Integrating geographic information systems with the Level 3 Probabilistic Risk Assessment of nuclear power plants to advance modeling of socio-technical infrastructure in emergency response applications

Explicit incorporation of social and organizational factors into Level 1 Probabilistic Risk Assessment (PRA) has been theoretically and methodologically improved and now is in the process of development for Nuclear Power Plant (NPPs) applications. The goal of this study is to initiate the same paradigm of research for Level 3 PRA. Explicit incorporation of social factors, most specifically location-specific social factors into Level 3 PRA, can drastically affect decisions related to emergency planning, preparedness, and response (EPPR). With concerns about population response from a radiological accident such as the one that occurred at the Fukushima Daiichi Nuclear Power Plant in 2011, understanding the implications of the social makeup of the population in the vicinity of an NPP has the potential to give decision makers information about the effects of their decisions. This research proposes theoretical and methodological approaches to explicitly consider the social factors of the local population in NPP accident consequence modeling. In a Level 3 PRA, the MELCOR Accident Consequence Code System (MACCS2) developed by Sandia National Laboratory, is used by the U.S. Nuclear Regulatory Commission and nuclear industry in order to estimate the damages to public health and environment in the case of an NPP severe accident leading to a large radiological release into the atmosphere. The goal for this research is to derive and incorporate location-specific human and organizational factors, socio-political/ socio-economic climate, and community-specific characteristics into a Level 3 PRA. This has been done “externally” by the integration of MACCS2 with Geographic Information Systems (GIS). Esri’s ArcGIS Version 10.2 software is utilized to operationalize this study. A Bayesian Belief Network (BBN) methodology is also proposed as an approach to “internally” incorporate social risk-contributing factors into a Level 3 PRA code. In this research, social vulnerability construct is used, as a surrogate for a causal model, to integrate social factors with a Level 3 PRA. There have been over five decades of research dedicated to the development of quantifiable social vulnerability factors and models that point toward a prediction of consequences to a population, given a specific hazard. Most of these studies have been concentrated on natural hazards; yet, none have been applied to the man-made hazard (i.e., radiation) related to NPPs. This research study combines social and technical contextual factors with radiation and contamination hazard characteristics based on a specific NPP in order to advance risk assessment and management for NPP severe accidents. Specific demographic information is integrated into social vulnerability and includes house value, age, minority status, and gender. This social vulnerability is associated with the population’s ability to evacuate the area, namely to define evacuation delay time and evacuation speed within the population evacuation model. This research spans two very diverse areas of study; (1) Probabilistic Risk Assessment (PRA) as originated in nuclear engineering, and (2) social vulnerability analysis which is primarily conducted in geography and the social sciences. The contributions of this research include: 1. Theoretical contributions to support applying social vulnerability frameworks to NPP accident consequence analysis, covered in chapter 2. This research is the first of its kind to bridge the gap between social vulnerability theories and nuclear power risk analysis, and consists of a thorough literature review spanning many diverse areas of research 2. Methodological contributions toward combining an accident consequence code such as MACCS2 with the quantification of social vulnerability in the form of a social vulnerability index, covered in chapter 3. This methodology has been established in natural hazards research, and never in the context of probabilistic nuclear accident consequence codes. 3. Methodological contributions toward the integration of an accident consequence code such as MACCS2 with Geographic Information Systems (GIS) to visualize risk information and to explicitly and externally integrate social factors with MACCS2. This has been demonstrated in chapters 3 and 4. 4. Methodological contributions to explicitly and internally merge social vulnerability indices with the evacuation module in MACCS2, using Bayesian Belief Network (BBN). This has been explained in chapter 5. 5. Practical contributions including explicit consideration of location-specific social factors in Level 3 PRA that will help develop: (i) more realistic modeling of population response and, therefore, a more accurate estimation of NPP severe accident risk; and (ii) more advanced management of NPPs severe accident risk by facilitating the analysis of the effects of change in risk due to changes in the underlying socio-technical risk contributing factors. This will certainly help advance models and applications of risk-informed EPPR, particularly in focusing on location-specific populations who rank highest with respect to risk. A further contribution is to visualize location-specific radiological risk around a NPP in order to improve risk communication with the public and policy makers

