Transactions of the American Nuclear Society, Vol. 107, San Diego, California, November 11–15, 2012
For an efficient incorporation of the transport effect
in core calculations, the Simplified P3 (SP3) equations are
employed in nodal diffusion codes.1,2 The conventional
nodal methods such as the nodal expansion method can be
readily applied to solve the transverse-integrated SP3
equation as reported by Lee et al.
1
A semi-analytic
solution involving exponential functions can also be used
for the SP3 equation and one of the examples is the
source expansion nodal method(SENM).3
Unlike the
traditional nodal solution approach that employs either
one-node or two-node configuration, the whole 1-D
solution approach turned out to be beneficial if the coarse
mesh finite difference (CMFD) formulation involves only
node average scalar fluxes excluding the second angular
moments.4,5 The absence of the second angular moment in
the CMFD solution poses a problem that the transverse
leakage of the second angular flux cannot be updated
using the CMFD solution. In the following a new SP3
nodal solution method involving the semi-analytic
solutions for the three directions in Cartesian geometry
within the P1 CMFD framework that does not involve the
second angular moment is briefly described. The SP3
solution accuracy is then examined against the diffusion
solutions for various benchmark problems. The effect of
the second angular flux treatment schemes is also
examined.
