Strength evaluation of a steam distribution device in the Ignalina NPP accident localisation system

The Ignalina NPP has a pressure suppression type of confinement, which is referred to as the accident localization system (ALS). The ALS prevents the release of the radioactive material from the NPP to the environment during a loss-of-coolant accident (LOCA). Ten water pools are located in the two ALS towers (five pools in each tower), which separate the dry well from the wet well. These water pools condense the accident-generated steam and prevent high overpressures in the compartments.The steam distribution device (SDD), with the vertical vent pipes (nozzles) that are inserted under the water of the condensing pools, connects the dry well and the wet well. In case of an accident, these components must be capable of withstanding the dynamic loads generated by a LOCA for successful pressure suppression function.This paper presents the transient analysis of the SDD and their connections to the vertical steam corridors following a LOCA. A thermo-hydraulic analysis of the SDD was performed using the state-of-the-art COCOSYS code to determine pressure and temperature histories resulting from a LOCA. The finite element code NEPTUNE was used to evaluate the structural integrity of the SDD and its supporting reinforced concrete wall. Results show that, although portions of the SDD undergo plastic response and the outside surface of the vertical steam corridor reinforced concrete wall cracks, the structural integrity of the SDD and wall are maintained during a LOCA.     

Analysis of energy efficiency practices of SMEs in rural Ghana: an application of product generational dematerialization method

Energy is a key input in industrial production, education and health and is one of the main drivers of economic growth in developing economies. However, expanding energy access in the rural areas is one of the key challenges faced by policy makers in developing countries such as Ghana. In this regard, small- and medium-sized enterprises (SMEs) in developing countries face the hydra-headed challenges of energy access, power outages, access to finance and access to market. In some cases, whilst energy efficiency appears to be improving at the national level, the story at the rural areas is different due to overdependence on biomass and other traditional forms of energy and relatively low access compared to urban areas. This research is structured in three steps. In the first step, the product generational dematerialization method is applied to examine the energy efficiency consumption of electricity and fossil fuels. In a second step, the energy efficiency practices of small and medium scale enterprises are investigated. In a third step, the general unrestricted model (GUM) is employed to investigate the relationship between energy efficiency, productivity and carbon emissions. The key findings of the study (i) confirm that the consumption of energy has not been efficient, (ii) show that the reduction in energy consumption among SMEs can be attributed mostly to blackouts and not efficiency and (iii) productivity is a major driver of energy efficiency. In a nutshell, the national analysis shows that improved productivity from more energy-efficient technologies is not responsible for energy reduction. Rather, an analysis of the rural energy situation shows that blackouts render energy reductions unintentionally. Moreover, energy-efficient practices are observed to be nearly non-existent within rural SMEs. The study recommends that public education on energy efficiency is increased and that new appliances rather than second-hand one are used to save energy.