Safety Method for the Pre-conceptual Phase of Sodium-cooled Fast Reactors

2021 ◽  
Author(s):  
Sophie Ehster ◽  
Luca Ammirabile ◽  
Evaldas Bubelis ◽  
Bernard Carluec ◽  
Jean-Baptiste Droin ◽  
...  
Keyword(s):  
Fast Reactors ◽  
Main Equipment ◽  
Analysis Methodology ◽  
Safety Function ◽  
Common Cause Failures ◽  
European Nuclear ◽  
Safety Features ◽  
Design Options ◽  
Systematic Identification ◽  
Different Levels

Abstract The ESFR-SMART European project (Contract number: 754501) focuses on the development of innovative safety design options for future Sodium-cooled Fast Reactors (SFRs). The goal of this paper is to show how the Objective Provision Tree (OPT) method, which is part of the Integrated Safety Analysis Methodology (ISAM) developed by Generation IV Forum (GIF), can help in defining safety guidelines for the definition and the study of ESFR-SMART innovative design options. The OPT method provides a view of the implementation of main safety functions in accordance with defence-in-depth principle and has been adapted to ESFR-SMART needs. Guidance for a consistent and homogeneous application has been developed. The method is applied to each safety function with a specific adaptation for the confinement function. Beyond the allocation of the main equipment ensuring the safety functions to the different levels of defence-in-depth, the adapted method proposes a systematic identification of the mechanisms likely to degrade them. Then, safety features to cope with these mechanisms are investigated as well as the potential common cause failures of main equipment belonging to different levels of defence-in-depth. This adapted method allows to study and then to improve the independence between the levels of defence-in-depth as required for future reactors in Europe by Western European Nuclear Regulators' Association (WENRA). The paper provides the outline of guidance for OPT method adaptation to ESFR-SMART project needs, examples of application and main outcomes of the use of the method.

Thermal hydraulic challenges of Gas Cooled Fast Reactors with passive safety features

2009 ◽  
Vol 239 (5) ◽  
pp. 840-854 ◽  
Author(s):  
Michael A. Pope ◽  
Jeong Ik Lee ◽  
Pavel Hejzlar ◽  
Michael J. Driscoll
Keyword(s):  
Passive Safety ◽  
Fast Reactors ◽  
Safety Features

scholarly journals Safety of Machinery – Determination of Performance Level / Bezpieczeństwo Maszyn – Wyznaczanie Poziomu Zapewnienia Bezpieczeństwa

2013 ◽  
Vol 25 (1) ◽  
pp. 75-84
Author(s):  
Leszek Kasprzyczak
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
Performance Level ◽  
Common Cause ◽  
Safety Function ◽  
Common Cause Failures ◽  
Mean Time

Abstract The article presents a method for determining the performance level (PL) on the basis of the PN-EN ISO 13849-1 standard, which is harmonized with the machinery directive 2006/42/EC. The risk assessment and risk reduction criteria, according to PN-EN ISO 12100, were briefly characterized. The focus was put on determining the required performance level PLr on the basis of a risk graph. The method was presented how to use a safety function composed of input-, logicaland execution subsystems. It was demonstrated how to determine the achieved PL for a safety function composed of hardware elements on the basis of a safety category, mean time to dangerous failures (MTTFd), diagnostic coverage (DC), and immunity to common cause failures (CCF).

Safety Feature of EU-ABWR for Fukushima Accident

2014 ◽  
Author(s):  
Kazuhiro Kamei ◽  
Masatomo Kuroda ◽  
Yoshihiro Kojima ◽  
Kazuki Yano
Keyword(s):  
Severe Accident ◽  
Fukushima Accident ◽  
Safety Feature ◽  
Active Systems ◽  
Safety Requirements ◽  
Diversity Principle ◽  
European Nuclear ◽  
Safety Features ◽  
Safety Systems ◽  
The Eu

European Advanced Boiling Water Reactor (EU-ABWR) is developed by Toshiba. EU-ABWR accommodates an armored reactor building against Airplane Crash, severe accident mitigation systems, the N+2 principle in safety systems, the diversity principle and a large output of 1600 MWe. These features enable EU-ABWR’s design objectives and principles to be consistent with the safety requirements of Western European Nuclear Regulators’ Association (WENRA) and Finnish YVL guides. By designing safety features of the EU-ABWR based on Defense in Depth Principle, EU-ABWR has a capability to mitigate Design Extension Conditions like Fukushima Accident by using a combination of passive and active systems. Furthermore, a severe accident is mitigated passively without containment venting for at least 72 hours.

