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DOE OSTI2022

Fire, insect and disease‐caused tree mortalities increased in forests of greater structural diversity during drought

Abstract Structural diversity is an emerging dimension of biodiversity that accounts for size variations in organs among individuals in a community. Previous studies show significant effects of structural diversity on forest growth, but its effects on forest mortality are not known, particularly at a large scale. To address this knowledge gap, we quantified structural diversity using stem structural diversity (SSD) based on both tree diameter and height. We obtained U.S. Forest Service Forest Inventory and Analysis (FIA) data from over 2400 plots across southcentral U.S. forests that have suffered a recent drought. Using data from multiple sampling times, we calculated SSD and compared the relative importance of SSD, species diversity, functional diversity and other stand attributes in determining tree mortalities caused by fire, insects and diseases. We also used FIRETEC, a physics‐based fire model, to test the effect of SSD on canopy consumption by fire. Our results showed that (1) SSD was positively associated with tree mortalities caused by all three disturbances; (2) species richness was negatively associated with insect‐ and disease‐caused mortalities; (3) functional diversity was negatively associated with fire‐ and disease‐caused mortalities and (4) more phylogenetically related species had more similar mortality rates by insect and disease but not fire. Moreover, the FIRETEC model showed increasing canopy consumption by fire in stands with greater SSD. Together, the different tree mortalities during drought associated with SSD more consistently than the other biodiversity metrics were evaluated. Synthesis . Our results suggest that SSD could be considered in modelling forest dynamics and planning management to sustain forest health under disturbances.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2023

Prescribed fire selects for a pyrophilous soil sub‐community in a northern California mixed conifer forest

Abstract Prescribed fire is a critical strategy for mitigating the effects of catastrophic wildfires. While the above‐ground response to fire has been well‐documented, fewer studies have addressed the effect of prescribed fire on soil microorganisms. To understand how soil microbial communities respond to prescribed fire, we sampled four plots at a high temporal resolution (two burned, two controls), for 17 months, in a mixed conifer forest in northern California, USA. Using amplicon sequencing, we found that prescribed fire significantly altered both fungal and bacterial community structure. We found that most differentially abundant fungal taxa had a positive fold‐change, while differentially abundant bacterial taxa generally had a negative fold‐change. We tested the null hypothesis that these communities assembled due to neutral processes (i.e., drift and/or dispersal), finding that >90% of taxa fit this neutral prediction. However, a dynamic sub‐community composed of burn‐associated indicator taxa that were positively differentially abundant was enriched for non‐neutral amplicon sequence variants, suggesting assembly via deterministic processes. In synthesizing these results, we identified 15 pyrophilous taxa with a significant and positive response to prescribed burns. Together, these results lay the foundation for building a process‐driven understanding of microbial community assembly in the context of the classical disturbance regime of fire.

Microbiology↗

DOE OSTI2021

Fire alters plant microbiome assembly patterns: integrating the plant and soil microbial response to disturbance

Summary It is increasingly evident that the plant microbiome is a strong determinant of plant health. While the ability to manipulate the microbiome in plants and ecosystems recovering from disturbance may be useful, our understanding of the plant microbiome in regenerating plant communities is currently limited. Using 16S ribosomal RNA (rRNA) gene and internal transcribed spacer (ITS) region amplicon sequencing, we characterized the leaf, stem, fine root, rhizome, and rhizosphere microbiome of < 1‐yr‐old aspen saplings and the associated bulk soil after a recent high‐intensity prescribed fire across a burn severity gradient. Consistent with previous studies, we found that soil microbiomes are responsive to fire. We extend these findings by showing that certain plant tissue microbiomes also change in response to fire. Differences in soil microbiome compositions could be attributed to soil chemical characteristics, but, generally, plant tissue microbiomes were not related to plant tissue elemental concentrations. Using source tracking modeling, we also show that fire influences the relative dominance of microbial inoculum and the vertical inheritance of the sapling microbiome from the parent tree. Overall, our results demonstrate how fire impacts plant microbiome assembly, diversity, and composition and highlights potential for further research towards increasing plant fitness and ecosystem recovery after fire events.

