ASTM D8377-21 pdf free download.Standard Guide for High Temperature Strength Measurements of Graphite Impregnated with Molten Salt.
1.1 This guide covers the best practice for strength incasurements at elevated temperature of graphite impregnated with molten salt.
1.2 The values stated in SI units are to he regarded as standard. No other units of measurement are included in this standard.
3. Summary of Guide
3.1 There is currently a set of ASTM standards as stated in
2.1 that can be applied to graphite for different strength measurements (Test Methods C65 1, C695, C749, D8289). Each of these standards has been developed specifically to provide a method of measurement for graphite as a single material. However, in some applications such as in molten salt reactors, graphite components are submerged in a molten salt. In order to assess the effect of molten salt on graphite components, a method may be necessary for the measurement of strength for graphite specimens both impregnated with molten salt and at elevated temperatures (see Section 4). The objective of this guide is to provide advice on the application of selected standards for graphite specimens impregnated with molten salt and tested at elevated temperatures. This includes transportation of graphite specimens impregnated with molten salt, temperature measurement, equipment for measuring compressive, tensile, or flexural strength at elevated temperature. and safe handling of the molten salt.
4. Significance and Use
4.1 The Molten Salt Reactor is a nuclear reactor which uses graphite as reflector and structural material, and molten salt as coolant. The graphite components will be submerged in the molten salt during the lifetime of the reactor. The porous structure of graphite may lead to molten salt permeation, which can affect the thermal and mechanical properties of graphite. Consequently, it may be necessary to measure the various strengths of the manufactured graphite materials after impregnation with molten salt and before exposure to the reactor environment in a range of test configurations in order for designers or operators to assess their performance.
4.2 For gas-cooled reactors, the strength of a graphite specimen is usually measured at room temperature. However, for molten salt reactors, the operating temperature of the reactor must be higher than the melting temperature of the salt, and so the salt will be in solid state at room temperature. Consequently, room temperature measurements may not be representative of the performance of the material at its true operating conditions. It is therefore necessary to measure the strength at an elevated temperature where the salt is in liquid form.ASTM D8377 pdf download.