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Published in Tom Bell, Katsuya Akamatsu, Stainless Steel 2000, 2020
H. Berns, R.L. Juse, J.W. Bouwman, B. Edenhofer
As mentioned previously, the content of nitrogen at the surface Ns is governed by Sieverts’ law; i.e. by the partial pressure of nitrogen pN2. Steels of high Cr and low Ni content may require pN2 of less than 1 bar. In this case, a hot-wall chamber furnace may be filled with a N2/Ar mixture of ambient pressure. This type of furnace offers the advantage of a rapid liquid quench to counter nitride precipitation. A hot-wall furnace for pN2>1 bar would require a special creep-resistant design and is not available.
Reaction Equilibria in Systems Containing Components in Condensed Solution
Published in David R. Gaskell, David E. Laughlin, Introduction to the Thermodynamics of Materials, 2017
13.24 A crucible containing 100.0 g of silver at 1000°C is placed in the reaction chamber of a Sieverts’ apparatus. The chamber is evacuated and filled with 50 cm3 (STP) of argon, which measures the dead volume of the chamber. An external manometer reads the pressure of argon as 0.9 atm. The chamber is reevacuated and filled with oxygen, and it is found that 251.5 cm3 (STP) are required to produce a gas pressure of 0.9 atm in the chamber. Calculate the solubility of O in the Ag (as atom percent) and calculate the value of the Sieverts’ law constant at 1000°C.
Modeling of Transport Processes in Liquid-Metal Fusion Blankets: Past, Present, and Future
Published in Fusion Science and Technology, 2023
The use of this equation assumes the dilution approximation. This requires that the concentration of the admixture C is small (below the saturation concentration, C < Cs), such that the admixture is fully dissolved in the LM and almost does not affect the flow. Equation (9) can be applied to both the tritium transport and the transport of corrosion products in a blanket, but the source term and the BCs are different between these two cases. In the case of tritium transport, the interfacial BCs are derived using the so-called Sieverts’ law. This gas law states that the solubility of a diatomic gas in metal is proportional to the square root of the partial pressure of the gas constituents.51 As the partial pressure is continuous across the interface and the solubility of tritium is different between the PbLi and RAFM steel, the Sieverts’ law suggests that the tritium concentration experiences a jump at the interface between the PbLi and RAFM:
The Source Permeator System and Tritium Transport in the TEX PbLi Loop
Published in Fusion Science and Technology, 2023
Thomas F. Fuerst, Chase N. Taylor, Paul W. Humrickhouse
The hydrogen permeation transport processes in the modular SP are shown in Fig. 3b. Hydrogen is introduced to the shell side of the SP at a pressure (in units of pascals). Sieverts’ law describes the equilibrium formed between the molecular gas-phase pressure and dissociated atomic concentration at the solid outer metal surface (in units of mol Q‧m−3). Atomic hydrogen interstitially diffuses through the SP metal membrane with a molar flux (in units of mol Q‧m−2‧s−1) as described by Fick’s first law. The hydrogen concentration on the downstream solid inner surface (in units of mol Q‧m−3) forms an equilibrium with the concentration in the liquid PbLi boundary layer (in units of mol Q‧m−3) based on the ratio of hydrogen solubility between the PbLi and SP metal.
Operational Tritium Inventories in the EU-DEMO Fuel Cycle
Published in Fusion Science and Technology, 2022
J. C. Schwenzer, C. Day, T. Giegerich, A. Santucci
An upper bound of the gaseous inventories is given when using the inlet tritium concentration over the complete length of the tube on both sides. Assuming ideal gas behavior, the molar inventory of the diatomic gas is then evaluated via the ideal gas law at the conditions given in Table II. In a steady-state diffusion-limited permeation regime, the concentration profile in a one-dimensional slab (as first approximation of the foil, neglecting its curvature) establishes linearly between the surface concentrations on both sides of the foil. The molar inventory of monatomic tritium is then , with the molar amount of atomic tritium in units of mol; the volume of the foil in units of m3; and clum and cperm the concentration of monatomic tritium in units of in the foil on the lumen side and the permeate side, respectively. This surface concentration is given by Sieverts law as , with the Sieverts constant and the partial pressure of T2 above the foil. In a first approximation, this solubility is independent of the isotopologue.13 Serra et al. report for D2 in Pd25Ag at 450°C, which is also used for tritium here.14