Interface conditions for few group equations with flux-adjoint weighted constants (LWBR Development Program)

Technical Report · Mon Jan 01 04:00:00 EST 1968

OSTI ID:6725409

Buslik, A J

Few-group diffusion equations are derived from variational principles. It is shown that by a proper choice of trial functions it is possible to derive a few-group theory in which interface boundary conditions of continuity of few-group fluxes and currents are obtained, even when the few-group constants are obtained by flux-adjoint weighting. The analysis is facilitated by the use of functionals which incorporate the interface condition of flux continuity by means of Lagrange Multipliers. Two functionals are used, giving two variants of the theory. Both functionals have as Euler equations the P-1 approximation to the time-independent, eigenvalue form of the energy-dependent transport equation. In addition, the current and flux interface boundary conditions are part of the complement of Euler conditions of the functionals. The functionals admit trial functions discontinuous in space and energy. The two functionals differ in that the one functional has both flux and current arguments, whereas the other functional has only flux arguments and yields the P-1 equations in second-order diffusion form. (NSA 22: 39556)

• Research Organization: Bettis Atomic Power Lab., Pittsburgh, PA (USA)
• DOE Contract Number: AT(11-1)-GEN-14
• OSTI ID: 6725409
• Report Number(s): WAPD-TM-733
• Country of Publication: United States
• Language: English

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