Quantification of the Long-Term Performance of Steels T91 and 316L in Oxygen-Containing Flowing Lead-Bismuth Eutectic at 550°C

Abstract

The long-term performance of ferritic/martensitic steel T91 and austenitic 316L in oxygen-containing flowing lead-bismuth eutectic at 550°C was investigated by exposing the materials for up to 15,000 h in the CORRIDA loop. The velocity of the liquid-metal flow was 2 m/s and the concentration of dissolved oxygen averaged 1.6×10−6 mass %. The resulting corrosion processes and products were analyzed and quantified using metallographic methods.

Long term corrosion resistance of alumina forming austenitic stainless steels in liquid lead

“…Previous studies in the literature [7][8][9][10][11][12][13][14][15] have shown similar behavior in LBE for the same type of alloys and test conditions, and thus the presented results were expected. Although both alloys were attacked by liquid lead, the magnitudes of the attacks were different.…”

“…The predominant issue when designing LFR systems is the choice of corrosion resistant steels [5,6]. Liquid lead and lead bismuth eutectic (LBE) attacks structural steels, such as AISI 316L and 15-15 Ti at temperatures in excess of 500°C, thus limiting the operation temperature of the reactor [7][8][9][10][11][12][13][14][15]. Alumina forming FeCrAl alloys have been proposed as a promising solution, both as bulk steels [5,[16][17][18][19][20][21][22] and more recently through surface alloying [8,23,24].…”

Long-term corrosion of austenitic steels in flowing LBE at 400 °C and 10 −7 mass% dissolved oxygen in comparison with 450 and 550 °C

“…In both cases the near-surface zone of the steel does not show depletion in steel constituents beyond the corrosion front. Similar corrosion appearances were observed in LBE with 10 À6 mass% dissolved oxygen, but as a result of local failure of spinel layer (AO), representing general corrosion mode, or Cr-based oxide film (PS) [5,17,18]. Both, selective and non-selective leaching are governed by the transport of solved elements in the boundary layer and subsequent transfer to the liquid metal bulk [6].…”

“…At 10 À6 mass% dissolved oxygen, the austenitic steels mostly show AO accompanied by spinel formation [5,17,18]. With time, after local failure of scale, a local SBA via selective leaching occurs.…”

Corrosion kinetics of Steel T91 in flowing oxygen-containing lead–bismuth eutectic at 450°C

“…at the interface with LBE and steel, respectively. Some oxide has penetrated the steel along grain boundaries, but, in contrast to the performance of the same material at higher temperature [26,36], an important internal oxidation zone has not developed underneath the spinel layer. The spinel layer itself has a layered sub-structure with local Cr-enrichment especially at the spinel/steel interface (Fig.…”