scholarly journals Reduced heat flow in light water (H2O) due to heavy water (D2O)

2008 ◽  
Vol 93 (3) ◽  
pp. 034101 ◽  
Author(s):  
William R. Gorman ◽  
James D. Brownridge
Keyword(s):  
Heat Flow ◽  
Heavy Water ◽  
Light Water ◽  
Reduced Heat Flow

Tailoring neutron beam properties by target-moderator-reflector optimisation

2021 ◽  
pp. 1-16
Author(s):  
Paul Zakalek ◽  
Jingjing Li ◽  
Sarah Böhm ◽  
Ulrich Rücker ◽  
Jörg Voigt ◽  
...  
Keyword(s):  
Neutron Beam ◽  
Heavy Water ◽  
Neutron Production ◽  
Neutron Sources ◽  
Light Water ◽  
Cold Neutrons ◽  
Efficient Coupling ◽  
Borated Polyethylene ◽  
Compact Design ◽  
Neutronic Performance

Compact accelerator-driven neutron sources allow to operate multiple optimised target-moderator-reflector (TMR) units adapted to the requirements of the respective instruments. The compact design of the TMR units allows an efficient coupling of neutron production, neutron moderation and extraction, but requires a novel way of optimisation. The neutronic performance of different TMR units based on polyethylene, heavy water and a mixture of heavy and light water moderators together with Pb and Be reflectors and a borated polyethylene absorber is discussed. Extraction channels for thermal and cold neutrons are investigated regarding the energy and time spectra.

scholarly journals Three- and Four-Site Models for Heavy Water: SPC/E-HW, TIP3P-HW, and TIP4P/2005-HW

2021 ◽  
Author(s):  
Johanna-Barbara Linse ◽  
Jochen S. Hub
Keyword(s):  
Molecular Dynamics ◽  
Heavy Water ◽  
Room Temperature ◽  
Deuterium Oxide ◽  
Water Structure ◽  
Light Water ◽  
Pair Potentials ◽  
Effective Pair ◽  
Water Models ◽  
Dynamics Simulations

Heavy water or deuterium oxide, D<sub>2</sub>O, is used as solvent in various biophysical and chemical experiments. To model such experiments with molecular dynamics simulations, effective pair potentials for heavy water are required that reproduce the well-known physicochemical differences relative to light water. We present three effective pair potentials for heavy water, denoted SPC/E-HW, TIP3P-HW, and TIP4P/2005-HW. The models were parametrized by modifying widely used three- and four-site models for light water, with aim of maintaining the specific characteristics of the light water models. At room temperature, the SPC/E-HW and TIP3P-HW capture the modulations relative to light water of the mass and electron densities, heat of vaporization, diffusion coefficient, and water structure. TIP4P/2005-HW captures in addition the density of heavy water over a wide temperature range.

scholarly journals Three- and Four-Site Models for Heavy Water: SPC/E-HW, TIP3P-HW, and TIP4P/2005-HW

2021 ◽  
Author(s):  
Johanna-Barbara Linse ◽  
Jochen S. Hub
Keyword(s):  
Molecular Dynamics ◽  
Heavy Water ◽  
Room Temperature ◽  
Deuterium Oxide ◽  
Water Structure ◽  
Light Water ◽  
Pair Potentials ◽  
Effective Pair ◽  
Water Models ◽  
Dynamics Simulations

Heavy water or deuterium oxide, D<sub>2</sub>O, is used as solvent in various biophysical and chemical experiments. To model such experiments with molecular dynamics simulations, effective pair potentials for heavy water are required that reproduce the well-known physicochemical differences relative to light water. We present three effective pair potentials for heavy water, denoted SPC/E-HW, TIP3P-HW, and TIP4P/2005-HW. The models were parametrized by modifying widely used three- and four-site models for light water, with aim of maintaining the specific characteristics of the light water models. At room temperature, the SPC/E-HW and TIP3P-HW capture the modulations relative to light water of the mass and electron densities, heat of vaporization, diffusion coefficient, and water structure. TIP4P/2005-HW captures in addition the density of heavy water over a wide temperature range.