16rRNA↗

DOE OSTI2012

Fire Safety Tests for Spherical Resorcinol Formaldehyde Resin: Data Summary Report

A draft safety evaluation of the scenario for spherical resorcinol-formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping, which may be overly bounding based on the fire performance data from the manufacturer of the ion exchange resin selected for use at the WTP. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI), following the American Society for Testing and Materials (ASTM) standard procedures, through a subcontract managed by Pacific Northwest National Laboratory (PNNL). For some tests, the ASTM standard procedures were not entirely appropriate or practical for the SRF resin material, so the procedures were modified and deviations from the ASTM standard procedures were noted. This report summarizes the results of fire safety tests performed and reported by SwRI. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. All as-received SwRI reports are attached to this report in the Appendix. Where applicable, the precision and bias of each test method, as given by each ASTM standard procedure, are included and compared with the SwRI test results of the SRF resin.

cesium ion exchange↗

DOE OSTI2013

Comprehensive Air Monitoring Report for Measurements during the Las Conchas Fire at Los Alamos National Laboratory

During the Las Conchas Fire, ambient air was monitored for radionuclides and particulate matter at and around Los Alamos National Laboratory (the Laboratory). During the fire, a variety of samplers were deployed, including the radiological air sampling network, high-volume air samplers, Tapered Element Oscillating Microbalances (PM 2.5 and PM 10), and environmental continuous air monitors. These different types of samplers provided real time, more in-depth retrospective information on air quality. In total, roughly 220 air samples were collected, and the results were consistent with other regional fires. Laboratory officials and Los Alamos County used real-time data to make public health risk determinations according to the Air Quality Index. Particulate levels were elevated and exceeded the National Ambient Air Quality Standard during the fire because of smoke. Elevated levels of naturally occurring radon decay products, consistent with all forest fires, were detected. Gross-alpha measurements had an average of range of 400 aCi/m 3 to 13,400 aCi/m 3 . Measurements of gross beta during the fire had a range of 34,000 aCi/m 3 to 74,000 aCi/m 3 . These values are not statistically different from national or regional averages.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

Slipstream pilot-scale demonstration of a novel amine-based post-combustion technology for carbon dioxide capture from coal-fired power plant flue gas

Post-combustion CO 2 capture (PCC) technology offers flexibility to treat the flue gas from both existing and new coal-fired power plants and can be applied to treat all or a portion of the flue gas. Solvent-based technologies are today the leading option for PCC from commercial coal-fired power plants as they have been applied in large-scale in other applications. Linde and BASF have been working together to develop and further improve a PCC process incorporating BASF’s novel aqueous amine-based solvent technology. This technology offers significant benefits compared to other solvent-based processes as it aims to reduce the regeneration energy requirements using novel solvents that are very stable under the coal-fired power plant feed gas conditions. BASF has developed the desired solvent based on the evaluation of a large number of candidates. In addition, long-term small pilot-scale testing of the BASF solvent has been performed on a lignite-fired flue gas. In coordination with BASF, Linde has evaluated a number of options for capital cost reduction in large engineered systems for solvent-based PCC technology. This report provides a summary of the work performed and results from a project supported by the US DOE (DE-FE0007453) for the pilot-scale demonstration of a Linde-BASF PCC technology using coal-fired power plant flue gas at a 1-1.5 MWe scale in Wilsonville, AL at the National Carbon Capture Center (NCCC). Following a project kick-off meeting in November 2011 and the conclusion of pilot plant design and engineering in February 2013, mechanical completion of the pilot plant was achieved in July 2014, and final commissioning activities were completed to enable start-up of operations in January 2015. Parametric tests were performed from January to December 2015 to determine optimal test conditions and evaluate process performance over a variety of operation parameters. A long-duration 1500-hour continuous test campaign was performed from May to August 2016 at a selected process condition to evaluate process performance and solvent stability over a longer period similar to how the process would operate as a continuously running large-scale PCC plant. The pilot plant integrated a number of unique features of the Linde-BASF technology aimed at lowering overall energy consumption and capital costs. During the overall test period including startup, parametric testing and long-duration testing, the pilot plant was operated for a total of 6,764 hours out of which testing with flue gas was performed for 4,109 hours. The pilot plant testing demonstrated all of the performance targets including CO 2 capture rate exceeding 90%, CO 2 purity exceeding 99.9 mol% (dry), flue gas processing capacity up to 15,500 lbs/hr (equivalent to 1.5 MWe capacity slipstream), regeneration energy as low as 2.7 GJ/tonne CO 2 , and regenerator operating pressure up to 3.4 bara. Excellent solvent stability performance data was measured and verified by Linde and BASF during both test campaigns. In addition to process data, significant operational learnings were gained from pilot tests that will contribute greatly to the commercial success of PCC. Based on a thorough techno-economic assessment (TEA) of the Linde-BASF PCC process integrated with a 550 MWe supercritical coal-fired power plant, the net efficiency of the integrated power plant with CO 2 capture is increased from 28.4% with the DOE/NETL Case 12 reference to 30.9% with the Linde-BASF PCC plant previously presented utilizing the BASF OASE® blue solvent [Ref. 4], and is further increased to 31.4% using a Linde-BASF PCC plant with BASF OASE® blue solvent and an advanced stripper interstage heater (SIH) configuration. The Linde-BASF PCC plant incorporating the BASF OASE® blue solvent also results in significantly lower overall capital costs, thereby reducing the cost of electricity (COE) and cost of CO 2 captured from $147.25/MWh and $56.49/MT CO 2 , respectively, for the reference DOE/NETL Case 12 plant, to $128.49/MWh and $41.85/MT CO2 for process case LB1, respectively, and $126.65/MWh and $40.66/MT CO 2 for process case SIH, respectively. With additional innovative Linde-BASF PCC process configuration improvements, the COE and cost of CO 2 captured can be further reduced to $125.51/MWh and $39.90/MT CO 2 for a further optimized PCC process defined as LB1-CREB. Most notably, the Linde-BASF process options assessed have already demonstrated the potential to lower the cost of CO 2 captured below the DOE target of $40/MT CO 2 at the 550 MWe scale for second generation PCC technologies. Project organization, structure, goals, tasks, accomplishments, process criteria and milestones will be presented in this report along with highlights and key results from parametric and long-duration testing of the Linde-BASF PCC pilot. The parametric and long-duration testing campaigns were aimed at validating the performance of the PCC technology against targets determined from a preliminary techno-economic assessment. The stability of the solvent with extended operation in a realistic power plant setting was measured with performance verified. Additionally, general solvent classification information, process operating conditions, normalized solvent performance data, solvent stability test results, flue gas conditions data, CO 2 purity data in the gaseous product stream, steam requirements and process flow diagrams, and updated process economic data for a scaled-up 550 MWe supercritical power plant with CO 2 capture are presented and discussed in this report.

