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DOE OSTI2024

The Radiation Detection for Nuclear Security Summer School: Fiscal Year 2024 Report

The Pacific Northwest National Laboratory (PNNL) hosts the Radiation Detection for Nuclear Security (RDNS) Summer School. This unique course provides students with an overview of nuclear security missions, the technical foundation of applied radiation detection technology, and interactive demonstrations and exercises to connect theory to practice in an evolving research and development area. Fiscal year 2024, an off-year year for the school, included reviewing course content, and sharing about the school in a student engagement session at the Institute of Nuclear Materials Management Annual Meeting. Planning is underway for the 10 th RDNS summer school is planned for the summer of 2025.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

The Italian Summer Students Program at Fermilab and other US Laboratories: 40 years of education in particle physics and technology

Since 1983 the Italian groups collaborating with Fermilab (US) have been running a 2-month summer training program for Master students. While in the first year the program involved only 4 physics students, in the following years it was extended to engineering students. Many students have extended their collaboration with Fermilab with their Master Thesis and PhD. The program has involved almost 600 Italian students from more than 20 Italian universities. Each intern is supervised by a Fermilab Mentor responsible for the training program. Training programs spanned from Tevatron, CMS, Muon (g-2), Mu2e and SBN and DUNE design and data analysis, development of particle detectors, design of electronic and accelerator components, development of infrastructures and software for tera-data handling, quantum computing and research on superconductive elements and accelerating cavities. In 2015 the University of Pisa included the program within its own educational programs. Summer Students are enrolled at the University of Pisa for the duration of the internship and at the end of the internship they write summary reports on their achievements. After positive evaluation by a University of Pisa Examining Board, interns are acknowledged 6 ECTS credits for their Diploma Supplement. In the years 2020 and 2021 the program was canceled due to the sanitary emergency but in 2022 it was restarted and allowed a cohort of 21 students in 2022, and a cohort of 27 students in 2023 to be trained for nine weeks at Fermilab. We are now organizing the 2024 program.

Barzi, Emanuela↗
DOE OSTI2024

Five Year Wildfire Risk Reduction Action Plan for the Electric Power Industry

The U.S. DOE and the Electric Power Research Institute convened a wildfire advisory group to bring together knowledge of ignition risks, electric utility needs, the applicability of available technology, and existing technology gaps. The outcome is a five-year action plan, containing recommendations on RD&D projects, that if completed by the year 2030, may accelerate the power industry’s ability to substantially reduce wildfire ignition risks. When reviewing this document please consider it is a snapshot in time for the years 2023 and 2024, could be obsolete by the end of the decade. The following list comprises the titles and topics for the proposed follow-on demonstrations: 1. Hybrid Undergrounding RD&D, 2. Live Downed Conductor Detection RD&D, 3. Fault Energy Reduction RD&D, 4. Advanced Inspection and Response Drone, 5. Fault and PQ Event Signature Repository, 6. Advanced and Intelligent Sensor Nodes, 7. Fire Friendly Asset Coatings and Coverings, and 8. Environmental Monitoring Action Plan.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Report on Initial Sodium Testing on the Thermal Hydraulic Experimental Test Article (THETA) (Fiscal Year 2024 Final Report)

