Accuracy of nodal transport and simplified P3 fluxes in benchmark tests

Here the authors summarize recent work exploring the accuracy of fluxes computed both by nodal transport methods and by the simplified spherical harmonics (SP/sub l/) method. Apparently, significant errors in nodal transport fluxes were first noted by Wagner et al and attributed to the isotopic transverse leakage (ITL) approximation. Later Lawrence detected substantial errors due to the ITL approximation in his nodal transport (NTT) solution of the International Atomic Energy Agency (IAEA) Stepanek benchmark problem. Gelbard concluded on theoretical grounds that nodal transport fluxes, computed in x,y geometry using ITL, should be much more accurate on the coordinate axes than halfway between them and that, at 45 deg from the axes, nodal transport methods using ITL should give only about half of the true transport correction. The authors look for such an error pattern in the papers