20 FOSSIL-FUELED POWER PLANTS↗

DOE OSTI2017

SNL/JAEA Collaborations on Sodium Fire Benchmarking.

Two sodium spray fire experiments performed by Sandia National Laboratories (SNL) were used for a code - to - code comparison between CONTAIN - LMR and SPHINCS. Both computer codes are used for modeling sodium accidents in sodium fast reactors. The comparison between the two codes provides insights into the ability of both codes to model sodium spray fires. The SNL T3 and T4 experiments are 20 kg sodium spray fires with sodium spray temperature s of 200 deg C and 500 deg C, respe ctively. Given the relatively low sodium temperature in the SNL T3 experiment, the sodium spray experienced a period of non - combustion. The vessel in the SNL T4 experiment experienced a rapid pressurization that caused of the instrumentation ports to fail during the sodium spray. Despite these unforeseen difficulties, both codes were shown in good agreement with the experiment s . The subsequent pool fire that develops from the unburned sodium spray is a significant characteristic of the T3 experiment. SPHIN CS showed better long - term agreement with the SNL T3 experiment than CONTAIN - LMR. The unexpected port failure during the SNL T4 experiment presented modelling challenges. The time at which the port failure occurred is unknown, but is believed to have occur red at about 11 seconds into the sodium spray fire. The sensitivity analysis for the SNL T4 experiment shows that with a port failure, the sodium spray fire can still maintain elevated pressures during the spray.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2018

