Observations of dry-bulb, wet-bulb and air pressure can characterise extreme enthalpy at local scale for the present climate, but a methodology for future climate change impact assessment on enthalpy is yet to be defined. Currently, it is unclear how enthalpy in the UK will vary in the next 100 years, making it difficult to assess how the HVAC systems of a nuclear power plant will be affected. From a non-nuclear perspective, insights into future enthalpy values experienced in the UK are vital in knowing what effect that could have on UK energy infrastructure, markets and on the human health of the population.
The main output of this work would be to establish a methodology, to provide estimates of enthalpy for the present and future climate via the use of UKCP18 (or other) climate change projections. From a safety analysis aspect, it would be useful to include the capability to project trends in the 10,000- year (and more frequent) return level and how these may impact specific sites or groups of sites. From an operational aspect, useful metrics will revolve around the duration of high enthalpy events and whether these may become longer under climate change. Via such an assessment, we will build and adopt best practice in measuring, managing and quantifying the impact of enthalpy on performance of our current fleet.
Project (2): “The impact of extreme rainfall and its future projections on our current fleet”.
Frequency and intensity of extreme natural hazard events are likely to alter under climate change. This needs to be accounted for in any design through improved resilience measures and adaptation planning. EDF has been utilising data provided by UKCP18 to test future robustness to climate change.
Extreme rainfall events are a concern for nuclear power plant operation and safety as they have potential to cause damage to the plants infrastructure and pose a safety risk (e.g. inundation). Therefore, it is necessary to provide accurate estimates of the risks associated with extreme precipitation on all timescales. UKCP18 projected trends in average precipitation show increases in winter rainfall and decreases in summer rainfall but hourly precipitation extremes are projected to increase in all seasons in future. Localised projections (e.g. UKCP18 CPM 2.2 km) are the primary source of information for daily rainfall extremes in summer or changes on hourly timescales as there is improved representation of the diurnal cycle of convection, the spatial structure of rainfall and its duration-intensity characteristics, and the intensity of hourly precipitation extremes. But there are still deficiencies in depicting smaller scale mechanisms e.g. summer convective events – localised intense thunderstorms and the localised datasets are not temporally continuous. Applying methodologies such as extreme value analysis on non-continuous datasets is not advised, and thus the UKCP18 CPM dataset cannot be used to analyse extreme events and estimate return levels.
This work should estimate changes in: rainfall characteristics (e.g. intensity, occurrence) for the present climate as well as in the future via the use of UKCP18 (or other) climate change projections, 10,000-year return levels (and more frequent) and how these will change per sites of interest. Via this work we will build and adopt best practice in measuring, managing and quantifying the impact of rainfall on current fleet performance.