Publications related to Control rod

Monte Carlo analysis of BWR geometries using a cycle check-up methodology

Mathieu Hursin, Hakim Ferroukhi, Dimitri Rochman, Abdelhamid Dokhane, Alexander Vasiliev

Recent fuel anomalies at a Swiss power plant have motivated the development at PSI of the "Cycle Check-Up" (CHUP) methodology which consists in performing Monte Carlo transport calculations using nuclide compositions and thermal-hydraulic boundary conditio ...

Pergamon-Elsevier Science Ltd2023

Advanced methodologies for modeling and assessment of SFR safety functions

Janos Bodi

The present doctoral work was performed to contribute to the conceptual design development and safety assessment of a Generation IV Sodium Fast Reactor (SFR) in the frame of the European Sodium Fast Reactor Safety Measures Assessment and Research Tools (ES ...

EPFL2022

Miniature and Minimalistic Neutron Detectors for Online High-Resolution Experiments in the Zero-Power Reactor CROCUS

Fanny Vitullo

The continuous strive for more efficient and reliable nuclear power plants is leading to increasing complexity in the design and operations of reactors. As a consequence, comprehensive analyses are required to assess the reactor's safety during normal and ...

EPFL2022

Progress and challenges in the theory and modeling of complex concentrared alloys

William Curtin, Satish I Rao

The high atomic-scale complexity inherent in the aptly named complex concentrated alloys, or high entropy alloys, presents unique challenges in understanding (1) the structure and motion of defects that control mechanical properties and (2) the thermodynam ...

SPRINGER HEIDELBERG2022

Highly localized azimuthal measurements in the CROCUS reactor towards the validaiton of high-fidelity neutronics codes

Andreas Pautz, Vincent Pierre Lamirand, Pavel Frajtag, Fanny Vitullo

Highly localized in-core measurements are necessary for the validation of neutron transport calculations with high spatial resolution. In the present work, a miniature neutron detector developed at EPFL in collaboration with PSI was used to carry out a set ...

2021

Optimization of multi-group energy structures for diffusion analyses of sodium-cooled fast reactors assisted by simulated annealing - Part I: Methodology demonstration

Konstantin Mikityuk, Vincenzo Anthony Di Nora

This study presents an approach to the selection of optimal energy group structures for multi-group nodal diffusion analyses of Sodium-cooled Fast Reactor cores. The goal is to speed up calculations, particularly in transient calculations, while maintainin ...

2021

Investigation on the effect of eccentricity for fuel disc irradiation tests

Andreas Pautz, Carlo Fiorina, Alessandro Scolaro

A varying degree of eccentricity always exists in the initial configuration of a nuclear fuel rod. Its impact on traditional LWR fuel is limited as the radial gap closes relatively early during irradiation. However, the effect of misalignment is expected t ...

2021

Development of a Novel Finite Volume Methodology for Multi-Dimensional Fuel Performance Applications

Alessandro Scolaro

Fuel performance codes are an essential tool for ensuring the safe and economic opera-tion of nuclear reactors. Traditionally, these codes have been developed following a simple 1.5-D modelling approach, where the fuel behavior is simplified by assuming ax ...

EPFL2021

Structural performance and mechanical properties investigation of spent nuclear fuel rods under static and dynamic bending loads

Efstathios Vlassopoulos

Currently, most Spent Nuclear Fuel (SNF) is kept safely in storage either at on-site facilities or at centralized interim storage sites. Moreover, many countries face delays in implementing their waste management programmes for SNF and high-level waste dis ...

EPFL2021

Understanding the impact of poison distribution on the performance of Diesel oxidation catalysts

Oliver Kröcher, Davide Ferri

Detailed understanding of the poisoning mechanism in Diesel oxidation catalysts (DOCs) is the key to prevent long term catalyst deterioration in vehicles. The present work studies artificial phosphorus (P) poisoning methods applied to a commercial DOC. Cor ...

