【国外标准】 Standard Specification for Blended Uranium Oxides with 235U Content of Less Than 5 % for Direct Hydrogen Reduction to Nuclear Grade Uranium Dioxide (Withdrawn 2013)

This specification covers blended uranium oxides with a 235U content of less than 5% for direct hydrogen reduction to nuclear grade uranium dioxide. For commercial-grade uranium oxide with an isotopic content of 235U between that of natural uranium and 5%, the isotopic limits shall apply. Physical and chemical requirements include: uranium content, oxygen-to-uranium ratio, impurity content, equivalent boron content, bulk density, moisture content, ability to flow, particle size, and reduction and sinterability. Maximum concentration limit is specified for impurity elements such as: aluminum, barium, beryllium, bismuth, calcium+magnesium, carbon, chlorine, chromium, cobalt, copper, fluorine, iron, lead, manganese, molybdenum, nickel, phosphorus, silicon, sodium, tantalum, thorium, tin, titanium, tungsten, vanadium, and zinc. The identity of a lot shall be retained throughout.1.1 This specification covers blended uranium trioxide (UO3), U3O8, or mixtures of the two, powders that are intended for conversion into a sinterable uranium dioxide (UO2) powder by means of a direct reduction process. The UO2 powder product of the reduction process must meet the requirements of Specification C 753 and be suitable for subsequent UO2 pellet fabrication by pressing and sintering methods. This specification applies to uranium oxides with a 235U enrichment less than 5 %.1.2 This specification includes chemical, physical, and test method requirements for uranium oxide powders as they relate to the suitability of the powder for storage, transportation, and direct reduction to UO2 powder. This specification is applicable to uranium oxide powders for such use from any source.1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents, for health and safety, or for shipping. Observance of this specification does not relieve the user of the obligation to conform to all international, national, state, and local regulations for processing, shipping, or any other way of using uranium oxide powders (see 2.2 and 2.3).1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 The following safety hazards caveat pertains only to the test methods portion of the annexes in 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 and health practices and determine the applicability of regulatory limitations prior to use.