ICAPP'12, Chicago, USA, June 24-28, 2012, on CD-ROM
The traditional subgroup method which has been applied for lattice transport
calculations has an inherent limitation for non-uniform temperature distributions. As a measure
to incorporate temperature dependence into the subgroup formulation, the subgroup level and
number density adjustment method have been proposed. In this paper, the temperature dependent
subgroup formulations employed for reflecting the non-uniform temperature effects on the
resonance spatial self-shielding are examined for the whole core transport calculation with the
thermal feedback. For 2D pin-cell problem with non-uniform temperature profiles, the inherent
limitation of conventional subgroup method is confirmed. And the improvement in terms of
reactivity is observed with the proposed adjustment scheme. For the real PWR core calculation
with thermal feedback in the hot-full-power condition, the noticeable correction for the fuel
temperature coefficient by about 10% more negative is obtained with the correction schemes.
