Microvascular cutaneous coverage in wounds that expose the Achilles tendon: case report

Achilles tendon rupture, being one of the main tendon ruptures present, surgery being the most favourable option even taking into account complications such as infections and skin necrosis, it is necessary to develop techniques which help to reduce complications and increase benefits. The methods follow-up of 2 cases of patients with skin defects in the region of the Achilles tendon in patients who were treated at the "Luis Guillermo lbarra lbarra" national rehabilitation institute during the period 2020-2021 in the Traumatology service, treated with radial free flap forearm, using the description of the most used flaps in the literature. Results in both cases integrity of the free radial forearm flap in its entirety, functional recovery for walking, ability to put shoes back on, and without the need for reoperation, as well as a high level of satisfaction by patients. Conclusions if we are talking about an Achilles tendon rupture with a significant skin defect, the free radial forearm flap is an adequate option, if we are talking about a complete defect, the composite flap is the best option, remember that the decision on what type of flap will be used will depend on of the size of the lesion

Modeling of corium spreading under water layer - validation on the large mass prototypic PLINIUS-2 platform

International audienceCorium coolability after a postulated severe accident involving core meltdown and RPV failure is an important issue. This article deals with spreading and cooling of a corium in a water layer.Currently, the THEMA code, developed at CEA with EDF sponsorship , deals only with the spreading of corium on dry surface with a radiative-convective exchange coefficient. The spreading is then mainly controlled by inertial and viscous forces.In the presence of a water layer in the reactor pit, corium spreading is principally controlled by the yield stress in crust at the flow front. This required the development of a dedicated model. First, the corium crust formation modeling (upper and flow front) was needed. Thanks to this model, the crust thickness evolution with time can be described. An analogy with FinketGriffiths [1] model of volcanic lava was made.Parametric studies show that for a given flow rate, higher yield stresses gives higher height and smaller radius, and with the same stress, the larger the flow rate is, the smaller the height is and the larger the radius is.The aim is to improve the THEMA code taking into account the corium spreading in a water layer. For this, the following modifications should be done-The forces related to the yield stress in crust at the flow front have to be implemented in the momentum balance equation of THEMA; -The power associated with the tensile strength of the crust has to be added in the energy balance equation of THEMA.Finally, to validate the model, some experiments with large mass of prototypic corium are proposed. Indeed, as crust yield stress values and conductivity of corium crust are essential but very poorly known, first, dedicated experiments will be considered to measure these thermophysical data used in the model. Then, the validation of this new version of THEMA will require experiments in more representative conditions which could be carried out in the future PLINIUS-2 experimental platform in Cadarache

Limestone-Siliceous and Siliceous concretes thermal damaging at high temperature

Pré-publication : Construction and Building Materials 228 (2019) 116671Limestone-siliceous and siliceous concretes are used in reactor pits of French nuclear power plants. In case of severe nuclear reactor accident, failure of the reactor vessel would lead to interaction between molten corium (hot melt of nuclear fuel) and concrete. This paper focuses on the thermal degradation of both limestone-siliceous and siliceous concretes till 1000°C. Thermo-Gravimetric Analysis (TGA) and Mercury Intrusion Porosimetry (MIP) are used to measure mass loss and porosity modification. As concretes are heterogeneous materials, sampling and representativeness have been addressed. TGA experiments show larger mass loss for limestone-siliceous concretes due to the decarbonation of calcium carbonate gravels when T>800°C. MIP experiments demonstrate a 100% increase of porosity for limestone-siliceous (resp. siliceous) concretes when T> 500°C (resp. T> 800°C). The consequences of these results are discussed in the frame of experimental tests on prototypical corium systems aimed at describing the key-phenomena involved in molten corium concrete interaction

Needs for large mass prototypic corium experiments the PLINIUS-2 platform

International audienceCorium is the molten material formed after meltdown of a nuclear reactor core during a severe accident. In order to improve the understanding and modelling of corium behavior, experiments are needed both for LWRs and GenIV fast reactors. Experiments using low temperature simulant materials, thanks to lower costs and constraints, allow the testing of a larger number of configurations and the determination of correlations. But some crucial corium phenomena cannot be reproduced at low temperatures such as the importance of radiation heat transfer or the presence of a large (up to 1000 K) liquidus-solidus interval. Consequently, some experiments are performed with high temperature simulant materials alumina thermite as well as refractory oxides. However, it is not feasible to simulate all the aspects of corium phenomenology, especially its high temperature physico-chemistry. Therefore, even though the use of depleted uranium implies a series of protective and regulatory measures, the need for prototypic corium experimented is supported through several examples Another important aspect of experiment design deals with scaling. Small or medium scale corium experiments are easier to operate and only a few large scale (>100 kg) facilities have been built. Several effects are only visible with significant masses, as for instance, the formation of a corium cake during FCI or all the phenomena controlled by crust strength, such as underwater spreading or corium jet ablation. CEA is currently designing a new large prototypic corium platform PLINIUS-2 for both LWR and SFR corium experimental research. Its main characteristics will be presented

Molten Core Concrete Interaction Test in VULCANO Facility Preventing Initial Interfacial Crusts

