Chemistry control analysis of lead alloys systems to be used as nuclear coolant or spallation target

Abstract

This study presents the lead alloy system chemistry analysis for use as nuclear coolant or spallation target in ADS related systems in order to set down the needs for purification processes and monitoring. The study is limited here to the two main impurities, oxygen and iron. The analysis of the various potential pollution sources that may occur during the various operating modes is given, as well as a first pollution rate assessment. In order to limit the consequences in term of contamination (clogging) and corrosion, it is necessary to define specifications for operation as regards oxygen and iron content in the fluid. As iron cannot be measured and controlled up to now, the best specification is to set the oxygen as high as possible, defined by the cold leg interface temperature to ensure tolerable contamination, in order to maximize the oxidation area to ensure corrosion protection by self-healing oxide layer for the entire system.

Corrosion behavior of steels in liquid lead–bismuth with low oxygen concentrations

“…The active oxygen control technique in LBE has been one of key technologies to form self-heeling protective oxides on steels and to prevent slag formation and plugging [3][4][5]. The oxygen concentration was controlled within the range between Fe 3 O 4 formation and PbO formation.…”

“…Schematic diagram about effectiveness of oxide films as a corrosion barrier in liquid LBE. In the active control of oxygen in liquid LBE[3][4][5], the lower and upper limits are set to the oxygen potential of Fe 3 O 4 formation and that of PbO formation, respectively.Fig. 18.…”

A mass transfer correlation for packed bed of lead oxide spheres in flowing lead–bismuth eutectic at high Péclet numbers

“…3 The parameter y + is used in CFD to determine the dimensionless thickness of the boundary layer. 4 Low-Reynolds models use a refined mesh (y + $ 1) close to wall in order to resolve directly the viscous sub-layer. each sphere and the wall, which limit the use of a structured mesh.…”

“…The dissolved oxygen activity should be maintained above the dissolution limit of the protective oxide layer of the structural materials to reduce fast dissolution of metallic elements. On the other hand, the dissolved oxygen activity should be kept below the solubility limit of oxygen in LBE to avoid precipitation of solid lead oxide (PbO) [4]. In order to maintain the oxygen activity within these limits, oxygen should be supplied precisely and continuously to the system to compensate for the consumption of oxygen by the oxidation of fuel cladding and structural steels.…”

An approach to quantifying the chemical conditions necessary to form a magnetite layer on steels in lead and lead–bismuth eutectic

“…The Russian nuclear submarine research program found a solution to this problem in using oxygen concentration control in the coolant to promote self-healing oxide layer formation on the steel surfaces [30]. Many excellent and comprehensive articles explaining the fundamentals and details of this process and how it is controlled have been published by CEA [31][32][33], LANL [34][35][36][37][38], FZK [39,40] and other groups and researchers previously. Much of the current state of knowledge is summarized in the 2007 OEC/NEA handbook [29].…”