Multiphysics analysis of the MSFR helium bubbling system: A comparison between neutron diffusion, SP3 neutron transport and Monte Carlo approaches

Cervi, Eric; Lorenzi, Stefano; Luzzi, L.; Cammi, Antonio

doi:10.1016/j.anucene.2019.04.029

Cited by 37 publications

(11 citation statements)

References 14 publications

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“…23 In this regard, the present work may pave the way to future implementations of the adjoint method in 3D simulation tools for nuclear reactor analysis, such as the multiphysics toolkit OpenFOAM. 34 An interesting research direction can be the extension and the assessment of the proposed method with application to the 3D geometry of the MSFR, keeping into account the helium bubbling system, [35][36][37] fuel compressibility effects, 38,39 and solid wall deformation feedbacks on reactivity. [40][41][42] through the project "Nuclear Innovation Center for Haeorum Alliance".…”

Section: Discussionmentioning

confidence: 99%

Adjoint‐based sensitivity analysis of circulating liquid fuel system for the multiphysics model of molten salt reactor

et al. 2020

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Summary The strongly coupled behaviors between neutronics and thermal‐hydraulics of liquid‐fueled molten salt reactors make it difficult to evaluate system behaviors, due to the transport of precursors along moving fuel. Extending an adjoint‐based method on the multiphysics approach, different assumptions on temperature dependencies of nuclear and thermophysical properties of salt are included in the local sensitivity analysis of a circulating liquid fuel system. Local sensitivity of various types of system response in steady‐state is analyzed for 39 parameters including coupling models, reactor design values, and kinetic constants of delayed neutron and decay heat precursors for a simplified 1D model of molten salt fast reactor. Extended adjoint‐based sensitivity analysis method for MSR is successfully validated achieving 1.38% deviation on average between a recalculation and adjoint method, comparing local sensitivities to all parameters. Also, it takes 66.3 times less in computational time compared with the recalculation method for evaluating the sensitivity of the same type of system response. The importance of all the parameters to the system response is analyzed according to the assumptions on temperature dependencies to nuclear data and salt properties. The most influencing ones are fission energy‐related terms, and their importance increases when temperature dependencies are taken into account, compared with constant properties. Changes of influences on the sensitivity are investigated from the relative changes of the parameter values in various system response types, and it implies the importance to consider the multiphysics modeling on the local sensitivity analysis.

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Section: Discussionmentioning

confidence: 99%

Adjoint‐based sensitivity analysis of circulating liquid fuel system for the multiphysics model of molten salt reactor

et al. 2020

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“…Figure 7a shows the results for the absolute variation ∆k eff in pcm with respect to the FOM, in function of burnup in MWd/kgU. For all cases, taking into account other verifications against Monte Carlo codes, as in [38][39][40][41][42], variations of hundreds of pcm represent a good level of approximation. Major differences are shown by the reconstruction with five basis functions, reaching absolute variations of criticality greater than 400 pcm for low (<10 MWd/kgU) and high (>60 MWd/kgU) burnup.…”

Section: Pod Modes (Offline Phase)mentioning

confidence: 93%

“…As expected, the case with five basis functions is less stable, with a fluctuation that reaches a maximum around 200 pcm and minimum at around −800 pcm. However, taking into account the code-to-code comparisons in [38][39][40][41][42] , we can consider acceptable ∆k eff in the order of hundreds of pcm.…”

Section: Rom Case: Power At 326 W/cm the Case Of The Snapshot Generamentioning

confidence: 99%

Development of a Reduced Order Model for Fuel Burnup Analysis

Castagna

Aufiero²,

Lorenzi

et al. 2020

Energies

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Fuel burnup analysis requires a high computational cost for full core calculations, due to the amount of the information processed for the total reaction rates in many burnup regions. Indeed, they reach the order of millions or more by a subdivision into radial and axial regions in a pin-by-pin description. In addition, if multi-physics approaches are adopted to consider the effects of temperature and density fields on fuel consumption, the computational load grows further. In this way, the need to find a compromise between computational cost and solution accuracy is a crucial issue in burnup analysis. To overcome this problem, the present work aims to develop a methodological approach to implement a Reduced Order Model (ROM), based on Proper Orthogonal Decomposition (POD), in fuel burnup analysis. We verify the approach on 4 years of burnup of the TMI-1 unit cell benchmark, by reconstructing fuel materials and burnup matrices over time with different levels of approximation. The results show that the modeling approach is able to reproduce reactivity and nuclide densities over time, where the accuracy increases with the number of basis functions employed.

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“…In addition, a power iteration routine, based on the keigenvalue method, is also implemented for the estimation of the multiplication factor. The present SP3 model has been tested and verified in [8,9], while its limits for the present application will be discussed in parallel publications.…”

Section: The Neutronics Modelmentioning

confidence: 99%

“…, which is linked to the neutron flux by Eqs. (9) and (10), is chosen as criterion to switch between the Lagrangian and the Eulerian point of views. To this aim, the arbitrary velocity is defined as follows:…”

Section: The Neutron Flux Is Lower At the Boundary Where Amentioning

confidence: 99%