Tritium Decontamination of Contaminated System With Tritiated Heavy Water by Drying Treatment

2016 ◽  
Author(s):  
Haruhiko Kadowaki ◽  
Akira Matsushima ◽  
Yoshiaki Nakajima
Keyword(s):  
Heavy Water ◽  
Water Purification ◽  
Thermal Reactor ◽  
Vacuum Drying ◽  
Light Water ◽  
Long Period ◽  
Water Purification System ◽  
Purification System ◽  
Drying Treatment ◽  
Rotary Type

Advanced thermal reactor “FUGEN” is a heavy water-moderated boiling light water-cooled pressure tube-type reactor. Because tritium had been generated in the heavy water during the reactor operation, the heavy water system and helium system were contaminated by tritium. The chemical form of the tritium was water molecule in FUGEN. For the drying treatment of heavy water contaminated by tritium, air-through drying and vacuum drying were applied to the system drying. The air-through drying has an advantage that can reduce the risk of tritium leakage, because the drying equipment can be constructed as closed-circuit. On the other hand, the vacuum drying can dry the whole system because dead end of piping can be aspirated. Helium system, heavy water purification system and rotary type dehumidifier were chosen for the object in this study. It was demonstrated that both methods were effective for drying treatment of heavy water in system. Helium system, low-contamination and non inclusion, could finish the vacuum drying rapidly. However, Heavy water purification system needed long period for drying treatment. The result showed that it needed long period to dry up if the objects include the adsorbent of water such as alumina pellet, resin and silica gel. But it can be accelerated by replacement absorbed heavy water to light water from the result of drying treatment of the rotary type dehumidifier.

Pistons of DI-Diesel Engines with Reduced Heat Flow

1989 ◽  
Author(s):  
Peter Reipert ◽  
Siegfried Mielke ◽  
Gunder Essig
Keyword(s):  
Heat Flow ◽  
Diesel Engines ◽  
Reduced Heat Flow

scholarly journals Heeding the Lessons of History

2012 ◽  
Vol 134 (07) ◽  
pp. 28-33
Author(s):  
Gail H. Marcus
Keyword(s):  
Heavy Water ◽  
Economic Performance ◽  
First Generation ◽  
Passive Safety ◽  
Light Water Reactors ◽  
Light Water ◽  
Reactor Technology ◽  
Technological Developments ◽  
Water Reactors ◽  
Over Time

This article focuses on learning from the successes and failures of the first-generation reactor development. Reactor designs have evolved over time to meet increasingly rigorous demands for safety and to take advantage of technological developments to improve their economics, but these changes have been piecemeal. Although light-water reactors are the most common reactor technology in use today, heavy-water reactors were actually developed earlier. The earliest demonstration of a heavy-water moderated and cooled reactor took place in May 1944 at Argonne. The reasons for the domination of water-cooled reactors, and particularly of light-water reactors, are complex. The article suggests that it is interesting to speculate on how the new initiative to develop more advanced designs may play out. There are already strong pressures to focus on the integral light-water design; based on well-understood light-water technology, the argument goes, such designs will be much easier to develop and license. In the longer term, however, some of the non-light water reactors could ultimately achieve greater levels of passive safety, efficient fuel utilization, economic performance, and proliferation resistance.

scholarly journals VALIDATION OF THE POLARIS CANDU EXTENSION FOR LATTICE PHYSICS

2021 ◽  
Vol 247 ◽  
pp. 02009
Author(s):  
Simon Younan ◽  
David Novog
Keyword(s):  
Heavy Water ◽  
Reasonable Agreement ◽  
Method Of Characteristics ◽  
Nuclear Data ◽  
Light Water Reactor ◽  
Minimal Amount ◽  
Light Water ◽  
Speed Up ◽  
Shielding Methods ◽  
Good Agreement

Polaris is a new lattice physics package, introduced in version 6.2 of the SCALE package. It uses a method of characteristics transport solver and the embedded self-shielding method. It is able to model light water reactor systems with a minimal amount of input. The goal of this project is to include support for CANDU models in Polaris for the next version of SCALE. So far, the model has been implemented and shown to give results with reasonable agreement to other SCALE sequences. This study extends the model to a reflector model, and shows that most quantities agree well with other codes. Some quantities, such as keff and assembly discontinuity factors, are sensitive to meshing. This study also performs a correlation between the TRITON and Polaris sequences using Sampler to perturb the nuclear data. Overall, there is good agreement between the two codes, though coolant void reactivity is only moderately correlated, likely due to the differences in resonance self-shielding methods. Additionally, this work shows that a coarser mesh can be used to speed up uncertainty calculations compared to the mesh used for a best estimate. Finally, this work shows that the mass lumping feature in CENTRM significantly affects heavy water moderated calculations, whether using TRITON or calculating self-shielding factors, and thus should be disabled for heavy water calculations.

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