scholarly journals ANALYSIS OF THE FIRST COLIBRI FUEL RODS OSCILLATION CAMPAIGN IN THE CROCUS REACTOR FOR THE EUROPEAN PROJECT CORTEX

2021 ◽  
Vol 247 ◽  
pp. 21010
Author(s):  
V. Lamirand ◽  
A. Rais ◽  
O. Pakari ◽  
M. Hursin ◽  
A. Laureau ◽  
...  
Keyword(s):  
Early Stage ◽  
Experimental Program ◽  
Central Position ◽  
Neutron Detectors ◽  
Fuel Rods ◽  
European Project ◽  
Neutron Noise ◽  
Radiation Noise ◽  
Oscillation Frequencies ◽  
Flow Blockage

The Horizon2020 European project CORTEX aims at developing an innovative core monitoring technique that allows detecting anomalies in nuclear reactors, such as excessive vibrations of core internals, flow blockage, or coolant inlet perturbations. The technique will be mainly based on using the fluctuations in neutron flux recorded by in-core and ex-core instrumentation, from which the anomalies will be differentiated depending on their type, location and characteristics. The project will result in a deepened understanding of the physical processes involved, allowing utilities to detect operational problems at a very early stage. In this framework, neutron noise computational methods and models are developed. In parallel, mechanical noise experimental campaigns are carried out in two zero-power reactors: AKR-2 and CROCUS. The aim is to produce high quality neutron noise-specific experimental data for the validation of the models. In CROCUS, the COLIBRI experimental program was developed to investigate experimentally the radiation noise induced by fuel rods vibrations. In this way, the 2018 first CORTEX campaign in CROCUS consisted in experiments with a perturbation induced by a fuel rods oscillator. Eighteen fuel rods located at the periphery of the core fuel lattice were oscillated between ±0.5 mm and ±2.0 mm around their central position at a frequency ranging from 0.1 Hz to 2 Hz. Signals from 11 neutron detectors which were set at positions in-core and ex-core in the water reflector, were recorded. The present article documents the results in noise level of the experimental campaign. Neutron noise levels are compared for several oscillation frequencies and amplitudes, and at the various detector locations concluding to the observation of a spatial dependency of the noise in amplitude.

scholarly journals Neutron noise experiments in the AKR-2 and CROCUS reactors for the European project CORTEX

2020 ◽  
Vol 225 ◽  
pp. 04023 ◽  
Author(s):  
Vincent Lamirand ◽  
Adolfo Rais ◽  
Sebastian Hübner ◽  
Carsten Lange ◽  
Joachim Pohlus ◽  
...  
Keyword(s):  
Present Article ◽  
Computational Models ◽  
Early Stage ◽  
Noise Analysis ◽  
Experimental Program ◽  
Central Position ◽  
Horizon 2020 ◽  
Proper Actions ◽  
European Project ◽  
Neutron Noise

The present article gives an overview of the first experimental campaigns carried out in the AKR-2 and CROCUS reactors within the framework of the Horizon 2020 European project CORTEX. CORTEX aims at developing innovative core monitoring techniques that allow detecting anomalies in nuclear reactors, e.g. excessive vibrations of core internals. The technique will be mainly based on using the fluctuations in neutron flux, i.e. noise analysis. The project will result in a deepened understanding of the physical processes involved. This will allow utilities to detect operational problems at a very early stage, and to take proper actions before such problems have any adverse effect on plant safety and reliability. The purpose of the experimental campaigns in the AKR-2 and CROCUS reactors is to produce noise-specific experimental data for the validation of the neutron noise computational models developed within this framework. The first campaigns at both facilities consisted in measurements at reference static states, and with the addition of mechanical perturbations. In the AKR-2 reactor, perturbations were induced by two devices: a rotating absorber and a vibrating absorber, both sets in experimental channels close to the core. In CROCUS, the project benefited from the COLIBRI experimental program: 18 periphery fuel rods were oscillated at a maximum of ±2 mm around their central position in the Hz range. The present article documents the experimental setups and measurements for each facility and perturbation type.