ELSEVIER2021

Development and verification of pin-by-pin homogenized simplified transport solver Tortin for PWR core analysis

Andreas Pautz, Petra Mala

Currently, the pin-by-pin homogenized solvers are a very active research field as they can, unlike the nodal codes, directly predict the local power, while requiring significantly less computational resources than the heterogeneous transport codes. This pa ...

2020

A mm(3) Fiber-Coupled Scintillator for In-Core Thermal Neutron Detection in CROCUS

Andreas Pautz, Vincent Pierre Lamirand, Oskari Ville Pakari, Pavel Frajtag, Fanny Vitullo, Jean-Baptiste Mosset

This article presents the development, full-characterization, and in-core testing of a miniature neutron detector for the investigation of highly localized in-core neutronics effects in the zero-power reactor CROCUS, operated at the Ecole Polytechnique fed ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Statistical Burnup Distribution of Moving Pebbles in the High-Temperature Reactor HTR-PM

Andreas Pautz, Jiri Krepel, Fanny Vitullo, Horst-Michael Prasser

In the pebble-bed high-temperature reactor under construction in China, called the HTR-PM, the spherical fuel elements continuously flow downward in the cylindrical core. The burnup of each pebble is checked at the core outlet and, according to the achieve ...

ASME2020

Design and Simulation of Gamma Spectrometry Experiments in the CROCUS Reactor

Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, Oskari Ville Pakari, Fanny Vitullo

Gamma rays in nuclear reactors, arising either from fission or decay processes, significantly contribute to the heating and dose of the reactor components. Zero power research reactors offer the possibility to measure gamma rays in a purely neutronic envir ...

E D P SCIENCES2020

Extension of the nodal code DYN3D to SFR applications

Evgeny Nikitin

DYN3D is a well-established Light Water Reactor (LWR) simulation tool and is being extended for safety analyses of Sodium cooled Fast Reactors (SFRs) at the Helmholtz-Zentrum Dresden-Rossendorf. This thesis focuses on the first stage of the development pro ...

EPFL2019

High-Fidelity Determination of Nuclide Inventories for Radioactive Waste Disposal

Valentyn Bykov

The general license application (RBG) for the Swiss deep geological repository will be submitted in 2024. Furthermore, the decommissioning of the nuclear power plants (NPPs) is coming soon, with the Mühleberg NPP (KKM) scheduled to shut down in 2019. In su ...

EPFL2019

Pin-by-Pin Treatment of LWR Cores with Cross Section Equivalence Procedures and Higher-Order Transport Methods

Petra Mala

This thesis presents a systematic study on the merits and limitations on using pin-by-pin resolution and transport theory based approaches for nuclear core design calculations. Starting from the lattice codes and an optimal cross section generation scheme, ...

EPFL2018

Statistical Burnup Distribution Of Moving Pebbles In Htr-Pm Reactor

Andreas Pautz, Jiri Krepel, Fanny Vitullo, Horst-Michael Prasser

In the pebble-bed high temperature reactor under construction in China, called HTR-PM, the spherical fuel elements continuously flow downward in the cylindrical core. After the discharge, the burnup of each pebble is checked at the core outlet and, accordi ...

AMER SOC MECHANICAL ENGINEERS2018

Modelling of fuel fragmentation, relocation and dispersal during Loss-of-Coolant Accident in Light Water Reactor

Vladimir Vladimirov Brankov

Recent LOCA tests with high burnup fuel at the OECD Halden Reactor Project and at Studsvik demonstrated the susceptibility of the fuel to fragment to small pieces, to relocate and possibly cause a hot-spot effect and to be dispersed in the event of claddin ...

EPFL2017

Tribocorrosion in Pressurized High-Temperature Water: A Mass Flow Model Based on the Third-Body Approach

Stefano Mischler

Pressurized water reactors (PWR) used for power generation are operated at elevated temperatures (280-300 degrees C) and under high pressure (120-150 bar). In addition to these harsh environmental conditions some components of the PWR assemblies are subjec ...

Springer Verlag2016