Design of a 30 GHz Damped Detuned Accelerating Structure

Within the framework of the SLAC/CERN studies of 30 GHz linear colliders, an attempt has been made to scale as closely as possible the existing X-band NLC damped detuned accelerating structure to 30 GHz. A simple scaling was not possible because of mechanical and RF constraints. The 30 GHz design has 101 cells and a minimum aperture of 3.4 mm. In order to obtain acceptably small values for both the single-bunch transverse wakefield and the long-range multibunch wakefield a relatively large non-linear variation of the iris thickness was introduced in addition to the iris diameter variation. The resulting wakefield has a short-range value of 1290 V/pC/mm/m and a long range value below 10 V/pC/mm/m

Rewiring Neural Interactions by Micro-Stimulation

Plasticity is a crucial component of normal brain function and a critical mechanism for recovery from injury. In vitro, associative pairing of presynaptic spiking and stimulus-induced postsynaptic depolarization causes changes in the synaptic efficacy of the presynaptic neuron, when activated by extrinsic stimulation. In vivo, such paradigms can alter the responses of whole groups of neurons to stimulation. Here, we used in vivo spike-triggered stimulation to drive plastic changes in rat forelimb sensorimotor cortex, which we monitored using a statistical measure of functional connectivity inferred from the spiking statistics of the neurons during normal, spontaneous behavior. These induced plastic changes in inferred functional connectivity depended on the latency between trigger spike and stimulation, and appear to reflect a robust reorganization of the network. Such targeted connectivity changes might provide a tool for rerouting the flow of information through a network, with implications for both rehabilitation and brain–machine interface applications

Enabling Large-scale Heterogeneous Collaboration with Opportunistic Communications

Multi-robot collaboration in large-scale environments with limited-sized teams and without external infrastructure is challenging, since the software framework required to support complex tasks must be robust to unreliable and intermittent communication links. In this work, we present MOCHA (Multi-robot Opportunistic Communication for Heterogeneous Collaboration), a framework for resilient multi-robot collaboration that enables large-scale exploration in the absence of continuous communications. MOCHA is based on a gossip communication protocol that allows robots to interact opportunistically whenever communication links are available, propagating information on a peer-to-peer basis. We demonstrate the performance of MOCHA through real-world experiments with commercial-off-the-shelf (COTS) communication hardware. We further explore the system's scalability in simulation, evaluating the performance of our approach as the number of robots increases and communication ranges vary. Finally, we demonstrate how MOCHA can be tightly integrated with the planning stack of autonomous robots. We show a communication-aware planning algorithm for a high-altitude aerial robot executing a collaborative task while maximizing the amount of information shared with ground robots. The source code for MOCHA and the high-altitude UAV planning system is available open source: http://github.com/KumarRobotics/MOCHA, http://github.com/KumarRobotics/air_router.Comment: 7 pages, 8 figure

Intercalibration of four spectrofluorometric protocols for measuring RNA/DNA ratios in larval and juvenile fish

The ratio of tissue RNA to DNA (R/D) is a widely used index of recent growth and nutritional condition in larval and juvenile fish. To date, however, no standard technique for measuring nucleic acids has been adopted. Because methodological details can affect the estimate of R/D, researchers using different analytical protocols have been unable to compare ratios directly. Here, we report on the results of an international interlaboratory calibration of 4 spectrofluorometric protocols to quantify nucleic acids. Replicate sets of 5 tissue samples and 2 standards (common standards) were supplied to each of 5 researchers for analysis with their own methods and standards. Two approaches were evaluated for mitigating the observed differences in values: 1) the use of common nucleic acid standards and 2) standardizing to a common slope ratio (slope of DNA standard curve/slope of RNA standard curve or mDNA/mRNA). Adopting common standards slightly reduced the variability among protocols but did not overcome the problem. When tissue R/Ds were standardized based on a common mDNA/mRNA slope ratio, the variance attributed to analytical protocol decreased dramatically from 57.1% to 3.4%. We recommend that the ratio of the slopes of the standard curves be provided to facilitate intercomparability of R/D results among laboratories using different spectrofluorometric methods for the analysis of nucleic acids in fish