The Thermal Hydraulic Experimental Test Article (THETA) is a facility that is used to develop sodium components and instrumentation as well as to acquire experimental data for validation of reactor thermal hydraulic and safety analysis codes. The facility simulates nominal thermal hydraulic conditions as well as protected/unprotected loss of flow accidents in a sodium-cooled fast reactor (SFR). High fidelity distributed temperature profiles of the developed flow field may be acquired with Rayleigh backscatter based optical fiber temperature sensors. The facility was designed in partnership with systems code experts to tailor the experiment to ensure the most relevant and highest quality data for code validation. THETA is comprised of a traditional primary coolant and secondary coolant system. The primary system is submerged in the pool of sodium and consists of a pump, electrically heated core, intermediate heat exchanger, and connected piping and thermal barriers (redan). The secondary system, located outside of the sodium pool, consists of a pump, sodium to air heat exchanger, and connected piping and valves. In fiscal year 2023, thermal stratification tests were completed with the primary system online, while the secondary system was being constructed [1]. These tests had shown that the core barrel and intermediate heat exchanger (IHX) outlet required increased thermal insulation. The THETA primary system was removed from METL, cleaned, thermal insulators installed, and then inserted into METL Test Vessel 4. At the time of this writing the THETA primary and secondary system are operational. During this fiscal year 100+ hours of testing was completed to characterize thermal hydraulic phenomena associated with steady state and transient conditions in a pool type liquid metal cooled reactor. A majority of the testing campaign was completed to satisfy the experimental data acquisition requirements for the GAIN Voucher with Oklo, CRADA 2021-21121. THETA is still operational at the time of this publication and future testing is planned for fiscal year 2025. Work is underway to publish existing and future data to an online database to facilitate collaboration with SFR engineers looking to validate their systems code or computational fluid dynamics models.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

A Short Survey of Current Reactive Burn Model Capabilities as of Mid-Year 2025

The authors were tasked with writing a concise memo (now a short report) that adequately addresses the current ``state-of-the-art'' in the field of reactive flow modeling and burn models for mid-year 2025, along with identifying some of the modeling gaps. It is assumed that the reader has experience with burn models and running hydrocode simulations, and thus every effort is made to ensure brevity, clarity, and utility, so that this document will serve as a quick and useful reference. Note that “mid-year” was used in the title, as it is possible that advancements in artificial intelligence (AI) may significantly impact the field before the year is over.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2025

Evaluating Movement Patterns of the Rattlesnake Hills Elk Herd on Hanford for Calendar Years 2019-2024

Biologists first documented elk on the Hanford Site in 1972; since then, the elk herd known as the Rattlesnake Hills Elk Herd (RHEH) has grown substantially (PNNL-13331, Population Characteristics and Seasonal Movement Patterns of the Rattlesnake Hills Elk Herd: Status Report 2000). Through the 1990s, the core range of the RHEH was focused on the portion of the Hanford Reach National Monument known as the Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve. More recently, larger numbers of elk have been occupying the U.S. Department of Energy (DOE), Hanford Field Office (HFO), formerly the DOE, Richland Operations Office managed portion- of the Hanford Site, known as central Hanford (Figure 1-1). This began with bachelor groups of bulls occupying the site intermittently, and the herd has grown to resident herds, including bulls, cows, and calves. The Washington Department of Fish and Wildlife (WDFW) established a target herd size for the RHEH of less than 350 animals to minimize damages on adjacent private agricultural lands (Washington State Elk Herd Plan–Yakima Elk Herd [WDFW 2002]). Attempts to control the RHEH population through hunting on private lands and a relocation effort during 2000 have failed to limit growth of the population toward the WDFW target, and the herd exceeds 1,600 according to recent counts (PNNL-13331; DOE/RL- 2023-20, Hanford Annual Site Environmental Report for Calendar Year 2022). Although elk are present on central Hanford year-round, they continue to move between areas offsite, the ALE Reserve, and central Hanford throughout the year, and it is these movements that result in many of the elk-vehicle collisions (EVC) that occur along Hanford Site roads and on the Washington State highways bordering the site. In addition, changes in management strategies on the ALE Reserve, including recent and potential future tribal elk hunts, may alter herd behavior and result in additional animals transiting onto and off central Hanford.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Hanford Site Revegetation Monitoring Report for Fiscal Year 2022

