Multi-Link Vision stent vs. first-generation drug-eluting stents: systematic review and meta-analysis

n/

A reduced order model for fission gas diffusion in columnar grains

In fast reactors, restructuring of the fuel micro-structure driven by high temperature and high temperature gradient can cause the formation of columnar grains. The non-spheroidal shape and the non-uniform temperature field in such columnar grains implies that standard models for fission gas diffusion can not be applied. To tackle this issue, we present a reduced order model for the fission gas diffusion process which is applicable in different geometries and with non-uniform temperature fields, maintaining a computational requirement in line with its application in fuel performance codes. This innovative application of reduced order models as meso-scale tools within fuel performance codes represents a first-of-a-kind achievement that can be extended beyond fission gas behaviour.</p

A reduced order model for fission gas diffusion in columnar grains

In fast reactors, restructuring of the fuel micro-structure driven by high temperature and high temperature gradient can cause the formation of columnar grains. The non-spheroidal shape and the non-uniform temperature field in such columnar grains implies that standard models for fission gas diffusion can not be applied. To tackle this issue, we present a reduced order model for the fission gas diffusion process which is applicable in different geometries and with non-uniform temperature fields, maintaining a computational requirement in line with its application in fuel performance codes. This innovative application of reduced order models as meso-scale tools within fuel performance codes represents a first-of-a-kind achievement that can be extended beyond fission gas behaviour.</p

Current Concepts on Antiplatelet Therapy: Focus on the Novel Thienopyridine and Non-Thienopyridine Agents

Thienopyridines are a class of drug targeting the platelet adenosine diphosphate (ADP) 2 receptor. They significantly reduce platelet activity and are therefore clinically beneficial in settings where platelet activation is a key pathophysiological feature, particularly myocardial infarction. Ticlopidine, the first of the class introduced to clinical practice, was soon challenged and almost completely replaced by clopidogrel for its better tolerability. More recently, prasugrel and ticagrelor have been shown to provide a more powerful antiplatelet action compared to clopidogrel but at a cost of higher risk of bleeding complications. Cangrelor, a molecule very similar to ticagrelor, is currently being evaluated against clopidogrel. Considering the key balance of ischemic protection and bleeding risk, this paper discusses the background to the development of prasugrel, ticagrelor, and cangrelor and aims to characterise their risk-benefit profile and possible implementation in daily practice

Fuel performance simulations of ESNII prototypes: Results on the MYRRHA case study

Nominal and transient conditions of the ESNII prototypes were investigated in the INSPYRE Project using the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. This Deliverable presents the results of the simulations of the MYRRHA case study: MYRRHA nominal irradiation conditions and the occurrence of a beam power jump (over‐power) transient at the beginning and end of life of the fuel pin in reactor. Besides the application of the reference (“pre‐INSPYRE”) code versions, the activity involves the evaluation of the impact of the improved models of MOX fuel properties developed in INSPYRE and implemented in the three fuel performance codes. These modelling advances concern the thermal properties (thermal conductivity, melting temperature), mechanical properties (thermal expansion, Young’s modulus) and the mechanistic treatment of fission gas behaviour and release from MOX fuels. The results yielded by the pre‐INSPYRE and post‐INSPYRE versions of the codes involved are presented and assessed in terms of evolution in time, as well as axial and radial profiles of significant quantities, both integral and local. Then, the code results are compared with the design limits set for the MYRRHA fuel pins, in particular the maximal fuel temperature admitted, which prevents fuel melting, and the maximal allowed cladding plasticity that ensures the cladding integrity. The outcome is a complete compliance of the pin behaviour with the design limits, respecting adequate margins even in the case of the hottest fuel pin and in the case of beam power jump transients

Assessment of INSPYRE-extended fuel performance codes against the SUPERFACT-1 fast reactor irradiation experiment

Design and safety assessment of fuel pins for application in innovative Generation IV fast reactors calls for a dedicated nuclear fuel modelling and for the extension of the fuel performance code capabilities to the envisaged materials and irradiation conditions. In the INSPYRE Project, comprehensive and physics- based models for the thermal-mechanical properties of UePu mixed-oxide (MOX) fuels and for fission gas behaviour were developed and implemented in the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. As a follow-up to the assessment of the reference code versions (“pre- INSPYRE”, NET 53 (2021) 3367e3378), this work presents the integral validation and benchmark of the code versions extended in INSPYRE (“post-INSPYRE”) against two pins from the SUPERFACT-1 fast reactor irradiation experiment. The post-INSPYRE simulation results are compared to the available integral and local data from post-irradiation examinations, and benchmarked on the evolution during irradiation of quantities of engineering interest (e.g., fuel central temperature, fission gas release). The comparison with the pre-INSPYRE results is reported to evaluate the impact of the novel models on the predicted pin performance. The outcome represents a step forward towards the description of fuel behaviour in fast reactor irradiation conditions, and allows the identification of the main remaining gaps

