Generation and Mapping of Fuel Types for Fire Risk Assessment

Fuel mapping is key to fire propagation risk assessment and regeneration potential. Previous studies have mapped fuel types using remote sensing data, mainly at local-regional scales, while at smaller scales fuel mapping has been based on general-purpose global databases. This work aims to develop a methodology for producing fuel maps across European regions to improve wildland fire risk assessment. A methodology to map fuel types on a regional-continental scale is proposed, based on Sentinel-3 images, horizontal vegetation continuity, biogeographic regions, and biomass data. A vegetation map for the Iberian Peninsula and the Balearic Islands was generated with 85% overall accuracy (category errors between 3% and 28%). Two fuel maps were generated: (1) with 45 customized fuel types, and (2) with 19 fuel types adapted to the Fire Behaviour Fuel Types (FBFT) system. The mean biomass values of the final parameterized fuels show similarities with other fuel products, but the biomass values do not present a strong correlation with them (maximum Spearman’s rank correlation: 0.45) because of the divergences in the existing products in terms of considering the forest overstory biomass or not.

Spatiotemporal Analysis of Active Fires in the Arctic Region during 2001–2019 and a Fire Risk Assessment Model

The increasing frequency of active fires worldwide has caused significant impacts on terrestrial, aquatic, and atmospheric systems. Polar regions have received little attention due to their sparse populations, but active fires in the Arctic cause carbon losses from peatlands, which affects the global climate system. Therefore, it is necessary to focus on the spatiotemporal variations in active fires in the Arctic and to assess the fire risk. We used MODIS C6 data from 2001 to 2019 and VIIRS V1 data from 2012 to 2019 to analyse the spatiotemporal characteristics of active fires and establish a fire risk assessment model based on logistic regression. The trends in active fire frequency based on MODIS C6 and VIIRS V1 data are consistent. Throughout the Arctic, the fire frequency appears to be fluctuating and overall increasing. Fire occurrence has obvious seasonality, being concentrated in summer (June–August) and highest in July, when lightning is most frequent. The frequency of active fires is related to multiple factors, such as vegetation type, NDVI, elevation, slope, air temperature, precipitation, wind speed, and distances from roads and settlements. A risk assessment model was constructed based on logistic regression and found to be accurate. The results are helpful in understanding the risk of fires in the Arctic under climate change and provide a scientific basis for fire prediction and control and for reducing fire-related carbon emissions.

Fire Risk Assessment of Transient Ignition Sources in Domestic Nuclear Power Plants

The fire risk of a nuclear power plant is evaluated using fixed and transient ignition sources. In terms of the overall fire risk, the proportion of transient ignition sources is very small. However, because the uncertainty due to the difference between the assumptions and the modeling method is relatively large, it is necessary to establish a methodology to address this. In this study, the new transient ignition source evaluation method presented in NUREG/CR-6850, the ignition source frequency revised in NUREG-2169, and the input parameters for transient fire modeling presented in NUREG-2233 were used to evaluate the fire risk assessment for transient ignition sources. In this new evaluation methodology, the fire ignition frequency is quantitatively evaluated based on the characteristics of the area, and an area-based scenario evaluation method considering the location of the transient ignition source is proposed for the evaluation within the area. As a result of applying the new methodology to the switchgear room of a reference nuclear power plant, an approximately 70% risk reduction was confirmed compared to the existing EPRI TR-105928 method. In the future, if fire risk assessment for transient ignition sources in nuclear power plants is applied using the results of this study, it is expected that areas whose control is important in the event of a fire can be determined, which should help reduce highly rated fire risks.