Asymptotic analysis of the several competitive equations to solve the time-dependent neutron transport equation

Conference · Sat Oct 01 04:00:00 EDT 1994

OSTI ID:10187986

Shin, U; Miller, Jr, W F ^[1]; Morel, J E ^[2]

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1. California Univ., Berkeley, CA (United States)
2. Los Alamos National Lab., NM (United States)

Using conventional diffusion limit analysis, we asymptotically compare three competitive time-dependent equations (the telegrapher`s equation, the time-dependent Simplified P{sub 2} (SP{sub 2}) equation, and the time-dependent Simplified Evcn-Parity (SEP) equation). The time-dependent SP{sub 2} equation contains higher order asymptotic approximations of the time-dependent transport equation than the other equations in a physical regime in which the time-dependent diffusion equation is the leading order approximation. In addition, we derive the multigroup modified time-dependent SP{sub 2} equation from the multigroup time-dependent transport equation by means of an asymptotic expansion in which the multigroup time-dependent diffusion equation is the leading, order approximation. Numerical comparisons of the timedependent diffusion, the telegrapher`s, the time-dependent SP{sub 2}, and S{sub 8} solutions in 2-D X-Y geometry show that, in most cases, the SP{sub 2} solutions contain most of the transport corrections for the diffusion approximation.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10187986
• Report Number(s): LA-UR--94-3154; CONF-950420--7; ON: DE95001022
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220100
663610
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ASYMPTOTIC SOLUTIONS
ITERATIVE METHODS
MULTIGROUP THEORY
NEUTRON DIFFUSION EQUATION
NEUTRON PHYSICS
NEUTRON TRANSPORT THEORY
THEORY AND CALCULATION
TIME DEPENDENCE