ASTM C1458-24

1.1 This test method describes the nondestructive assay (NDA) of plutonium, tritium, and ²⁴¹Am using heat flow calorimetry. For plutonium the typical range of applicability, depending on the isotopic composition, corresponds to ~0.1 g to ~12 kg quantities while for tritium the typical range is from ~0.001 g to ~400 g. This test method can be applied to materials in a wide range of container sizes up to 380 L. It has been used routinely to assay items whose thermal power ranges from 0.001 W to 135 W.

1.2 This test method requires knowledge of the relative abundances of the plutonium isotopes and the ²⁴¹Am/Pu mass ratio to determine the total plutonium mass.

1.3 This test method provides a direct measure of tritium content.

1.4 This test method provides a measure of  ²⁴¹Am either as a single isotope or mixed with plutonium.

1.5 The values stated in SI units are to be regarded as standard. Half-life values expressed in years are also regarded as standard, where one year equals 365.25 days. No other units of measurement are included in this standard.

1.6 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.

1.7 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.