Modern electrical components are susceptible to damage from the high levels of radiation and extreme temperatures found near reactors in terrestrial nuclear power plants and in aerospace applications. Radiation-hardened electronics are being developed, largely for the aerospace industry, but they sometimes rely on application-specific, small-batch semiconductor fabrication processes. These processes tend to be prohibitively expensive to develop and maintain outside major industrial facilities or governmental agencies. Recently, commercially available, non-radiation-rated junction-gate field-effect transistors (JFETs) were shown to maintain their functionality at gamma doses exceeding 1 MGy, suggesting that nonrated, commercially available electrical components could be used to develop systems that are tolerant to ionizing radiation. However, gamma ray survival is not indicative of neutron dose survival, and few studies characterize JFETs under neutron irradiation. To address this knowledge gap, a JFET-based analog multiplexer and optical pulse-width modulation encoder was developed and irradiated using a 252 Cf source to 1.6 × 10 13 n/cm 2 . The multiplexed optical encoder (MOE) system maintained functionality throughout testing and showed little evidence of radiation effects. These results indicate that circuitry tolerant to fast neutron damage can be developed using low-cost, non-radiation-rated, commercially available JFETs, which could provide a lower production cost alternative to specialized semiconductor processes when designing and building electronics better able to survive neutron irradiation.

include results and assumptions in the activation analyses. Sections of this report and the appendices present interpretation of data and the classification definitions and requirements.

With their greater voltage breakdowns, higher current limitations, and faster switching speeds, wide bandgap semiconductors are increasing in market application over the traditionally dominant silicon devices. Silicon carbide semiconductors have been increasing the e ffi ciency and reducing the footprint of modern power electronics, and the increased electron mobility of gallium nitride semiconductors have been increasing the switching frequencies of radio frequency circuits. In extreme temperature ( > 225 ◦ C) applications and high radiation environments such as low earth orbit, deep space, and terrestrial nuclear reactors, silicon-based semiconductors degrade rapidly. Wide bandgap semiconductors are poised to disrupt the market for sensing, instrumentation, and communication circuitry in these hazardous environments by increasing the lifetime, safety, and reliability. This report outlines the advantages of using wide bandgap semiconductor materials in extreme temperature and radiation environments.

fresh and irradiated fuel. Operational neutron energy spectrums and breeding ratios also vary significantly across design concepts. Some concepts are burner reactors designed to transmute the spent nuclear fuel from LWRs or pressurized heavy water reactors (PHWRs), while others are breeder reactors designed to breed fissile 233U from naturally occurring fertile 232Th. Some MSR concepts are designed to be a part of a once-through fuel cycle, while others involve chemical separation. Those that include plans to recycle the fuel differ by whether the chemical processing would be done onsite, as a process connected to the fuel salt itself, or offsite at a reprocessing facility similar to how LWR or PHWR spent fuel is reprocessed in some countries. Each overall design concept contains various aspects of each of these features to produce a unique facility

Dry cask storage is one of two storage methods approved by the U.S. Nuclear Regulatory Commission for spent fuel after removal from reactor cores. Dry casks consist of a stainless steel canister enclosed in a concrete overpack to contain the hazardous radioactive spent fuel rods and provide radiation shielding. Monitoring spent fuel storage casks is desired to ensure the safe containment of the enclosed spent fuel, but is very difficult due to the related harsh temperature and radiation environment. The sensors and associated electronics to monitor temperature, pressure, and/or radiation need to survive high temperatures and radiation doses for extended time periods. For this reason, there is a severe need for radiation-hardened electrical systems that survive well beyond the existing capabilities of commercially available radiation-rated electronic components, which have primarily been developed for space applications. Junction-gate field-effect transistor (JFET) devices are inherently radiation hardened [exceeding 100 Mrad (Si)]. When JFETs are used as building blocks for sensing and communication electronics (i.e., oscillators, amplifiers, filters, and mixers), inherently radiation-hardened circuits can be achieved. To this end, JFET-based radiation-hardened electronics interfacing with cask-embedded sensors capable of driving modulated sensor signals through a stainless steel barrier were designed and tested at a dose rate of approximately 500 krad/h (Si) to beyond a 200-Mrad (Si) total ionizing dose. After 200 Mrad (Si), the sensor and communication circuit signals were correctly decoded at the receiver despite oscillator drift. The results from this experiment demonstrate the potential for creating more complex radiation-hardened JFET-based electrical systems for nuclear environments.