International audienceIn the frame of the Severe Accident Facilities for European Safety Targets (SAFEST) project,Karlsruhe Institute of Technology (KIT) and the Society for installation and Reactor Safety (GRS)have proposed to realize a Molten Corium Concrete Interaction (MCCI) test in the VULCANO facilitylocated at the PLINIUS experimental platform, CEA Cadarache. The MCCI test, named VBES-U5,was carried out on July 20th, 2017. 50kg of thermite has reacted to melt a prototypic corium in asiliceous concrete test section, which was then heated by induction. The test section was 2Dcylindrical with an inner diameter of 250 mm, an outer diameter of 500 mm, an inner height of 300mm and outer height of 475 mm. MCCI was carried out for 40 min which conducted to an axialablation of 10 mm and a radial ablation of 60 mm. Great care has been taken to prevent initial crustformation (corium composition such that initial contact temperature is above solidus, high powerduring the first minutes). Nevertheless, a pronounced radial ablation has been observed for thissiliceous concrete, similarly to previous VULCANO tests in which initial crust formation was likely tooccur

TBL1XR1 mutations in Pierpont syndrome are not restricted to the recurrent p.Tyr446Cys mutation

IF 2.264International audiencePierpont syndrome is a rare and sporadic syndrome, including developmental delay, facial characteristics, and abnormal extremities. Recently, a recurrent de novo TBL1XR1 variant (c.1337A > G; p.Tyr446Cys) has been identified in eight patients by whole‐exome sequencing. A dominant‐negative effect of this mutation is strongly suspected, since patients with TBL1XR1 deletion and other variants predicting loss of function do not share the same phenotype. We report two patients with typical Pierpont‐like syndrome features. Exome sequencing allowed identifying a de novo heterozygous missense TBL1XR1 variant in both patients, different from those already reported: p.Cys325Tyr and p.Tyr446His. The localization of these mutations and clinical features of Pierpont‐like syndrome suggest that their functional consequences are comparable with the recurrent mutation previously described, and provided additional data to understand molecular mechanisms of TBL1XR1 anomalies

Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool

International audienceOne of the most disputed issues raised by molten corium concrete interaction (MCCI) is how the 2D cavity ablation in an oxidic pool evolves why is the ablation anisotropic with siliceous concretes and isotropic with carbonaceous concretes. The work performed in the frame of the SARNET2 WP6 group during the last 4 years has enabled significant progress on this topic. This paper summarizes this progress using the analysis of recent 2D real material experiments in an oxidic pool and from analytical simulant experiments on 2D heat convection in a bubbling pool, including calculations and recalculations with MCCI codes available in Europe. Firstly, the effective heat transfer coefficients from the bulk pool to the bottom and lateral pool interfaces deduced from MCCI experiments lead to a range of a few 100 W/m2/K. By contrast, a detailed review of possible 2D convection mechanisms shows that the individual heat convection mechanisms (without taking a crust into account) such as gas bubbling convection and solutal convection overestimates the overall heat transfer coefficient, and does not account for the main trends of 2D ablation deduced from MCCI tests, which are very dependent on the composition of concrete components and aggregates. This fact, in turn, points to the effect of more complex pool/concrete interface structures. On the basis of a thorough interpretation of the experimental database and of a detailed comparison of MCCI code predictions, a set of the most realistic and consistent assumptions are identified and major remaining uncertainties are listed. © 2014 Elsevier Ltd

DISCOMS : Capteurs Répartis pour le surveillance du corium et la sûreté

International audienceThe Fukushima-Daiichi nuclear disaster showed that the need for safety must always prevail. This paper discusses the development of remote monitoring technologies to improve Nuclear Power Plants (NPPs) safety, in operation (Pressurized Water Reactors), under construction (the EPR reactors, i.e. the GEN 3 PWR), or for any other next generations of reactors. At Fukushima, the total loss of electrical power supplies has quickly led most of the instrumentation inoperative and the operator (TEPCO) with no way to monitor the status and the evolution of the accident. To overcome these important drawbacks, advantage can be taken from the considerable potential of distributed sensing technologies based on both "Optical Fiber Sensors" (Raman, Brillouin, and Rayleigh Reflectometries) and long-length "Self Powered Neutron Detectors" (SPNDs). The goal consists in inquiring about the status of the third barrier of confinement and to define possible mitigation strategies in case of severe accident, namely: i) reactor pressure vessel breakthrough and corium relocation outside the vessel, ii) concrete basemat erosion and iii) corium cooling. Such monitoring should consist in "sensing cables" embedded in concrete basemat below the reactor vessel and interrogated from a rear base where operators can work safely. In this context, DISCOMS, which stands for "DIstributed Sensing for COrium Monitoring and Safety", is a five-year project, managed by the French National Research Agency (ANR), dealing with the NPP safety improvement, from normal situation to severe accidents. Monitoring phases include reactor vessel breaching, corium flow, along with post-accidental period (corium cooling ex-vessel). Thus, optical fibers selected for their resistance to ionizing radiations and long length SPNDs, both judiciously deployed within the reactor concrete basemat, and the structures around it, will provide a useful real-time or on-demand monitoring, in normal operation, and more important in accidental and post-accidental situations