scholarly journals Fukushima Daiichi - A Case Study for BWR Instrumentation and Control Systems Performance during a Severe Accident Rev 0

2013 ◽  
Author(s):  
Dwight A Clayton ◽  
Willis P Poore, III
Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2092
Author(s):  
Simone Fiori

The aim of the present tutorial paper is to recall notions from manifold calculus and to illustrate how these tools prove useful in describing system-theoretic properties. Special emphasis is put on embedded manifold calculus (which is coordinate-free and relies on the embedding of a manifold into a larger ambient space). In addition, we also consider the control of non-linear systems whose states belong to curved manifolds. As a case study, synchronization of non-linear systems by feedback control on smooth manifolds (including Lie groups) is surveyed. Special emphasis is also put on numerical methods to simulate non-linear control systems on curved manifolds. The present tutorial is meant to cover a portion of the mentioned topics, such as first-order systems, but it does not cover topics such as covariant derivation and second-order dynamical systems, which will be covered in a subsequent tutorial paper.


2022 ◽  
Vol 166 ◽  
pp. 108812
Author(s):  
Vinay Kumar ◽  
Kailash Chandra Mishra ◽  
Pooja Singh ◽  
Aditya Narayan Hati ◽  
Mohan Rao Mamdikar ◽  
...  

2020 ◽  
Vol 32 (3) ◽  
pp. 511-528
Author(s):  
Roxana Corduneanu ◽  
Laura Lebec

PurposeDrawing on Simons's levers of control (LoC) framework, the primary aim of this study is to advance an understanding of the balance between empowerment and constraint in a non-profit UK organisation. In particular, this study examines the antecedents and manifestations of LoC (im)balance, in relation to employees' level of engagement with the control systems in place.Design/methodology/approachFor this study, 27 semi-structured interviews were conducted with different organisational members, from directors to non-managerial staff, to gain an in-depth appreciation of the main differences between managerial intentions in the design of management control systems (MCS) and employee perceptions regarding the role of such systems.FindingsThis research reveals that suppression of interactive systems and internal inconsistencies between different types of controls hinder the balance between empowerment and constraint. This imbalance is then found to have important consequences for employee buy-in, in some cases, defeating the purposes of control.Research limitations/implicationsThis study enhances our understanding of the gap between the design of control systems and the employee perceptions of it in an unusual organisational setting (non-profit and bringing together clinical and non-clinical staff and operations).Originality/valueThe study of MCS and its role in organisations has long been the focus of both academic and practitioner research. Yet, while extant literature focused on management's perspective on MCS, few studies have explored employees' attitudes and behaviours that accompany the implementation of control. What is more, little is known about the specific uses and behavioural outcomes of MCS in the context of non-profit organisations. Drawing on Simons's LoC framework, this paper addresses these gaps in the literature and investigates the balance between control and empowerment of employees in a UK non-profit organisation with significant clinical remit.


Author(s):  
Itsuki Naito ◽  
Taisuke Koyamada ◽  
Keisuke Yamamoto ◽  
Kingo Igarashi ◽  
Hideo Harada ◽  
...  

