Evaluation of the Passive Reactor Shutdown System Performance in European Sodium Fast Reactor

2021 ◽  
Author(s):  
Evaldas Bubelis ◽  
Michael Schikorr ◽  
Konstantin Mikityuk
Keyword(s):  
Fast Reactor ◽  
System Performance ◽  
Negative Consequences ◽  
Work Package ◽  
Safety Measures ◽  
Sodium Fast Reactor ◽  
Core Meltdown ◽  
Reactor Shutdown ◽  
Design Options ◽  
The Impact

Abstract The ESFR-SMART European project (Contract number: 754501) focuses on the development of innovative safety design options for European Sodium-cooled Fast Reactor (ESFR). The task of Work Package 1.3 is to assess the impact of the new safety measures on the reactor behaviour in the transients protected by either active or passive reactor shutdown systems. The aim of Task 4 in this Work Package is to evaluate the passive reactor shutdown system performance in the ESFR core. This paper deals with the results of this evaluation, which is based on the analysis of four transients passively protected by 12 Diversified Shutdown Device (DSD) rods. Simulations have been done with the SIM-SFR system code and demonstrated that DSD rods are capable to shutdown ESFR in a timely manner, in order to avoid the negative consequences of the analyzed transients. Although a total loss of heat sink transient is a practically eliminated event, it was included in the analysis to estimate the grace time before the core meltdown.

New Reactor Safety Measures for the European Sodium Fast Reactor - Part I: Conceptual Design

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi ◽  
Bernard Carluec
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Thermal Inertia ◽  
Lessons Learned ◽  
Reactor Safety ◽  
Fukushima Accident ◽  
Safety Level ◽  
Safety Measures ◽  
Sodium Fast Reactor ◽  
High Thermal Inertia

Abstract Following up the previous CP-ESFR project, the ESFR-SMART project considers the safety objectives envisaged for Generation-IV reactors, taking into account the lessons learned from the Fukushima accident, in order to increase the safety level of the European Sodium Fast Reactor (ESFR). In accordance with these objectives, guidelines have been defined to drive the ESFR-SMART developments, mainly simplifying the design and using all the positive features of Sodium Fast Reactors (SFR), such as low coolant pressure, efficiency of natural convection, possibility of decay heat removal (DHR) by atmospheric air, high thermal inertia and long grace period before a human intervention is needed. In this paper, a set of new ambitious safety measures is introduced for further evaluation within the project. The proposed set aims at consistency with the main lines of safety evolutions since the Fukushima accident, but it does not yet constitute the final comprehensive safety analysis. The paper gives a first review of the new propositions to enhance the ESFR safety, leading to a simplified reactor, forgiving and including a lot of passivity. This first version is supported by the various project tasks in order to assess the relevance of the whole design in comparison to the final safety objectives.

scholarly journals ESFR-SMART Core Safety Measures and Their Preliminary Assessment

2021 ◽  
Author(s):  
Andrei Rineiski ◽  
Clément Mériot ◽  
Marco Marchetti ◽  
Jiri Krepel ◽  
Christine Coquelet ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Severe Accident ◽  
Minor Actinides ◽  
Preliminary Assessment ◽  
Safety Measures ◽  
Horizon 2020 ◽  
The Core ◽  
Severe Accidents ◽  
Sodium Fast Reactor ◽  
Void Effect

Abstract A large 3600 MW-thermal European Sodium Fast Reactor (ESFR) concept has been studied in Horizon-2020 ESFR-SMART (ESFR Safety Measures Assessment and Research Tools) project since September 2017, following an earlier EURATOM project, CP-ESFR. In the paper, we describe new ESFR core safety measures focused on prevention and mitigation of severe accidents. In particular, we propose a new core configuration for reducing the sodium void effect, introduce passive shutdown systems, and implement special paths in the core for facilitation of molten fuel discharge in order to avoid re-criticalities after a hypothetical severe accident. We describe and assess the control and shutdown system, and consider options for burning minor actinides.

