Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “program design”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34

SAS4A/SASSYS-1 Validation with FFTF Tests

The FFTF liquid sodium cooled test reactor was built to assist the development and testing of advanced fuels and material for fast reactors. The goals of the FFTF Passive Safety Testing program included confirming the safety margins of FFTF as a liquid metal reactor, providing data for computer code validation, and demonstrating the inherent and passive safety benefits of its specific design features. The program included thirteen unprotected loss of flow without scram tests. In preparation for the Passive Safety Testing program, a series of individual reactivity feedback tests were performed which were designed to simulate and validate specific features and reactivity feedbacks of the FFTF core.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Moving Beyond Direct Load Control: A Maturity Model for Realizing the Promise of Demand Flexibility

This report discusses a new maturity model that regulators and utilities can use to guide and expand demand flexibility programs and enable the resources to provide more grid services. The model has six demand flexibility categories: planning and design; customer engagement; program operations; evaluation, measurement and verification; distributed energy resource orchestration; and data infrastructure. Within each category, capabilities are identified and described on a maturity scale that ranges from performing below expectations to improving on best practices.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Los Alamos National Laboratory Overview of the SAVY-4000 Design: Abstract Meeting the Challenge for Worker Safety

Incidents involving release of nuclear materials stored in containers of convenience such as food pack cans, slip lid taped cans, paint cans, etc. has resulted in defense board concerns over the lack of prescriptive performance requirements for interim storage of nuclear materials. Los Alamos National Laboratory (LANL) has shared in these incidents and in response proactively moved into developing a performance based storage container design, the SAVY-4000. The SAVY-4000 is the first vented general use nuclear material container demonstrated to meet the requirements of DOE M 441.1-1, Nuclear Material Packaging Manual. The SAVY-4000 is an innovative and creative design demonstrated by the fact that it can be opened and closed in a few seconds without torque wrenches or other tools; has a built-in, fire-rated filter that prevents the build-up of hydrogen gas, yet retains 99.97% of plutonium particulates, and prevents release of material even in a 12 foot drop. Finally, it has been tested to 500C for 2 hours, and will reduce the risk to the public in the event of an earthquake/fire scenario. This will allow major nuclear facilities to credit the container towards source term Material at Risk (MAR) reduction. The container was approved for nuclear material storage in theTA-55 Plutonium Facility on March 15, 2011, and the first order of 79 containers was received at LANL on March 21, 2011. The first four SAVY-4000 containers were packaged with plutonium on August 2, 2011. Key aspects of the SAVY-4000 vented storage container design will be discussed which include design qualification and testing, implementation plan development and status, risk ranking methodology for re-packaging, in use implementation with interface to LANMAS, surveillance strategy, the design life extension program as enhanced by surveillance activities and production status with the intent to extend well beyond the current five year design life.

42 ENGINEERING↗

Advanced Reactor Safeguards Program Roadmap

The Advanced Reactor Safeguards (ARS) program was established in 2020 as part of appropriations for the Advanced Reactor Demonstration Program (ARDP) through the Office of Nuclear Energy in the Department of Energy. The goal of this program is to help address near term challenges that advanced nuclear reactor vendors face in meeting domestic Material Control and Accountancy (MC&A) and Physical Protection System (PPS) requirements for U.S. construction. Existing regulations for safeguards and security, as outlined in the Code of Federal Regulations, were written for large light water reactors, and some of the requirements are not suited to smaller, safer advanced reactor designs. The ARS program seeks to remove roadblocks in the deployment of new and advanced reactors by solving regulatory challenges, reducing safeguards and security costs, and utilizing the latest technologies and approaches for robust plant monitoring and protection. Safeguards and Security by Design (SSBD), or the consideration of safeguards and security requirements early in the design process, is an overarching principle that guides this program. This roadmap discusses the goals of the ARS program, current research, and program plan for the next five years.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Online Lead/Water Heat Exchanger Sensor/System Feasibility-PNNL (Final Report)

