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DOE OSTI · 1908160

Subcritical Multiplication with a Fixed Source

Timmons, Daniel H.·Rising, Michael Evan·Perfetti, Christopher M.
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Abstract

In a subcritical, multiplying medium, the system multiplication describes the expected total number of neutrons created by a single source neutron. Subcriticality plays a large role in criticality safety and thus it is vital for the subcritical multiplication factor be accurate, especially as a system approaches criticality. This work examines the accuracy of calculating the system multiplication using the MCNP6.2 ® k-eigenvalue power iteration (KCODE) method when a fixed-point source is present in a multiplying medium, for near critical systems. This work compares the standard approach for calculating system multiplication, using the fixed-source calculational approach, to a new, single k-eigenvalue power iteration approach that incorporates a fixed-source component and a fission-source component into a single calculation. For the remainder of this paper, some theoretical background and numerical results for an approximate k eigenvalue approach, an accurate fixed-source approach and a new and more accurate k-eigenvalue approach to computing system multiplication are provided.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS97 MATHEMATICS AND COMPUTINGAnalytical MethodsEigenvalueMonte Carlo N-Particle Transport CodeNeutron SourceNuclear Criticality Safety Program (NCSP)Power Iteration

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Timmons, Daniel H., Rising, Michael Evan, Perfetti, Christopher M.. 2020-11-19. Subcritical Multiplication with a Fixed Source. https://doi.org/10.13182/t123-33408

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