scholarly journals New Reactor Safety Measures for the European Sodium Fast Reactor. Part II: Preliminary Assessment

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi ◽  
Jeremy Bittan ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Reactor Safety ◽  
Preliminary Assessment ◽  
Safety Measures ◽  
Decay Heat ◽  
European Project ◽  
Sodium Fast Reactor ◽  
Core Catcher ◽  
Gen Iv

Abstract The European project ESFR SMART offers innovative options of a sodium fast reactor to improve its safety. This paper explains the results of preliminary calculations made of the main options to verify the big lines of their feasibility. Design propositions and calculations are here provided of following innovative options: removal of the safety vessel, innovative decay heat removal systems, core catcher, thermal pumps and secondary loops. In conclusion, all these options seem able to fulfil the big lines of new safety rules for GEN-IV reactors. A status of the R&D necessary to validate these new options is also proposed.

Optimization of the European Sodium Fast Reactor Secondary Sodium Loop as Part of the ESFR-SMART Project

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi
Keyword(s):  
Fast Reactor ◽  
Reactor Safety ◽  
Secondary Circuit ◽  
Safety Measures ◽  
Design Option ◽  
Sodium Fast Reactor ◽  
The Cost ◽  
Research Tools

Abstract Based on feedback from existing reactors and current projects, the European Sodium Fast Reactor Safety Measures Assessment and Research Tools (ESFR SMART) project proposes an optimization of the secondary circuit with the main aim of improving safety. Besides, the optimization also leads to a simplification of the circuits and therefore to a reduction of the cost of the reactor. For the implementation of the proposed new design option, some points require further R&D to validate their feasibility.

Drainage and sewage system performance – Consequences of reductions in toilet flush volume

2019 ◽  
Vol 40 (5) ◽  
pp. 576-594 ◽  
Author(s):  
Isabella P Valencio ◽  
Orestes M Gonçalves
Keyword(s):  
Water Use ◽  
Water Consumption ◽  
Water Demand ◽  
System Performance ◽  
Water Shortage ◽  
Water Volume ◽  
Negative Consequences ◽  
Sewage System ◽  
The World ◽  
The Impact

This study aims to evaluate impacts of reducing toilet flush volume from 6.8 to 4.8 Lpf with laboratory and field studies. In laboratory, 260 tests were performed including water consumption, waste removal and solid transport tests, in 20 different toilets produced by national and international manufacturers. These tests demonstrated that a simple reduction in flush tank water level was not a viable solution for reducing flush volume, due to flush energy loss. Toilets are designed to work with certain water volume, and reducing this volume without studying the consequences that this could cause, can make with the toilet fail. Toilets approved according the standards ABNT NBR15097, ABNT NBR15491 and ASMEA112.19.2 were installed in 10 houses. The monitoring of water consumption and sewage system videos were conducted during eight months. When 6.8-Lpf toilets were installed, the average toilet water consumption was 16.6L/inhabitant/day. For 4.8-Lpf toilets, this value increased to 17.6. The number of flushes/person/day increased after toilets replacement, indicating that users applied successive flushes. Videos showed blockages in sewage system horizontal pipes. Findings from this study suggest that low-flush toilets do not decrease total water use, and may result in increased water use. In addition, they can cause clogging and solid deposit on sewage system. Practical application: Many management failures have affected the world water availability. Water demand has increased with population growth, and unless the equilibrium between water demand and supply is restored, the world will face increasing water shortage. However, it is essential to study the way of reducing water consumption. Without an effective analysis, instead of bringing benefits to population, water consumption reduction can lead to clogging and negative consequences on sewage system performance, causing disorder to them. It is recommended that manufacturers did not reduce the toilet water consumption without a study on the impact caused on the sewage systems, as well as designers should be careful when specifying sanitary appliances.