Respiratory monitoring using fibre long period grating sensors

We demonstrate the use of a series of in-line fibre long period grating curvature sensors on a garment, used to monitor the thoracic and abdominal volumetric tidal movements of a human subject. These results are used to obtain volumetric tidal changes of the human torso showing reasonable agreement with a spirometer used simultaneously to record the volume at the mouth during breathing. The curvature sensors are based upon long period gratings written in a progressive three layered fibre that are insensitive to refractive index changes. The sensor platform consists of the long period grating laid upon a carbon fibre ribbon, which is encapsulated in a low temperature curing silicone rubber

Light availability controls in the benthic nearshore ecosystem of the Elwha River

The Elwha River Restoration Project was the largest US dam removal project to date, both in dam height and sediment released. During dam removal in 2011–2014, ~18 Mt of sediment washed downriver, and macroalgae virtually disappeared from the adjacent nearshore ecosystem. The link between current benthic light availability and sediment delivery and transport has been investigated in order to understand conditions during dam removal. Seven instrument platforms were deployed on the 10-m isobath along a 16 km transect centered on the river mouth for seven fortnightly periods in 2016 and 2017 to monitor near-bed photosynthetically available radiation (PAR), suspended sediment, wave climate, current velocity, temperature, and salinity. Water-column profiles, bed sediment, and water samples were collected during deployments. Seasonally variable chlorophyll-a and colored dissolved organic matter did not contribute substantially to light attenuation compared to suspended sediment. Along the 10-m isobath within 1.5 km of the river mouth, the greatest light attenuation occurred when wave events coincided with or followed periods of high river discharge. However, discharge events lasting attenuation; energetic tidal currents promote rapid sediment export out of the nearshore environment. In the buoyant plume, maximum light attenuation occurred within 1 m of the surface, reducing light through the rest of the water column. Benthic PAR varied more during spring tides when plume location was more variable. Alongshore 1.5 to 8 km from the river mouth, light availability was not directly coupled to river discharge. Light attenuation occurred throughout the water column, influenced by resuspension due to strong currents and wave events. This subsurface attenuation would not be captured by remote sensing. Predicting benthic light availability over event, tidal, and seasonal timescales will improve management strategies designed to limit ecosystem damage during other dam removals or sediment delivery events

Adhesion of Silicone Elastomer Seals for NASA's Crew Exploration Vehicle

Silicone rubber seals are being considered for a number of interfaces on NASA's Crew Exploration Vehicle (CEV). Some of these joints include the docking system, hatches, and heat shield-to-back shell interface. A large diameter molded silicone seal is being developed for the Low Impact Docking System (LIDS) that forms an effective seal between the CEV and International Space Station (ISS) and other future Constellation Program spacecraft. Seals between the heat shield and back shell prevent high temperature reentry gases from leaking into the interface. Silicone rubber seals being considered for these locations have inherent adhesive tendencies that would result in excessive forces required to separate the joints if left unchecked. This paper summarizes adhesion assessments for both as-received and adhesion-mitigated seals for the docking system and the heat shield interface location. Three silicone elastomers were examined: Parker Hannifin S0899-50 and S0383-70 compounds, and Esterline ELA-SA-401 compound. For the docking system application various levels of exposure to atomic oxygen (AO) were evaluated. Moderate AO treatments did not lower the adhesive properties of S0899-50 sufficiently. However, AO pretreatments of approximately 10(exp 20) atoms/sq cm did lower the adhesion of S0383-70 and ELA-SA-401 to acceptable levels. For the heat shield-to-back shell interface application, a fabric covering was also considered. Molding Nomex fabric into the heat shield pressure seal appreciably reduced seal adhesion for the heat shield-to-back shell interface application