Non Destructive Evaluation of Containment Walls in Nuclear Power Plants

Two functions are regularly tested on the containment walls in order to anticipate a possible accident. The first is mechanical to resist at a possible internal over-pressure and the second is to prevent leakage. The reference accident LLOCA (Large Loss of Coolant Accident) is the rupture of a pipe in the primary circuit of a nuclear plant. In this case, the pressure and temperature can reach 5 bar and 180°C in 20 seconds. The national project ‘Non-destructive testing of the containment structures of nuclear plants’ aims at studying the non-destructive techniques capable to evaluate the concrete properties and its damaging or progression of cracks. This 4-year-project is segmented into two parts. The first consists in developing and selecting the most relevant NDEs (Non Destructive Evaluations) in the laboratory to reach these goals. These evaluations are developed in conditions representing the real conditions of the stresses generated during ten-yearly visits of the plants or those related to an accident. The second part consists in applying the selected techniques to two containment structures under pressure. The first (technique) is proposed by the ONERA (National Office for Aerospace Studies and Research of France) and the second is a mock-up of a containment wall on a 1/3 scale made by EDF (Electricity of France) within the VeRCoRs program. Communication bears on the part of the project that concerns the damaging and cracking follow-up. The tests are done in bending on 3 or 4 points in order to study the cracks’ generation, their propagation, as well as their opening and closing. The mostly ultrasonic techniques developed concern linear or non-linear acoustic: acoustic emission [1], LOCADIFF (Locating with diffuse ultrasound) [2], energy diffusion, surface waves velocity and attenuation, DAET (Dynamic Acousto-Elasticity Testing) [3]. The data contribute to providing the mapping of the parameters searched for, either in volume, in surface or globally. Image correlation is an important additional asset to validate the coherence of the data. The spatial normalization of the data allows proposing algorithms on the combination of the experimental data. The tests results are presented and they show the capacity and the limits of the evaluation of the volume, surface or global data. A data fusion procedure is associated with these results

Drug-resistant tuberculosis in pet ring-tailed Lemur, Madagascar

We diagnosed tuberculosis in an illegally wild-captured pet ring-tailed lemur manifesting lethargy, anorexia, and cervical lymphadenopathy. Whole-genome sequencing confirmed the Mycobacterium tuberculosis isolate belonged to lineage 3 and harbored streptomycin resistance. We recommend reverse zoonosis prevention and determination of whether lemurs are able to maintain M. tuberculosis infection.We thank Madagascar Ministry of the Environment and Forests for permission to study ring-tailed lemurs (no. 155/19/MEDD/SG/DGEF/DGRNE) and the lemur facility for permission to conduct surgery and sample the sick ring-tailed lemurs.Dr. LaFleur is an assistant professor at the University of San Diego, California, USA, and the founder and director of Lemur Love, a US-based nonprofit organization conducting research, conservation, and small-scale development in Madagascar. Her research examines the ecology of wild ring-tailed lemurs and the legal and illegal trades of wild-captured lemurs in Madagascar.The University of San Diego and Lemur Love, Inc. provided funding for this study.http://www.cdc.gov/eidam2022Medical Virolog

Non Destructive Evaluation of the durability and damages of concrete innuclear power plant

The “Non Destructive Evaluation of containment nuclear plant structures” project (ENDE) is a French project developed with 8 partners. Its aims are to control the containment of structures by Non Destructive Testing with ultrasonic, electromagnetic and electric techniques. The results are than combined together to consolidate the final evaluation. Two different objectives are proposed, the first is to estimate concrete properties and the second to follow concrete damages and cracks. The 4 years project was carried out in two steps (in laboratory and on site). The first step consists in realizing two sets of tests on concrete specimens in the laboratory. Objectives of the first set are to characterize the material and to quantify the sensitivity of the Non Destructive Evaluation (NDE) to durability indicators (elasticity modulus, strength, porosity, water content) of the concrete. Two new indicators (thermal damage and stress applied) are tested in order to take into account a possibility of an accident (LLCA). Such accident induces relatively very severe conditions (pressure=4.2 bar and temperature T=180°C) inside the containment The second set was developed to evaluate damaged zones and cracks. The data fusion of measured NDE parameters is applied and developed for each result with two specific processes. It allows to select most sensitive and efficient approaches. The second step consists in an investigation of selected non destructives parameters on a real structures that is containment structures under varying pressure. The presented results were obtained on a mock-up of a containment wall realized in a 1/3 scale and constructed by EDF (Electricity of France) within the VeRCoRs program. These tests are realized in 2017 and simulate the ten-year nuclear power plants control in which the two functions regularly tested are: the concrete mechanical properties and the containment walls leakage. This paper presents the ENDE project and some of in site obtained results