Alternative Neutron Detection Testing Summary

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. Most currently deployed radiation portal monitors (RPMs) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large area neutron detector. This type of neutron detector is used in the TSA and other RPMs installed in international locations and in the Ludlum and Science Applications International Corporation RPMs deployed primarily for domestic applications. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated wavelength-shifting plastic fibers. Reported here is a summary of the testing carried out at Pacific Northwest National Laboratory on these technologies to date, as well as measurements on 3He tubes at various pressures. Details on these measurements are available in the referenced reports. Sponsors of these tests include the Department of Energy (DOE), Department of Homeland Security (DHS), and the Department of Defense (DoD), as well as internal Pacific Northwest National Laboratory funds

Rats, assorted shit and ‘racist groundwater’: towards extra-sectional understandings of childhoods and social-material processes

Reflecting on a study of children’s outdoor play in a ‘white, working class estate’ in east London, this paper argues that social-material processes that are characteristically massy, indivisible, unseen, fluid and noxious have, problematically, remained hidden-in-plain-sight within multidisciplinary research with children and young people. For example, juxtaposing qualitative and autoethnographic data, we highlight children’s vivid, troubling narratives of swarming rats, smearing excrement, and percolating subsurface flows of water, toxins and racialised affects. In so doing, we develop a wider argument that key theorisations of matter, nature and nonhuman co-presences have often struggled to articulate the indivisibility of social-material processes from contemporary social-political-economic geographies. Over the course of the paper, as children’s raced, classed, exclusionary, disenfranchised narratives accumulate, we recognise the urgency of reconciling microgeographical accounts of play and materiality with readings of geographies of social-economic inequalities, exclusions, ethnicities, religions, memorialisations and mortalities. To this end, we initiate an argument for a move from intersectional to extra-sectional analyses that might retain intersectionality’s critical and political purchase, whilst simultaneously folding social-material complexities and vitalities into its theorisation

Effect of climate change on environmental flow indicators in the Narew Basin, Poland

Environmental flows—the quantity of water required to maintain a river ecosystem in its desired state—are of particular importance in areas of high natural value. Water-dependent ecosystems are exposed to the risk of climate change through altered precipitation and evaporation. Rivers in the Narew basin in northeastern Poland are known for their valuable river and wetland ecosystems, many of them in pristine or near-pristine condition. The objective of this study was to assess changes in the environmental flow regime of the Narew river system, caused by climate change, as simulated by hydrological models with different degrees of physical characterization and spatial aggregation. Two models were assessed: the river basin scale model Soil and Water Assessment Tool (SWAT) and the continental model of water availability and use WaterGAP. Future climate change scenarios were provided by two general circulation models coupled with the A2 emission scenario: IPSL-CM4 and MIROC3.2. To assess the impact of climate change on environmental flows, a method based conceptually on the “range of variability” approach was used. The results indicate that the environmental flow regime in the Narew basin is subject to climate change risk, whose magnitude and spatial variability varies with climate model and hydrological modeling scale. Most of the analyzed sites experienced moderate impacts for the Generic Environmental Flow Indicator (GEFI), the Floodplain Inundation Indicator, and the River Habitat Availability Indicator. The consistency between SWAT and WaterGAP for GEFI was medium: in 55 to 66% of analyzed sites, the models suggested the same level of impact. Hence, we suggest that state-of-the-art, high-resolution, global- or continental-scale models, such as WaterGAP, could be useful tools for water management decision-makers and wetland conservation practitioners, whereas models such as SWAT should serve as a complementary tool for more specific, smaller-scale, local assessments