Here, recent work to evaluate the prospects for surface acoustic wave (SAW) devices fabricated on bulk aluminum nitride (AlN) for elevated temperature and radiation environments is reported and discussed. The design and fabrication of an array of SAW devices using commercial wafers is described, including the non-standard fabrication approach taken to overcome the stress-induced warpage of the 50 mm diameter AlN substrates. Radio frequency performance characterization of the SAW devices, with resonance frequencies ranging from 0.5 GHz to 1.5 GHz, is described. The linear temperature coefficient of frequency (TCF) near room temperature was measured and is compared to theoretical results from other investigators. The effects of 8 MeV Al ion irradiation at 300°C and 500°C to damage levels of 0.01, 0.1 and 1 displacements per atom (dpa), as a proxy for neutron irradiation, was investigated. The ion irradiation damage was observed to decrease the SAW resonant frequency, and this effect is characterized and discussed. Significant degradation in the conductivity of the Ti/Al electrodes of the SAW devices was also observed and characterized. These experimental results provide a basis for further investigation of the prospects for development of SAW sensor devices in bulk AlN material for application in elevated temperature and radiation environments.

describes the final version of the circuit which has been proven to successfully meet the experiment requirements.

Many nuclear facilities, such as spent fuel storage dry casks and nuclear reactor pressure vessels, are entirely sealed by metal layers to prevent harmful radiation. For safety and security operations, the tem-perature, pressure, radiation, and humidity inside the vessel needs to be closely monitored. However, no practical technology is currently available to realize the through-wall data communication and monitor-ing for these vessels due to the inside harsh environment of high temperature and nuclear radiation. In this paper, an innovative self-powered wireless through-wall data communication system for the nuclear environment is presented, which demonstrates a successful solution to such challenges. The presented system is composed of four modules, i.e., energy harvester with power management circuits, ultrasound wireless communication using high-temperature piezoelectric transducers, electronic circuits for sensing and data transmission, and radiation shielding for electronics. Constitutive functions of each module were firstly designed and followed by the system integration. Experiments were conducted subsequently to validate the designed functions and evaluate the performance of the integrated system. Results showed that the average power of over 40 mW was harvested from the thermal flow inside the nuclear spent fuel canisters which could provide enough energy to operate the sensing and data communication systems. The gamma radiation test results showed that the thermoelectric energy harvester and ultra-sound transceivers can withstand radiation dosing over 100 Mrad. Furthermore, temperature shock tests demonstrated that the entire system including the shielded electronics can survive and maintain their functionalities at temperatures as high as 195celcius. Under the in-lab mocked-up high temperature conditions and radiation shielding, the proposed system is foreseen to survive and operate stably for fifty years inside a nuclear spent fuel canister, and send the frequency modulated data out of the canister for 3 s in every 10 min. (c) 2022 Elsevier Ltd. All rights reserved.

To assist the US Department of Energy in defining a course for Office of Nuclear Energy–funded radiation-hardened (rad-hard) electronics research, Oak Ridge National Laboratory (ORNL) will focus on three main tasks in FY21. The first task will investigate the survivability of silicon junction-gate field-effect transistors (Si-JFETs) through a 100 Mrad total ionizing dose (TID) experiment and report the test results. The second task will investigate wide bandgap (WBG)-based JFET devices and sources. The third task is an investigation into commercially available systems and components and will be performed to determine whether a standardized list of devices can be identified for reactor instrumentation application. If the devices are feasible, then this list will provide direction to designers and equipment suppliers for selection of components to meet specific reactor requirements.

Radiation-hardened (rad-hard) electronics have been the shortcoming in nuclear sensing and instrumentation. Placing advanced sensors and associated electronics closer to a nuclear reactor core will improve reactor control and operation through increased signal accuracy, precision, and fidelity, resulting in safer, more efficient energy production. However, the extreme temperature and bombarding radiation environment of nuclear applications make research and development into electronics and electronic materials technologies essential to enabling improved safety, monitoring, and control of the existing nuclear reactor fleet and the next generation of reactors, including microreactors. To help the US Department of Energy (DOE) define a course for the Office of Nuclear Energy (NE)-funded rad-hard electronics research, Oak Ridge National Laboratory staff present this summary of the state-of-the-art (SOA) technology for the design and implementation of rad-hard electronics and systems, including research efforts and commercial offerings. A collection of technological gaps associated with reactor applications are compiled herein. Based on the radiation degradation mechanisms discussed in this report, along with the state-of-the-art summary survey and a compiled list of gaps, a high-level research plan of future NE funding direction was developed and is provided. This report outlines these activities and provides a summary of SOA electronics technology for rad-hard instrumentation in reactors, a list of the major technology gaps observed, and a draft plan for addressing the present and future needs of reactor instrumentation.