On-line structural health corrosion monitoring in advanced lead fast reactor heat exchangers and molten salt reactor heat exchangers is desirable for detecting tube degradation prior to leaks that may allow mixing of heat exchanger fluids or release of radiological contamination beyond the design containment boundary. This program, On-Line Lead/Water Heat Exchanger Sensor/System Feasibility – PNNL 76092, demonstrates feasibility for an ultrasonic torsional wave mode sensor attached to the outside of a long (30.5-m) heat exchanger tube in the stagnant flow area where the tube joins a heat exchanger plenum and where it is possible to protect a sensor and cable from high-force flows. The sensor must be cable connected to a monitoring instrument near the heat exchanger. The sensor and cable management approach for periodic in-service inspection will be impractical to implement on existing heat exchangers; rather permanently mounted sensors must be installed in conjunction with heat exchanger fabrication. Previous work has shown low-temperature lead zirconate titanate (PZT) piezoceramic sensors are able to detect anomalies of interest in 3.0-m long tubes. These sensors have hereby been extended to a 30.5-m long tube more representative of commercial power heat exchanger designs. The program will continue to investigate higher temperature piezoelectric ceramics and long-term performance of high temperature adhesives and sealants and mechanical pressure coupling for 350-500 °C lead reactor environments and higher temperature (700 °C) molten salt environments.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

B341 MoMs Hydraulic System Design & Installation

This Statement of Work Document outlines the program equipment siting requirements for Building 341 to be installed at Lawrence Livermore National Laboratory (LLNL). The Subcontractor, who will be designing and installing B341 programmatic equipment hydraulic system, will be expected to provide engineering and construction support from procurement through installation. This scope of work includes the following: a) Walkdown and survey existing condition of Mechanics of Material (MoMs) programmatic equipment at B231. b) Engineering design, procurement, and installation of hydraulic system for MOMs programmatic equipment. c) Engineering design, procurement, and installation of indoor and outdoor hydraulic pumps. d) Engineering design of program equipment pits. e) Engineering design of new trenches to match existing B341 trenches.

42 ENGINEERING↗

Urban Dispersion Virtual Workshop: Designing the Next Generation Urban Dispersion Field Programs

The overarching objective of this workshop is to start the process of planning and implementing the “Next Generation of Urban Dispersion Studies”. We have organized this program to bring people interested in this complex problem together. We have representation from different disciplines, different agencies, and different academic institutions. The workshop is organized around several questions: • What are the needs of the emergency response community and how do we design models and experiments to address them? • What model improvements do the user communities need? • How do we design tracer release and sampling to address questions temporal (e.g., diurnal and seasonal variation) and spatial (e.g., land/urban/water gradients) for the broadest applicability? • What are the next-generation measurements needed to improve the data sets? • How do we implement the next generation urban dispersion experiments? The Virtual workshop format is exciting. We view this as an experiment which, if successful, will bring a large group of people together from the community to design the next generation urban experiments. We have many agencies participating: DOE-BER, DHS, FEMA, NNSA, NARAC, DTRA, NYPD, and NIST. The registration list includes over 40 people including participants from well beyond the US including Spain and Canada.

54 ENVIRONMENTAL SCIENCES↗

Design, Manufacturing and Performance Considerations in Reactor System, Components and Materials

Idaho National Laboratory (INL) is the national and global leader of the Department of Energy (DOE) ’s nuclear energy research, development, and demonstration programs. Developing critical design criteria of new advanced reactor systems, components and materials requires an understanding of fabrication and the irradiation environment during normal operating and accident conditions. Next generation researchers and designers, are, therefore challenged not only by demands for ever improved performance but must also work to shorten the development and commercialization lifecycle for new nuclear reactors and systems to remain competitive. This provides unique and exciting opportunities for all contributors to this field of study. This presentation will offer a strategic overview of the competitively funded R&D awards by the Advanced Methods for Manufacturing (AMM) program of the DOE’s office of Nuclear Energy (NE). This program conducts research and development (R&D) to accelerate innovations by reducing the cost and schedule of constructing new nuclear plants and to make fabrication of nuclear power plant components faster, cheaper, and more reliable. By evaluating state-of-the-art practices found in other large manufacturing industries, the nuclear community has identified six major areas of innovation to reach the objectives of this DOE-NE program. Additionally, typical research case studies performed at INL, will be presented, showing the vast variety of opportunities for which, the next generation of researchers can seek solutions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Incentivizing Distributed Solar: Best Practices (Presentation)

The presentation discussed findings of a recent NREL technical report on best practices for designing and implementing incentives for small and mid-sized residential and commercial distributed solar energy projects. Topics covered included: factors to consider in setting and modifying incentive levels over time, differentiating incentives to encourage various market segments, and administrative issues such as providing equitable access to incentives and customer protection. In addition, the presentation explored how incentive programs can be designed to respond to changing market conditions while attempting to provide a longer-term and stable environment for the solar industry. The findings of the report were based on interviews with program administrators, regulators, and industry representatives as well as data from numerous incentive programs nationally, particularly the largest and longest-running programs.

