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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Development of dispensing hardware for safe fueling of heavy duty vehicles

The development of safe dispensing equipment for the fueling of heavy duty (HD) vehicles is critical to the expansion of this newly and quickly expanding market. This paper discusses the development of a HD dispenser and nozzles assembly (nozzle, hose, breakaway) for these new, larger vehicles where flow rates are more than double compared to light duty (LD) vehicles. This equipment must operate at nominal pressures of 700 bar, -40o C gas temperature, and average flow rate of 5-10 kg/min at a high throughput commercial hydrogen fueling station without leaking hydrogen. The project surveyed HD vehicle manufacturers, station developers, and component suppliers to determine the basic specifications of the dispensing equipment and nozzle assembly. The team also examined existing codes and standards to determine necessary changes to accommodate HD components. From this information, the team developed a set of specifications which will be used to design the dispensing equipment. In order to meet these goals, the team performed computational fluid dynamic, pressure modelling, and temperature analysis in order to determine the necessary parameters to meet existing safety standards modified for HD fueling. The team also considered user, operational, and maintenance requirements, such as freeze lock which has been an issue which prevents the removal of the nozzle from LD vehicles. The team also performed a failure mode and effects analysis (FMEA) to identify the possible failures in the design. The dispenser and nozzle assembly will be tested separately, and then installed on an innovative, HD fueling station which will use a HD vehicle simulator to test the entire system.

08 HYDROGEN↗
DOE OSTI2023

Nuclear Criticality Safety Pipeline Course with Hands-On Experimental Training at Lawrence Livermore's Inherently Safe Subcritical Assembly Training Center

The Nuclear Criticality Safety Divisions at Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL) have partnered with Prof. Massimiliano Fratoni of the University of California Berkeley to offer a semester long course on nuclear criticality safety. This course is part of a larger pipeline project among many of the Department of Energy (DOE) laboratories designed to stimulate student interest in the field of criticality safety. The course focuses on teaching the fundamentals of criticality safety, familiarity with national and consensus standards, and preparing criticality safety evaluations. Students also receive hands-on experience with special nuclear material by performing experiments with the Inherently Safe Subcritical Assembly (ISSA) at LLNL. Guest lectures are taught remotely and in-person by criticality safety engineers at LLNL and LANL, giving students an opportunity to interact with professionals in the field. The students complete a semester long project involving developing and writing a criticality safety evaluation. As universities tend to focus heavily on nuclear power and advanced nuclear reactor design, this course gives students a better understanding and perspective of what criticality safety entails. The goal of this pipeline course is to introduce students to criticality safety as another available field for nuclear engineers. It is also a way for criticality safety programs to identify talented students who have the interest and aptitude to work in criticality safety for hire upon graduation. LLNL and LANL have both hosted past students as summer students, participated in student's graduate projects, and hired students as criticality safety engineers. This has provided a unique opportunity for criticality safety programs to spot young talent with better retention outcomes.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

There Are Safe Limits for Radioactivity - Does WIPP Need to Filter its Exhaust Air? - 17165

