ASTM C776-17(2022)

ABSTRACT This specification covers sintered uranium dioxide pellets containing 235U for use in nuclear reactors. Chemical requirements include uranium content, impurity content, stoichiometry, and moisture content. Maximum concentration limits are specified for impurity elements such as: aluminum, carbon, calcium+magnesium, chlorine, chromium, cobalt, fluorine, hydrogen, iron, nickel, nitrogen, silicon, and thorium. Chemical analyses shall be performed. Nuclear requirements include isotopic content and equivalent boron content. The following are physical characteristics of the material: dimensions, pellet density, grain size and pore morphology, pellet integrity – SCOPE 1.1 This specification is for finished sintered UO2 pellets. It applies to UO2 pellets containing uranium (U) of any 235U concentration for use in nuclear reactors. 1.2 This specification recognizes the presence of reprocessed U in the fuel cycle and consequently defines isotopic limits for UO2 pellets made from commercial grade UO2. Such commercial grade UO2 is defined so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated U. UO2 falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel fabrication plant or in the fuel design. 1.3 This specification does not include (a) provisions for preventing criticality accidents, (b) requirements for health and safety, (c) avoidance of hazards, or (d) shipping precautions and controls. Observance of this specification does not relieve the user of the obligation to be aware of and conform to all federal, state, and local regulations pertaining to possessing, shipping, processing, or using source or special nuclear material. Examples of U.S. Government documents are Code of Federal Regulations (Latest Edition), Title 10, Part 50, Title 10, Part 70, Title 10, Part 71, and Title 49, Part 173. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 The following precautionary caveat pertains only to the technical requirements portion, Section 4, of this specification: 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 or regulatory limitations prior to use. 1.6 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.