scholarly journals The COLIBRI experimental program in the CROCUS reactor: characterization of the fuel rods oscillator

2020 ◽  
Vol 225 ◽  
pp. 04020 ◽  
Author(s):  
Vincent Lamirand ◽  
Pavel Frajtag ◽  
Daniel Godat ◽  
Oskari Pakari ◽  
Axel Laureau ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Oscillation Amplitude ◽  
Experimental Program ◽  
Pressurized Water ◽  
Fuel Rods ◽  
Horizon 2020 ◽  
Neutron Noise ◽  
Water Reactors

The present article presents the mechanical characterization of the fuel rods oscillator developed for the purposes of the COLIBRI experimental program in CROCUS. COLIBRI aims at investigating the radiation noise related to fuel vibrations. The main motivation is the increased amplitudes in the neutron noise distributions recorded in ex- and in-core detectors that have been observed in recent years in Siemens pre-Konvoi type of pressurized water reactors. Several potential explanations have been put forward, but no definitive conclusions could yet be drawn. Among others, changes in fuel assembly or pin vibration patterns, due to recent modifications of assembly structural designs, were pointed out as a possible cause. Computational dynamic tools are currently developed within the Horizon 2020 European project CORTEX, to help with understanding the additional noise amplitude. The COLIBRI program is used for their validation. An in-core device was designed, tested, and licensed between 2015 and 2019 for fuel rods oscillation in CROCUS, in successive steps from out-of-pile tests with dummy fuel rods to critical in-core tests. The characterization of its mechanical behavior is presented, in air and in water, and as a function of the load, for safety and experimental purposes. The device allows simultaneously oscillating up to 18 fuel rods. The maximum oscillation amplitude is 5 mm, while the maximum allowed frequency is 2 Hz, i.e. in the frequency range in which the induced neutron flux fluctuations are most pronounced in nuclear power plants.

scholarly journals Problem Decomposition and Information Minimization for the Global, Concurrent, On-line Validation of Neutron Noise Signals and Neutron Detector Operation

2020 ◽  
Vol 11 (6) ◽  
pp. 1-12
Author(s):  
Tatiana Tambouratzis
Keyword(s):  
Nuclear Reactor ◽  
Time Windows ◽  
Divide And Conquer ◽  
Neutron Detectors ◽  
Pressurized Water ◽  
Core Dataset ◽  
Neutron Noise ◽  
Minimum Number ◽  
On Line ◽  
Cross Correlations

This piece of research introduces a purely data-driven, directly reconfigurable, divide-and-conquer on-line monitoring (OLM) methodology for automatically selecting the minimum number of neutron detectors (NDs) – and corresponding neutron noise signals (NSs) – which are currently necessary, as well as sufficient, for inspecting the entire nuclear reactor (NR) in-core area. The proposed implementation builds upon the 3-tuple configuration, according to which three sufficiently pairwise-correlated NSs are capable of on-line (I) verifying each NS of the 3-tuple and (II) endorsing correct functioning of each corresponding ND, implemented herein via straightforward pairwise comparisons of fixed-length sliding time-windows (STWs) between the three NSs of the 3-tuple. A pressurized water NR (PWR) model – developed for H2020 CORTEX – is used for deriving the optimal ND/NS configuration, where (i) the evident partitioning of the 36 NDs/NSs into six clusters of six NDs/NSs each, and (ii) the high cross-correlations (CCs) within every 3-tuple of NSs, endorse the use of a constant pair comprising the two most highly CC-ed NSs per cluster as the first two members of the 3-tuple, with the third member being each remaining NS of the cluster, in turn, thereby computationally streamlining OLM without compromising the identification of either deviating NSs or malfunctioning NDs. Tests on the in-core dataset of the PWR model demonstrate the potential of the proposed methodology in terms of suitability for, efficiency at, as well as robustness in ND/NS selection, further establishing the “directly reconfigurable” property of the proposed approach at every point in time while using one-third only of the original NDs/NSs.

