1.1 本试验方法是试验方法的替代方法 C698型 用于测定核级烧结混合氧化物（MOX）燃料芯块中的碳。试验方法中给出的碳测定方法 C698型 包括在高频感应炉中用氧气燃烧MOX球团中的碳，并使用热导池检测产生的二氧化碳。本试验方法中提出的碳测定方法包括在高频感应炉中用氧气燃烧MOX颗粒中的碳，然后检测产生的二氧化碳（CO 2. )使用非色散红外探测器（NDIR）。在检测CO之前，通过纤维素过滤器从载气流中剥离氧化硫 2. . 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准可能涉及危险材料、操作和设备。本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前咨询并建立适当的安全和健康实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 MOX用作核反应堆燃料。本试验方法旨在确定颗粒的碳含量是否符合燃料规范的要求。规范中给出了这些要求的示例 C833 . 5.2 该方法适用于PuO含量高达12%的所有烧结MOX颗粒 2. 当UO 2. 和PuO 2. 满足规范要求 C753 和 C757 . 方法不确定度与样品中碳的浓度有关。在较低浓度下，相对不确定性增加。当碳含量接近典型碳含量规范限值（100μg碳/g铀+钚金属）时，方法不确定度约为5 %, 但由于缺乏矩阵匹配的认证标准物质，难以确定准确的方法性能。

1.1 This test method is an alternative to Test Method C698 for the determination of carbon in nuclear grade sintered mixed oxide (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. The method for the determination of carbon presented in this test method consists of combusting carbon contained in MOX pellets with oxygen in a high-frequency induction furnace and subsequent detection of the resulting carbon dioxide (CO 2 ) 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 CO 2 . 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 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. ====== Significance And Use ====== 5.1 MOX is 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 up to 12 weight % PuO 2 when the UO 2 and PuO 2 meet the requirements of Specifications C753 and C757 . The method uncertainty is related to the concentration of the carbon in the sample. At lower concentrations, the relative uncertainty increases. At carbon contents close to the typical carbon content specification limit (100 μg carbon/g U + Pu metal) the method uncertainty is on the order of 5 %, but exact method performance is difficult to determine due to the lack of matrix matched certified reference material.