Pilot Plant (WIPP) underground repository resulted in the release of americium and plutonium (mostly {sup 241}Am) into the environment and contaminated portions of the repository, primarily along the ventilation path from the location of the incident. The WIPP uses a ventilation system to ensure that underground air is circulated through the repository and to ensure that air quality conditions are safe for the workers. Since the air in the repository exits to the surface through an exhaust shaft, this shaft is the sole potential pathway for airborne radioactivity release from the repository. During normal operations before the 2014 incident, exhaust air was released to the environment unfiltered, with an automatic switch to filtration when airborne radioactivity was detected immediately down-stream from the active waste disposal operation. However, since the radiation release event, the WIPP ventilation system has been, and will likely remain in what is called 'filtration mode,' (i.e., exhaust air is routed through a HEPA filter system). Redirection of the ventilation system through the HEPA (High Efficiency Particulate Air) filter system was necessary at the peak of the radiation release event to protect aboveground workers at the site and the public in the surrounding areas; however, it has hampered recovery efforts and has exacerbated the inherent safety issues of working underground. As a component of the Carlsbad Environmental Monitoring and Research Center's (CEMRC) WIPP environmental monitoring program, airborne radioactivity samples are collected daily in the exhaust shaft ventilation air as it reaches the surface, and before entering the HEPA filters. Since June 2014, airborne radiation levels entering the HEPA filters have averaged about 1% of a derived air concentration (DAC) for {sup 241}Am. An airborne radioactivity level of one DAC is equivalent to a potential worker internal dose exposure of 50 mSv per work year, if a worker were continuously exposed for a full work year (2000 hours). During Project Reach and throughout decontamination campaigns conducted in Panel 7 for several months in 2015, these unfiltered levels rose to 3-5% of a DAC, with a one week spike reaching almost one DAC in June 2015, during decontamination of the most heavily contaminated exhaust drift in Panel 7. Since that period, the unfiltered levels have never exceeded 2% of a DAC. Going forward, the question is, should WIPP resume unfiltered discharge of its underground ventilation air? Evaluation of more than two years of underground ventilation sampling data indicates that residual radioactivity levels in the underground no longer warrant HEPA filtration in order to meet either worker or environmental protection criteria. In terms of radiological risk at or in the vicinity of the WIPP site, the increased risk from resuming unfiltered ventilation is exceedingly small and would not result in a hypothetical dose to a member of the public in excess of the 100 micro Sv per year limit for periodic confirmatory sampling as required for operating repositories by the Environmental Protection Agency (40 CFR 191). In addition, the requirement for respiratory protection for workers underground exposed to 1-2% of a DAC is questionable, given the added industrial safety risk of heavy equipment operation while wearing respirators. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Proposal of a Categorization of the Disused Sealed Radioactive Sources with a View to Safe - 17285

In the Nuclear and Energy Research Institute (IPEN-CNEN/Brazil) many works to improve and develop characterization of radioactive waste techniques have been deployed by the Radioactive Waste Management Department (IPEN-CNEN/SP). In this line, this work aims to suggest a new categorization of sealed sources, which considers their activities, as suggested by the International Atomic Energy Agency (IAEA), but also the time required for the activity to decrease to a safe value. We considered the sealed sources categorization system suggested by the IAEA and we applied such categorization system to various sources currently stored by institutes of Brazilian Nuclear and Energy Commission (CNEN). Then, we also applied the categorization system defined herein, it follows that the categorization system presented by the IAEA has many applications and their use should not be abandoned. However, since the new proposed categorization systems allow to differentiate sources that in the IAEA system are in the same category, they can help define the long-term management of radioactive waste. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Progression of Safe and Compliant Demolition of Hanford's Plutonium Finishing Plant - 16566

Department of Energy contractor CH2M HILL Plateau Remediation Company (CH2M) is about to begin demolition of the Plutonium Finishing Plant (PFP). The facility is located on the Hanford Site and produced plutonium metal during the Cold War. Production was stopped in 1988, the facility was formally shut-down in 1996 and material processing completed in 2004. The project team, partnering with DOE-Richland Operations Office (DOE-RL), is in the final stages of preparing to demolish the building by the Tri-Party Agreement Milestone date of September 30, 2016. Since 2008, employees have prepared approximately 85 percent of the building for demolition. All of the 52 pencil-shaped processing tanks and 95 percent of the 238 glove boxes have been removed. Work is progressing on dispositioning remaining glove boxes, filter boxes and ventilation ducts and chemical and drain lines. Demolition is scheduled to start in early 2016. In addition to wrapping up tasks like source term removal (or preparation for removal during pre-demolition) and decontamination, the project is also developing the strategy and process to perform physical open air demolition, including the use of 3D renderings and computer generated illustrations of building infrastructure to safely and compliantly demolish the building. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Safely Managing CNL's Shutdown Prototype Power Reactors - 30 years of Experience - 19157

Canadian Nuclear Laboratories (CNL) has over 30 years of experience managing three prototype power reactors from shutdown through storage with surveillance and into preparation from final decommissioning. CNL is responsible for the safe storage with surveillance of three prototype power reactors; Nuclear Power Demonstration (NPD), Gentilly-1(G1) and Douglas Point (DP). Each of the Canadian prototype power reactor sites have been maintained using different post shutdown management strategies, which were based on the site location, configuration, and intended designation of the respective sites. This paper will discuss the post shutdown strategies employed at the three sites, including details of their shutdown strategy, current conditions, and experience gained from the period of storage with surveillance. (author)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

The Role of Indian Tribes in the Safe, Secure, and Routine Transportation of Spent Nuclear Fuel and High-Level Radioactive Waste - 19463