Preliminary Analysis of In-Vessel Corium Confinement and Cooling in a Large Sodium Fast Reactor

2012 ◽  
Author(s):  
Franco Polidoro ◽  
Flavio Parozzi
Keyword(s):  
Fast Reactor ◽  
Preliminary Analysis ◽  
Structural Integrity ◽  
Mechanical Energy ◽  
Severe Accident ◽  
Sodium Fast Reactor ◽  
Safety Margins ◽  
Core Catcher ◽  
Core Meltdown ◽  
Accident Conditions

Considering a reasonable range of core meltdown accidents that can be postulated for GenIV sodium fast reactors, good safety margins exist for corium confinement and cooling inside the reactor vessel. Coolable conditions can be reached with the adoption of an ad-hoc device in the lower plenum, i.e. core catcher, capable to intercept the downward motion of the molten material and assure its cooling. Such device has to be designed to withstand to extreme thermal-mechanical conditions that rise as consequence of the large mechanical energy release and high temperature of molten corium. As this study has been carried out in the frame of the Collaborative Project on European Sodium Fast Reactor (CP ESFR) of the 7th Framework Programme Euratom, on the basis of the postulated accident conditions assumed for a reference 1500 MWe pool-type sodium fast reactor, the present work provides a preliminary analysis of the thermal response of a possible core catcher placed within the vessel. The dynamic thermal behaviour of the corium-structure-coolant system is analyzed with the computer code CORIUM-2D, an original simulation tool developed by RSE - Ricerca Sul Sistema Energetico, with the aim to assess the thermal interaction among corium, structures and coolant under severe accident conditions in both Light Water Reactors (LWRs) and Liquid Metal Fast Breeder Reactors (LMFBRs). The results of the numerical simulations show that the steady-state coolable configuration of core debris and the structural integrity of main containment structures can be reached in a number of partial core meltdown situations.

Word from the Horizon-2020 EU ESFR-SMART Project Coordinator

2021 ◽  
Author(s):  
Konstantin Mikityuk
Keyword(s):  
Fast Reactor ◽  
Safety Measures ◽  
Horizon 2020 ◽  
Project Coordinator ◽  
Support Organizations ◽  
Sodium Fast Reactor ◽  
Medium Enterprise ◽  
Radiation Science ◽  
Asme Journal ◽  
Research Centres

Abstract This Special Issue of the ASME Journal of Nuclear Engineering and Radiation Science includes 2 editorials and 25 technical papers presenting main achievements of the Horizon-2020 European Union ESFR-SMART project (European Sodium Fast Reactor Safety Measures Assessment and Research Tools) supported by the EURATOM grant and launched in September 2017. ESFR-SMART gathers a consortium of 19 organizations (see Figure 1): Research centres, industries, universities, Technical and Scientific Support Organizations as well as Small to Medium Enterprise aiming at enhancing further the safety of Generation-IV Sodium Fast Reactors (SFRs) and, in particular, of the commercial-size European Sodium Fast Reactor (ESFR) in accordance with the European Sustainable Nuclear Industrial Initiative (ESNII) roadmap.

Conflicts in Biafra, Katanga and Cabinda as a result of the geopolitical legacy of colonialism

2020 ◽  
Vol 2020 (10-3) ◽  
pp. 238-246
Author(s):  
Olga Dzhenchakova
Keyword(s):  
Democratic Republic ◽  
Economic Factor ◽  
Colonial Period ◽  
Sub Saharan Africa ◽  
Negative Consequences ◽  
Post Colonial ◽  
Republic Of The Congo ◽  
Sub Saharan ◽  
The Republic ◽  
The Impact

The article considers the impact of the colonial past of some countries in sub-Saharan Africa and its effect on their development during the post-colonial period. The negative consequences of the geopolitical legacy of colonialism are shown on the example of three countries: Nigeria, the Democratic Republic of the Congo and the Republic of Angola, expressed in the emergence of conflicts in these countries based on ethno-cultural, religious and socio-economic contradictions. At the same time, the focus is made on the economic factor and the consequences of the consumer policy of the former metropolises pursuing their mercantile interests were mixed.

