More Like this

1. Effect of Liquid Miscibility Gap on Defects in Inconel 625–GRCop42 Joints through Analysis of Gradient Composition Microstructure

   https://doi.org/10.3390/jmmp8010042  

   Preis, Jakub; Xu, Donghua; Paul, Brian K; Eschbach, Peter A; Pasebani, Somayeh (February 2024, Journal of Manufacturing and Materials Processing)

   Joining of Cu-based dispersion-strengthened alloys to Ni-based superalloys has garnered increased attention for liquid rocket engine applications due to the high thermal conductivity of Cu-based alloys and high temperature tensile strength of Ni-based superalloys. However, such joints can suffer from cracking when joined via liquid state processes, leading to part failure. In this work, compositions of 15–95 wt.% GRCop42 are alloyed with Inconel 625 and characterized to better understand the root cause of cracking. Results indicate a lack of miscibility between Cu-deprived and Cu-rich liquids in compositions corresponding to 30–95 wt.% GRCop42. Two distinct morphologies are observed and explained by use of CALPHAD; Cu-deprived dendrites with Cu-rich interdendritic zones at 30–50 wt.% GRCop42 and Cu-deprived spheres surrounded by a Cu-rich matrix at 60–95 wt.% GRCop42. Phase analysis reveals brittle intermetallic phases precipitate in the 60–95 wt.% GRCop42 Cu-deprived region. Three cracking mechanisms are proposed herein that provide guidance on the avoidance of defects Ni-based superalloy to Cu-based dispersion strengthened alloy joints. 

   more » « less
2. Priorities and Considerations in Advancing the Training of Nuclear Reactor Operators Through Mixed Reality

   Jain, Eakta; Enqvist, Andreas (January 2021, American Nuclear Society Winter Meeting and Technology Expo)

   Nuclear reactor safety is unique in that even after an incident is identified and the reactor shut down, the possibility of damage to people and environment does not stop: there is a long tail to the incident due to decay heat and potential for radiation leakage, which must also be contained properly, as exemplified in Fukushima where most radiation releases happened after initial earthquake and plant shut-down. Nuclear reactors generate close to 20% of the energy required by our nation. There is increasing interest in nuclear power as a low emissions alternative to fossil fuel-based power. Investments in the next generation of nuclear power plants include many nuclear startups such as NuScale and high-profile investments by Bill Gates’ Terra Power. Nuclear reactor operators are critical personnel who operate nuclear reactors, monitor the health of the operation, and are the first line of defense in case of an incident. Though the Nuclear Regulatory Commission creates and maintains standards and procedures for nuclear safety, their programmatic mandate involves are focused on existing technology, in the form of commercial nuclear power plants and other uses of nuclear materials through licensing, inspection and enforcement activities. This report summarizes the collected thoughts and insights from a diverse working group on the intersection of next generation technology with the training of future nuclear reactor operators. 

   more » « less
3. Kinetics and Modeling of Counter-Current Leaching of Waste Random-Access Memory Chips in a Cu-NH3-SO4 System Utilizing Cu(II) as an Oxidizer

   https://doi.org/10.3390/ma16186274  

   Lin, Peijia; Werner, Joshua; Ali, Zulqarnain Ahmad; Bertucci, Lucas; Groppo, Jack (September 2023, Materials)

   The leaching of Cu in ammoniacal solutions has proven an efficient method to recover Cu from waste printed circuit boards (WPCBs) that has used by many researchers over the last two decades. This study investigates the feasibility of a counter-current leaching circuit that would be coupled with an electrowinning (EW) cell. To accomplish this objective, the paper is divided into three parts. In Part 1, a leaching kinetic framework is developed from a set of experiments that were designed and conducted using end-of-life waste RAM chips as feed sources and Cu(II)-ammoniacal solution as the lixiviant. Various processing parameters, such as particle size, stirring rates, initial Cu(II) concentrations, and temperatures, were evaluated for their effects on the Cu recovery and the leaching rate. It was found that the particle size and initial Cu(II) concentration were the two most important factors in Cu leaching. Using a 1.2 mm particle size diameter and 40 g/L of initial Cu(II) concentration, a maximum Cu recovery of 96% was achieved. The Zhuravlev changing-concentration model was selected to develop the empirically fitted kinetic coefficients. In Part 2, kinetic data were adapted into a leaching function suitable for continuously stirred tank reactors. This was achieved via using the coefficients from the Zhuravlev model and adapting them to the Jander constant concentration model for use in the counter-current circuit model. Part 3 details the development of a counter-current circuit model based on the relevant kinetic model, and the circuit performance was modeled to provide a tool that would allow the exploration of maximum copper recovery whilst minimizing the Cu(II) reporting to electrowinning. A 4-stage counter-current circuit was modeled incorporating a feed of 35 g/L of Cu(II), achieving a 4.12 g/L Cu(II) output with 93% copper recovery. 

