Federal Executive Branch
Here's a look at documents from the U.S. Executive Branch
Featured Stories
USGS Study Uses Color to Make Streamflow Maps Easier to Read
WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has released Scientific Investigations Report 2025-5085 titled 'Using visualization science to inform the design of environmental decision-support tools--A case study of the U.S. Geological Survey WaterWatch,' by Michael D. Gerst, Melissa A. Kenney and Emily Read. Issued in 2025 from the U.S. Geological Survey in Reston, Virginia, the report, produced under the Groundwater and Streamflow Information Program, evaluates how color choices and map design affect public understanding of WaterWatch streamflow anomaly maps.
The study focuses
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WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has released Scientific Investigations Report 2025-5085 titled 'Using visualization science to inform the design of environmental decision-support tools--A case study of the U.S. Geological Survey WaterWatch,' by Michael D. Gerst, Melissa A. Kenney and Emily Read. Issued in 2025 from the U.S. Geological Survey in Reston, Virginia, the report, produced under the Groundwater and Streamflow Information Program, evaluates how color choices and map design affect public understanding of WaterWatch streamflow anomaly maps.
The study focuseson USGS "Watches," including WaterWatch, which display real-time hydrologic information such as streamflow conditions across the United States. The authors set out to test whether replacing a traditional rainbow color ramp with a divergent brown-blue colormap and adjusting map legends could improve how users interpret streamflow percentiles. They developed six research questions that probe mapping colors to streamflow levels, understandability, efficiency and user preferences in response to different map designs.
To answer these questions, Gerst, Kenney and Read conducted two online surveys, recruiting hundreds of respondents and filtering responses to ensure data quality. Participants viewed versions of WaterWatch maps that used either the control rainbow colormap or the treatment brown-blue colormap, with and without legend "priming." The experimental protocol asked respondents to match colors with relative streamflow levels, estimate percentile classes and complete tasks measuring response time and accuracy.
Map design modifications focused on shifting from the multihued rainbow scheme to a brown-blue scale that more intuitively signals dry-to-wet conditions. The authors describe the divergent brown-blue treatment as aligning low flows with brown tones and high flows with blue tones, aiming to leverage common color associations. The data analytic plan specified statistical tests to compare correct rankings, perceived understandability, efficiency and stated preferences between the two color schemes and legend conditions.
Results show that respondents were more likely to correctly rank and interpret streamflow levels when using the brown-blue colormap than when using the rainbow scheme. Changes in colormap improved understandability measures, while priming users with a legend further aided performance in some tasks. "Effect on efficiency of changing colormaps" and "effect on efficiency of priming with a legend" were also evaluated, with findings indicating modest gains in task speed alongside accuracy improvements under certain combinations of map and legend design.
User preference data indicate that many respondents favored the brown-blue colormap over the rainbow ramp for interpreting hydrologic information. The authors discuss implications for redesigning USGS WaterWatch and related environmental decision-support tools, arguing that visualization science can guide refinements that make complex data products more accessible to both expert and public audiences. The report concludes that integrating empirical testing of visualization choices into tool development can enhance communication of streamflow anomalies and support better-informed environmental decisions.
-- Moira Sirois, Targeted News Service
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View full text here: https://pubs.usgs.gov/sir/2025/5085/sir20255085.pdf
[Category: USGS]
USGS Study Tracks Decades of Sediment Build-Up Behind Nevada's Arrow Canyon Dam
WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has issued Scientific Investigations Report 2025-5106, titled 'Sediment accumulation rates and volume in Pahranagat Wash above Arrow Canyon Dam in northern Moapa Valley, Nevada,' by Jon W. Wilson, Boris Poff and Christopher C. Fuller, prepared by the Water Resources Mission Area in cooperation with the Bureau of Land Management. The report, published in 2025 from USGS offices in Reston, Va., evaluates how fast sediment has accumulated and how much material is impounded behind Arrow Canyon Dam, with work conducted between 2016 and 2022
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WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has issued Scientific Investigations Report 2025-5106, titled 'Sediment accumulation rates and volume in Pahranagat Wash above Arrow Canyon Dam in northern Moapa Valley, Nevada,' by Jon W. Wilson, Boris Poff and Christopher C. Fuller, prepared by the Water Resources Mission Area in cooperation with the Bureau of Land Management. The report, published in 2025 from USGS offices in Reston, Va., evaluates how fast sediment has accumulated and how much material is impounded behind Arrow Canyon Dam, with work conducted between 2016 and 2022to inform management decisions for the site.