This report describes the monitoring of areas revegetated by various contractors on the Hanford Site. Revegetation sites include those revegetated by the River Corridor Closure Contractor and CH2M Hill Plateau Remediation Company that were transitioned to Mission Support Alliance (MSA) in 2017. These sites, along with sites revegetated by MSA between 2017 and 2020, were transitioned to Hanford Mission Integration Solutions (HMIS) in 2021. HMIS performs revegetation monitoring activities for these transitioned sites and for sites revegetated by HMIS and other contractors in subsequent years to determine revegetation site success. This report contains data collected in 2022 documenting the recovery of revegetation areas associated with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 cleanup of National Priorities List waste sites and restoration of lands disturbed by ongoing mission activities at the Hanford Site in Richland, Washington. It contains vegetation monitoring data for 53 sites selected to be representative sites for areas planted between the years of fiscal year (FY) 2007 and FY 2022.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

FY26 Mid-Year Report Self-Diagnostic Capabilities for Neutron Instruments

This year we will transfer the latest version of INCC6 with last year’s self-diagnostic features to the IAEA. In FY25 we completed the development of three automated self diagnostic features into INNC6. The completion of these features marked the final stable version of INCC 6.0 ready for release to the IAEA and other users. In the first half of the Fiscal Year 2026 we have worked with LANL’s Feynman Center and Export Control office to attain a license for exporting INCC6 to the IAEA. We have successfully attained the export license for INCC6, and contacts at the IAEA have been granted permission to receive INCC6. We are in the final stage of writing the version 6 user manual. Once this is complete, we will deliver INCC6 to the IAEA for testing.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2026

Toward Trustworthy Autonomous Science: A Two-Year Community Roadmap

One year ago, the AISLE roadmap argued that autonomous laboratories operated as isolated islands and proposed a grassroots network organized around five critical dimensions. The field has since moved faster than that roadmap anticipated: multi-agent systems have produced experimentally validated hypotheses, self-driving laboratories have grown more interoperable and orchestrated, reasoning-trained and domain foundation models have raised the capability ceiling, and the Genesis Mission has placed autonomous experimentation at the center of U.S. federal science strategy, with industry emerging as a primary actor. Progress has met a sobering counter-current, including a corrected flagship discovery result, benchmarks showing that agents which rival experts on closed-ended questions still complete only a fraction of open-ended research, and fabricated citations surfacing at leading venues. We read this as the defining tension of the field: producing a candidate discovery is no longer the hard part, but verifying it is, and this asymmetry now limits autonomous science more than raw model capability. Accordingly, we update the roadmap around seven dimensions, revisiting the original five and elevating two former cross-cutting concerns, trust, verification, and reproducibility, and safety, security, and governance, to first-class status. We assess the original milestones (M1 through M14) as achieved, partially achieved, reframed, or open, add four new milestones (M15 through M18) for the elevated dimensions, and scope the path forward to a two-year horizon, with the first year concentrating on interfaces, protocol adoption, and the scaffolding of verification, and the second targeting federation, zero-trust coordination, and governance. Throughout, we position the grassroots network as the interoperability fabric that lets national programs, international initiatives, and commercial platforms connect rather than re-silo.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2021

Springtime Drought Shifts Carbon Partitioning of Recent Photosynthates in 10-Year Old Picea mariana Trees, Causing Restricted Canopy Development