Research on High Energy Efficient Servo Drive with Safety Integrated Function

2013 ◽  
Vol 773 ◽  
pp. 221-226
Author(s):  
Xian Feng Chen ◽  
Wei Min Zhang
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Motion Control ◽  
Energy Efficient ◽  
Control Level ◽  
High Energy ◽  
Servo Drive ◽  
Safety Function ◽  
Safety Features ◽  
The Relationship

This paper focus on energy consumption and safety function of servo drive, and analysis of the safety integrated functions of the servo drive and its energy consumption features. Servo drive with "safety energy efficiency" concept was proposed based on motion control level. This paper has analyzed the energy consumption distribution characteristics formula of the servo drive architecture, and then, explain the characteristics of safety integrated function from the control path of servo drive. With analyzing the distribution of energy consumption and its safety integrated function, the safety energy efficiency model" is established, which reveals the relationship between servo drive's safety features and energy efficiency. Finally, the application prospects safety energy efficiency model was shown from the view of practical point.

RELIABILITY MODELING AND ANALYSIS OF COMPLEX HIERARCHICAL SYSTEMS

2005 ◽  
Vol 12 (06) ◽  
pp. 477-492 ◽  
Author(s):  
LIUDONG XING
Keyword(s):  
System Level ◽  
Hierarchical Systems ◽  
Reliability Modeling ◽  
Common Cause ◽  
Modeling And Analysis ◽  
Dynamic Fault Tree ◽  
Common Cause Failures ◽  
Computer Based ◽  
Imperfect Coverage ◽  
Different Levels

In this paper we consider the problem of reliability modeling and analysis of hierarchical computer-based systems (HS) with modular imperfect coverage (MIPC) and common-cause failures (CCF). The MIPC and CCF can cause vertical dependence that runs through different levels of the system as well as horizontal dependence that runs across components or modules on the same system level. The consideration of these dependencies poses unique challenges to existing HS reliability analysis methods. We propose an efficient decomposition and aggregation approach named EDA-HS to the reliability evaluation of complex hierarchical systems with both MIPC and CCF as one way to meet the above challenges in an efficient and elegant manner. Our approach is to decouple the effects of both MIPC and CCF from the combinatorics of the solution. The approach is represented in a dynamic fault tree by a proposed probabilistic functional dependency gate and a proposed CCF gate modeled after the existing FDEP gate. We present the basics and advantages of the EDA-HS approach by working through an analysis of an example HS subject to MIPC and CCF.

Calculation of Bowing Reactivity of Core Assemblies in Liquid Metal Fast Reactors

2013 ◽  
Author(s):  
Xingkai Huo ◽  
Hong Yu ◽  
Pan Cao ◽  
Li Xu ◽  
Yun Hu ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Large Temperature ◽  
Inherent Safety ◽  
Irradiation Creep ◽  
Fast Reactors ◽  
Small Magnitude ◽  
Analysis System ◽  
Safety Features ◽  
China Experimental Fast Reactor ◽  
Reactivity Change

In liquid-metal-cooled fast reactors, the temperature rise and its gradients over the core region, sometimes with an addition of the accumulated irradiation creep and swelling, result in a radial core expansion and the bowing of subassemblies, both of which lead to the radial displacements of fuel and reflector materials. In spite of the small magnitude of such displacements, the reactivity change due to radial core expansion and bowing of subassemblies during a transient, such as unprotected loss-of-flow (ULOF), is significant in magnitude and plays one of the most important roles among all inherent safety features; the focus is on the change of the power-to-flow ratio (P/F) from 1.0 to 2.0, during which a large temperature gradient is induced. A 3-D code, named PERMOV, is developed for the calculation of such reactivity feedback, at present as a part of the Neutronics Analysis System (NAS); NAS is a 3-D nodal code, independently developed by researchers in China Experimental Fast Reactor; and at the same time, the code PERMOV has a high portability, making it available to run with other mature core physics codes.

Analysing use of evidence in public policymaking processes: a theory-grounded content analysis methodology

2020 ◽  
Vol 16 (1) ◽  
pp. 65-82 ◽  
Author(s):  
Itzhak Yanovitzky ◽  
Matthew Weber
Keyword(s):  
Content Analysis ◽  
Research Evidence ◽  
Persuasive Communication ◽  
Evidence Based ◽  
Policy Documents ◽  
The Public ◽  
Analysis Methodology ◽  
Frequent Use ◽  
Analysis Instrument ◽  
Different Levels

A broad range of methodologies is routinely employed to track and analyse use of research evidence in public policymaking. However, available methods and tools are mostly equipped to track ‘evidence’ but are less equipped to capture and represent ‘use’ of evidence. In particular, existing methods overlook policymakers’ frequent use of evidence for political persuasion and bargaining. Drawing on established theories and research tools from the field of persuasive communication, we developed a content analysis instrument for tracking and analysing policymakers’ use of evidence based on the information contained in policy documents. We provide a specific example of applying this tool and demonstrate how it may be used to generate rich and nuanced insights regarding the scope, nature, and timing of policymakers’ evidence use at different levels and phases of the public policymaking process. We conclude with a discussion of potential strengths and limitations and offer recommendations regarding the optimal application of this methodology.

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