Concerns over buried cultural sites and flood risk
The study responds to concerns from the Moapa Band of Paiutes and local historical preservation groups that fine-grained sediment trapped behind the 1934 Civilian Conservation Corps-built flood-control dam has buried culturally important sites. The report notes that sediment now fills the upstream pool to within about 7 feet of the crest and extends roughly 1 mile upstream, while the dam no longer functions as an effective flood-control structure for homes and tribal lands downstream in Moapa Valley.
Pahranagat Wash, an ephemeral tributary to the Muddy River draining about 994 square miles, conveys floodwaters through a narrow canyon at the dam site north of Moapa. Streamflow records from a gaging station downstream of the dam between 1988 and 1993 show very low average discharges with intermittent peaks, underscoring that sediment is transported mainly during infrequent high-flow events rather than steady flow.
Radiometric methods show declining deposition rates
To reconstruct the history of infilling, USGS scientists drilled two deep cores near the upper and middle parts of the impounded area and collected a shallower, high-resolution core closer to the dam, then analyzed sediment samples for lead 210 and cesium 137 isotopes. The team used excess lead 210 profiles and the constant flux-constant sedimentation model to estimate an overall sedimentation rate of 2.4 inches per year, while cesium 137 patterns were used to bracket three distinct time periods since dam construction.
Using cesium 137 peaks associated with nuclear testing fallout, the report calculates that sediment deposition rates behind the dam decreased from 9.4 inches per year between 1934 and 1951 to 4.2 inches per year from 1951 to 1964, and then to 1.0 inch per year between 1964 and 2019. "The sediment deposition rate decreases over time," the authors write, explaining that the storage pool trapped a larger share of sediment in the early years after construction, then gradually filled so that later floods were able to transport more material downstream.
Mapping reveals impounded volume
High-resolution elevation data collected in 2022 with an uncrewed aircraft system and processed into a 1 meter digital elevation model allowed the researchers to delineate the impounded sediment surface and derive 1 foot contour maps. Combining those maps with core-based depth estimates, the team divided the deposit into upstream, midstream and downstream segments and assumed linear changes in thickness within each segment to approximate total volume.
By multiplying the surface area of each segment by its average sediment thickness, the report estimates a total sediment volume of about 4.3 x 10⁷ cubic feet behind Arrow Canyon Dam. The authors caution that assuming the plan-view area of the impounded sediment at the surface is the same at depth likely overestimates the true volume, noting that additional coring to better define the original canyon-bottom geometry would refine this estimate.
Management implications for Arrow Canyon
The report concludes that even if all the sediment were removed, the dam's pool would probably refill quickly because floodwaters in Pahranagat Wash carry substantial sediment loads that are readily trapped by the structure. This behavior, combined with the dam's reduced flood-control effectiveness and the burial of cultural sites, is identified as a central consideration for the Bureau of Land Management as it weighs options for managing or modifying the dam.
"This information will assist the BLM in determining which strategies are feasible for the management of the site," the report states, emphasizing that a clearer understanding of timing, rates and volume of sediment accumulation is essential for evaluating alternatives ranging from partial sediment removal to potential structural changes.