Springtime bud-break and shoot development induces substantial carbon (C) costs in trees. Drought stress during shoot development can impede C uptake and translocation. This is therefore a channel through which water shortage can lead to restricted shoot expansion and physiological capacity, which in turn may impact annual canopy C uptake. We studied effects of drought and re-hydration on early season shoot development, C uptake and partitioning in five individual 10-year old Picea mariana [black spruce] trees to identify and quantify dynamics of key morphological/physiological processes. Trees were subjected to one of two treatments: (i) well-watered control or (ii) drought and rehydration. We monitored changes in morphological [shoot volume, leaf mass area (LMA)], biochemical [osmolality, non-structural carbohydrates (NSC)] and physiological [rates of respiration (R d ) and light-saturated photosynthesis ( A sat )] processes during shoot development. Further, to study functional compartmentalization and use of new assimilates, we 13 C-pulse labeled shoots at multiple development stages, and measured isotopic signatures of leaf respiration, NSC pools and structural biomass. Shoot water potential dropped to a minimum of −2.5 MPa in shoots on the droughted trees. Development of the photosynthetic apparatus was delayed, as shoots on well-watered trees broke-even 14 days prior to shoots from trees exposed to water deficit. R d decreased with shoot maturation as growth respiration declined, and was lower in shoots exposed to drought. We found that shoot development was delayed by drought, and while rehydration resulted in recovery of A sat to similar levels as shoots on the well-watered trees, shoot volume remained lower. Water deficit during shoot expansion resulted in longer, yet more compact (i.e., with greater LMA) shoots with greater needle osmolality. The 12 C: 13 C isotopic patterns indicated that internal C partitioning and use was dependent on foliar developmental and hydration status. Shoots on drought-stressed trees prioritized allocating newly fixed C to respiration over structural components. In conclusion, temporary water deficit delayed new shoot development and resulted in greater LMA in black spruce. Since evergreen species such as black spruce retain active foliage for multiple years, impacts of early season drought on net primary productivity could be carried forward into subsequent years.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Modeling of streamflow in a 30 km long reach spanning 5 years using OpenFOAM 5.x

Abstract. Developing accurate and efficient modeling techniques for streamflow at the tens-of-kilometers spatial scale and multi-year temporal scale is critical for evaluating and predicting the impact of climate- and human-induced discharge variations on river hydrodynamics. However, achieving such a goal is challenging because of limited surveys of streambed hydraulic roughness, uncertain boundary condition specifications, and high computational costs. We demonstrate that accurate and efficient three-dimensional (3-D) hydrodynamic modeling of natural rivers at 30 km and 5-year scales is feasible using the following three techniques within OpenFOAM, an open-source computational fluid dynamics platform: (1) generating a distributed hydraulic roughness field for the streambed by integrating water-stage observation data, a rough wall theory, and a local roughness optimization and adjustment strategy; (2) prescribing the boundary condition for the inflow and outflow by integrating precomputed results of a one-dimensional (1-D) hydraulic model with the 3-D model; and (3) reducing computational time using multiple parallel runs constrained by 1-D inflow and outflow boundary conditions. Streamflow modeling for a 30 km long reach in the Columbia River (CR) over 58 months can be achieved in less than 6 d using 1.1 million CPU hours. The mean error between the modeled and the observed water stages for our simulated CR reach ranges from −16 to 9 cm (equivalent to approximately ±7 % relative to the average water depth) at seven locations during most of the years between 2011 and 2019. We can reproduce the velocity distribution measured by the acoustic Doppler current profiler (ADCP). The correlation coefficients of the depth-averaged velocity between the model and ADCP measurements are in the range between 0.71 and 0.83 at 75 % of the survey cross sections. With the validated model, we further show that the relative importance of dynamic pressure versus hydrostatic pressure varies with discharge variations and topography heterogeneity. Given the model's high accuracy and computational efficiency, the model framework provides a generic approach to evaluate and predict the impacts of climate- and human-induced discharge variations on river hydrodynamics at tens-of-kilometers and decadal scales.

58 GEOSCIENCES↗
NASA NTRS1972

Change in the eleven-year modulation at the time of the June 8, 1969, Forbush decrease.

The functional form of the modulation for the 11-year variation changed abruptly after the Forbush decrease of June 8, 1969. This change in the 11-year modulation suggests that this Forbush decrease was an integral part of the 11-year variation. Some details of the change as observed by neutron monitors and by spacecraft at low energies are discussed.

Lockwood, J. A.↗
NASA NTRS1973

Optical stability of coatings exposed to four years space environment on OSO-III.

The Thermal Control Coatings Experiment flown on OSO 3 in the near-earth space environment was designed to measure changes in the solar absorptance and IR emittance of selected test coatings. The present work describes results obtained from four years in orbit. Changes in solar absorptance of the coatings are illustrated as a function of equivalent sun hours, and it is seen that five of eleven coatings considered exhibit no change in solar absorptance over four years or 7500 equivalent sun hours. The effects of micrometeoroids on polished metal surfaces are judged to be negligible for a near-earth mission of four years.