14 SOLAR ENERGY↗

Age and Method of Release Affect Migratory Performance of Hatchery Steelhead

Abstract Hatchery programs that are designed to aid recovery of natural populations of anadromous salmonids, including steelhead Oncorhynchus mykiss, require locally derived, natural-origin broodstock. In such programs, achieving smoltification size thresholds may require extending hatchery rearing beyond age 1. We compared out-migration survival and travel rates of 142,990 PIT-tagged steelhead smolts released at age 1 (S1 rearing strategy) or age 2 (S2 rearing strategy) over five release years at Winthrop National Fish Hatchery (WNFH, Okanogan County, Washington). An S2 rearing cycle produced larger smolts with more uniform size distributions, resulting in higher survival during the first portion of their out-migration than for S1 smolts in three of the five release years. The S2 smolts migrated more rapidly to the ocean than S1 smolts in all years except 2011 and arrived in the Columbia River estuary 5.4 d earlier on average than the S1 smolts. The S1 steelhead that did not leave during the volitional release were subsequently forced from the hatchery to measure their survival. Nonvolitional S1 migrants were smaller and had survival rates that were 2.3–66.3 times lower than those of S1 steelhead that left WNFH on their own. The same was true for S2 steelhead, but the magnitude of the survival difference between volitional migrants and fish forced from the raceways was less variable and ranged from 2.5- to 4.6-fold. We conclude that S2 rearing can be a successful strategy for producing smolts from local natural-origin broodstock, with out-migration survival and travel times that are equivalent to or better than those of S1 smolts produced from nonlocal broodstock. Received July 25, 2016; accepted March 31, 2017 Published online May 31, 2017

Tatara, Christopher P.↗

Lessons Learned from Performing a Human Factors Engineering Validation of an Upgraded Digital Control System in a Nuclear Power Plant Control Room

The United States' fleet of nuclear power plants (NPPs) have exceeded their original 40-year licenses and many are seeking license renewals to continue operations into the future. To support continued operation the Department of Energy's (DOE) Light Water Reactor Sustainability Program (LWRS) provides support for utilities to maintain and upgrade their power production capabilities. Control room modernization is one focus area, which aims to modernization the analog control rooms with digital controls and human-system interfaces (HSIs). The Turbine Control System (TCS) is a non-safety related system undergoing modernization efforts at multiple plants and utilities. Considerable human factors research efforts, comprised of expert reviews and operator in the loop studies were performed to develop human factors compliant and usable TCS. This report documents the final phase of the human factors engineering program used to design and validate the new digital TCS. According to the NUREG-0711 review guide, one of the last steps of human factors engineering program prior to implementation is human factors validation. This report details the method, results and conclusions from the human factors validation study of a collaborating utilities TCS slated to be implemented in one of their plants. One control room team consisting of two control room supervisors and two reactor operators participated in the validation. All team members had participated in the BNP TCS training program foregoing the TCS validation. Performance measures included task performance, situation awareness and workload, expert observation of any negative influences of human-system interface features on control room team performance, and interviews with the participating operators. Performance criteria were based on the performance scores and the topics identified by interviews and expert observations. The results showed that the crew using the new TCS clearly could achieve their overall objectives in the test scenarios with sufficient situation awareness. The new TCS compared to the old system provided clear improvements of the control room work regarding shell and chest warming and regarding valve and other system testing. However, a number of Human Engineering Discrepancies (HEDs) were identified. HEDs were prioritized (level 1, 2 or 3) according to potential safety, plant availability, operability or personnel performance consequences. Since no priority 1 HEDs were identified there is no HFE reason not to continue implementation of the TCS. The TCS upgrade is acceptable if the Priority 2 HEDs are resolved and dispositioned in a satisfactory way. Priority 3 HEDs should be noted and considered for future modifications.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

