ASTM C1457-18

5.1 Uranium dioxide is used as a nuclear-reactor fuel. Gadolinium oxide is used as an additive to uranium dioxide. In order to be suitable for this purpose, these materials must meet certain criteria for impurity content. This test method is designed to determine whether the hydrogen content meets Specifications C753, C776, C888, and C922.

1.1 This test method applies to the determination of hydrogen in nuclear-grade uranium oxide powders and pellets to determine compliance with specifications. Gadolinium oxide (Gd₂O₃) and gadolinium oxide-uranium oxide powders and pellets may also be analyzed using this test method.

1.2 This standard describes a procedure for measuring the total hydrogen content of uranium oxides. The total hydrogen content results from absorbed water, water of crystallization, hydro-carbides and other hydrogenated compounds which may exist as fuel's impurities.

1.3 This test method covers the determination of 0.05 to 200 μg of residual hydrogen.

1.4 This test method describes an electrode furnace carrier gas combustion system equipped with a thermal conductivity detector.

1.5 The preferred system of units is micrograms hydrogen per gram of sample (μg/g sample) or micrograms hydrogen per gram of uranium (μg/g U).

1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.