BS ISO 11311:2011
Withdrawn
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
Nuclear criticality safety. Critical values for homogeneous plutonium-uranium oxide fuel mixtures outside of reactors
01-04-2023
07-31-2011
This International Standard specifies common reference critical values (of which the effective neutron multiplication factor, keff is equal to 1) for homogeneous water-moderated plutonium-uranium oxide mixtures based on an inter-code comparison of calculated critical values.
It is applicable to operations with unirradiated mixed uranium-plutonium oxide (MOX) outside nuclear reactors.
A classical validation approach for these systems is difficult because of the paucity of critical experiments for MOX fuel.
Various reference systems, in terms of isotopic compositions, thicknesses of water reflection, and densities of oxide are evaluated by different combinations of calculation codes and nuclear data libraries (i.e. different calculation schemes, see AnnexB).
The critical values defined in this International Standard are the lowest of those calculated by each of these calculation schemes and accepted as credible.
The values in this International Standard are reference values and not absolute critical values.
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