-- Moira Sirois, Targeted News Service
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View full text here: https://pubs.usgs.gov/sir/2025/5106/sir20255106.pdf
[Category: USGS]
USGS Probes Decades of Algal Bloom Risks at Colorado's Blue Mesa Reservoir
WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has issued Scientific Investigations Report 2025-5109, titled 'Environmental Characterization of Blue Mesa Reservoir and Potential Causes of and Management Strategies for Harmful Algal Blooms, 1970 through 2023, Curecanti National Recreation Area, Colorado,' by Katherine Walton-Day, Natalie K. Day, M. Alisa Mast, Rachel G. Gidley, Evan J. Gohring, Tyler V. King, Warren C. Day, Nicole D. Gibney and Nancy J. Bauch. Released in 2025 from the agency's Reston, Virginia, offices, the document was prepared in cooperation with the National Park
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WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Geological Survey has issued Scientific Investigations Report 2025-5109, titled 'Environmental Characterization of Blue Mesa Reservoir and Potential Causes of and Management Strategies for Harmful Algal Blooms, 1970 through 2023, Curecanti National Recreation Area, Colorado,' by Katherine Walton-Day, Natalie K. Day, M. Alisa Mast, Rachel G. Gidley, Evan J. Gohring, Tyler V. King, Warren C. Day, Nicole D. Gibney and Nancy J. Bauch. Released in 2025 from the agency's Reston, Virginia, offices, the document was prepared in cooperation with the National ParkService and several western Colorado water districts to address the emergence and management of harmful algal blooms in the State's largest body of water.
Spanning conditions from 1970 through 2023, the report characterizes long-term trends in hydrology, climate, water quality and nutrient loads in Blue Mesa Reservoir and its tributaries, with an emphasis on how these factors may influence cyanobacteria growth. Analyses of growing-season data show that while mean reservoir levels exhibit no clear trend over the full period, recent years include some of the lowest growing-season levels since 1970, intensifying concern about how changing storage and release patterns interact with bloom dynamics. The authors also document an upward trend in release volumes during the growing season, which has shortened water residence times and could alter the physical and chemical environment that supports or constrains algal proliferation.
The study reports statistically significant increases in growing-season air temperatures from 1970 to 2023 and corresponding increases in surface water temperatures across the Iola, Cebolla and Sapinero basins of the reservoir. At a key Gunnison River monitoring site upstream from the reservoir, annual streamflow has declined over several decades, a pattern the report links to potential changes in precipitation, snowmelt timing, temperature and water use. Together, these climatic and hydrologic shifts point toward warmer, and at times lower, water conditions that may favor cyanobacterial growth under certain nutrient regimes.
Since 2001, the U.S. Geological Survey and partners have collected growing-season water-quality data that underpin trend analyses for clarity, nutrients and trophic state. Using the seasonal Kendall test, the authors identify statistically significant upward trends in chlorophyll-a and trophic state index based on chlorophyll-a in all three main basins, indicating a shift toward higher trophic states over the 23-year record. "These results provide evidence that water temperatures and productivity in Blue Mesa have risen during the past several decades," the report notes, while emphasizing that changes in Secchi disk depth have not yet matched the chlorophyll increases in a way that would dramatically reduce clarity.
Nutrient data for the reservoir and selected tributaries show weak but upward tendencies in total phosphorus and the trophic state index based on phosphorus in the Iola and Cebolla basins between 2001 and 2023. The magnitude of these phosphorus trends is small relative to laboratory reporting limits, leading the authors to caution that the apparent increases, although consistent with warming and productivity signals, may only partly reflect actual environmental change. Tributary sampling and load calculations are used to better understand external nutrient inputs, complementing reservoir monitoring and offering insight into how watershed processes contribute to bloom risk.
Produced in cooperation with the National Park Service, Colorado River Water Conservation District, Upper Gunnison River Water Conservancy District, Gunnison County, Project 7 Water Authority and the Uncompahgre Valley Water Users Association, the report offers managers a synthesized view of more than five decades of data as they evaluate strategies for harmful algal bloom mitigation. The authors conclude that the combination of warming temperatures, evolving hydrologic conditions and subtle nutrient shifts underscores the importance of continued monitoring and adaptive management at Blue Mesa Reservoir.