Results of the benchmark between pre- and post-INSPYRE code versions on selected experimental cases

This report presents the results of the simulation of the SUPERFACT-1, RAPSODIE-I and NESTOR-3 irradiation experiments using the fuel performance codes TRANSURANUS, MACROS, GERMINAL. The simulations aim at the evaluation of the code improvements made during the INSPYRE project. The comparison of the integral pin performance results with experimental measurements available from the irradiation experiments considered and the comparison between the code results are presented. Both the results obtained using the ‘pre-INSPYRE’ code versions and the improved ‘post-INSPYRE’ ones, in which novel data and models originating from other Work Packages of the INSPYRE Project were implemented, are provided

Sodium Bicarbonate Treatment during Transient or Sustained Lactic Acidemia in Normoxic and Normotensive Rats

Introduction Lactic acidosis is a frequent cause of poor outcome in the intensive care settings. We set up an experimental model of lactic acid infusion in normoxic and normotensive rats to investigate the systemic effects of lactic acidemia per se without the confounding factor of an underlying organic cause of acidosis. Methodology Sprague Dawley rats underwent a primed endovenous infusion of L(+) lactic acid during general anesthesia. Normoxic and normotensive animals were then randomized to the following study groups (n = 8 per group): S) sustained infusion of lactic acid, S+B) sustained infusion+sodium bicarbonate, T) transient infusion, T+B transient infusion+sodium bicarbonate. Hemodynamic, respiratory and acid-base parameters were measured over time. Lactate pharmacokinetics and muscle phosphofructokinase enzyme's activity were also measured. Principal Findings Following lactic acid infusion blood lactate rose (P<0.05), pH (P<0.05) and strong ion difference (P<0.05) drop. Some rats developed hemodynamic instability during the primed infusion of lactic acid. In the normoxic and normotensive animals bicarbonate treatment normalized pH during sustained infusion of lactic acid (from 7.22\ub10.02 to 7.36\ub10.04, P<0.05) while overshoot to alkalemic values when the infusion was transient (from 7.24\ub10.01 to 7.53\ub10.03, P<0.05). When acid load was interrupted bicarbonate infusion affected lactate wash-out kinetics (P<0.05) so that blood lactate was higher (2.9\ub11 mmol/l vs. 1.0\ub10.2, P<0.05, group T vs. T+B respectively). The activity of phosphofructokinase enzyme was correlated with blood pH (R2 = 0.475, P<0.05). Conclusions pH decreased with acid infusion and rose with bicarbonate administration but the effects of bicarbonate infusion on pH differed under a persistent or transient acid load. Alkalization affected the rate of lactate disposal during the transient acid load

A model describing intra-granular fission gas behaviour in oxide fuel for advanced engineering tools

The description of intra-granular fission gas behaviour is a fundamental part of any model for the prediction of fission gas release and swelling in nuclear fuel. In this work we present a model describing the evolution of intra-granular fission gas bubbles in terms of bubble number density and average size, coupled to gas release to grain boundaries. The model considers the fundamental processes of single gas atom diffusion, gas bubble nucleation, re-solution and gas atom trapping at bubbles. The model is derived from a detailed cluster dynamics formulation, yet it consists of only three differential equations in its final form; hence, it can be efficiently applied in engineering fuel performance codes while retaining a physical basis. We discuss improvements relative to previous single-size models for intra-granular bubble evolution. We validate the model against experimental data, both in terms of bubble number density and average bubble radius. Lastly, we perform an uncertainty and sensitivity analysis by propagating the uncertainties in the parameters to model results

Third Yearly Activity Report

The calculation work performed during the 3rd project year in WP2 as well as the R&amp;D activities carried out in WP3, WP4 and WP5 are described in this report. In addition, the work dedicated to the project management (WP1) as well as to WP6 regarding the dissemination/communication activities and the education/training program (e.g. the follow-up of the mobility program between different organizations in the consortium, training on simulation tools and activities accomplished by PhD/post-doctoral students) is also reported