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The purification of salt is indispensable for mitigating the corrosion of structural materials for molten salt reactors or other molten salt applications. This study develops a salt-purification system to synthesize and purify NaF-KF-UF4 salt (FUNaK) using Ar purging and hydrofluorination of impurities. Chronoamperometry is also used to remove metallic impurities in the hydrofluorinated FUNaK. This purified FUNaK is then used for a static corrosion test of stainless steel 316H (SS316H) to study the effectiveness of salt purification in mitigating its corrosion. For comparison, results from a previous study about the corrosion of SS316H by thermally purified FUNaK are used. FUNaK with UF3 is also synthesized for a static corrosion test with the same condition to investigate the impact of UF3 on corrosion. The results show that the corrosion of SS316H is significantly reduced by using the chemically purified FUNaK compared to thermally purified FUNaK. [ABSTRACT FROM AUTHOR]

The present study tested Type 316L stainless steel (SS316L) with and without a preformed boride layer in a molten chloride salt at 800°C for 100 h. The results showed that the preformed boride layer on the specimen surface is stable and can completely inhibit the depletion of Cr of the steel. No attack layer by the molten salt was detected for the specimen with the preformed boride layer. Therefore, the data from the present study indicate that a preformed boride layer can be a protective layer to mitigate the corrosion of SS316L by molten salts. [ABSTRACT FROM AUTHOR]

The characteristics of pitting corrosion of Type 304L stainless steel (SS) exposed to highly concentrated chloride solutions were studied through the evaluation of the corrosion potential, the pitting potential, the structure of the passive layer and the statistics of pitting depth and density. Both as-received and weld metal samples were studied. The weld metal sample was machined from the welding zone of a butt weld of Type 304L SS. The results showed an accelerated anodic dissolution and depressed film resistance at the welding zone, but no dramatic change on pitting corrosion was observed from the statistics of pitting during the test duration up to 720 h. The pitting corrosion resistance was significantly affected by the chloride concentration and slightly affected by the temperature under the investigated conditions. [ABSTRACT FROM PUBLISHER]