NESC VII European Project: Demonstration of Warm Pre-Stressing Effect in Biaxial Loading Conditions: Bending Tests on 18MND5 Cruciform Specimens and Their Interpretation

2012 ◽  
Author(s):  
C. Jacquemoud ◽  
T. Yuritzinn ◽  
S. Marie ◽  
D. Moinereau ◽  
M. Nédélec ◽  
...  
Keyword(s):  
Cleavage Fracture ◽  
Biaxial Loading ◽  
Experimental Results ◽  
Experimental Program ◽  
Loading Conditions ◽  
Bending Tests ◽  
Loading Cycle ◽  
European Project

In the framework of the NESC VII European project, a large experimental program has been dedicated to characterize the Warm Pre-Stressing (WPS) effect in different testing configurations. One of the CEA (France) contributions to this project is the realization of five point bending tests on large cruciform specimens considering different WPS loading cycles. The five cruciform specimens, sponsored by EDF (France) and IRSN (France), are made of 18MND5 steel. Two of them have been tested on a same LCF (Load-Cool-Fracture) loading cycle and two others on the same LCTF (Load-Cool-Transient-Fracture) loading cycle. The experimental results presented in this paper give a successful demonstration of the WPS effect in biaxial loading conditions either on a LCF or on a LCTF cycle. During the test interpretations, different models have then been tested and compared in order to evaluate their ability to predict the cleavage fracture in the case of different WPS loading cycles. They all provide very conservative predictions whatever loading cycle is concerned.

scholarly journals Potential for the blood- biomarker cell free UPK2 RNA to detect recurrence during monitoring after surgical resection of adenocarcinoma of the lung

2020 ◽  
Author(s):  
Ji Zhu ◽  
Qijue Lu ◽  
Bin Li ◽  
Huafei Li ◽  
Cong Wu ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Lung Adenocarcinoma ◽  
Malignant Tumors ◽  
Early Stage ◽  
Enrichment Analysis ◽  
Postoperative Recurrence ◽  
Expression Level ◽  
Central Position ◽  
Lung Cancers ◽  
Gene Modules

Abstract Background: Lung cancer is one of the most common malignant tumors in the world. Non-small-cell lung cancer (NSCLC) accounting for top of all diagnosed lung cancers. Lung adenocarcinoma(LUAD) is the most common subtype in NSCLC. This study attempts to identify and validate biomarkers that can be used to monitor recurrence after LUAD surgery. Methods: In this research, we downloaded lung adenocarcinoma data from the TCGA database and selected postoperative recurrence samples, and then performed WGCNA analysis to find key co-expression gene modules. Enrichment analysis of key gene modules was also performed using the DAVID database. Finally, we performed a survival analysis of the most interesting biomarker UPK2 obtained from the TCGA analysis in the Oncomine database and evaluated its impact on prognosis. We collected 132 blood samples from patients with early-stage lung adenocarcinoma who were tested the expression level of free mRNA in the plasma.Results: The results revealed that UPK2, KLHDC3, GALR2 and TYRP1 occupied a central position in the co-expression network which were also significantly correlated with the survival of patients. The expression level of free UPK2 in the plasma relative to GADPH in non-relapsed patients was 0.1623, and in relapsed patients, it was 0.2763. ROC was used to evaluate the effectiveness of free UPK2 mRNA in the blood for monitoring postoperative recurrence, with an AUC of 0.767 and a 95% confidence interval of 0.675-0.858. At the same time, patients with high expression of free UPK2 mRNA had significantly poorer survival than those with low expression of UPK2. Conclusions: The expression level of free UPK2 mRNA in plasma has the potential as an indicator of postoperative recurrence in patients with early LUAD. This may have guiding significance for the subsequent clinical treatment of patients.

