Critical Masses for Unreflected Metal Spheres
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Critical masses of bare metal spheres for 33 actinide isotopes, using the SCALE/XSDRNPM one-dimensional, discrete-ordinates system, are presented. ENDF/B-VI, ENDF/B-VII, and JENDL-3.3 cross sections were used in the calculations. Results are given for isotopes of U, Np, Pu, Am, Cm, and Cf and for one isotope of Es. Calculated k-infinity values for 41 actinides are also given. For the nonthreshold or low-threshold fission nuclides, a good approximation for the nuclide k-infinity is the value of nubar at 1 MeV. A correlation between the calculated critical mass (kg) and the fission spectrum averaged value of F is given for the elements U, Np, Pu, Cm, and Cf as CM (kg) = exp (A + B ln(F)) (1). The values of A and B are element dependent and vary slightly for each of the five elements. The method described here is mainly applicable for nonthreshold fission nuclides (15 of the 31 nuclides considered in this paper). We conclude that equation (1) is useful for predicting the critical mass for nonthreshold fission nuclides if we have accurate values of the fission spectrum averaged F.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1026714
- Resource Relation:
- Conference: NCSD 2009-Nuclear Criticality Safety Division Topical Meeting, Richland, WA (United States), 13-17 Sep 2009
- Country of Publication:
- United States
- Language:
- English
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Critical masses of bare metal spheres using SCALE/XSDRN