Accelerated Coupled Monte Carlo-Thermal Hydraulic Calculations using a Hybrid GTF-Diffusion-based Prediction Block: First Results

Bailey Painter, Stefano Terlizzi, Dan Kotlyar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Accurate predictions of spatial power and temperature distributions require the coupling of a neutron transport solver with a thermal-hydraulic (TH) feedback. Nowadays, Monte Carlo (MC) codes are widely coupled to TH solvers, typically via a Picard iteration (PI) method, due to the higher fidelity that such frameworks can produce. To speed up a PI, a prediction step can produce an improved initial guess for a source distribution and feed it to the MC code. Recent work [1, 2] investigated a prediction step that uses generalized transfer functions (GTFs) to predict the macroscopic cross sections' variations following a perturbation in TH properties, such as coolant density. The previous method also relied on first order perturbation (FOP) theory to predict perturbed power profiles, rather than using an expensive MC iterate. The implemented FOP method relied on generating a fission matrix from which the forward and adjoint eigenmodes were extracted and later used to for power calculations. The generation of the fission matrix can introduce a significant computational overhead, therefore undermining the performance of the proposed hybrid technique when applied to high-dimensional problems, e.g., full core calculations. This work attempts to improve the GTF-FOP prediction step by replacing the FOP solver with a nodal diffusion solver, thus eliminating the need to calculate a fission matrix. The GTF-diffusion step was tested for various moderator density perturbations. In each case, the predicted power distribution showed good agreement with the reference case. The latter is attributed to the generally good prediction of most spatially distributed macroscopic cross sections, except the transport cross section, which will become the focus of future work.

Original languageEnglish (US)
Title of host publicationProceedings of the International Conference on Physics of Reactors, PHYSOR 2022
PublisherAmerican Nuclear Society
Pages2216-2224
Number of pages9
ISBN (Electronic)9780894487873
DOIs
StatePublished - 2022
Event2022 International Conference on Physics of Reactors, PHYSOR 2022 - Pittsburgh, United States
Duration: May 15 2022May 20 2022

Publication series

NameProceedings of the International Conference on Physics of Reactors, PHYSOR 2022

Conference

Conference2022 International Conference on Physics of Reactors, PHYSOR 2022
Country/TerritoryUnited States
CityPittsburgh
Period5/15/225/20/22

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Safety, Risk, Reliability and Quality
  • Nuclear and High Energy Physics
  • Radiation

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