5.1 MOX pellets are used as a nuclear-reactor fuel. This test method is designed to determine whether the carbon content of the pellets meet the requirements of the fuel specification. Examples of these requirements are given in Specification C833.

5.2 This method is suitable for all sintered MOX pellets containing a mass fraction of PuO₂ of 12 % or less when the UO₂ and PuO₂ meet the requirements of Specifications C753 and C757. The method uncertainty is related to the mass fraction of the carbon in the sample. At lower carbon mass fraction values, the relative uncertainty increases. At carbon mass fraction values close to the typical carbon specification limit of 100 μg/g, the method relative uncertainty is on the order of 5 %, but exact method performance is difficult to determine due to the lack of a matrix matched certified reference material.

1.1 This test method for the determination of carbon in mixed oxide (MOX) pellets consists of combusting carbon with oxygen in a high-frequency induction furnace and subsequent detection of the resulting carbon dioxide (CO₂) using a non-dispersive infrared detector (NDIR). Sulfur oxide is stripped from the carrier gas stream by a cellulose filter prior to the detection of CO₂.

1.2 This test method is an alternative to Test Method C698 for the determination of carbon in nuclear grade sintered MOX fuel pellets. The method for the determination of carbon presented in Test Method C698 consists of combusting carbon contained in MOX pellets with oxygen in a high-frequency induction furnace and detecting the resulting carbon dioxide using a thermal conductivity cell.

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 may involve hazardous material, operations, and equipment. 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.