HOW CLIMATE CHANGE CAN INFLUENCE THE AGRICULTURE IN UKRAINE: A REVIEW

2020 ◽  
Author(s):  
N. Maidanovych ◽  
Keyword(s):  
Climate Change ◽  
Crop Yields ◽  
Soil Surface ◽  
Winter Period ◽  
Negative Consequences ◽  
Resource Saving ◽  
Impact Of Climate Change ◽  
Positive Effects ◽  
Average Annual Temperature ◽  
The Impact

The purpose of this work is to review and analyze the main results of modern research on the impact of climate change on the agro-sphere of Ukraine. Results. Analysis of research has shown that the effects of climate change on the agro-sphere are already being felt today and will continue in the future. The observed climate changes in recent decades have already significantly affected the shift in the northern direction of all agro-climatic zones of Europe, including Ukraine. From the point of view of productivity of the agro-sphere of Ukraine, climate change will have both positive and negative consequences. The positives include: improving the conditions of formation and reducing the harvesting time of crop yields; the possibility of effective introduction of late varieties (hybrids), which require more thermal resources; improving the conditions for overwintering crops; increase the efficiency of fertilizer application. Model estimates of the impact of climate change on wheat yields in Ukraine mainly indicate the positive effects of global warming on yields in the medium term, but with an increase in the average annual temperature by 2 ° C above normal, grain yields are expected to decrease. The negative consequences of the impact of climate change on the agrosphere include: increased drought during the growing season; acceleration of humus decomposition in soils; deterioration of soil moisture in the southern regions; deterioration of grain quality and failure to ensure full vernalization of grain; increase in the number of pests, the spread of pathogens of plants and weeds due to favorable conditions for their overwintering; increase in wind and water erosion of the soil caused by an increase in droughts and extreme rainfall; increasing risks of freezing of winter crops due to lack of stable snow cover. Conclusions. Resource-saving agricultural technologies are of particular importance in the context of climate change. They include technologies such as no-till, strip-till, ridge-till, which make it possible to partially store and accumulate mulch on the soil surface, reduce the speed of the surface layer of air and contribute to better preservation of moisture accumulated during the autumn-winter period. And in determining the most effective ways and mechanisms to reduce weather risks for Ukrainian farmers, it is necessary to take into account the world practice of climate-smart technologies.

Financial Risks of the Bank: Assessment and Mechanism of Neutralization

2020 ◽  
Vol 22 (1) ◽  
pp. 6-12
Author(s):  
Nelia Volkova ◽  
◽  
Alina Mukhina ◽  
Keyword(s):  
Risk Assessment ◽  
Financial Stability ◽  
Financial Risk ◽  
Stable Operation ◽  
Financial Risks ◽  
Negative Consequences ◽  
Conceptual Approach ◽  
Relevant Today ◽  
Banking Institution ◽  
The Impact

Abstract. Introduction. The issue of financial risk management of commercial banks is quite relevant today, because the activity of banks is the most risky of all. The presence of risks in banking can lead to unexpected losses, namely the loss of own resources. That’s why for the stable operation of the bank without loss the priority is to assess the financial risks, which is the basis for their further neutralization. Purpose. The purpose of the article is to develop conceptual provisions for assessment financial risks and justifying the need to neutralize them. Results. The article analyzes the impact of risks on the financial stability of a banking institution. The main methods of bank risk assessment are considered. All these include the statistical method, the analytical method, the expert method, the analogue method and the combined method. The necessity of neutralization of financial risks in order to avoid negative consequences is substantiated. Also the methods of bank risks neutralization are considered. It should be noted that these methods of neutralization can not only be used, but also supplement the list with new methods must be done, which in the future will protect the bank from the influence of undesirable factors. A conceptual approach to the assessment and neutralization of financial risks is proposed. This conceptual approach aims to ensure effective assessment of the level of risk with their subsequent neutralization Conclusions. Use of a conceptual approach will allow an effective risk assessment and decision-making to avoid or accept risk. Thanks to using this approach, the banking institution will be able to react swiftly to the presence of financial risks and to prevent the occurrence of negative consequences, which may lead to a violation of the financial stability of the bank.

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