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The Oak Ridge National Laboratory is planning to build the Second Target Station (STS) at the Spallation Neutron Source (SNS). STS will host a suite of novel instruments that complement the First Target Station’s beamline capabilities by offering an increased flux for cold neutrons and a broader wavelength bandwidth. A novel neutron imaging beamline, named the Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D), is among the first eight instruments that will be commissioned at STS as part of the construction project. CUPI2D is designed for a broad range of neutron imaging scientific applications, such as energy storage and conversion (batteries and fuel cells), materials science and engineering (additive manufacturing, superalloys, and archaeometry), nuclear materials (novel cladding materials, nuclear fuel, and moderators), cementitious materials, biology/medical/dental applications (regenerative medicine and cancer), and life sciences (plant–soil interactions and nutrient dynamics). The innovation of this instrument lies in the utilization of a high flux of wavelength-separated cold neutrons to perform real time in situ neutron grating interferometry and Bragg edge imaging—with a wavelength resolution of δλ/λ ≈ 0.3%—simultaneously when required, across a broad range of length and time scales. This manuscript briefly describes the science enabled at CUPI2D based on its unique capabilities. The preliminary beamline performance, a design concept, and future development requirements are also presented.

Irradiation testing of fuel-bearing molten salts is critical for supporting the development and demonstration of molten salt reactors (MSRs). These experiments can inform several important reactor design and safety parameters, including source term modeling, the evolution of thermophysical properties with burnup, and the degradation of structural materials under reactor-relevant conditions. Idaho National Laboratory is designing an instrumented and heated high-temperature molten-salt-fueled irradiation capsule to study the behavior of the fuel salt during in-pile irradiation. This paper details the neutronics, thermal, and mechanical analyses performed to date. Parametric studies were performed to assess a range of materials, different experiment dimensions, two in-reactor positions, and the fuel enrichment used. The principal recommendations are to select a peripheral reactor position in order to alleviate neutronic constraints, a thin salt annulus to achieve thermal design objectives, and high-temperature alloys that provide additional safety margins.

Nuclear batteries in the form of a semiconductor and radioisotope combination, whether of a betavoltaic or alphavoltaic, are promising miniature power sources due mainly to their potential to attain high power densities with long shelf and operational lifetime. Limitations in the performance of this type of nuclear battery consist typically of low power conversion efficiencies (PCE @ 0.1-3.6%), small output power ( , mostly at nW), and radiation damage to the hosting semiconductor devices. In this paper, we have proposed and experimentally validated different techniques to improve nuclear batteries’ PCE. A thin scintillator layer has been added into the battery structure to boost PCE through the combination of indirect (light generation) and direct (electron–hole pair generation) collection of radiation energy. The scintillator layer also serves as an energy degrader to reduce the charged particles’ energy, consequently increasing their stopping power and energy deposition in the sensitive region of the devices.

The measurable charged-particle produced from the fast neutron interactions with the Si and C nucleuses can make a wide bandgap silicon carbide (SiC) sensor intrinsically sensitive to neutrons. The 4H-SiC Schottky detectors have been fabricated and tested at up to 500 °C, presenting only a slightly degraded energy resolution. The response spectrum of the SiC detectors were also obtained by exposing the detectors to external neutron beam irradiation and at a near-core location where gamma-ray field is intense. The fast neutron flux of these two locations are ∼ 4 . 8 × 1 0 4 cm − 2 ⋅ s − 1 and ∼ 2 . 2 × 1 0 7 cm − 2 ⋅ s − 1 , respectively. At the external beam location, a Si detector was irradiated side-by-side with SiC detector to disjoin the neutron response from Si atoms. The contribution of gamma ray, neutron scattering , and charged-particles producing reactions in the SiC was discussed. The fast neutron detection efficiencies were determined to be 6 . 43 × 1 0 − 4 for the external fast neutron beam irradiation and 6 . 13 × 1 0 − 6 for the near-core fast neutron irradiation.