Human Health Risk Assessment Methods for PV, Part 1: Fire Risks

The photovoltaic (PV) industry has experienced rapid growth in recent years due in part to the development of public policies to address climate change and energy security. Some industry stakeholders have expressed concerns regarding potential human inhalation exposure to hazardous materials should a PV module array be exposed to fire, particularly in a residential or commercial rooftop application. To evaluate these concerns, fire hazard analysis methods are presented that can estimate emissions that may occur when PV modules (hereafter mostly referred to simply as 'modules') are exposed to fire, estimate the associated chemical concentrations in ambient air downwind from the fire, and finally compare these exposure-point concentrations to health-protective screening levels. Specifically, this report presents an analysis of potential human health impacts associated with chemical release from modules during a building fire for three PV technologies, focusing on airborne release of the highest-prioritized chemical element for each: Pb content in crystalline-silicon (c-Si) modules, Cd content in thin film cadmium telluride (CdTe) modules, and Se content in thin film copper indium selenide (CIS) modules. The intent of this analysis is to demonstrate the application of the proposed methods for modules exposed to fire in a quantitative yet illustrative manner. In particular, this report quantifies what are expected to be the worst-case potential health impacts over a wide range of possible conditions, including building/fire size, downwind receptor location, exposure duration, and meteorological conditions, utilizing a Gaussian plume modeling approach that is typically used in regulatory contexts.

14 SOLAR ENERGY↗

DOE OSTI2019

AOI2 - Initial Engineering, Testing, and Design of a Commercial-Scale Postcombustion CO 2 Capture System on an Existing Coal-Fired Generating Unit (Project Carbon)

The continued long-term use of North Dakota lignite is likely dependent on creating a business case for carbon capture, utilization, and storage (CCUS) that also addresses society’s desire to reduce carbon emissions. CCUS coupled with enhanced oil recovery appears to be the most feasible option for utilities to sustain and grow the lignite industry. Establishing a market where lignite-powered utilities provide carbon dioxide (CO 2 ) to oil producers depends upon having a cost-effective method to capture CO 2 . The application of CO 2 capture technology to lignite-fired flue gas has challenges in addition to the cost of capture, including the effects of the buildup of heat-stable salts, aerosol formation, degradation of solvents or solid sorbents, or subsequent solvent loss. Lignite, especially North Dakota lignite, presents its own set of challenges that include the combination of high sodium, sulfur, and ash contents; NO x reduction; and footprint limitations. Project Carbon was designed to address these technical barriers and provide pre-FEED (preliminary front-end engineering and design) information necessary for additional commercial demonstrations to move forward. A long-term pilot-scale evaluation of Mitsubishi Heavy Industries’ (MHI’s) KS-1™ solvent at Minnkota Power Cooperative’s lignite-fired Milton R. Young Station Unit 2 (MRY2) was a major objective of the project. The purpose of the test was to demonstrate the technology’s compatibility with MRY2’s flue gas over an extended period of time. During the long-term test, aerosol sampling and measurement were performed, and a pilot-scale baghouse was tested to determine the effect of bag material and operation on aerosol concentrations in the flue gas. Project engineering and design work were performed to support the other major project objective: a pre-FEED study of CO 2 capture at MRY2. Finally, a techno-economic assessment (TEA) of the application of CO 2 capture to MRY2 was performed. This project was performed over a period of 28 months, with a total budget of $12,700,000. The U.S. Department of Energy’s (DOE’s) National Energy Technology Laboratory, through the Energy & Environmental Research Center’s (EERC’s) Cooperative Agreement, the North Dakota Industrial Commission, and industry partners ALLETE and Minnkota Power Cooperative, funded the project. The pilot-scale test system at MRY2 performed very well for the continuous test period of 83 days. The CO 2 capture plant achieved stable operation while utilizing MHI’s KS-1™ solvent and the MHI amine emission reduction unit. No major concerns were encountered when capturing CO 2 from lignite-fired flue gas. Challenges were encountered because the cooling water temperature was warmer than needed for the capture system to operate efficiently. This affected the ability of the solvent to capture CO 2 and promoted solvent loss through solvent entrainment caused by high CO 2 gas temperature within a cyclone separator. The KS-1™ solvent and the lignite-derived flue gas were analyzed during the long-term test. Analysis of the solvent indicates that, although some metals and heat-stable salts increased over the course of the long-term test, they were at levels that can be treated with filtration and reclaiming and do not pose a concern for effective solvent operation. Fourier transform infrared (FTIR) spectrometry was successfully used to determine the composition of the lignite-derived flue gas as well as concentrations of select components of the flue gas at various locations within the EERC’s CO 2 capture system. The formation of aerosols during the capture process is of interest, as are approaches for their reduction, especially in a baghouse. Testing of aerosol removal was performed using the EERC’s portable baghouse. It was found that both Ryton and polytetrafluoroethylene (PTFE) membrane bags were effective at reducing the level of aerosols during steady-state operation. During backpulse events, however, the amount of aerosols passing through the bags was an order of magnitude lower for the Ryton bags than the PTFE membrane bags. The testing showed that proper design of the baghouse air-to-cloth ratio as well as minimization of backpulsing can dramatically reduce the amount of aerosols that pass through the bags and remain in the flue gas stream exiting a baghouse system. A technology maturation plan (TMP) was performed to enable successful development of the Kansai Mitsubishi Carbon Dioxide Recovery® (KM CDR®) Process for application to a combustion flue gas for which the process has not yet been demonstrated. In the TMP, new challenges to the MHI CO 2 capture technology during its application to MRY2 were identified. These challenges included capture from lignite-fired (as opposed to subbituminous coal-fired) flue gas, a larger scope than previous applications of the technology, and implementation in a colder climate that could affect process and equipment operability. Because MRY2 is located where stack icing in the winter could be problematic, a rime icing study was performed. Rime icing modeling indicated that, under both 100% and 50% operating loads, there is a potential for many icing events during any given part of the year in which below-freezing weather conditions exist. The models showed that a critical amount of rime ice could be formed at the stack top during two or more events per year. CO 2 capture plant stack height and location will need to be determined in order to minimize the formation of rime ice. It was found that the integration of the MHI CO 2 capture process into the normal operation of the MRY2 steam turbine is a viable alternative to a cogeneration facility to provide steam and power for the carbon capture facility. The research performed under this project showed that CO 2 capture at a lignite-fired power plant can successfully be performed. No known fatal flaws that would prevent the continued development of the MRY2 CO 2 capture facility were identified during the pre-FEED study. A TEA performed following DOE methodology shows that applying capture technology to MRY2 may not only meet but exceed the DOE-recognized state-of-the-art baseline.