-- Moira Sirois, Targeted News Service
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View full text here: https://pubs.usgs.gov/sir/2025/5109/sir20255109.pdf
[Category: USGS]
PNNL: Zero Trust Report Maps Federal Path Away From Perimeter Defense
WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-35697, titled 'Zero Trust Cybersecurity Concepts and Models for Application,' authored by Joel Doehle, Ian Johnson, Pierce Russell, Clifton Eyre, Mark Watson, and Penny McKenzie, and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The document, dated February 2024, synthesizes concepts and models for transitioning to a Zero Trust Architecture (ZTA), with a focus on how the Department of Homeland Security's Countering Weapons of Mass Destruction Office can apply Zero Trust to
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WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-35697, titled 'Zero Trust Cybersecurity Concepts and Models for Application,' authored by Joel Doehle, Ian Johnson, Pierce Russell, Clifton Eyre, Mark Watson, and Penny McKenzie, and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The document, dated February 2024, synthesizes concepts and models for transitioning to a Zero Trust Architecture (ZTA), with a focus on how the Department of Homeland Security's Countering Weapons of Mass Destruction Office can apply Zero Trust tochemical, biological, radiological, and nuclear detection systems and networks.
The report defines Zero Trust as a cybersecurity paradigm built on the assumption that network breaches are inevitable and that no user, device, or asset should be implicitly trusted based on its location inside a perimeter. Instead, entities are continuously monitored and access decisions are made through dynamic risk assessment that draws on multiple attributes, including device configuration, user behavior, and threat context. The authors trace the concept to John Kindervag's work in 2008 and highlight its elevation in the federal government through Executive Order 14028, which directs agencies to adopt ZTA as a core part of cybersecurity strategy.
A central theme in the document is the shift from perimeter-centric security toward protection built around what it calls data, applications, assets, and services, or DAAS. For each of these elements, organizations are urged to define "protect surfaces" and design controls from the inside out, guided by mission-specific business outcomes and risk tolerance. Access policies are expected to specify in granular terms who or what can reach a given resource, from where, under what conditions, and subject to which additional checks, such as device health or intrusion detection status.
The authors also describe how Zero Trust principles have been codified in seven tenets from the National Institute of Standards and Technology, emphasizing that all data sources and services are treated as resources, all communications are secured regardless of network location, and all authentication and authorization are dynamic and continuously enforced. Logging, monitoring, and analytics play a crucial role in this model, supporting centralized visibility into assets, infrastructure, and communications so that context can inform every access decision. Implementing Zero Trust is characterized as a gradual journey that demands careful mapping of workflows and sensitive resources rather than a quick technology swap.
To translate abstract principles into practice, the report outlines "pillars" that organize Zero Trust implementation across an enterprise. Drawing on models from the Cybersecurity and Infrastructure Security Agency and the Department of Defense, it describes pillars for identity, devices, networks, applications and workloads, and data, supported by crosscutting functions such as visibility and analytics, automation and orchestration, and governance. For identity, for example, the report highlights multi-factor authentication, least-privilege permissions, and privileged access management, while the devices pillar encompasses endpoint protection, patch management, and posture assessment.
The document dedicates a substantial section to Zero Trust maturity models that break the transition into phases, from traditional practices through initial, advanced, and optimal stages. In the earliest phase, organizations typically rely on manual provisioning, fragmented logging, and limited encryption, while later stages introduce automation of configuration and patching, centralized log analysis, and contextual access tied to device compliance and behavior. At the optimal level, the report describes an environment where phishing-resistant multi-factor authentication is standard, micro-segmentation isolates applications and systems, data are continuously inventoried and labeled, and access decisions are continuously re-evaluated with behavior-based analytics and dynamic policies.
Issued in February 2024, 'Zero Trust Cybersecurity Concepts and Models for Application' positions these concepts and models as a foundation for subsequent work that will apply them to DHS Countering Weapons of Mass Destruction use cases. The authors close by framing Zero Trust not only as a technical architecture but as an organizational trajectory--one that hinges on governance, mission alignment, and a staged increase in automation and analytics to reduce risk from sophisticated cyber threats.