Radiation effects induced by gamma rays on battery performance were investigated by measuring the capacity and resistance of a series of battery coin cells in-situ directly under gamma radiation and ex-situ. An experimental setup was developed to charge and discharge batteries directly under gamma radiation, equipped with precise temperature control, at The Ohio State University Nuclear Reactor Lab. Latent effects induced by gamma radiation on battery components directly influence their performance. Charge and discharge capacity and overall resistance throughout a time span of several weeks post irradiation were monitored and compared to control groups. It was found that exposure to gamma radiation does not significantly alter the available capacity and the overall cell resistance immediately, however, battery performance significantly decreases with time post irradiation. Also, batteries exposed to a higher cumulative dose showed close-to-zero capacity at two-week post irradiation.

The performance degradation and durability of a Li-ion battery is a major concern when it is operated under radiation conditions, for instance, in deep space exploration, in high radiation field, or rescuing or sampling equipment in a post-nuclear accident scenario. This paper examines the radiation effects on the electrode and electrolyte materials separately and their effects on a battery's capacity loss and resistance increase. A 60 Co irradiator (34.3 krad/h) was used to provide 0.8, 4.1, and 9.8 Mrad dose to LiFePO 4 electrodes and 0.8, 1.6, and 5.7 Mrad to 1 M LiPF 6 in 1:1 wt% EC:DMC electrolytes. This study shows that the coin cells assembled with irradiated components have higher failure rate (ca. 70%) than that of control group (ca. 14%). A significant battery capacity fade post irradiation was observed. The electrolyte also shows a darkened color a few weeks or months after irradiation. The discovery of this latent effect may be significant because a battery may degrade significantly even showing no sign of degradation immediately after exposure. We investigated electrolyte composition by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and nuclear magnetic resonance spectroscopy prior and post irradiation. Polymerization reactions and HF formation are considered as the cause of the discoloration.

Boron is used widely in thin-film solid-state devices for neutron detection. The film thickness and boron concentration are important parameters that relate to a device׳s detection efficiency and capacitance. Neutron depth profiling was used to determine the film thicknesses and boron-concentration profiles of boron carbide-based polymers grown by plasma enhanced chemical vapor deposition (PECVD) of ortho-carborane (1,2-B 10 C 2 H 12 ), resulting in a pure boron carbide film, or of meta-carborane (1,7-B 10 C 2 H 12 ) and pyridine (C 5 H 5 N), resulting in a pyridine composite film, or of pyrimidine (C 4 H 4 N 2 ) resulting in a pure pyrimidine film. The pure boron carbide film had a uniform surface appearance and a constant thickness of 250 nm, whereas the thickness of the composite film was 250–350 nm, measured at three different locations. In the meta-carborane and pyridine composite film the boron concentration was found to increase with depth, which correlated with X-ray photoelectron spectroscopy (XPS)-derived atomic ratios. A proton peak from 14 N (n,p) 14 C reaction was observed in the pure pyrimidine film, indicating an additional neutron sensitivity to nonthermal neutrons from the N atoms in the pyrimidine.

Silicon carbide (SiC) and gallium nitride (GaN) semiconductors are two detector candidates for high flux neutron monitoring entailing high temperature and high radiation environments owing to their wide band gap and high resistance to radiation damage. While the neutron elastic scattering with carbon (C) and silicon (Si) makes SiC intrinsically sensitive to neutrons, neutron interaction with nitrogen (N) by way of 14N(n,p)14 C reaction provides neutron sensitivity to GaN. In this study, we investigated reactor-based high flux neutron monitoring with in-house fabricated SiC detectors and studied the feasibility of neutron detection using GaN. As proof-of-concept for GaN neutron sensitivity, we evaluated SiC detectors coupled with nitrogen based (N-based) neutron converter materials, and commercially purchased AlGaN photo sensors. Spectral response as well as raw waveform data from SiC, SiC coupled with N-based converter layers, and AlGaN sensors were acquired while exposing the detectors to a mixed neutron–gamma field of a research reactor at ex-core locations at various power levels. The experimental SiC detector spectra were compared against Geant4 Monte Carlo (MC) simulations, which agreed with the measurement results. The reactor power determined using SiC detector raw data correlated well with that indicated by a standard compensated ion chamber (CIC). The AlGaN sensors showed promising results with a correlation between sensor response and reactor power. The current study demonstrates SiC as a suitable detector for high flux neutron monitoring with good radiation tolerance based on near-core irradiation.

