Uncertainty handling during nuclear accidents.

In the years following Chernobyl, many reports and projects reflected on how to improve emergency management processes in dealing with an accidental offsite release of radiation at a nuclear facility. A common observation was the need to address the inevitable uncertainties. Various suggestions were made and some of these were researched in some depth. The Fukushima Daiichi Disaster has led to further reflections. However, many of the uncertainties inherent in responding to a threatened or actual release remain unaddressed in the analyses and model runs that are conducted to support the emergency managers in their decision making. They are often left to factor in allowances for the uncertainty through informal discussion and unsupported judgement, and the full range of sources of uncertainty may not be addressed. In this paper, we summarise the issues and report on a project which has investigated the handling of uncertainty in the UK’s national crisis cell. We suggest the R&D programmes needed to provide emergency managers with better guidance on uncertainty and how it may affect the consequences of taking different countermeasures

Consistency Index-Based Sensor Fault Detection System for Nuclear Power Plant Emergency Situations Using an LSTM Network

A nuclear power plant (NPP) consists of an enormous number of components with complex interconnections. Various techniques to detect sensor errors have been developed to monitor the state of the sensors during normal NPP operation, but not for emergency situations. In an emergency situation with a reactor trip, all the plant parameters undergo drastic changes following the sudden decrease in core reactivity. In this paper, a machine learning model adopting a consistency index is suggested for sensor error detection during NPP emergency situations. The proposed consistency index refers to the soundness of the sensors based on their measurement accuracy. The application of consistency index labeling makes it possible to detect sensor error immediately and specify the particular sensor where the error occurred. From a compact nuclear simulator, selected plant parameters were extracted during typical emergency situations, and artificial sensor errors were injected into the raw data. The trained system successfully generated output that gave both sensor error states and error-free states

Health and safety: Preliminary comparative assessment of the Satellite Power System (SPS) and other energy alternatives

Data readily available from the literature were used to make an initial comparison of the health and safety risks of a fission power system with fuel reprocessing; a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a central-station, terrestrial, solar photovoltaic power system; the satellite power system; and a first-generation fusion system. The assessment approach consists of the identification of health and safety issues in each phase of the energy cycle from raw material extraction through electrical generation, waste disposal, and system deactivation; quantitative or qualitative evaluation of impact severity; and the rating of each issue with regard to known or potential impact level and level of uncertainty

Environmental Risk Analysis: Problems and Perspectives in Different Countries

The authors discuss various industrial accidents, which have led to growing concerns about the potential hazards and risks involved in chemical process industries

The Decision to Reactivate a First-Generation Soviet Nuclear Power Plant: Conceptual and Decision-Analytic Frameworks

Explores a variety of factors that led to reopening the Armenian Metsamor facility notwithstanding general agreement that this is unwarranted technologically

Prospects for Nuclear Power

The prospects for a revival of nuclear power were dim even before the partial reactor meltdowns at the Fukushima nuclear plant. Nuclear power has long been controversial because of concerns about nuclear accidents, proliferation risk, and the storage of spent fuel. These concerns are real and important. In addition, however, a key challenge for nuclear power has been the high cost of construction for nuclear plants. Construction costs are high enough that it becomes difficult to make an economic argument for nuclear, even before incorporating these external costs. This is particularly true in countries like the United States where recent technological advances have dramatically increased the availability of natural gas.

The vulnerability of rules in complex work environments: dynamism and uncertainty pose problems for cognition

Many complex work environments rely heavily on cognitive operators using rules. Operators sometimes fail to implement rules, with catastrophic human, social and economic costs. Rule-based error is widely reported, yet the mechanisms of rule vulnerability have received less attention. This paper examines rule vulnerability in the complex setting of airline transport operations. We examined ‘the stable approach criteria rule’, which acts as a system defence during the approach to land. The study experimentally tested whether system state complexity influenced rule failure. The results showed increased uncertainty and dynamism led to increased likelihood of rule failure. There was also an interaction effect, indicating complexity from different sources can combine to further constrain rule-based response. We discuss the results in relation to recent aircraft accidents and suggest that ‘rule-based error’ could be progressed to embrace rule vulnerability, fragility and failure. This better reflects the influence that system behaviour and cognitive variety have on rule-based response. Practitioner Summary: In this study, we examined mechanisms of rule vulnerability in the complex setting of airline transport operations. The results suggest work scenarios featuring high uncertainty and dynamism constrain rule-based response, leading to rules becoming vulnerable, fragile or failing completely. This has significant implications for rule-intensive, safety critical work environments

An assessment of national risk: General concepts and overall approach

The analysis of risk presented by carbon fiber utilization in commercial aviation is reported. The discussion is presented in three parts: (1) general concepts; (2) overall approach; and (3) risk evaluation and perspective

Environmental Racism and Biased Methods of Risk Assessment

Based on analysis of a risk assessment for a proposed Louisiana uranium enrichment facility, the authors argue that environmental injustice occurs when assessors\u27 scientific methods cause de facto discrimination