Millard, J. P.↗
NASA NTRS1973

Solar flares during the past 1000 years as revealed by lunar studies

The intensities of proton fluxes of energy greater than 50 MeV in several recent solar flares are obtained from measurements of Ar-37 radioactivity as a function of depth in lunar material. These intensities agree within a factor of 2 with measurements made by detectors aboard satellites. The intensities of the solar proton fluxes of greater than 200-MeV and greater than 50-MeV energy averaged over the past 1000 years are estimated from measurements of Ar-39 radioactivity as a function of depth in lunar material. The intensity of greater than 200-MeV solar-flare protons obtained from Ar-39 in Fe, when averaged over the past 1000 years, was equal to that of galactic cosmic rays. This result indicates that the 19th solar cycle, which had a number of very energetic solar flares, was more typical of solar activity during the past 1000 years than was the 20th.

Fireman, E. L.↗
NASA NTRS1978

The relationship of air temperature variations over the northern hemisphere during the secular and 11-year solar cycles

A comparison was made of air temperature anomaly maps for the months of January and July against a background of high and low secular solar activity, with and without regard for the 11 year cycle. By comparing temperature variations during the 11 year and secular cycles, it is found that the 11 year cycle influences thermal conditions more strongly than the secular cycle, and that temperature differences between extreme phases of the solar cycles are greater in January than in July.

Ryzhakov, L. Y.↗
NASA NTRS1980

On lunar evidence for a possible large increase in solar flare activity approximately 2 x 10 to the 4th years ago

Data from lunar materials which may be interpreted as suggesting an increase in solar cosmic ray activity approximately 20,000 years ago is examined. The evidence includes the iron track within pit data of Hartung and Storzer (1974), the lunar whole rock pit and track data, lunar C-14 radioactivity data, lunar Ni-59 radioactivity data, the impact pit and iron track data of Morrison and Zinner (1975, 1977) and the lunar thermoluminescence data. While numerous explanations are possible for each set of data, it is shown that the first four data sets may be explained by a past increase in solar cosmic ray activity, and the remaining data sets are not necessarily incompatible with solar activity a factor of 20 to 40 times higher than at present for several thousand years prior to about 20,000 years ago.

Zook, H. A.↗
NASA NTRS1982

Propellant/material compatibility program and results: Ten-year milestones

The analyses and results of a test program to establish the effects of long term (10 years or more) contact of materials with earth-storable propellants for the purpose of designing chemical propulsion system components which are used for current as well as future planetary spacecraft are described. The period from the publication of JPL TM 33-779 IN 1976 through the testing accomplished in 1981 is covered. The following propellants are reported herein: hydrazine, monomethylhydrazine and nitrogen tetroxide. Materials included the following: aluminum alloys, corrosion resistant steels and a titanium alloy. The results of the testing of more than 80 specimens are included. Material ratings relative to the ten year milepost were assigned. Some evidence of propellant decomposition was found. Titanium is rated as acceptable for ten year applications. Aluminum and stainless steel alloys are also rated as acceptable with few restrictions.

Moran, C.↗
NASA NTRS1983

An investigation to model radar backscatter from ridged first year sea ice for the period ending December 31, 1981

The response of the microwave scatterometer to meter scale roughness of first year sea ice was investigated. An empirical, one dimensional model was developed to predict the back scattered power from ridged first year sea ice of known surface topography, by interpreting the surface as a series of angular facets and summing the proportional power from each facet. The model is evaluated by comparing the predicted values to scatterometer measurements obtained during NASA's Sea Ice Radar Experiment (SIRE). The input to the model is surface slope, which for SIRE was calculated from the ice topography, as measured by an airborne laser profiler. The correlation between the predicted and the measured power is .62 to .68. It is concluded that the model adequately describes the backscatter from regions of first year sea ice whose dimensions are of a few tens of meters.

Jackson, B. L. W.↗