Far too often federally recognized Indian Tribes are the last stakeholders invited to the table to discuss a particular issue with potentially wide-ranging impacts. Indian tribes were the first governments on this continent. With respect to the future transportation of spent nuclear fuel (SNF) or high-level radioactive waste (HLW), Indian tribes are potentially impacted in a myriad of ways: economics, cultural, environmental, health and safety. Yet few regulators fully understand and appreciate the legal and political standing of Indian tribes. This paper will examine the ways in which Indian tribes must be involved with the planning for safe, secure and routine SNF and HLW shipments and the ways in which the federal government is obligated to involve tribes. Indian tribes are similar to states in that they are responsible for the health and safety of its members (which they themselves define). Tribes, like states, make, implement, interpret, and enforce laws, and provide public services - healthcare, public education, social services, drug treatment, public safety and emergency management, transportation, managing natural resources, public housing, and environmental and cultural preservation. Many tribes also operate economic enterprises - manufacturing, farming, forestry, and gaming. The most basic principle of Indian law is the principle of 'sovereignty,' that is, an Indian tribe possesses all the powers of any sovereign state. Tribal governments are not subject to state or local jurisdiction but are subject to federal jurisdiction. The tribes enjoy a government-to-government relationship (and expectation) with the federal government (i.e., agencies, like the Department of Energy, the Nuclear Regulatory Commission). Of paramount concern to Indian tribes is the doctrine of Trust Responsibility, the general principle that the federal government's conduct 'in dealing with the Indians should therefore be judged by the most exacting fiduciary standards.' With respect to SNF/HLW this means that the federal government has an obligation (or a Trust Responsibility) to ensure that tribal people, lands and resources are protected. Equally important is the expectation that federal agencies will work with the Indian tribes on a government-to-government basis before undertaking any action with potential negative consequences on the tribe's people, land or resources. The concept of government-to-government consultation between Indian tribes and the United States is long standing and well recognized. As expressed in Executive Order 13175, 'Consultation and Coordination with Indian Tribal Governments': 'Consultation - Each federal agency must have an accountable process to ensure meaningful and timely input by tribal officials in the development of regulatory policies that have tribal implications.' The purpose of consultation is to ensure that Indian tribes are consulted before government officials make decisions that may have an impact on their lives and territories. The three agencies involved with SNF and HLW transportation - the US Department of Transportation (DOT), the US Nuclear Regulatory Commission (NRC), and the US Department of Energy (DOE) - have had various degrees of success with respect to direct consultation with Indian tribes. Given that there is plenty of lead-time before the first shipments commence, there should be ample time to develop a strategy for ensuring that tribes are equal partners when planning and preparing for shipments of SNF and HLW to the first interim storage facility. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

A Simplified Multi-Path Event Tree for the Integral, Inherently-Safe Light Water Reactor (I{sup 2}S-LWR)

The Integral, Inherently-Safe Light Water Reactor (I{sup 2}S-LWR) concept aims to raise the bar for nuclear power plant safety while maintaining the economic advantages of large, gigawatt-scale plants.1 To obtain this goal, the project safety team seeks to eliminate initiating events where possible, maximize passivity of safety systems, and optimize a balance of redundancy, diversity, and simplicity of safety systems.2 Achievement of these objectives, particularly the last set, requires detailed, quantitative risk information from the earliest stages of development. Therefore, despite limited design information, we have constructed a preliminary probabilistic risk assessment (PRA) for I{sup 2}S-LWR. Safety implementation for I{sup 2}S-LWR, then, requires an iterative process involving system design, thermal-hydraulic (T/H) and neutronic deterministic analyses, and risk-informing PRA studies. Due to this parallelism, it is vital those team members without PRA expertise quickly and correctly understand preliminary PRA results. To this end, we have developed a method to condense the entire PRA into a single, multi-path event tree (MPET). (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Criticality hazard identification technique for development of safe operating limits and restrictions - 14367