All-Digital Plug and Play Passive RFID Sensors for Energy Efficient Building Control

This is the final report for the project “All-Digital Plug and Play Passive RFID Sensors for Energy Efficient Building Control”, funded by DOE, and performed by Clemson University, Phase IV Engineering and Harvard University from October 1, 2016 to December 31, 2020. The main objective of this project is to develop, demonstrate and pre-commercialize a novel, plug & play, battery-free, wireless sensor technology to enable low-cost (<$10 per node) indoor and outdoor temperature and humidity measurement for energy efficient building controls and operations. The proposed technology is based on the novel concept of all-digital sensing and its seamless integration with the passive RFID technology. This project focuses on the design, fabrication, material optimization, interrogation electronics, validation, and demonstration of the novel sensor nodes for building applications. The specific objectives of this research program include: (1) Design, fabricate and optimize a compact, robust, and high-resolution digitizer, which could convert rotation angle into digital numbers. (2) Develop the multi-physics-based modeling and simulation of the temperature/humidity transducer to derive a rational design of the architecture, dimension, structure, materials (i.e., mechanical, electrical, thermal and hygroscopic) properties and functions of the sensor node. (3) Design, fabricate and optimize the bi-material based humidity sensitive coil which could linearly transduce the environmental relative humidity variations to rotation angles. (4) Design, fabricate and optimize an UHF RFID platform which could support long-range passive wireless communications of 8-bit digital numbers. (5) Design, fabricate and optimize the miniaturized all-digital sensor using MEMS technology. (6) Validate the integrated all-digital sensing system in a real building environment to test the system’s performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Celebrating 30 Years of K-12 Educational Programming at Fermilab

In 1980 Leon Lederman started Saturday Morning Physics with a handful of volunteer physicists, around 300 students and all the physics teachers who tagged along. Today Fermilab offers over 30 programs annually with help from 250 staff volunteers and 50 educators, and serves around 40,000 students and 2,500 teachers. Find out why we bother. Over the years we have learned to take advantage of opportunities and confront challenges to offer effective programs for teachers and students alike. We offer research experiences for secondary school teachers and high school students. We collaborate with educators to design and run programs that meet their needs and interests. Popular school programs include classroom presentations, experience-based field trips, and high school tours. Through our work in QuarkNet and I2U2, we make real particle physics data available to high school students in datadriven activities as well as masterclasses and e-Labs. Our professional development activities include a Teacher Resource Center and workshops where teachers participate in authentic learning experiences as their students would. We offer informal classes for kids and host events where children and adults enjoy the world of science. Our website hosts a wealth of online resources. Funded by the U.S. Department of Energy, the National Science Foundation and Fermilab Friends for Science Education, our programs reach out across Illinois, throughout the United States and even around the world. We will review the program portfolio and share comments from the volunteers and participants.

