ANS 8.12 87th Edition, January 1, 1987
nuclear criticality control and safety of plutonium-uranium fuel mixtures outside reactors
Includes all amendments and changes through Reaffirmation Notice , February 11, 2011
Additional Comments: C/R
Published By:American Nuclear Society (ANS)
This standard is applicable to operations with plutonium-uranium oxide fuel mixtures outside nuclear reactors, except the assembly of these materials under controlled conditions, such as in critical experiments. Basic criteria are presented for plutonium-uranium fuel mixtures in single units of simple shape containing no more than 30 wt% plutonium combined with uranium containing no more than 0.71 wt% 235U. The limits for uniform aqueous mixtures (solution) are applicable to homogeneous mixtures and slurries in which the particles constituting the mixture are uniformly distributed and have a diameter no larger than 127 μm (0.005 in.), i.e., are capable of being passed through 120 mesh screen.2
This standard does not include the details of administrative controls, the design of processes or equipment, the description of instrumentation for process control or detailed criteria to be met in transporting fissionable materials.
2Mixtures containing particles 60-100 μm in size have been considered by experimenters to be homogeneous IV. 1. NEELEY and H. E. HANDLER, "Measurement of Multiplication Constant for Slightly Enriched Homogeneous UO3-Water Mixtures and Minimum Enrichment for Criticality," HW-70310 Hanford Atomic Products Operations (August 1961) and v. I. NEELEY, J. A. BERBERET and R. H. MASTERSON, "koo of Three Weight Per Cent 235U Enriched UO3 and UO2 (NO3)2 Hydrogeneous Systems," HW-66882, Hanford Atomic Products Operations (September 1961)].