools, as well as summarizing the experience gained by Member States to date. The publication is in line with the ultimate objective of all nuclear safety knowledge management activities, which is to sustain and improve the competence of individuals and the capacity of organizations or countries to use such knowledge effectively and responsibly.