20 FOSSIL-FUELED POWER PLANTS↗

DOE OSTI2019

Guidance on the Evaluation of Models for LNG fires

This report provides datasets that can be used to validate models for Liquefied Natural Gas ( LNG ) fires, specifically those used to predict the thermal hazards from various types of fires from accidents involving LNG at land-based facilities. The datasets presented include pool fires, trench fires, jet fires, fireballs, and vapor cloud fires. Recommendations are provided regarding the method of quantification and the presentation of information for reporting the comparison.

03 NATURAL GAS↗

DOE OSTI2019

Pipe Overpack Container Fire Testing: Phase II-B

The Pipe Overpack Container (POC) was developed at Rocky Flats to transport plutonium residues with higher levels of plutonium than standard transuranic (TRU) waste to the Waste Isolation Pilot Plant (WIPP) for disposal. In 1996 Sandia National Laboratories (SNL) conducted a series of tests to determine the degree of protection POCs provided during storage accident events. One of these tests exposed four of the POCs to a 30-minute engulfing pool fire. This test resulted in one of the POCs generating sufficient internal pressure to pop off its drum lid and expose the top of the pipe container (PC) to the fire environment. The initial contents of the POCs were inert materials that would not generate large internal pressure within the PC if heated. However, POCs are now being used to store combustible Transuranic (TRU) waste at Department of Energy (DOE) sites. At the request of DOE's Office of Environmental Management (EM) and National Nuclear Security Administration (NNSA), SNL started conducting a new series of fire tests in 2015 to examine whether PCs with combustibles would reach a temperature that could result in: (1) decomposition of inner contents and (2) subsequent generation of sufficient gas to cause the PC to over-pressurize and release its inner contents. In 2016, Phase II of the tests showed that POCs tested in a pool fire failed within 3 minutes of ignition with the POC lid ejecting. These POC lids were fitted with a NUCFIL-019DS filter and revealed that this specific filter did not relieve sufficient pressure to prevent lid ejection. In the Fall of 2017, Phase II-A was conducted to expose POCs to a 30-minute pool fire with similar configurations to those tested in Phase II, except that the POC lids were fitted with an UltraTech (UT) 9424S filter instead. That specific filter was chosen because of its design to help relieve internal pressure during the fire and thus prevent lid ejection. In Phase II-A, however, setups of two POCs stacked upon one another were never tested, which led to this phase of tests, Phase II-B. This report will describe the various tests conducted in Phase II-B, present results from these tests, and implications for the POCs based on the test results will be discussed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2021

Development of a Nitrogen and Magnesium Oxide based Class A, B & D Suffocating Fire System (SFSS) for Gloveboxes