99 GENERAL AND MISCELLANEOUS↗

City of Phoenix - Energize Phoenix Program

Energize Phoenix (EPHX) was designed as an ambitious, large-scale, three-year pilot program to provide energy efficiency upgrades in buildings, along Phoenix’s new Light Rail Corridor – part of a federal effort to reduce energy consumption and stimulate job growth, while simultaneously reducing the country’s carbon footprint and promoting a shift towards a green economy. The program was created through a 2010 competitive grant awarded to the City of Phoenix who managed the program in partnership with Arizona State University (ASU), the state’s largest university, and Arizona Public Service (APS), the state’s largest electricity provider. The U.S. Department of Energy (DOE) Better Buildings Neighborhood Program (BBNP) and the American Recovery and Reinvestment Act (ARRA) of 2009 provided $25M in funding for the EPHX program. The Light Rail Corridor runs through the heart of downtown Phoenix, making most high-rise and smaller commercial buildings eligible to participate in the EPHX program, along with a diverse mix of single and multi-family residential buildings. To ensure maximum impact and deeper market penetration, Energize Phoenix was subdivided into three unique parts: i. commercial rebate program, ii. commercial financing program, and iii. residential program Each component was managed by the City of Phoenix in partnership with APS. Phoenix was fortunate to partner with APS, which already operated robust commercial and residential rebate programs within its service territory. Phoenix tapped into the existing utility contractor network, provided specific training to over 100 contracting firms, and leveraged the APS rebate program structure (energy efficiency funding) to launch the EPHX commercial and residential rebate programs. The commercial finance program was coordinated and managed through a contract with National Bank of Arizona, NBAZ, which also provided project capital leveraging EPHX finance funds. Working in unison, approved contractors jointly produced more than 161,000 labor hours in pursuit of EPHX goals over the life of the project. Labor hours were spread among electricians, heating, ventilating and air-conditioning (HVAC) technicians, marketing professionals, engineers, sales, and administrative support staff across the approved contractor workforce. Program participants received both the utility rebate along with the EPHX rebate, and depending on project size and utility rebate structure some projects resulted in low to no-cost upgrades for customers. Phoenix also partnered with ASU, a grant sub-recipient, to leverage the institution’s expertise in research and data analysis. In this partnership, ASU accepted marketing responsibilities for the grant and partnered with DRA Communications (DRA), a Phoenix-based marketing firm, to create and communicate the message out to the marketplace. The EPHX program has completed its energy upgrade activities. A review of the work completed by ASU revealed that the EPHX program substantially exceeded the program’s stated goals by retrofitting/upgrading over 33 million sq ft of commercial space (30 million sq ft goal exceeded by 11%) and 2,014 residential units (1,700 unit goal exceeded by 18%) along the Light Rail Corridor. The program helped stimulate economic growth by adding $31million to the local economy and enhanced an already robust energy efficiency contractor network. This contractor network will continue to promote utility energy incentives to sustain energy efficiency upgrade activities in the future. Finally, EPHX helped reduce participants annual energy consumption by 135 million kilowatt-hour (kWh) translating into over $12.5 million of annual energy cost avoidance for the community. This also resulted in projected payback period of 4.5 years for total investment by all parties and reduced greenhouse gas emissions by over 95,000 metric tons of carbon dioxide equivalent (CO2e).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Development of X-Ray FEL Oscillators with Higher Out-Coupling Efficiency

This program focused on the development of high-outcoupling efficiency resonators for x-ray free-electron laser oscillators (XFELOs). The goal was to produce a viable design for an XFELO that can be implemented on the LCLS-II which is the x-ray FEL facility under construction at the Stanford Linear Accelerator Center (SLAC). The program designed at regenerative amplifier (RAFEL) design that employs a high-gain undulator with a low-Q resonator with the goal of producing a scientific design for the RAFEL as well as a software suite that can be used to design XFELOs. The Phase I program considered a resonator consisting of six diamond Bragg reflectors/mirrors with two focusing lenses. This resonator was used in conjunction with the electron beam produced by the LCLS-II and the HXR undulator to design a RAFEL producing 3.05 keV photons in the fundamental resonance and 9.15 keV photons in the 3rd harmonic. The research program included the extension of the Optics Propagation Code (OPC) to describe Bragg reflection from diamond crystal mirrors and went on to use OPC, in conjunction with the MINERVA simulation code to treat the undulator interaction, to simulate the RAFEL. Simulations were conducted in both the steady-state and time-dependent regimes to determine the basic performance characteristics of the RAFEL.

43 PARTICLE ACCELERATORS↗

The DESI Fiber View Camera System

The Dark Energy Spectroscopic Instrument (DESI) is a 5000 fiber multi-object spectrometer now being installed at the prime focus of the 4 m Mayall telescope at Kitt Peak. Using DESI to measure ~35 million galaxy redshifts and using the Baryon Acoustic Oscillation (BAO) technique to measure distances, the results will probe the nature of the recently discovered mysterious component of our universe called dark energy. Computer controlled robotic positioners move the 120 μm diameter fibers to positions of galaxies whose location on the sky have been obtained in a previous target selection imaging survey. To achieve good throughput the fibers should be centered on the target position to within 3 μm. The robotic positioners however are only capable of a 50 μm precision on their first move. To achieve the desired precision, the Fiber View Camera (FVC) system has been implemented. The FVC, located near the hole in the primary mirror of the Mayall telescope, has been designed to take an exposure of the focal plane, located at the prime focus some 12 m above the FVC, after the robotic positioners have completed their first move. The FVC is intended to measure the fiber locations with a precision of 3 μm and issue a set of fiber coordinate corrections for the second move correcting the fiber positions by the robotic positioners. Tests show that after two iterations better than 99% of the fibers will be in their intended location to within the desired precision. This paper describes the design of the FVC system, the R&D program preceding the final design, and the tests that have been carried out to demonstrate that the FVC can achieve the required precision.