-- Moira Sirois, Targeted News Service
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View report at: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-35697.pdf
PNNL: Technical Brief Charts Path to Integrate EV Charging Into Building Energy Codes
WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-31576-1, titled 'Electric Vehicle Charging for Residential and Commercial Energy Codes Technical Brief,' authored by V. R. Salcido, M. Tillou, E. Franconi, K. Cheslak, and M. Young and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The document, dated December 2024, compiles market data, policy examples, economic analysis, and sample code language to help national, state, and local authorities embed electric vehicle (EV) charging infrastructure requirements into residential
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WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-31576-1, titled 'Electric Vehicle Charging for Residential and Commercial Energy Codes Technical Brief,' authored by V. R. Salcido, M. Tillou, E. Franconi, K. Cheslak, and M. Young and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The document, dated December 2024, compiles market data, policy examples, economic analysis, and sample code language to help national, state, and local authorities embed electric vehicle (EV) charging infrastructure requirements into residentialand commercial energy codes.
The brief situates its recommendations against rapid growth in EV adoption and forecasts for charging demand, noting that U.S. EV sales rose 47 percent between 2020 and 2021 and accounted for 18.8 percent of new light duty vehicle sales in the fourth quarter of 2023, even though EVs still make up roughly 1.2 percent of vehicles on the road. Edison Electric Institute projections cited in the report estimate about 26.4 million EVs on U.S. roads by 2030, requiring roughly 12.9 million additional charge ports across homes, multifamily dwellings, workplaces, and public sites. The authors argue that failing to expand charging infrastructure at a similar pace risks stranding consumers without access to reliable charging.
On the benefits side, the report emphasizes that EVs can lower operating and maintenance costs for drivers, with fuel-efficiency equivalent to up to 130 miles per gallon and annual fuel savings on the order of hundreds of dollars compared with gasoline vehicles, as well as reduced maintenance from the absence of conventional engine components. It notes that roughly three-quarters of U.S. vehicles belong to residents of single-family or duplex homes with access to an outlet within 20 feet of parking, but about a third of vehicles are associated with households lacking reliable off street parking, underscoring the need to extend charging access to multifamily housing and commercial properties.
A central finding of the brief is that integrating EV ready infrastructure during new construction is far more cost-effective than retrofits. Drawing on analyses for California utilities and local governments, the authors report that installing Level 2 EV ready infrastructure in new 60 unit multifamily buildings or 60 space offices can cost less than half the per space retrofit expense, with retrofit penalties driven by trenching, panel upgrades, and rework of existing surfaces. One cited case shows retrofit costs of about 3,232 per Level 2 space versus 1,166 during new construction for an office scenario, and California Air Resources Board estimates that statewide avoided retrofit costs for Level 2 installations could total hundreds of millions of dollars between 2020 and 2025 if infrastructure is built in from the start.
To guide policy and code writers, the technical brief surveys how 12 states and 53 local jurisdictions have already adopted EV-related requirements through building codes, zoning ordinances, and green construction standards. Examples range from California's CALGreen code, which calls for EV-capable infrastructure in at least 35 percent of parking spaces at new multifamily buildings and up to 30 percent of spaces in some nonresidential projects, to city ordinances in Denver, Vancouver, Honolulu, and others that specify minimum shares of EV installed, EV ready, and EV capable parking spaces depending on building type and lot size. The document also references the International Green Construction Code's provisions for EV ready spaces and notes that EV infrastructure language proposed and approved for the 2021 and 2024 International Energy Conservation Code was moved into optional appendices after appeals, leaving adoption decisions to states and localities.