Nuclear power is playing an important role in energy supply in modern society. The safety of nuclear power plant is thus an important issue. Due to the harmful effects of radiation to human body, robots are used when and where the radiation level in the plant is high. Thus study of the radiation effects on robots, especially on the critical components of robots becomes an urgent issue. In this paper, we investigate the impact of the radiated lithium-ion battery to mobile robots. Mobile robots especially visual tracking guided robot can be used to perform multiple tasks in a nuclear environment. Under radiation, the lithium-ion battery will degrade in terms of capacity, which means if the battery is used as a normal battery, the mobile robot will not perform satisfactorily. We first present the result on the battery degradation due to radiation. Then we study the impact to the robot if it is powered by a radiated battery. The performance of the robot is evaluated under two different conditions, before and after the radiation, and by three different experiments. The radiation effects on the robot performance are shown and analyzed.

There is an increasing trend for data owners to store their data in a third-party cloud server and buy the service from the cloud server to provide information to other users. To ensure confidentiality, the data is usually encrypted. Therefore, an encrypted data searching scheme with privacy preserving is of paramount importance. Predicate encryption (PE) is one of the attractive solutions due to its attribute-hiding merit. However, as cloud is not always trusted, verifying the searched results is also crucial. Firstly, a generic construction of Publicly Verifiable Predicate Encryption (PVPE) scheme is proposed to provide verification for PE. We reduce the security of PVPE to the security of PE. However, from practical point of view, to decrease the communication overhead and computation overhead, an improved PVPE is proposed with the trade-off of a small probability of error.

Lithium Ion Batteries (LIBs) are widely used in research, industry and households, especially equipped in autonomous systems, such as mobile robots in air, land, or sea. More importantly, some of the environments are filled with nuclear radiation and with high temperature. The performance of LIBs in these environments are crucial to sustained operations of these systems. Unfortunately, how an LIB may degrade the operation of such systems has not been seriously studied in the field. Researches on LIBs material, performance, sustainability, etc. have been done through recent decades. Many kinds of cathode, electrolyte and anode material have been discovered and several configurations, like coin cells, cylinder cells, and prismatic cells have been developed for different operating conditions. The concern is still on the performance degradation and reliability when operating in radiation and high temperature environments such as in outer space exploration, to power robots in hot cell, and equipment for performing rescue or sampling missions at post-nuclear accidents. In this study, we designed an in situ methodology to monitor LIBs performance degradation when operating (cycling) under gamma radiation with a post-accident dose rate (~30krad/h), in terms of capacity fade and impedance rise. Coin cells were assembled using commercial cathode material and electrolyte, with Li as reference electrode. An ex-situ irradiation -testing protocol was also adopted in this study, as we were interested in investigating separate radiation effects on individual battery components. Additionally, the effect of radiation on battery materials may be different at various temperature environment, for example, in space or in a nuclear accident field. We have conducted battery performance under irradiation while heating (80 °C) or cooling (-40 °C). Ex situ studies, including cathode material X-ray diffraction (XRD), and characterizations with Fourier Transform Infrared (FTIR) spectroscopy, ultraviolet–visible spectroscopy (UV-vis) spectroscopy and electron paramagnetic resonance (EPR) will also be discussed.