Applications CLOSED

Sensitivities of neutron transport modes with Monte Carlo Methods

Despite being the reference neutron transport method, Monte Carlo used to be limited in its capacity to calculate sensitivities (relative change in output associated with a change in input, such as a cross-section), or adjoint-based outputs, such as kinetics parameters (effective delayed neutron fractions, etc.). This has completely changed with the very fast development of perturbation methods and generalization in most of the codes in the last decade [1]. This field is still growing and few researchers have focused on the question of the statistical convergence of those new objects when compared to the large bibliography that exists for other parameters, such as eigenvalues, in particular for problems with high dominance ratios, i.e. when the second eigenvalue is very close from the first one, the inverse of k_eff. Another very active field of research related to Monte Carlo is its use for the calculation of higher modes than the first eigenvalue or for other modes types. Many applications are based on the use of the modes of different formalisms, which are often “matrix filled” formalisms, i.e. formalisms that use matrices built from Monte Carlo tallies such as “Fission Matrices”. Kinetics calculations are historically based on spectral analysis and can now rely on Monte Carlo associated parameters for which sensitivities are also available [2]. 

The convergence of local variables such as local fluxes in Monte Carlo may be much slower than global ones, e.g. k_eff. The convergence of their sensitivities with the number of histories simulated is not well known and their actual convergence may be doubtful as it depends on « new » parameters of the Monte Carlo method used for the calculations of sensitivities such as the number of « latent » generations [3]. We expect that the convergence speed of the sensitivities of the modes would be faster, if they could be calculated.

The objective of this project is to work on the combination of the two dynamic fields discussed above and extend the sensitivity capacities of Serpent2 [4] for the calculation of the sensitivities of modes to different perturbations, such as nuclide densities or nuclear data, and to study the convergence speed of those new output parameters.

This PhD is part of the joint “NEEDS” project called SUDEC (Sensitivity Uncertainty comparison for Depletion Calculations) in which CNRS, CEA and IRSN work together to study the propagation of uncertainty in fuel burn-up calculations. Those fuel burn-up calculations rely on the calculation of reaction rates that can be considered as local variables that could be projected on an adequate mode base. The student will then contribute to the project by developing a key component of it and will benefit from the collective work and competencies of the partners.

Indicative timeline

Year 1

Tools discovery. Convergence tests of sensitivities of existing Serpent 2 outputs.

Preliminary set up of innovative mode calculation sensitivities.

Year 2

Development and tests of the performance of the sensitivities of the modes.

Research and set up of reduced models of coupling, with TH and/or depletion.

Year 3

End of developments.

In depths studies with the tools developed.
Manuscript and defence preparations.

PhD Director

Adrien Bidaud has 20 years of experience in the field of nuclear data uncertainty and sensitivities. Besides this research and the associated teaching activities, he also teaches and develops interdisciplinary research projects in long term energy prospective with energy economists. He is the co-chair of the Energy and Nuclear Engineering program of the Engineering school PHELMA of Grenoble Institute of Technology.

Laboratoire de Physique Subatomique et Cosmologie (http://lpsc.in2p3.fr)

The aim of the research at LPSC is to improve our knowledge about the most elementary particles and about the forces that govern their interactions. It helps to broaden our understanding of the universe, its structure and its evolution. These activities require the development of sophisticated, state-of-the-art instrumentation, a strong theoretical research activity as well as strong modelling competencies that support the experiments during the preparatory stages and during the data analysis.

The research also affects our everyday lives; for example, it enables to come up with innovative solutions in the field of nuclear power or cancer treatment and to train a new generation of researchers, teachers and engineers.

Candidates interested in teaching activities may be offered to contribute to the nuclear engineering curriculum of Grenoble Institute of Technologie (school PHELMA) and Université Grenoble Alpes, which include for instance electronics, mathematics, signal processing, nuclear instrumentation lab sessions, numerical methods, numerical methods projects etc.

Bibliography

[1] “Review of Early 21st-Century Monte Carlo Perturbation and Sensitivity Techniques for k- Eigenvalue Radiation Transport Calculations”, Brian Kiedrowski, Nuclear Science and Engineering, 2017, 185:3, 426-444, https://doi.org/10.1080/00295639.2017.1283153

[2] “Perturbation and sensitivity calculations for time eigenvalues using the Generalized Iterated Fission Probability, Alexis Jinaphanh, Andrea Zoia,

2019, Annals of Nuclear Energy, 133, 678-687, https://doi.org/10.1016/j.anucene.2019.06.062

[3] « Sensitivity Analysis and Its Convergence Through Monte Carlo Calculations for the UAM GEN-III Benchmark: Application to Power Distributions », Pamela Lopez and Adrien Bidaud, Proceedings of the Conference: Mathematics and Computational Methods Applied to Nuclear Science and Engineering, Raleigh, North Carolina, USA, April 2021

[4] “A collision history-based approach to sensitivity/perturbation calculations in the continuous energy Monte Carlo code SERPENT”, Manuele Aufiero et al., Annals of Nuclear Energy, 2015, https://doi.org/10.1016/j.anucene.2015.05.008.

