Thermophysical properties of high-density, sintered monoliths of yttrium dihydride in the range 373–773 K

Shivprasad, Aditya; Vogel, Sven C.; Mehta, Vedant; Cooper, M.W.D.; Saleh, Tarik A.; White, Joshua T.; Wermer, Joseph R.; Luther, Erik; Trellue, Holly R.

doi:10.1016/j.jallcom.2020.156303

Cited by 17 publications

(18 citation statements)

References 43 publications

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“…Parker also reported heat capacity, as measured using an ice calorimeter, in the temperature range of 273 to 1081 K [13]. More recently, Ito, et al and Shivprasad, et al measured the heat capacity of yttrium dihydride using DSC [14], [16]. It is also observed that the results of DFT modeling by Shivprasad et al are also consistent with the experimental data up to a temperature of approximately 700 K (427 ℃).…”

Section: Heat Capacitymentioning

confidence: 68%

“…Above this temperature, the modeling results and experimental data appear to diverge. This could be due to changes in hydrogen content experimentally from passing from the two-phase to the single-phase region or, as was hypothesized by Shivprasad et al, to the initial formation of Frenkel pair defects [14]. However, the concentration of gas impurities for each of the referenced studies is not known.…”

Section: Heat Capacitymentioning

confidence: 94%

“…The thermophysical properties of metal hydrides have been measured using a variety of techniques. Thermal expansion and the coefficient of thermal expansion (CTE) have been measured using dilatometric methods, as well as XRD and neutron diffraction [11]- [14]. With the current ability to obtain high-quality neutron diffraction data, this technique is also preferred for thermal expansion measurements of metal hydrides.…”

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

“…Like the phase formation thermodynamics, heat capacity is also traditionally measured using calorimetric methods [13], [15], [16]. Thermal diffusivity may be measured using laser flash analysis, where the sample is exposed to a laser and the measured heat rise across the sample is an indication of the material thermal diffusivity [16], [14]. Finally, thermal conductivity may be either measured via a thermal Advanced Moderator Material Handbook 09/30/2020 3 conductivity probe or from the product of the density calculated from the CTE, the heat capacity, and the thermal diffusivity, all as a function of temperature.…”

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

“…In addition to characterization of the material properties, nuclear cross section data to predict performance of the material is important to understand. Modeling of material performance such as interatomic forces and crystal lattice parameters can occur using DFT codes [14], [20]- [24]. Validation of results from DFT codes has occurred using neutron time-of-flight powder diffraction and other measurements.…”

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

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Advanced Moderator Material Handbook

Shivprasad

Cutler

Jewell

et al. 2020

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High hydrogen density moderators such as metal hydrides are an important research topic within the DOE NE Microreactor Research, Development, and Deployment (RD&D) Program due to their ability to retain hydrogen to much higher temperatures than other hydrogenous media. This class of moderators, which includes yttrium dihydride (YH2), thermalizes neutrons in the system such that the overall fuel mass or the required uranium enrichment in the system can be significantly reduced. Knowledge of material properties, both in the as-fabricated and irradiated state, are important to understanding moderator performance during steady-state and transient reactor operation. Provided in this document is the Advanced Moderator Material Handbook, which provides a detailed summary of the literature data on yttrium dihydride, thermomechanical and other property data, and a critical evaluation of that data. This handbook also provides a description of ongoing experiments to understand in-reactor performance, such as irradiations in ATR, as well as nuclear data from an integral critical experiment at NCERC. The majority of this report focuses on measured values but also includes some modeling results for comparison where applicable.

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Section: Heat Capacitymentioning

confidence: 68%

Section: Heat Capacitymentioning

confidence: 94%

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

Section: Summary Of Measurement Techniquesmentioning

confidence: 99%

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Advanced Moderator Material Handbook

Shivprasad

Cutler

Jewell

et al. 2020

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Effects of Hydrogen Redistribution at High Temperatures in Yttrium Hydride Moderator Material

Trellue

Long

Luther

et al. 2021

JOM

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Advanced materials development, manufacturing, and modeling capabilities for innovative reactor designs support nuclear security and mission-focused science through enhanced technology for safer and more efficient and secure production of nuclear energy. The high temperature moderator material yttrium hydride poses a significant enhancement in small reactor design by thermalizing (slowing down) neutrons and decreasing the required fuel mass for a system. The research presented here supports understanding hydrogen distribution in yttrium hydride through: (1) the development of neutron-based hydrogen imaging and crystallographic characterization that allows us to understand fundamental diffraction behaviors and to observe changes in hydrogen distribution as a function of temperature and (2) subsequent neutron multiplication (reactivity) effects of changes in hydrogen distribution using measurement-based cross sections in a sample microreactor design. The main conclusions from the work are that: (1) hydrogen does not redistribute significantly below temperatures of 800°C in yttrium hydride and (2) hydrogen redistribution affects the reactivity slightly but not significantly.

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