Traditional physical (PHY) layer protocols contain chains of signal processing blocks that have been mathematically optimized to transmit information bits efficiently over noisy channels. Unfortunately, this same optimality encourages ubiquity in wireless communication technology and enhances the potential for catastrophic cyber or physical attacks due to prolific knowledge of underlying physical layers. Additionally, optimal signal processing for one channel medium may not work for another without significant changes in the software protocol. Any truly resilient communications protocol must be capable of immediate redeployment to meet quality of service (QoS) demands in a wide variety of possible channel media. Contrary to many traditional approaches which use immutable man-made signal processing blocks, this work proposes generating real-time blocks {\it ad hoc} through a machine learning framework, so-called deepmod, that is only relevant to the particular channel medium being used. With this approach, traditional signal processing blocks are replaced with machine learning graphs which are trained, used, and discarded as needed. Our experiments show that deepmod, using the same machine intelligence, converges to viable communication links over vastly different channels including: radio frequency (RF), powerline communications (PLC), and acoustic channels.

Fabric drying is an energy-intensive process, which generally involves blowing hot dry air across tumbling wet fabric to facilitate evaporation and moisture removal. Most of the energy supplied is used to overcome the enthalpy of vaporization for water. Although this process tends to be inefficient, it is fairly simple and forms the basis for the majority of existing clothes dryer technology today. To address the relatively low efficiency, a new method of drying called "direct contact ultrasonic fabric drying" is proposed. The process involves using high-frequency vibration introduced by piezoelectric transducers, which are in contact with wet fabric. The vibration is used to extract water droplets from the fabric mechanically. In this study, a total of 24 individual transducers are used in a module to dry a 142 cm(2) sized fabric. The performance characterization of this single module has enabled successful scale-up of the system to a midscale prototype dryer, which can be used to ultrasonically dry clothing-sized fabric (similar to 750 cm(2)). The first-generation ultrasonic fabric dryer fabricated uses as little as 17% of the energy needed by traditional evaporation-based drying techniques. In addition to experimental data, this paper presents the results of a kinetic and scaling analysis that provides some important insights into ultrasonic drying.

Passive, wireless surface acoustic wave (SAW) sensor systems can be approached from a radar perspective, where the SAW device is thought of as a cooperative target. This paper investigates the use of a commercial-off-the-shelf software defined radio to interrogate wireless SAW sensors with a randomly generated interrogation pulse. The USRP B200mini is utilized as the transceiver platform with custom field-programmable gate array (FPGA) modifications to generate the random interrogation waveform and provide synchronization and buffering to the received signal. Each transmit sample bit in the FPGA is fed by an independent linear-feedback shift register, which generates pseudo-random I and Q samples for the interrogation pulse. An RF daughterboard has also been developed and integrated with the B200mini to increase the transmit power, provide filtering of the RF signals, and switch a signal antenna between the transmit and receive channels. Radio control and matched filter correlator post-processing are accomplished using Python. Design and implementation details for the FPGA modifications, RF daughterboard, and post-processing are discussed. The system is demonstrated by wirelessly interrogating SAW temperature sensors at 915 MHz.

Signal source separation is an important aspect of both measurement and signature intelligence (MASINT) as well as modern commercial smart grid applications. In some MASINT scenarios, real-time signal processing is required in a small physical form factor, which can become prohibitive with the high sample rates required of modern signal identification algorithms. We develop a new Fast Fourier Transform (FFT) algorithm, the Aliased FFT (AFFT), that exploits spectral redundancy and sparsity in the signal to drastically reduce the number of computations required from O(N log N), for the normal FFT, to one that approaches the idealized O(K log K) for a K-sparse signal. We also develop a signal source separation algorithm using harmonically aligned signal projections (HASP) that is useful for transforming a one-dimensional signal of interest (SOI) into a two-dimensional image in such a way to facilitate automated feature extraction. An automated feature extractor is described which can accurately achieve super-resolution far beyond that of the traditional FFT by again taking advantage of the harmonic structure present in the SOI. We demonstrate HASP and this feature extractor for the application of load disaggregation-identifying the presence of certain types of devices connected to a power system.