Key-words: Neutronics, Nuclear Data sensitivity, Uncertainty analysis, Monte Carlo, Perturbation Theory.

Profile: Candidates must have a background in Reactor Physics, with a demonstrated knowledge of Neutron Transport. Some experience in Monte Carlo codes would be an asset.

Contact

Adrien Bidaud

LPSC – Groupe Physique des Réacteurs

Téléphone : 0476284045 email : bidaud@lpsc.in2p3.fr

THE PHD SHALL START IN: FALL 2022 – TO APPLY, CONTACT PROF. BIDAUD As  Soon As Possible

Studying in Grenoble

https://www.univ-grenoble-alpes.fr/education/why-choose-uga/why-choose-uga-713448.kjsp

https://international.univ-grenoble-alpes.fr/getting-organized/the-steps-of-your-stay/the-practical-guide-for-international-doctoral-students-795458.kjsp?RH=1611732328710

SCK CEN is welcoming PhD Applications until MARCH 23, 2022

Fields are diverse: nuclear technology, materials, radiation protection, waste & disposal, decommissioning, etc…

The list of available topics:

• 161Tb-labeled radiopharmaceuticals targeting mucin receptors for treatment of pancreatic cancer
• Advancement of personal neutron dosimetry by establishment of flexible reference simulated neutron workplace fields and computational neutron dosimetry
• Assessment of out-of-field doses in proton therapy with variation of clinical parameters
• Deep learning for 3D porous media reconstruction of clay and cement-based materials
• Development of a Numerical Multi-Physics Method to Analyze the Vibration Characteristics of Rotating Components in Liquid Metal
• Development of a thorium based target for the production and release of Ac225 at the ISOL facility of MYRRHA
• Development of fast and sensitive methods for radiotoxicological and biodistribution studies/analyses of radionuclides used in medical applications (e.g. 225Ac)
• Development of new ligands for selective separation of americium
• Development of TRNT radiopharmaceuticals targeting Hsp90
• Evolution of transport, microstructural and hygro-mechanical properties of cementitious materials subjected to coupled chemical degradation via a multiscale approach
• Experimental analysis of nuclear fuel depletion : method development, validation and uncertainty assessment
• Fecal microbiotal transplantation as a method for improving the outcomes of the dual radio- and immunotherapies within a colorectal cancer mouse model
• Finite element investigations of loading rate and crack configuration effects to extract fracture toughness from the Charpy impact test
• Formation mechanisms of nanovoid and nanobubble superlattices in fissile materials
• Functional characterization of D630023F18Rik in the DNA damage response and brain development
• HERMMES – Hadron Energy Resolved Measurement using Magnetic Electron Separation
• Impact of carbonation on corrosion, mechanical and transport properties of blended cements
• Improving Nuclear Fuel Microstructure Characterization By Multivariate Statistical Analysis of Scanning Electron Microscopy Data
• Influence of redox conditions and organic matter on the partitioning and mobility of naturally occurring radionuclides (NOR‘s) in geothermal systems
• Investigating the radioprotective mechanisms of biotic food supplements using human gut organoids-derived bioreactor
• Machine learning for accurate and efficient uncertainty quantification in radiological waste characterization
• Neutron Data Benchmarking at the VENUS-F zero power reactor for MYRRHA
• Optimization of computational dosimetry of workers in dismantling and decommissioning using machine learning
• Oxidation and corrosion mechanisms in actinide oxide systems
• Personal online dosimetry of astronauts using computational methods
• Photonuclear cross-section measurements for the production of medical radioisotope Actinium-225
• Quantitative Assessment of Corrosion Products Release Rate in Liquid LBE
• Shape controlled thorium dioxide precipitation routes
• Fuel Materials
• Small-scale mechanical punch testing for fusion and fission structural materials
• Sorption of radionuclides onto C-S-H and C-A-S-H at various degradation stages
• Super-resolved analysis of lamin-mediated DNA damage repair after high LET irradiation and its applicability to predictive modelling of individual radiation sensitivity in cancer patients
• The role of miRNAs in regulating dose rate and plant developmental-dependent responses to gamma-irradiation in rice

SCK CEN is looking for 2 PhD researchers in Nuclear Fusion & Geothermal system