Testing related to the development and performance of a “Proof of Concept” Nitrogen/Magnesium Oxide Suffocating Fire System (SFSS) was conducted at Fire and Pump Service Group (FPSG) located in Rancho Dominguez, California. The SFSS Engineering Team (SFSSET), consisting of FPSG and Los Alamos National Laboratory (LANL) personnel researched, developed a prototype, and conducted testing to determine effective means to deliver magnesium oxide (MgO) sand into a glovebox (GB) in a class D fire event. The prototypes development also established the effective coverage area of a magnesium oxide suppression system as well as demonstrated that the GB inert atmosphere could be maintained during and after the release of the MgO sand to control Class A, B and D fires. Previous testing conducted on nitrogen based SFSS provided evidence that the nitrogen based SFSS controlled Class A and B fires (Ralph Clayton, Los Alamos National Laboratory, Brandon Troc and Frank Broidy, Fire and Pump Service Group 2020).Final testing was conducted within a mock GB capable of simulating an inert glovebox atmosphere. Testing demonstrated that the inert atmosphere can be maintained during and after discharge of the MgO sand over a coverage area.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2024

Test and Validate Distributed Coaxial Cable Sensors for in situ Condition Monitoring of Coal-Fired Boiler Tubes

This project aims to test, validate, and advance the technology readiness level (from TRL5 to TRL7) of a novel low-cost distributed stainless-steel/ceramic coaxial cable sensing (SSC-CCS) technology for in situ monitoring of the boiler tube temperature in existing coal-fired power plants. The novel SSC-CCS sensing technology and associated condition-based monitoring (CBM) software to be demonstrated in this project will lead to an improved understanding of the boiler tube failure mechanisms and a prognostic system to improve the overall performance, reliability, and flexibility of the nation’s coal-fired power plant fleet. A boiler tube monitoring system with distributed coaxial cable temperature sensors and a sensor acquisition system was constructed. The high-temperature coaxial cable sensor with a length of 1.3m was made by using a quartz tube (1mm inner diameter (ID) and 6mm outer diameter (OD)) to concentrically separate a 304 stainless-steel (SS) rod (1mm OD) and SS tube (7.94mm OD and 6.16mm ID). The sensor acquisition system includes a vector network analyzer (VNA), a radio frequency (RF) power amplifier, multiple switches and a USB hub. The distributed stainless-steel quartz coaxial cable sensor (SSQ-CCS) had a linear response to temperature with a resolution uncertainty of σ = 0.77℃. To withstand the harsh conditions of 3,300 steam pressures and 800℃ high temperatures, the sensor was shielded by a protective tube made of the same material as the boiler tube. The protection tube had an OD of 1.5 inches and a thickness of 0.25 inches. In the laboratory tests, the sensor showed good sensitivity and fast response. The drift was bounded between +0.33% and -0.67% during a test at 600℃ for 350 hours, indicating good stability of the sensor. A field test was conducted where four sensors were welded on four superheat tubes (SH-Ts) at a coal-fired power station over 400 days. Conventional thermocouples were welded to the superheater tubes alongside the coaxial cable sensors for the purpose of comparison. Two sensors were capable of distributed sensing, with three multiplexed sensing sections. The other two sensors were single section. During the 400-day test period, the power plant experienced startups and shutdowns. At the steady state operations, the temperature of the boiler tube is about 600℃ (1112°F). The sensors recorded the entire coal-firing processes (start-up, steady state, and shut-down) and the glitch event. A GSM modem and a Watchdog were added to the system to ensure reliable data recording. The GSM modem sent daily messages to plant managers and Clemson team to inform the status of the sensor system. If the system was not normally working, the Watchdog would reboot the system automatically. The new coaxial cable based distributed sensing technology has been proven to be successful in both laboratory and field tests. A comprehensive four-stage multi-physics computational framework has been developed to assist the design, optimization, installation, and operation of SSQ-CCS. With the consideration of various operation conditions, we predict the distributions of flue gas temperatures within coal-fired boilers, the temperature correlation between the boiler tube and SSQ-CCS, and the safety of SSQ-CCS. A conditional-based monitoring system is implemented as well. The computational framework developed in this work can guide the future operation of coal-fired plants and other power plants for the safety prediction of boiler operations.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2025

Dissection of Carbon and Nitrogen Cycling in Post-Fire Soil Environments using a Genome- Informed Experimental Community (Final Technical Report)

