Neutronics analysis of full MOX BWR core simulation experiments – FUBILA: Part 2

Abstract

A part of the experimental program FUBILA was dedicated to the study of core physics characteristics of full MOX BWR cores by testing five experimental cores: a core inserted with a B 4 C control blade, a core loaded with UO 2 fuel rods, the core loaded with Gd 2 O 3 -UO 2 fuel rods, a core loaded with 10 6 10 MOX assemblies and a core loaded with time-elapsed MOX fuel. The present article describes analysis results of the experimental data with deterministic analysis codes and a continuous energy Monte Carlo code coupled with major nuclear data libraries. The calculated critical k eff' s with the Monte Carlo calculations range from 0.999 to 1.007. Those of the transport calculations with sixteen energy groups are close to those of the Monte Carlo calculations while those of diffusion calculations with the same sixteen energy groups are systematically smaller by 70.3 to 70.5% Dk than those of the Monte Carlo calculations. The RMSs of differences between the calculated and measured core radial fission rates are 2 to 3%, 1 to 2%, and 1 to 2% for the diffusion, transport and Monte Carlo calculations, respectively. For the analysis of the Gd 2 O 3 -UO 2 fuel rod loaded core, the C/Es of the radial fission rates were improved by adopting a detailed lattice calculation model and a newly measured thermal and resonance cross-sections of Gadolinium.

Feedback on neutron capture cross sections of 238Pu and 241Am from analyses of measured isotopic compositions of irradiated LWR fuels and MOX core physics experiments

“…The core configurations of critical cores referred from the FUBILA program in this paper are shown in Figure 4 and Table 2 [22]. The four BWR mockup assemblies in the center of the core (a test region) were composed by the FUBILA-MOX fuel rods (total Pu concentrations: 3 wt%, 5 wt%, 8.5 wt% and 11.5 wt%) for the 9 × 9 reference, control blade and time-elapsed reference cores.…”

“…One of the MOX core physics experiments implemented at the EOLE critical facility is the FUBILA program which dedicated to the study of core physics characteristics of the full MOX ABWR core [3,21,22]. The program has a unique feature that the experimental critical cores consisted of two types of MOX fuel rods with two different Pu vectors.…”

“…Schematic diagram of core radial configurations of critical experimental cores in the FUBILA program[22].…”

Neutron cross section sensitivity analysis of UO2and MOX core physics experiments on light water reactors

“…The same test MOX rods were used as those in driver regions of FUBILA experimental cores mentioned in the next paragraph. Figure 3 shows the core configurations of a FU-BILA 9 × 9 reference core, which is a BWR mockup full MOX core consisting of four mockup MOX assemblies in a 9 × 9 lattice in the test region, and a FUBILA Gd 2 O 3 -UO 2 rod core, which is a BWR mockup MOX core consisting of two MOX assemblies partly loaded with Gd 2 O 3 -UO 2 rods and two MOX assemblies partly loaded with UO 2 rods [3,12]. The MOX rods, which -UO 2 rods was 2.55 wt%.…”

“…As part of integral tests of the new library based on experimental data, analysis of UO 2 and MOX core physics experiments on light water reactors (LWRs) has been performed using a continuous energy Monte Carlo calculation code coupled with JENDL-4.0 [2,3]. According to the references, the analyzed effective neutron multiplication factors (k eff 's) of the UO 2 cores significantly increases by using JENDL-4.0 in place of JENDL-3.3 [4]; however, those of MOX cores showed small changes less than 0.1% k/kk even though the thermal and resonance cross sections of major U, Pu, and Am isotopes had been revised in JENDL-4.0.…”