Current status of the reactor physics code WIMS and recent developments

Lindley, Ben; Hosking, John; Smith, Peter; Powney, D. J.; Tollit, Brendan; Newton, T. D.; Perry, R.J.; Ware, Tim; Smith, Paul N.

doi:10.1016/j.anucene.2016.09.013

Cited by 56 publications

(18 citation statements)

References 3 publications

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“…Aged Pu, where all Pu241 has decayed to Am241 (5.60%wt Am). Before results were gathered, an initial comparison was carried out using WIMS (Lindley, et al, 2017) (Askew, et al, 1966) and the Monte Carlo code, Serpent (Leppanen, et al, 2015), with nuclear data library ENDF/B-VII (Chadwick, et al, 2006) for a single, two-dimensional, 10x10 bottom-of-core fuel assembly (as described in Table 2). Fuel was assumed to be 4.9% enriched UO2 with a discharge burnup of 60 GWd/tHM as per the proposed UK ABWR design.…”

Section: Methods 21 Pu Vectors and Model Set-upmentioning

confidence: 99%

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part II: BWRs

Morrison

Parks

2020

Annals of Nuclear Energy

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UK plutonium is expected to be managed using uranium-plutonium (U-Pu) mixed oxide (MOX) fuels in Light Water Reactors (LWRs). However, studies have shown that thorium-plutonium (Th-Pu) may be preferential. Part I of this study considered the effect of americium (Am) in UK Pu in Pressurized Water Reactors (PWRs) and found that, while the reactivity response was sensitive to isotopic and spectral variations, trends were predictable. Part II focusses on separation of Am in Boiling Water Reactors (BWRs) and compares fuel performance to the uniformly distributed and spatially separated cases outlined in Part I. Comparable incineration rates are achievable but, while a single PWR assembly bears a greater mass of Am/Pu than a single BWR assembly, the full BWR core may be capable of operating with significantly greater fissile masses. Transmutation of Am241 to Am242 appears preferable to fast fission of Am241 as increased incineration occurs in lower void, bottom-of-assembly locations.

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Section: Methods 21 Pu Vectors and Model Set-upmentioning

confidence: 99%

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part II: BWRs

Morrison

Parks

2020

Annals of Nuclear Energy

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“…The additional Pu vectors assume incremental increases in Am241 up to 30%wt. Assembly-level calculations were performed using the established reactor physics code WIMS (version WIMS10A) (Lindley, et al, 2017) (Askew, et al, 1966) and nuclear data library ENDF/B-VII (Chadwick, et al, 2006). An initial benchmarking study was carried out against published data for a Th-Pu fuelled, standard PWR (International Atomic Energy Agency, 2003) to ensure the accuracy of the model.…”

Section: Methods 21 Pu Vectors and Model Set-upmentioning

confidence: 99%

“…An initial benchmarking study was carried out against published data for a Th-Pu fuelled, standard PWR (International Atomic Energy Agency, 2003) to ensure the accuracy of the model. Results were generated by first performing an approximate flux solution using 172 neutron energy groups with geometric approximations inherent to the code (Lindley, et al, 2017) and then by performing a more detailed final solution using 47 groups and the method of characteristics. Thermal and epithermal region energies are split into a larger number of groups than the fast region, as these represent the energy ranges where most interactions occur in standard and reduced moderation PWRs.…”

Section: Methods 21 Pu Vectors and Model Set-upmentioning

confidence: 99%

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part I: PWRs

Morrison

Parks

2020

Annals of Nuclear Energy

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UK plutonium is expected to be managed using uranium-plutonium (U-Pu) mixed oxide (MOX) fuels in Light Water Reactors (LWRs). However, studies have shown that thorium-plutonium (Th-Pu) may be preferential. Research has mostly focussed on recycle of reactor grade Pu with limited minor actinide (MA) content. This study will determine if large quantities of americium (Am) in UK Pu may be restrictive to recycle schemes by determining the effect this has on reactivity feedback coefficients, fissile loading and incineration potential. Addition of Am is shown to result in predictable trends in reactivity feedback coefficients and spatial separation of Am and Pu is found to offer potential advantages over uniformly loaded fuel in terms of maximising fissile loading and incineration. Separation may also offer benefits in terms of targeting Am destruction, particularly if multiple recycle schemes are pursued, as this would maximise the fissile loading requirements while keeping reactivity feedback coefficients negative.

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“…In this study, we have used deterministic reactor physics code WIMS 10 20,21 for the lattice-level calculation while considering JEF 2.2 nuclear data library and 6 energy group structure 9–12,17,22–24 . WIMS performs deterministic neutron transport calculations for every pin in a fuel assembly using an established calculation route through sequence of separate modules 19,20,22,25,26 .…”

Section: Design and Calculational Methodsmentioning

confidence: 99%

Neutronic investigation of alternative & composite burnable poisons for the soluble-boron-free and long life civil marine small modular reactor cores

Alam

Almutairi

Ridwan

et al. 2019

Sci Rep

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Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to combat global warming, and that also includes the commercial freight shipping sector. In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not use soluble boron for reactivity control, but it is then a challenge to achieve an adequate shutdown margin throughout the core life while maintaining reactivity control and acceptable power distributions in the core. High-thickness ZrB2 150 μm Integral Fuel Burnable Absorber (IFBA) is an excellent burnable poison (BP) candidate for long life soluble-boron-free core. However, in this study, we want to minimize the use of 150 μm IFBA since B-10 undergoes an (n, α) capture reaction, and the resulting helium raises the pressure within the plenum and in the cladding. Therefore, we have considered several alternative and novel burnable BP design strategies to minimize the use of IFBA for reactivity control in this study: (Case 1) a composite BP: gadolinia (Gd2O3) or erbia (Er2O3) with 150 μm thickness ZrB2 IFBA; (Case 2) Pu-240 or Am-241 mixed homogeneously with the fuel; and (Case 3) another composite BP: Pu-240 or Am-241 with 150 μm thickness ZrB2 IFBA. The results are compared against those for a high-thickness 150 μm 25 IFBA pins design from a previous study. The high-thickness 150 μm 25 IFBA pins design is termed the “IFBA-only” BP design throughout this study. We arrive at a design using 15% U-235 fuel loaded into 13 × 13 assemblies with Case 3 BPs (IFBA+Pu-240 or IFBA+Am-241) for reactivity control while reducing 20% IFBA use. This design exhibits lower assembly reactivity swing and minimal burnup penalty due to the self-shielding effect. Case 3 provides ~10% more initial (beginning-of-life) reactivity suppression with ~70% less reactivity swing compared to the IFBA-only design for UO2 fuel while achieving almost the same core lifetime. Finally, optimized Case 3 assemblies were loaded in 3D nodal diffusion and reactor model code. The results obtained from the 3D reactor model confirmed that the designed core with the proposed Case 3 BPs can achieve the target lifetime of 15 years while contributing to ~10% higher BOL reactivity suppression, ~70% lower reactivity swings, ~30% lower radial form factor and ~28% lower total peaking factor compared to the IFBA-only core.

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Current status of the reactor physics code WIMS and recent developments

Cited by 56 publications

References 3 publications

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part II: BWRs

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part II: BWRs

The effect of Am241 on UK plutonium recycle options in thorium-plutonium fuelled LWRs – Part I: PWRs

Neutronic investigation of alternative & composite burnable poisons for the soluble-boron-free and long life civil marine small modular reactor cores

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