Related papers: Compound cryopump for fusion reactors
Comparing with ITER, the experimental fusion machine under constraction, the next step test fusion power plant, DEMO will be characterized by very long pulse/steady-state operation and much higher plasma volume and fusion power. The…
Asymmetries in deuterium-tritium (D-T) particle transport and divertor pumping speeds are shown to enhance tritium self-sufficiency in fusion power plants. Using a diffusive particle transport model that links the plasma core, separatrix,…
Muon catalyzed fusion in deuterium has traditionally been studied in gaseous and liquid targets. The TRIUMF solid-hydrogen-layer target system has been used to study the fusion reaction rates in the solid phase of D_2 at a target…
We revisit the assumption that reactors based on deuterium-deuterium (D-D) fusion processes have to be necessarily developed after the successful completion of experiments and demonstrations for deuterium-tritium (D-T) fusion reactors. Two…
It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these…
Helium (He) retention in tungsten (W) is a concern in fusion reactors since it could be detrimental to plasma facing components performance and influence the fusion fuel balance. He being not soluble in W, it tends to agglomerate on…
The growing demand for sustainable cryogenic operations at Fermilab has underscored the need to improve helium management, particularly at the Industrial Building 3A (IB3A) test facility. IB3A characterizes and tests superconductors,…
A three-stage metal hydride hydrogen compressor (MHHC) system based in AB2-type alloys has been set-up. Every stage can be considered as a Sieverts-type apparatus. The MHHC system can work in the pressure and temperature ranges comprised…
He-3/He-4 dilution refrigerators (DR) are very common in sub-Kelvin temperature research. We describe a pulse tube precooled DR where a separate He-4 circuit condenses the He-3 of the dilution loop. Whereas in our previous work the dilution…
Fermionic path integral Monte Carlo simulations have been applied to study the equilibrium properties of the hydrogen and deuterium in the density and temperature range of 1.6 < rs < 14.0 and 5000K < T < 167000K. We use this technique to…
We report on the achievement of quantum degeneracy in both components of a Bose-Fermi mixture of metastable helium atoms, $^4$He* and $^3$He*. Degeneracy is achieved via Doppler cooling and forced evaporation for $^4$He*, and…
We present a novel cooling method that uses the phase separation and evaporative cooling of 3He to reach and continuously maintain sub-kelvin temperatures. While less complex than a dilution refrigerator, the system performs similarly to a…
The understanding of complex and/or large vacuum systems operating at cryogenic temperatures requires a specific knowledge of the vacuum science at such temperatures. At room temperature, molecules with a low binding energy to a surface are…
We describe experiments where 2D atomic hydrogen gas is compressed thermally at a small "cold spot" on the surface of superfluid helium and detected directly with electron-spin resonance. We reach surface densities up to 5e12 1/cm^2 at…
For the first time the pellet cycle of a multiple-isotope plasma is successfully reproduced with reduced turbulent transport modelling, within an integrated simulation framework. Future nuclear fusion reactors are likely to be fuelled by…
Deuterium fractionation is known to enhance the [DCO+]/[HCO+] abundance ratio over the D/H elemental ratio of about 1e-5 in the cold and dense gas typically found in pre-stellar cores. We report the first detection and mapping of very…
Efficient removal of helium ash is a critical requirement for the operation of fusion power plants, as its accumulation can dilute the core fuel and degrade plasma performance. While past studies suggested that helium exhaust in burning…
We present a family of multi-stage preconditioners for coupled thermal-compositional-reactive reservoir simulation problems. The most common preconditioner used in industrial practice, the Constrained Pressure Residual (CPR) method, was…
We demonstrate successful "dry" refrigeration of quantum fluids down to $T=0.16$\,mK by using copper nuclear demagnetization stage that is pre-cooled by a pulse-tube-based dilution refrigerator. This type of refrigeration delivers a…
We report on the implementation of degenerate Raman sideband cooling of $^{40}$K atoms. The scheme incorporates a 3D optical lattice, which confines the atoms and drives the Raman transitions. The optical cooling cycle is closed by two…