In its core technical sections, the brief defines key concepts--"EV capable," "EV ready," and "EVSE installed" spaces--and presents model code language that can be overlaid on the IECC or ASHRAE 90.1. For residential buildings, the sample provisions would generally require at least one EV capable space per one and two family dwelling and set percentage-based requirements for EV capable and EV ready spaces in multifamily developments, along with raceway, panel capacity, and labeling specifications. For commercial occupancies, the proposed language includes a table of minimum EVSE, EV ready, and EV capable percentages by use group (such as assembly, office, education, residential, and parking garages), plus detailed rules on system capacity sizing, energy management systems, and accessibility of charging stations.
The report also explains two main adoption strategies: inserting EV provisions directly into the mandatory body of the energy code or treating them as appendices that become binding only when explicitly adopted by the authority having jurisdiction. It notes that the first approach offers greater clarity and consistency, while the second may be administratively simpler but risks lower visibility and enforcement without targeted training for code officials and designers. In both cases, the authors recommend aligning energy-code provisions with relevant sections of the National Electrical Code, International Residential Code, International Building Code, and International Fire Code to ensure safety and interoperability.
Issued in December 2024, 'Electric Vehicle Charging for Residential and Commercial Energy Codes Technical Brief' positions EV ready building requirements as a relatively low-cost policy lever to support EV adoption, reduce consumer charging costs, and prepare the built environment for future vehicle to grid capabilities. The brief concludes by inviting states and local governments to seek additional technical assistance from DOE and PNNL for customized impact analyses, jurisdiction-specific code language, and integration of EV provisions into broader efforts to update and strengthen building energy codes.
-- Moira Sirois, Targeted News Service
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View report at: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-31576-1.pdf
PNNL: Plan Lays Out Risk-Based Path to License Transportable Maritime Nuclear Power Plant
WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-34962 Rev. 1, titled 'Plan for the Development and Application of a Risk Assessment Approach for Transportation Package Approval of a Transportable Nuclear Power Plant for Maritime Shipment,' authored by A.B. Rigato, S.J. Maheras, H.E. Adkins, Jr., G.A. Coles, and S.M. Short and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The January 2024 document outlines a probabilistic risk assessment strategy to support licensing a transportable nuclear power plant, including both unirradiated
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WASHINGTON, Dec. 25 (TNSLrpt) -- Pacific Northwest National Laboratory has issued report PNNL-34962 Rev. 1, titled 'Plan for the Development and Application of a Risk Assessment Approach for Transportation Package Approval of a Transportable Nuclear Power Plant for Maritime Shipment,' authored by A.B. Rigato, S.J. Maheras, H.E. Adkins, Jr., G.A. Coles, and S.M. Short and prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830. The January 2024 document outlines a probabilistic risk assessment strategy to support licensing a transportable nuclear power plant, including both unirradiatedand irradiated TRISO-fueled cores, as a maritime transportation package meeting 10 CFR Part 71 requirements.
The authors note that applying the conventional deterministic transportation package licensing framework to a transportable nuclear power plant (TNPP) will be challenging because its functional requirements differ from those of a thick-walled cylindrical cask, prompting a proposed exemption request under 10 CFR 71.12 supported by quantitative risk insights. The plan assumes a factory-preloaded, roughly 20 megawatt thermal TRISO-fueled microreactor that transitions from a Type A(F) package when shipped with fresh fuel to a Type B(F) package once operated and containing spent nuclear fuel. The approach is intended as a living document, adaptable to evolving vendor designs and regulatory feedback, and relevant to both domestic and international shipments.
At the core of the strategy is a transportation probabilistic risk assessment (PRA) methodology that builds on earlier work for highway shipment of the Project Pele demonstration reactor and extends it to sea transport. The plan describes how regulatory approach, safety goals, and risk evaluation guidelines would be defined, including potential use of quantitative health guidelines or surrogates analogous to core damage frequency and large early release fraction used in power reactor applications. It stresses early engagement with the U.S. Nuclear Regulatory Commission on risk acceptance criteria, given that current transportation regulations lack explicit PRA-based thresholds.
