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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.

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At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Experimental Investigation of Melting and Solidification Processes of Phase Change Material Heat Exchanger

Rapid development and validation of PCM embedded heat exchangers (PCM-HX) concepts warrant a purpose-built test bench. This paper describes a test facility built for testing various PCM-HX configurations and phase change temperatures that will serve to validate the performance of novel PCM-HX designs. The entire test rig is placed in a temperature-controlled environmental chamber. Inside the PCM-HX containers, up to 48 T-type thermocouples can be spatially distributed on and around the tubes depending on the HX type to capture the phase change process over time. In this paper, a straight tube embedded in PCM having a phase change temperature of 37°C in cylindrical containers is tested. The PCM-HX uses water as an in-tube working fluid. Based on the measured data, the energy balance is analyzed, and its temperature distribution is presented. Here, the maximum deviation between the predicted stored energy and the energy stored calculated from experimental measurements is less than 5%.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Liquid Condensation and Solidification Behavior of Hydrogen Isotopes in Foams

A foam shell, 1.2 mm outer diameter with a 35 μm thick foam layer, is used to quickly form a solid deuterium layer for ICF. Figures show the visible light microscope image and a corresponding schematic representation. In each case, images show the empty foam shell, with the dark and light patches due to the foam imperfections; the foam shell with liquid deuterium filling the foam (in this case, the liquid level exceeds the foam level because the deuterium will shrink when it freezes); and an image of the shell taken 10 minutes after the center image, after the temperature was reduced by 2 K to freeze the deuterium. This image shows that the majority of the solid deuterium has no observable defects, with the exception of the isolated crystal that formed on the foam surface. The next step is to get the correct level of liquid and cooling rate to prevent the extra crystal on the surface. In contrast, typical ICF DT fuel layers require ~13 hours to solidify in order to be defect free with a success rate of approximately 20%.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Foam and Unreacted Material Reduction in Magnesium Oxysulfate for SRPPF Waste Solidification

A magnesium oxysulfate (MOS) grout formulation has been proposed to solidify the liquid effluent from the Savannah River Plutonium Processing Facility (SRPPF) Aqueous Recovery System (ARS). This formulation uses a combination of light-burnt MgO, anhydrous MgSO 4 , and dead-burnt MgO resulting in a grout with good mixability and acceptable density. The setting time for the grout is within the operational limits of the SRPPF facility and the leachate pH is ~9.4, which is within the assumed pH range of the brine from the Waste Isolation Pilot Plant (WIPP). When first tested at the 1-gallon small-scale and 55-gallon full-scale, there was a significant foam layer that raised concerns of a nonhomogeneous final form. A nonhomogeneous mixture could have variable density throughout the waste form and therefore allow for unequal shielding. To reduce the potential for unequal shielding in the final form, a series of foam reduction tests were carried out and a final formulation of 28 wt% light burnt MgO, 10 wt% MgSO 4 , and 62 wt% dead burnt MgO was used to remove the foam in under two hours while still maintaining a mix that has an acceptable density, mix time, peak temperature, and set time.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Waste Form Development for Solidification of Liquid Secondary Wastes to Support Hanford Direct Feed Low Activity Waste Vitrification - 17484

The US Department of Energy/Office of River Protection DOE/ORP has funded a program led by Washington River Protection Solutions (WRPS) to develop and test cementitious waste forms for immobilization of liquid secondary waste (LSW) at the Hanford site in Southeastern Washington State. The LSW comprises a concentrated brine from processing liquid effluents at Hanford's Effluent Treatment Facility. The liquid effluents include condensates from the 242-A tank waste evaporator and future offgas condensates from the Low Activity Waste (LAW) Vitrification Facility. To facilitate waste form formulation development and testing, WRPS developed LSW simulants and engaged subject matter experts at the Savannah River National Laboratory (SRNL) and Pacific Northwest National Laboratory (PNNL). This paper describes results of recent work done to develop and test a grout formulation tailored to address the elevated sulfate levels in Hanford LSW. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Dual solidification process of BN-350 liquid radioactive waste using high technology polymers and newly designed encapsulation techniques - 15198

Application of high technology polymers no.910 and no.960 manufactured by NOCHAR, USA, for treatment of liquid radioactive waste (LRW) have demonstrated good results at test sites worldwide. At the BN-350 site (Aktau, Kazakhstan), the tests were conducted successfully with contaminated oil, alkaline and salt containing LRW. This paper represents the results of immobilization of NOCHAR polymers, saturated with LRW, into solid matrix to comply with Kazakhstan regulatory requirements for long term storage and/or disposal. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Solidification technology for organic liquid waste combined with solid materials from Cernavoda NPP, Romania - 16453

Canadian Deuterium Uranium (CANDU{sup R}) reactor designs were initially developed in the late 1950's and 1960's by the Atomic Energy of Canada Limited (AECL) in partnership with Ontario Power Generation. CANDU{sup R} 6 reactors are Pressurized Heavy Water Reactors (PHWRs), with an integrated containment system and are designed as either multi or single unit systems. Two single CANDU 6 systems are currently operating at Cernavoda with an additional two units expected to be brought online in the near future. The radioactive waste produced by the plant is currently stored in a waste interim storage facility located on-site. The main sources of radioactive waste in a CANDU plant are: - Primary Heat Transport (PHT) systems, - Moderator systems, - Other sources of radionuclides. The radioactive waste management system at Cernavoda Nuclear Power Plant (NPP) was designed to maintain acceptable levels of safety for workers and to protect human health and the environment from exposure to unacceptable levels of radiation. During the operation of the Cernavoda NPP, a series of waste streams have been generated for waste treatment purposes. One important waste stream is the combination of solid materials and liquid organic waste, creating flammable solids. Flammable solids represent solid materials, such as cloth, plastic, contaminated with oil containing gamma nuclides and H-3 from maintenance activities. This paper explores a method to solve the problem of liquid residues on solid materials by the application of absorbent materials. The existence of liquid residues on solid materials is a common problem at nuclear power stations globally. The primary issue centers on an effective method of eliminating the liquid to allow for the final acceptance and disposal of the solid waste by regulators. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

The impact of oxygen precipitation on dislocation generation at small angle grain boundaries during seed‐assisted directional solidification of silicon

We have investigated the source of dislocations generated during growth and subsequent cooling of quasi‐monocrystalline silicon. Bi‐crystals of silicon separated by ∼5.2° tilt small angle grain boundary have been directionally solidified at two different pulling rates, i.e., 3 and 13 μm s −1 . We observe higher density of grain boundary‐associated dislocations at the ingot pulled at a lower rate. This observation is explained by the impact of oxygen precipitation behavior at the grain boundary.

Autruffe, Antoine↗