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Title: Analysis of detailed neutron fluxes in a PWR pressure vessel by two- and three-dimensional PALLAS transport codes

Journal Article · · Nucl. Technol.; (United States)
OSTI ID:5315664

To examine the effect of modeling of a pressurized water reactor (PWR) on predicting neutron field at the beltline of its pressure vessel (PV), neutron transport calculations were performed for various models of a 1000-MW(electric) class PWR in three different geometries-(R,theta), (R,Z), and a combination of (X,Y,Z) and (R,theta). A three-dimensional calculation with PALLAS-XYZ is used as a standard for the other two-dimensional (R,theta) and (R,Z) calculations made with PALLAS-2DRT and -2DCY. The source normalization essential for the (R,theta) calculation is reasonably made by dividing the total source neutrons by an effective core length, which provides calculated results in fair agreement with those calculated with a standard model for both radial attenuation and azimuthal variation of the integral fluxes above 1.0 and 0.1 MeV and also of displacements per atom (dpa). The (R,Z) calculations made in two different models were reviewed to find which model is more reasonable in evaluating neutron integral fluxes and dpa in a pressure vessel without underestimation. The effect of neglect of the axial leakage in (R,theta) transport calculations on neutron fluxes in a PV at the beltline region indicates little effect up to the distance before the vessel outer surface in contrast with an appreciable effect outside it.

Research Organization:
Ship Research Institute, Tokai Branch, Tokai-mura, Ibaraki-ken
OSTI ID:
5315664
Journal Information:
Nucl. Technol.; (United States), Vol. 62:2
Country of Publication:
United States
Language:
English