Molten salt environment creep testing extensometry system

A system for creep testing, fatigue testing, creep-fatigue testing, or relaxation testing of materials in a high-temperature molten salt environment, the system comprising:

• a vessel having an upper end and a lower end, the vessel comprising one or more gas ports for maintaining a controlled inert gas environment within the vessel;
• a test specimen having a tubular gage portion for containing a molten salt;
• a first pull rod portion positioned within the vessel and extending downwardly from or through the upper end of the vessel, the first pull rod portion having a first specimen grip at a lower end of the first pull rod portion, the first specimen grip coupled to an upper end of the test specimen;
• a second pull rod portion positioned within the vessel below the first pull rod portion, the second pull rod having a second specimen grip at an upper end of the second pull rod portion, the second specimen grip coupled to a lower end of the test specimen;
• a basin ring coupled to the lower end of the test specimen and configured to catch the molten salt if the molten salt leaks from the test specimen;
• an extensometry system configured to measure elongation of a test specimen while a load is applied, the extensometry system comprising:
• a fixed axial member coupled to the first pull rod portion or the upper end of the test specimen;
• and
• an axially translating member extending through the basin ring, wherein the axially translating member and the basin ring moves down relative to the fixed axial member as the test specimen elongates.