For maritime risk modeling, the report focuses on accident scenarios dominated by ship-to-ship collisions and severe fires, drawing on the earlier SAND98 1171 "SeaRAM" framework but tailoring it to transportable reactor cargo. Scenario development includes adapting event trees that track whether the TNPP-carrying ship is struck, the location of impact relative to the reactor hold, potential hull penetration and cask crush or shear, fire initiation and spread, and possible sinking. Hull damage and cask crush probabilities are informed by work such as Minorsky's collision energy correlations and more recent analyses indicating that stowing reactor packages away from a vessel's center of mass can reduce damage risk.
The plan relies heavily on operational experience and data from Nuclear Transport Solutions (NTS), whose INF 3 class ships have carried a wide range of high-activity nuclear materials for decades without a recorded release. NTS reports more than 5 million nautical miles sailed over roughly 180 INF 3 shipments of spent fuel, plutonium, mixed oxide fuel, vitrified high-level waste, and other radioactive cargo, all incident-free, with routes connecting Barrow-in-Furness to ports across Europe, North America, Asia, and Australia. As a conservative benchmark, the authors also incorporate casualty statistics for liquefied natural gas and liquefied petroleum gas tankers from SAND98 1171, later analyses by Gucma and Mou, and recent SP Global maritime data, which show collision and fire rates per nautical mile far below those of the general merchant fleet.
To quantify accident consequences, the report proposes using the Department of Energy's five factor source term equation, combining material at risk, damage ratio, airborne release fraction, respirable fraction, and leak path factor. It anticipates different treatment for scenarios involving radionuclide releases from ruptured TRISO particles, unruptured particle dispersal, or intact containment, drawing on prior studies of TRISO environmental transport and dose to refine assumptions for airborne and respirable fractions. The authors acknowledge substantial uncertainty in high energy impact and fire behavior for advanced fuel and package designs and call for further work to establish defensible bounding values and damage models as designs mature.
Defense-in-depth and compensatory measures feature prominently, particularly the safety attributes of INF 3 vessels operated by NTS. The report highlights double hulls, hull reinforcement, enhanced damage stability and buoyancy, redundant navigation and communication systems, specialized cargo monitoring and cooling, extensive firefighting capabilities including hold flooding, and dedicated radiation monitoring as elements that bolster safety margins beyond probabilistic estimates. It also points to operational practices such as satellite weather routing, escort strategies, crew training, and potential pairing of INF 3 ships for mutual support as additional measures that could be credited qualitatively and quantitatively in licensing.
In its conclusion, 'Plan for the Development and Application of a Risk Assessment Approach for Transportation Package Approval of a Transportable Nuclear Power Plant for Maritime Shipment' argues that a risk-informed pathway grounded in the exceptional performance record of purpose-built nuclear fuel carriers, supplemented by conservative LNG/LPG tanker statistics and structured PRA modeling, can demonstrate very low probabilities of release for TNPP sea transport. The authors recommend future work on detailed TNPP damage modeling, sensitivity and uncertainty analyses, and potential extension of the framework to rail and air transport, positioning the plan as a foundation for vendors seeking exemptions and long-term regulatory evolution toward PRA-based transport licensing.
-- Moira Sirois, Targeted News Service
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View report at: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-34962Rev1.pdf
New Report Shows Forests Deeply Valued by Owners and Visitors Across the United States
WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Department of Agriculture, Forest Service has released a report titled 'Indicator 6.44: the importance of forests to people, 2013-2019,' authored by Michelle J. Thompson, Sonia R. Bruck, Stephanie J. Chizmar, Jesse D. Henderson and Gregory E. Frey, and designated FS-Indicator-6.44-2030. Issued on 1 November 2025 in Washington, D.C., the document examines how strongly people value forests by analyzing survey data from family forest owners and visitors to national forests.
The report explains that forests provide economic, environmental, social and spiritual
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WASHINGTON, Dec. 25 (TNSLrpt) -- The U.S. Department of Agriculture, Forest Service has released a report titled 'Indicator 6.44: the importance of forests to people, 2013-2019,' authored by Michelle J. Thompson, Sonia R. Bruck, Stephanie J. Chizmar, Jesse D. Henderson and Gregory E. Frey, and designated FS-Indicator-6.44-2030. Issued on 1 November 2025 in Washington, D.C., the document examines how strongly people value forests by analyzing survey data from family forest owners and visitors to national forests.
