Corrosion Phenomena of Eurofeer Steel in Pb-17Li Stationary Flow at Magnetic Field

Abstract

Search of new energy sources draws the increasing attention to use for this purpose of reactors. In the Europe some years the program EUROATOM uniting scientific of the many countries for the decision of constructive problems at designing of fusion reactors operates. One of the main things in this program is the problem of liquid metals breeder blanket behaviour. Structural material of blanket should meet high requirements because of extreme operating conditions. Therefore the knowledge of the effect of metals flow velocity, temperatures and also a neutron irradiation and a magnetic field on the corrosion processes are necessary. At the moment the eutectic lead -lithium (Pb-17Li) is considered as the most suitable tritium breeder material [1–3]. In turn as a structural material have been tested both many austenitic and ferritic-martensitic steels [2–4]. As the optimum variant is considered steel EUROFER 97, which corrosion rate in liquid Pb-17Li eutectic is the least [3,4]. However, these results have been received without taking into account influence of a strong magnetic field. At the same time, this influence should be essential, as because of change of hydrodynamics of a liquid metal flow, and because of interaction of a magnetic field with a ferromagnetic steel. It has been shown in [5,6] that the magnetic field leads to increase of corrosion rate for austenitic (316L) and martensitic (1,4914) steels. Experimental data for EUROFER 97, and also a theoretical substantiation of the phenomenon are absent, that creates essential difficulties for forecasting working capacity of blanket construction. The aim of presented work were the theoretical and experimental investigations of magnetic field influence on the corrosion of EUROFER 97 steel exposed to flowing Pb-17 Li in specific designed loop.

Numerical study of corrosion of ferritic/martensitic steels in the flowing PbLi with and without a magnetic field

“…This analysis suggests scaling laws for the mass loss in rectangular ducts in the form: ML $ e pT U q m B s 0 for the side wall, and ML $ e pT U q m for the Hartmann wall, where q, s $ 0.5. The observations made on the effect of a magnetic field on corrosion rate in laminar MHD flows in a rectangular duct are in good qualitative agreement with the experimental data obtained at the Institute of Physics, Latvia (Riga experiment) [4,10,11]. Namely, the increase of the corrosion rate by factor of 2-3 when the magnetic field is applied and much higher corrosion rates at the inlet section can be seen in both experimental and present numerical data.…”

“…In the case of the Hartmann walls, the thickness of the Hartmann boundary layer is smaller than that of the concentration boundary layer, while in the case of the side walls both boundary layers are comparable in thickness. The observed differences in the corrosion behavior between the Hartmann and side walls suggest that in MHD rectangular duct flows, most of the mass loss occurs from the side walls, whereas all experimental studies [4,10,11] have focused on the Hartmann walls.…”

“…The main effect of the magnetic field on corrosion processes seems to be due to changes in the velocity profile, mostly due to steeper velocity gradients in the near-wall region and associated changes in the temperature distribution in the flow and at the material interface with the solid metal. Only a few experimental studies [4,[9][10][11] have been performed in the presence of a magnetic field, predicting significant increase in the wall mass loss, up to 2-3 times, if a magnetic field is applied. These results still need to be explained and/or reexamined.…”