Simulate the effect of integral burnable absorber on the neutronic characteristics of a PWR assembly

Abstract

This article examines the effect of an integral burnable absorber (IBA) on the neutronic characteristics of Pressurized Water Reactor (PWR) to provide possible improvements for the fuel management. MCNPX code was used to design a three dimensional model for PWR assembly. The designed model has been validated by comparing the output data with a previously published data. MCNPX code was used to analyze the radial thermal neutron flux and the radial power distribution through PWR assembly with and without IBA. Gadolinium is burnable absorber material that was used in the IBA rods. The gadolinium element suppressed the power in the regions where they were distributed. The existence of IBA rods has a large effect on the Kinf. This effect decreases gradually with burnup due to the degradation of gadolinium. The gadolinium isotopes degradation was analyzed with burnup. Different numbers of IBA rods were investigated to optimize the suitable number that can be used in the PWR assembly. The gadolinium effect on the concentration of 135Xe and 149Sm resulting from the fission process was analyzed.

Computational benchmark for fuel assembly of VVER-1000 using the Monte Carlo Serpent code

“…Within the scope of the pres ent work, cal cu lations were made for U/Gd FA of a VVER-1000 re ac tor [28] The FA in fig. 1 con sists of: 300 FE, 12 U/Gd FE [29], 18 in stru men tal tubes and 1 cen tral tube.…”

Burnup-Dependent Neutron Spectrum Behaviour of a Pressurised Water Reactor Fuel Assembly

“…Several studies have covered neutron spectrum hardening and softening as it relates to burnable absorber-doped fuel and other reactor transients. For example, Galahom [11] mentions neutron spectrum hardening in relation to the use of burnable absorbers and, in an IAEA Techdoc [12], it is discussed in the context of extended burnup. However, not much work has been covered that primarily focuses on the status of the neutron spectrum with respect to hardening or softening at EOL.…”

In-Reactor Behaviour and Economic Assessment of Enriched Gadolinia Burnable Absorbers

“…Additionally, some forms of BA harden the neutron spectrum and reduces the 235 U depletion and thus, results in higher fissile 239 Pu breeding during reactor operation (Uguru et al, 2020). These fissile 239 Pu nuclei provides higher reactivity at the end of the fuel's life (Galahom, 2018). With gadolinium's high thermal neutron capture cross-section, gadolinium oxide (Gd 2 O 3 ) is one of the most attractive and regularly used BAs.…”