(cosmology:) dark energy↗

Diffusion Welding of Alloys for Molten Salt Service – Status Report

The present work is concerned with heat exchanger development for molten salt service, including the proposed molten salt reactor (MSR), a homogeneous reactor in which the fuel is dissolved in a circulating fluid of molten salt. It is an outgrowth of recent work done under the Next Generation Nuclear Plant (NGNP) program; what the two reactor systems have in common is an inherently safe nuclear plant with a high outlet temperature that is useful for process heat as well as more conventional generation The NGNP program was tasked with investigating the application of a new generation of nuclear power plants to a variety of energy needs. One baseline reactor design for this program is a high temperature, gas-cooled reactor (HTGR), which provides many options for energy use. These might include the conventional Rankine cycle (steam turbine) generation of electricity, but also other methods: for example, Brayton cycle (gas turbine) electrical generation, and the direct use of the high temperatures characteristic of HTGR output for process heat in the chemical industry. Such process heat is currently generated by burning fossil fuels, and is a major contributor to the carbon footprint of the chemical and petrochemical industries. The HTGR, based on graphite fuel elements, can produce very high output temperatures; ideally, temperatures of 900°C or even greater, which has significant energy advantages. Such temperatures are, of course, at the frontiers of materials limitations, at the upper end of the performance envelope of the metallic materials for which robust construction codes exist, and within the realm of ceramic materials, the fabrication and joining of which, on the scale of large energy systems, are at an earlier stage of development. A considerable amount of work was done in the diffusion welding of materials of interest for HTGR service with alloys such as 617 and 800H. The MSR output temperature is also materials limited, and is projected at about 700°C. (RR E) A different set of alloys, such as Alloy N and 242, are needed to handle molten salts at this temperature. The diffusion welding development work described here builds on techniques developed during the NGNP work, as applied to these alloys. There is also the matter of dissimilar metal welding, since alloys suitable for salt service are generally not suited for service in gaseous oxidizing environments, and vice versa, and welding is required for the Class I boundaries in these systems, as identified in the relevant ASME codes.

02 PETROLEUM↗

Diffusion Welding of Alloys for Molten Salt Service - Status Report

The present work is concerned with heat exchanger development for molten salt service, including the proposed molten salt reactor (MSR), a homogeneous reactor in which the fuel is dissolved in a circulating fluid of molten salt. It is an outgrowth of recent work done under the Next Generation Nuclear Plant (NGNP) program; what the two reactor systems have in common is an inherently safe nuclear plant with a high outlet temperature that is useful for process heat as well as more conventional generation The NGNP program was tasked with investigating the application of a new generation of nuclear power plants to a variety of energy needs. One baseline reactor design for this program is a high temperature, gas-cooled reactor (HTGR), which provides many options for energy use. These might include the conventional Rankine cycle (steam turbine) generation of electricity, but also other methods: for example, Brayton cycle (gas turbine) electrical generation, and the direct use of the high temperatures characteristic of HTGR output for process heat in the chemical industry. Such process heat is currently generated by burning fossil fuels, and is a major contributor to the carbon footprint of the chemical and petrochemical industries. The HTGR, based on graphite fuel elements, can produce very high output temperatures; ideally, temperatures of 900 °C or even greater, which has significant energy advantages. Such temperatures are, of course, at the frontiers of materials limitations, at the upper end of the performance envelope of the metallic materials for which robust construction codes exist, and within the realm of ceramic materials, the fabrication and joining of which, on the scale of large energy systems, are at an earlier stage of development. A considerable amount of work was done in the diffusion welding of materials of interest for HTGR service with alloys such as 617 and 800H. The MSR output temperature is also materials limited, and is projected at about 700 °C. (RR E) A different set of alloys, such as Alloy N and 242, are needed to handle molten salts at this temperature. The diffusion welding development work described here builds on techniques developed during the NGNP work, as applied to these alloys. There is also the matter of dissimilar metal welding, since alloys suitable for salt service are generally not suited for service in gaseous oxidizing environments, and vice versa, and welding is required for the Class I boundaries in these systems, as identified in the relevant ASME codes.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