A new Monte Carlo method for neutron noise calculations in the frequency domain

Rouchon, Amélie; Zoia, Andrea; Sanchez, Richard

doi:10.1016/j.anucene.2016.11.035

Cited by 37 publications

(7 citation statements)

References 15 publications

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“…With respect to the noise measurement technique, a detailed characterization of the field of view of the detectors is required. A potential characterization for such field of view could be done through analog Monte Carlo calculations [9] where the response function of the detector to various patterns of local void content are calculated.…”

Section: Discussionmentioning

confidence: 99%

Validation of Axial Void Profile Measured by Neutron Noise Techniques in Crocus

et al. 2021

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Recently a joint project has been carried out between the Paul Scherrer Institut, the Ecole Polytechnique Federale de Lausanne and swissnuclear, an industrial partner, in order to determine the axial void distribution in a channel installed in the reflector of the zero power research reactor CROCUS, using neutron noise techniques. The main objective of the present paper is to report on the validation of the results against an alternative measurement technique using gamma-ray attenuation and simulations with the TRACE code. For the gamma-ray attenuation experiments, the channel used in CROCUS is installed out of the core in a Plexiglass water tank. The source and detector are fixed and the channel is moved axially to keep the geometry of the source/detector arrangement untouched. This is key to measure the void effect by gamma attenuation due to the low contrast of this technique. The paper compares the experimental results obtained with both techniques, with the outcomes of simulations carried out with the TRACE code. Even though the quantitative void fraction estimations are not consistent, the trends obtained with the simulation and experimental techniques are the same. The discrepancies between the various experimental techniques and the simulation outcomes are related to the heterogeneous distribution of the water-air mixture in the radial sections of the channel.

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Section: Discussionmentioning

confidence: 99%

Validation of Axial Void Profile Measured by Neutron Noise Techniques in Crocus

et al. 2021

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“…Previous investigations have shown that weight cancellation can be very effective in dealing with Monte Carlo problems using particles of both positive and negative weights [6,8,11,26]. In view of these considerations, in the following we will formally address the effect of cancellation on Eq.…”

Section: B Modeling Weight Cancellationmentioning

confidence: 99%

Exact weight cancellation in Monte Carlo eigenvalue transport problems

Belanger,

Mancusi,

Zoia

2021

Preprint

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Random walks are frequently used as a model for very diverse physical phenomena. The Monte Carlo method is a versatile tool for the study of the properties of the systems modelled as random walks. Often, each walker is associated with a statistical weight, used in the estimation of observable quantities. Weights are typically assumed to be positive; nonetheless, some applications require the use of positive and negative weights or complex weights, and often pose particular challenges with convergence. In this paper, we examine such a case from the field of nuclear reactor physics, where the negative particle weights prevent the power iteration algorithm from converging on the sought fundamental eigenstate of the Boltzmann transport equation. We demonstrate how the use of weight cancellation allows convergence on the physical eigenstate. To this end, we develop a novel method to perform weight cancellation in an exact manner, in three spatial dimensions. The viability of this algorithm is then demonstrated on a reactor physics problem.

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“…In the heterogeneous B 1 method, the angular neutron flux is factorized as where = the position vector, = the particle direction, E = the neutron energy, , and = the spatial fine structure of the neutron flux within a unit cell. Rouchon et al (2017). This paper adopts another way as follows.…”

Section: Critical Buckling Search and Directional Diffusion Coefficiementioning

confidence: 99%

Monte Carlo method for solving a B1 equation with complex-valued buckling in asymmetric geometries and generation of directional diffusion coefficients

Yamamoto

Sakamoto²

2018

Annals of Nuclear Energy

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Direction-dependent diffusion coefficients generated using a Monte Carlo method that explicitly solves a heterogeneous B 1 equation are validated in this paper. The validation is conducted by comparing the direction-dependent neutron leakage using directional diffusion coefficients with the results of a neutron transport calculation. This paper develops a new method for critical buckling search calculation to solve a heterogeneous B 1 equation for an asymmetric unit cell in which the critical bucking has a complex value. A complex-valued critical buckling can be searched using the differential operator sampling method for estimating the sensitivity coefficients of k eff with respect to the buckling. In an asymmetric unit cell, the neutron flux and the neutron current also have complex values. The real part of the neutron flux obtained by a critical buckling search calculation represents the neutron spectrum in the center portion of the finite geometry composed of the unit cells.

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A new Monte Carlo method for neutron noise calculations in the frequency domain

Cited by 37 publications

References 15 publications

Validation of Axial Void Profile Measured by Neutron Noise Techniques in Crocus

Validation of Axial Void Profile Measured by Neutron Noise Techniques in Crocus

Exact weight cancellation in Monte Carlo eigenvalue transport problems

Monte Carlo method for solving a B1 equation with complex-valued buckling in asymmetric geometries and generation of directional diffusion coefficients

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