This paper introduces the Instrumentation and Control (I&C) system for the proposed UK Advanced Boiling Water Reactor (UK ABWR) offered by Hitachi-GE Nuclear Energy, Ltd (Hitachi-GE). Hitachi-GE has been progressing the UK Generic Design Assessment (GDA) licensing process over the last 3 years. This is the process through which the Office for Nuclear Regulations (ONR) assesses the UK ABWR for suitability from a nuclear safety, security, environmental protection and waste management perspective and it is the first step towards proceeding with the construction phase in the UK. ONR’s regulatory expectations setting out relevant good practice are described in the Safety Assessment principles (SAPs), which are considered into the I&C design for UK ABWR. In addition, it has also been designed to take into account relevant good practices and regulations. In accordance with expectations derived from SAPs, the UK ABWR I&C systems are categorized and classified as required by IEC 61513 and IEC 61226. In addition, the overall I&C architecture, including all associated Human-Machine Interfaces (HMIs), abides by the principles independence and diversity of safety measures, segregation and separation of the protection and control systems. As a result, the UK ABWR I&C architecture is composed of major eight sub-systems. The eight sub-systems are: -Safety System Logic and Control system (SSLC) -Hardwired Backup System (HWBS) -Safety Auxiliary Control System (SACS) -Plant Control System (PCntlS) -Reactor/Turbine Auxiliary Control System (RTACS) -Plant Computer System (PCS) -Severe Accident Control and Instrumentation system (SA C&I) -Other dedicated C&I systems. The features for each sub-system such as redundancy of safety train or segregation among divisions are specified so that each sub-system will achieve its reliability as well as increase availability. While in the Japanese ABWR safety I&C system, the main protection system (SSLC), is microprocessor-based from the decades of successful operating experience in the past BWR, to meet the UK regulatory regime expectation on diversity between Class 1 platform and non-Class 1 platform, the SSLC (Class 1) for the UK ABWR is by Field Programmable Gate Array (FPGA). This system is currently under development and complies with IEC 62556. Its safety integrity level is planned to be SIL 3 (as a single division) and SIL 4 (as a four division system) as defined in IEC 61508. The HMIs which constitute an integral part of the I&C systems are also designed to comply with the I&C architecture regarding their categorization and classification with consideration of Human Factors (HF) modern methods taken into accounts.


2019 ◽  
Vol 15 (1) ◽  
pp. 30-57 ◽  
Author(s):  
Emer Curtis ◽  
Breda Sweeney

Purpose Prior literature provides little insight on how management control systems have responded to the growth of collaborative new product development (NPD). The purpose of this paper is to contrast the use of budgets to manage collaborative and in-house NPD and to consider the implications for enabling flexibility. Design/methodology/approach The paper reports on the findings of a case study company in the medical devices industry that uses two different business models for its NPD activities. While the company engages in in-house NPD for its own products, it also engages in collaborative NPD services with a range of customers. Findings The study illuminates how two types of budgets (annual and project) can have very different impacts on flexibility under different business models. The annual financial budgets imposed rigid constraints on in-house NPD and resulted in reduced flexibility, whereas in collaborative NPD, they had little impact on flexibility. Project budgets created hard operational constraints in collaborative NPD which generated a highly pressurised yet highly creative environment, whereas project budgets had little impact on flexibility in in-house NPD. Originality/value The study contributes detailed empirical insights into the control systems used to manage collaborative NPD from the supplier perspective, where creativity is largely responsive and contrasts these with the management of in-house NPD where creativity is largely expected. The authors also contribute an analysis of the key control systems and other factors that sustain flexibility in this highly pressurised open innovation environment.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 378
Author(s):  
Ercan Atam ◽  
Se-Woon Hong ◽  
Alessia Arteconi

Accurate modelling and simulation of temperature dynamics in large-scale orchards is important in many aspects, including: (i) for the calculation of minimum energy required to be used in optimal design of active frost prevention energy systems (fully renewable or partially renewable) to prevent freezing of fruit flowers, buds, or leaves; (ii) for testing frost prevention control systems before real-implementation which regulate active heating systems inside orchards targeted to prevent frost. To that end, in this study, first, a novel and sophisticated parametric computational thermofluid dynamics (CTFD) model for orchard air thermal dynamics for different orchard parameters (such as fruit type, climate, number of trees, their sizes, and distance between them) and boundary/initial conditions was developed and validated with field data from the literature. Next, the use of the developed parametric CTFD model was demonstrated through a case study to calculate the minimal thermal energy required to prevent frost under different frost levels in a test Prunus armeniaca orchard located in Malatya, Turkey, which is the world capital for dry apricot production.


Sign in / Sign up

Export Citation Format

Share Document