The report explains that forests provide economic, environmental, social and spiritualecosystem services, and that their importance can vary by region, demographics and evolving environmental attitudes. Unlike the prior Indicator 6.44 report, which relied on focus groups, this update leverages existing national datasets to enable more consistent future monitoring. It draws on the 2018 National Woodland Owners Survey (NWOS) to assess ecosystem services valued by family forest owners and on the 2013 and 2019 National Visitor Use Monitoring Survey (NVUM) to estimate how much visitors are willing to pay to travel to national forests.
Family forest ownerships--defined as family, individual, trust, estate or family partnerships owning at least one acre with at least 10 percent tree cover--control a large share of U.S. forests, and their views are central to the indicator. The authors group NWOS responses into three ecosystem service categories: cultural and spiritual, regulating, and provisioning. Cultural and spiritual services include passing land to heirs, recreation, hunting, raising a family, enjoying scenery and privacy; regulating services cover maintaining forest cover, wildlife habitat, biodiversity and water resources; provisioning services encompass uses such as non-timber forest products, firewood and timber.
Data from the 2018 NWOS show that an average of 94 percent of U.S. family forest owners said cultural or spiritual ecosystem services from their forests are important or very important, while 97 percent reported that regulating or provisioning services are important or very important. These percentages correspond to an estimated 331 million acres of forest land associated with cultural or spiritual services and 346 million acres associated with regulating or provisioning services. State-level maps indicate that at least 86 percent of private forest area in every State is owned by people who consider cultural or spiritual services important, and at least 73 percent by those who value regulating or provisioning services, with particularly high acreages in the South and North Regions.
To capture the importance of publicly owned forests, the report turns to NVUM data for national forests. Using a modified travel cost method, the authors estimate per-person willingness to pay (WTP) per trip by dividing reported trip expenditures by average party size and adjusting all values to 2016 dollars. Average trip distances vary by region--for example, visitors traveled the farthest to Alaska, with average one-way distances of 2,044 miles in 2013 and 859 miles in 2019.
The WTP analysis shows that visitors were willing to pay the most to visit national forests in Alaska, with per-person WTP of about 1,002 dollars in 2013 and 567 dollars in 2019 (in 2016 dollars). The South Region experienced the largest percentage increase in WTP between 2013 and 2019, rising by about 22 percent, while the Pacific Coast Region saw a 38 percent decline. Across all regions, visitors' positive WTP signals that the recreation opportunities and other benefits provided by national forests deliver value beyond out of pocket travel costs.
Comparing with the earlier Indicator 6.44 assessment, the authors note that the basic picture remains consistent: people attribute high importance to both consumptive and non consumptive forest uses, as well as to cultural and environmental values. However, direct comparison is limited because the earlier work relied on focus groups, whereas the current report is based on large scale survey data from specific user groups. The authors emphasize that more than 90 percent of family forest owners continue to report that cultural, spiritual, regulating or provisioning services are important or very important, aligning with the themes identified in the earlier focus group research.
The report also highlights substantial data gaps that prevent a complete accounting of the indicator. NWOS and NVUM do not capture the entire U.S. population, and NWOS does not include privately owned forests on Tribal lands, nor does it separate acreage strictly by economic, social, environmental or spiritual functions. The travel cost approach used for national forests may overstate value when trips serve multiple purposes, and limited information on substitutes and party-size variability introduces additional uncertainty. Despite these limits, the authors conclude that survey evidence from 2013-2019 demonstrates that forests remain deeply important to both private woodland owners and national forest visitors across the United States.
-- Moira Sirois, Targeted News Service
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The report is posted at: https://www.fs.usda.gov/research/publications/fs/Indicator-6-44.pdf