Canadian Nuclear Laboratories' (CNL) National Research Universal (NRU) reactor located at Chalk River Laboratories (CRL) first attained criticality in 1957. Outside of the reactor core, the safe handling and storage of fissile material including experimental fuel components is required to support NRU's ongoing missions of research and medical isotope production [1]. Management of this fissionable material relies heavily on experienced operating staff, who perform work in accordance with a defined set of limits and restrictions as laid out in a Criticality Safety Document (CSD). Historically, the development of CSDs has relied heavily upon criticality safety analysts to gain sufficient knowledge about the facility. This has resulted in significant labor costs due to heavy use of computational methods. This paper describes a new approach for CNL to identify potential criticality scenarios, a 'Criticality Hazard Identification' (CHI) technique, developed from traditional process-oriented hazard and operability analysis, to identify and define operating conditions, identify limits and restrictions for the handling of fissionable materials outside of the core. The approach permits thorough evaluation of potential criticality hazards, for both well-understood historical and proposed future activities, by better leveraging the knowledge of operations personnel as well as other subject matter experts. The resulting document provides a detailed record of the various scenarios that were considered. These improvements to the CSD development and documentation process provide an additional benefit in terms of ease of modification to include new or changed activities within the limits and conditions. (authors)

42 ENGINEERING↗
DOE OSTI2015

Safe solution dissolution of high flux isotope reactor cores - 14490

The H-Canyon facility at the Savannah River Site is the U.S.A.'s only remaining full-scale chemical separations plant. H-Canyon maintains the capacity to safely and efficiently disposition a large inventory of excess nuclear material from across the Department of Energy (DOE) complex and used nuclear fuel from foreign and domestic research reactors. One such fuel that H-Canyon may dissolve is cores from the High Flux Isotope Reactor (HFIR). By employing realistic analysis, the need for administrative controls was eliminated. A new criticality modeling approach has eliminated the need for administrative controls for HFIR dissolution operations in H-Canyon. The primary upsets of concern are an over-mass event and an overconcentration event. Several initiating events were considered for each type of upset. Over-concentration events were deemed to be not credible by taking credit for the chemistry of acid consumption, i.e. there are not enough moles of acid to dissolve enough moles of uranium in order to reach a critical configuration. Over-mass events were deemed to be not credible by taking credit for the annular design of the fuel elements. By using realistic analysis, both types of upsets have been shown to be subcritical, and therefore administrative controls are not needed to prevent an inadvertent criticality. In this paper, the new methodology for performing criticality analyses for dissolving HFIR fuel elements will be presented, and the elimination of administrative controls will be discussed. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Safe Operations at Roadway Junctions: Intelligent Roadway Infrastructure as Functional Interlocking

Automated vehicle (AV) technology is quickly maturing, and the corresponding infrastructure systems that evaluate traffic and communicate to vehicles requires sophisticated sensing and perception technologies, referred to as intelligent roadway infrastructure (IRI), to complement emerging AV capabilities. IRI provides signals to vehicles, indicating right-of-way for vehicles and communicating to approaching AVs that no other vehicle is failing to yield. This capability, denoted as safety-affirmative signaling, provides a green light or a green arrow as appropriate and affirms through communication links to connected vehicles when it is safe to proceed. About 36% of collisions occur at intersections, with most occurring upon left turns (22.2%) or crossing over (12.6%), and only a small percentage (1.2%) while turning right at an intersection. Of all intersection crashes about half (52.5%) of those vehicles were traveling through a signalized intersection 2. Safety-affirmative signaling would guarantee safety of AV fleet vehicles, by providing the interlocking principle, a term from automated train control that only allows progression through a railway intersection after affirming no opportunity for a crash exists. IRI through safety-affirmative signaling would bring performance and safety to complex roadway intersections where AV transit fleet service is most needed, as well as safety benefits to traditional, non-automated vehicles and vulnerable road users. The implementation of IRI has functional, programmatic, and technical challenges. Research work performed at the National Renewable Energy Laboratory (NREL) in an integrative approach encapsulating these themes, and termed infrastructure perception and control (IPC) is motivated by improved performance (travel time), improved safety (reduced collisions), and improved energy efficiency (less fuel burned and minimized production of greenhouse gases). IPC is intended not only for roadway and intersection applications but also in extension to inform complementary buildings and grid systems to enable better co-management, as vehicles and their charging needs become increasingly integrated into the built environment. The NREL IPC project presents an open-source framework, architecture, and supporting technology to implement IRI, addressing critical issues such as fusion of data, reliability, standardization of data interfaces, and confidence of detection. The framework is informed by previous experience in U.S. Department of Defense research technology, specifically in the use of radar to detect, identify, and track aerial threats. These principles combined with multi-sensor fusion provides for a complete digital twin with known and measurable confidence and accuracy from which safety-affirmative signaling can be developed and deployed.