Wildfires are a natural part of many forest ecosystems, with globally important carbon (C) storage and nutrient cycling consequences, and they are increasing in frequency and severity in Western North America. Forest fires affect soil C stocks in complex ways; some C is released into the atmosphere through combustion, while a large percentage of the C is added to the soil in the form of pyrogenic organic matter. Worldwide, it is estimated that 16% of soil organic matter is pyrogenic, while locally, this number may be as high as 80%. Understanding how wildfires affect soil organic matter cycling requires understanding how microbes respond to pyrogenic organic matter and other post-fire soil conditions. However, our understanding of microbial interactions within post-fire soil was in its infancy at the time of our proposal. Outstanding questions included: Which microbes are capable of degrading pyrogenic organic matter? What are the relevant genes and metabolites associated with this degradation? What are the key interactions among post-fire microbes? Key highlights of outcomes supported by this grant included training eleven early-career scientists and two early-career PIs, publication of twelve peer-reviewed papers, cross-lab collaborations that empowered complex scientific approaches, the development of an open-source automated gas sampler to drive novel insights in C cycling, enhanced understanding of post-fire microbial community dynamics, and novel genetic and molecular insights into microbial responses to fire.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Hanford Site Post-Fire Vegetation Monitoring Report for Calendar Year 2022

The Hanford Site is comprised of an expanse of shrub-steppe habitats that provide exceptional value to plants and animals located on the Site and in the surrounding greater Columbia Basin. The greatest threat to this habitat is fire-related conversion to a cheatgrass-dominated monoculture. In order to decrease future fire risk and to disrupt the positive feedback cycle between cheatgrass and fire, land managers can make efforts to restore native vegetation following a fire. The goal of this report is to analyze vegetation recovery post-fire in both restored and unrestored areas to inform future post-fire response actions.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2021

Hanford Site Post-Fire Vegetation Monitoring Report for Calendar Year 2021

The Hanford Site presents an expanse of shrub-steppe habitat that provides exceptional value to plants and animals located on the Site and in the surrounding greater Columbia Basin. The greatest threat to this habitat is fire-related conversion to a cheatgrass-dominated monoculture. In order to decrease future fire risk and to disrupt the positive feedback cycle between cheatgrass and fire, land managers can make efforts to restore native vegetation following a fire. The goal of this report is to analyze vegetation recovery post-fire in both restored and unrestored areas to inform future post-fire response actions.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Eucalyptus Are Unlikely to Escape Plantations and Invade Surrounding Forests Managed with Prescribed Fire in Southeastern US

Woody biomass production can increase through establishment of non-native tree species exhibiting greater growth potential than traditional native species. Interest in growing Eucalyptus in the southeastern US has raised concern over its potential spread and invasion, which could impact ecosystem properties and functions. Within the matrix of land use where Eucalyptus establishment is being considered in the southeastern US, surrounding pine forests managed with fire represent a likely pathway for invasion. We used greenhouse and field experiments to evaluate the potential invasion risk of Eucalyptus benthamii. We were specifically interested in determining if seeds could successfully germinate in fire-maintained pine forests and if fire-return intervals influenced germination through impacts on litter accumulation and light availability. The greenhouse experiment investigated the influence of light availability on germination success, whereas the field study investigated the influence of time since fire, and thus litter accumulation and light availability, on germination success. Percent germination was similar under non-shaded controls and moderate shade, but complete shade resulted in low germination rates. Germination was lower in the field compared to the greenhouse and was influenced by litter and light availability, which varied according to fire-return intervals. Litter increased, and light availability decreased, with time since burn. Germination was negatively related to litter depth and positively related to light availability, thereby decreasing with time since fire. Germination increased with litter removal but remained positively related to light availability after litter removal. Higher germination with litter removal suggests germination is influenced by litter, but higher germination with increased light availability, regardless of raking, suggests germination is also influenced by light availability. Despite these relationships, no seedlings persisted through the growing season. The low germination rates under a variety of field conditions coupled with the lack of persistence suggests establishment may be unlikely, regardless of the surrounding land matrix.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2016

Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires

Abstract. Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These “fire aerosols” can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5). Emissions of fire aerosols exert a global mean net radiative effect of −1.0 W m−2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect is particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (−0.2 W m−2). Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (−1.2 W m−2), while over Boreal Asia the overestimation is +43 % (−1.9 W m−2). The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.

54 ENVIRONMENTAL SCIENCES↗