ASTM C1816-24 - Standard Practice for The Ion Exchange Separation of Small Volume Samples Containing Uranium, Americium, and Plutonium Prior to Isotopic Abundance and Content Analysis

1.1 This practice is an alternative to Practice C1411 for the ion exchange separation in small mass samples (~5 μg of plutonium and up to 0.5 mg of uranium in 1 mL of solution) of uranium and plutonium from each other and from other impurities for subsequent isotopic abundance and content analysis by thermal ionization mass spectrometry (TIMS). In addition to being adapted to smaller sample sizes, this practice also avoids the use of hydrochloric acid (HCl) and hydrofluoric acid (HF) and does not require the use of two anion exchange columns as required in Practice C1411.

1.2 In chemically unseparated samples isobaric nuclides at mass 238 (²³⁸U and ²³⁸Pu), and mass 241 (²⁴¹Pu and ²⁴¹Am) will be measured together thus compromising the accuracy of the results of isotopic composition of Pu. Therefore, chemical separation of elements is essential prior to isotopic analyses. Concentrations and volumes given in the paragraphs below can be modified for larger sample sizes, different types of anion exchange resin, etc.

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

1.4 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.

1.5 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.