ADVANCED PROPULSION SYSTEMS,MATHEMATICS AND COMPUT↗
DOE OSTI2024

Digital Twinning and Predictive Modeling of Traffic for Safe, Efficient, and Reliable Intersections

Over the last decade, the advances in connected and autonomous vehicles (CAVs) have far surpassed the technological realm of transportation infrastructure. There is a growing need to have a technologically commensurate transportation infrastructure to enable safe and reliable movement of goods and people. The recent creation of Advanced Research Projects Agency - Infrastructure (ARPA-I) through the Infrastructure Investment and Jobs Act by the U.S. Department of Transportation (USDOT) has further amplified the need to revolutionize the transportation infrastructure system in the US. This need is perhaps felt most at traffic intersections, as more than 50 percent of the combined total of fatal and injury crashes occur at or near intersections. The proposed concept of Infrastructure Perception and Control (IPC) is aimed at bridging this technological gap by building a real-time digital twin of traffic by fusing detections from sensors installed at the intersection. This digital twin can then empower a wide variety of applications such as smart traffic signals or infrastructure-to-everything (I2X) communications. Smart signaling can help avoid crashes through early-prediction, while I2X can augment the CAV sensors under uncertain driving conditions and provide connected vehicles (CVs) with traffic information they can use to optimize their travel.

connected vehicles↗
DOE OSTI2025

Ensuring Safe, Effective, and Reliable Use of Artificial Intelligence-Based Applications for Nuclear Electricity Generation through a Systems Approach

There is a significant potential to reduce operating and maintenance cost at nuclear power plants using artificial intelligence (AI) and machine learning (ML). For instance, AI/ML has the potential to significant improve work management processes, condition reporting, and plant surveillance activities. However, the nuclear industry has been slow in adopting AI/ML due to several multifaceted barriers discussed in this paper. This work presents such multidisciplinary approach intended to 1) accelerate industry adoption of AI/ML-based applications at nuclear power plants and 2) ensure their safe, reliable, and effective use. This approach is discussed further in this work and will be used to address overarching challenges associated with AI deployment at scale to provide industry guidance that support accelerated adoption of AI/ML technologies throughout the industry.

99 - GENERAL AND MISCELLANEOUS↗
DOE OSTI2024

A safe reinforcement learning algorithm for supervisory control of power plants

Traditional control theory-based methods require tailored engineering for each system and constant fine-tuning. In power plant control, one often needs to obtain a precise representation of the system dynamics and carefully design the control scheme accordingly. Model-free Reinforcement learning (RL) has emerged as a promising solution for control tasks due to its ability to learn from trial-and-error interactions with the environment. It eliminates the need for explicitly modeling the environment’s dynamics, which is potentially inaccurate. However, the direct imposition of state constraints in power plant control raises challenges for standard RL methods. To address this, we propose a chance-constrained RL algorithm based on Proximal Policy Optimization for supervisory control. Our method employs Lagrangian relaxation to convert the constrained optimization problem into an unconstrained objective, where trainable Lagrange multipliers enforce the state constraints. In conclusion, our approach achieves the smallest distance of violation and violation rate in a load-follow maneuver for an advanced Nuclear Power Plant design.

constrained optimization↗
DOE OSTI2025

Levelized cost and carbon intensity of solar hydrogen production via water splitting using a scalable and intrinsically safe photocatalytic Z-scheme raceway system

Generating hydrogen from local energy resources such as solar or wind would unlock a low-carbon energy carrier that could be used to reduce greenhouse gas emissions in sectors such as industry and transportation. Yet, the allocation of new or existing power generation solely to hydrogen production remains contentious due to disputes regarding emissions accounting. Photocatalytic (PC) hydrogen production technologies offer a unique solution, as hydrogen is produced directly from solar energy and water, without the need for electricity generation. However, cost projections for all photocatalytic designs to date have suggested that they are not cost competitive compared to conventional electrolysis systems manufactured at scale. Herein, we offer the first illustrative benchmark of cost and carbon intensity of hydrogen produced in a type 2 “Z-scheme” photocatalytic reactor design, which employs suspended semiconducting nanoconductor particles organized into two stacked volumes in a raceway design. The “Z-scheme” system utilizes two separate photoabsorber particles, tuned to drive either the hydrogen evolution reaction or the oxygen evolution reaction individually, connected via a reversible, charge transfer redox couple in solution. Furthermore, the results suggest a highly competitive and scalable technology, that justifies further experimental validation and prototyping in the field.

Carbon↗