scholarly journals CORE SIM+ SIMULATIONS OF COLIBRI FUEL RODS OSCILLATION EXPERIMENTS AND COMPARISON WITH MEASUREMENTS

2021 ◽  
Vol 247 ◽  
pp. 21006
Author(s):  
A. G. Mylonakis ◽  
C. Demazière ◽  
P. Vinai ◽  
V. Lamirand ◽  
A. Rais ◽  
...  
Keyword(s):  
Experimental Data ◽  
Measured Data ◽  
Main Trend ◽  
Validation Process ◽  
Fuel Rods ◽  
The Core ◽  
University Of Technology ◽  
Neutron Noise ◽  
Original Experimental Data

At EPFL, the CROCUS reactor has been used to carry out experiments with vibrating fuel rods. The paper presents a first attempt to employ the measured data to validate CORE SIM+, a neutron noise solver developed at Chalmers University of Technology. For this purpose, the original experimental data are processed in order to extract the necessary information. In particular, detector recordings are scrutinized and detrended, and used to estimate CPSDs of detector pairs. These values are then compared with the ones derived from the CORE SIM+ simulations of the experiments. The main trend of the experimental data along with the values for some detectors are successfully reproduced by CORE SIM+. Further work is necessary on both the experimental and computational sides in order to improve the validation process.

European Project ATLAS+: Status of the WP1 Relative to the Experimental Program on Pipes and Specimens

2019 ◽  
Author(s):  
Patrick Le Delliou ◽  
Dominique Moinereau ◽  
Myriam Bourgeois ◽  
Szabolcs Szavai
Keyword(s):  
Fracture Mechanics ◽  
Experimental Work ◽  
Ferritic Steel ◽  
Large Scale ◽  
Assessment Tools ◽  
Ductile Material ◽  
Experimental Program ◽  
Small Scale ◽  
European Project ◽  
Experimental Programme

Abstract The 4-year European project ATLAS+ project was launched in June 2017. Its main objective is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. The transferability of ductile material properties from small scale fracture mechanics specimens to large scale components is one of the topics of the project. A large experimental work is conducted in support to development and validation of advanced tools for structural integrity assessment within the framework of the work-package 1 (WP 1): Design and execution of simulation oriented experiments to validate models at different scales. The experimental work is based on a full set of fracture mechanics experiments conducted on specimens and large scale components (several pipes and one mock-up), including a full materials characterization. Three materials are considered: • a ferritic steel 15NiCuMoNb5 (WB 36) • an aged austenitic stainless steel weld • a VVER dissimilar metal weld (DMW) This paper presents the WP 1, the experimental programme and summarizes the first results. A companion paper [1] presents in more details the experimental programme on the ferritic steel.

European Project ATLAS+: Status of the WP1 Relative to the Experimental Program on Pipes and Specimens

2020 ◽  
Author(s):  
Dominique Moinereau ◽  
Tomas Nicak ◽  
Anna Dahl
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Ductile Material ◽  
Experimental Program ◽  
Small Scale ◽  
Integrity Assessment ◽  
European Project

Abstract The 4-year European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) was launched in June 2017. One of its objectives is to study the transferability of ductile material properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment. The study of properties transferability is based on a wide experimental program — within the framework of work-package 1 (WP 1) — which includes a full set of fracture experiments conducted on conventional fracture specimens and on large scale components (mainly pipes). Three materials are considered in the program: a low-alloy ferritic steel 15NiCuMoNb5 (WB36) typical from feedwater line in German PWR, an aged austenitic stainless steel weld typical (narrow gap) from EPR and a typical VVER austenitic stainless steel dissimilar weld (DMW). Several European organizations are involved in the experimental work: EDF, CEA, Framatome, ARMINES, KIWA, Framatome GmbH, VTT, BZN, MTA-EK, and CIEMAT.

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