   more » « less
4. Uncertainty-Aware Day-Ahead Datacenter Workload Planning with Load-Following Small Modular Reactors

   https://doi.org/10.1145/3757892.3757905  

   Yang, Yijie; Wang, Dan; Shi, Jian; Wu, Chenye; Han, Zhu (July 2025, ACM SIGEnergy Energy Informatics Review)

   The rapid rise of AI applications has driven datacenters to unprecedented energy demands, which has prompted major tech companies to adopt on-site nuclear power plants (NPPs) alongside grid electricity. While existing research focuses on off-site NPPs in multi-energy systems optimized for investment returns, recent advances in small modular reactors (SMRs), particularly load-following SMRs (LF-SMRs), offer flexible, reliable power tailored for datacenter co-location. However, LF-SMRs are governed by a set of physical constraints, such as ramp rate and stability limits, making them unsuitable as fully dispatchable sources. This paper proposes a novel day-ahead workload scheduling approach that jointly coordinates datacenter operations and LF-SMR output, explicitly modeling these constraints. We develop a two-stage formulation that forecasts carbon-free grid energy from the grid using conformal prediction in the first stage and then optimizes LF-SMR output and workload scheduling via mixed-integer programming in the second stage. Evaluation on real workload traces shows that our method reduces carbon-based energy consumption by up to 43.44% compared to baselines that omit nuclear integration or ignore SMR limitations. 

   more » « less
5. The Regulated NiCu Cycles with the New ⁵⁷ Cu(p,γ) ⁵⁸ Zn Reaction Rate and Its Influence on Type I X-Ray Bursts: the GS 1826–24 Clocked Burster

   https://doi.org/10.3847/1538-4357/ac4d89  

   Lam, Yi Hua; Lu, Ning; Heger, Alexander; Jacobs, Adam Michael; Smirnova, Nadezda A.; Nieto, Teresa Kurtukian; Johnston, Zac; Kubono, Shigeru (April 2022, The Astrophysical Journal)

   Abstract During the X-ray bursts of GS 1826−24, a “clocked burster”, the nuclear reaction flow that surges through the rapid-proton capture process path has to pass through the NiCu cycles before reaching the ZnGa cycles that moderate further hydrogen burning in the region above the germanium and selenium isotopes. The 57 Cu(p, γ ) 58 Zn reaction that occurs in the NiCu cycles plays an important role in influencing the burst light curves found by Cyburt et al. We deduce the 57 Cu(p, γ ) 58 Zn reaction rate based on the experimentally determined important nuclear structure information, isobaric-multiplet-mass equation, and large-scale shell-model calculations. Based on the isobaric-multiplet-mass equation, we propose a possible order of 1 1 + - and 2 3 + -dominant resonance states and constrain the resonance energy of the 1 2 + state. The latter reduces the contribution of the 1 2 + -dominant resonance state. The new reaction rate is up to a factor of 4 lower than the Forstner et al. rate recommended by JINA REACLIB v2.2 at the temperature regime sensitive to clocked bursts of GS 1826−24. Using the simulation from the one-dimensional implicit hydrodynamic code K epler to model the thermonuclear X-ray bursts of the GS 1826−24 clocked burster, we find that the new 57 Cu(p, γ ) 58 Zn reaction rate, coupled with the latest 56 Ni(p, γ ) 57 Cu and 55 Ni(p, γ ) 56 Cu reaction rates, redistributes the reaction flow in the NiCu cycles and strongly influences the burst ash composition, whereas the 59 Cu(p, α ) 56 Ni and 59 Cu(p, γ ) 60 Zn reactions suppress the influence of the 57 Cu(p, γ ) 58 Zn reaction and diminish the impact of nuclear reaction flow that bypasses the important 56 Ni waiting point induced by the 55 Ni(p, γ ) 56 Cu reaction on the burst light curve. 

   more » « less