International Standard Problem No 50 – The University of Pisa contribution

The present paper deals with the participation of the University of Pisa in the last International Standard Problem (ISP) focused on system thermal hydraulic, which was led by the Korean Atomic Energy Research Institution (KAERI). The selected test was a Direct Vessel Injection (DVI) line break carried out at the ATLAS facility. University of Pisa participated, together with other eighteen institutions, in both blind and open phase of the analytical exercise pursuing its methodology for developing and qualifying a nodalization. Qualitative and quantitative analysis of the code results have been performed for both ISP-50 phases, the latter adopting the Fast Fourier Transfer Based Method (FFTBM). The experiment has been characterized by three dimensional behavior in downcomer and core region. Even though an attempt to reproduce these phenomena, by developing a fictitious three-dimensional nodalization has been realized, the obtained results were generally acceptable but not fully satisfactory in replicating 3D behavio

MELCOR-To-MELCOR Coupling Method in Severe Accident Analysis Involving Core and Spent Fuel Pool

A lot of effort has been spent to prevent the occurrence of SA in nuclear plant and to develop Severe Accidents (SA) Management to mitigate the consequences of a SA. Those consequences are mainly related to limit the release of fission product to the environment. The core in the vessel is not the only source of fission products as the Spent Fuel Pool (SFP) hosting the fuel removed by the core is, in some NPP, inside the containment and SA conditions can also occur. This is especially important in reactors having proximity between the RPV and SFP such as the VVER-1200. This close proximity implies that any SA occurring in the SFP potentially affects the RPV and vice-versa. This potential combination might cause unexpected evolution in the SA progression to whom the safety systems are not able to contain. MELCOR code is a widely used, flexible powerful SA code but it is incapable (due to the uniqueness of the COR package use inside the same input) to reproduce a situation in which both the fuel in vessel core and the fuel in the SFP, inside the same containment, are going to experience a severe accident scenario. The current study presents a MELCOR-to-MELCOR coupling method to simulate simultaneously scenarios with both, core and SFP, as sources capable of H2 generation, fuel damage and FP release in a VVER-1200 NPP. The coupling is performed by running two simulations in parallel and with the data exchange supervised and managed by a dedicated Python coupling supervising script developed at NINE

Interpretation of EU Regulation 2022/1426 on the Type Approval of Automated Driving Systems

In 2022, the European Commission adopted the first worldwide legislation concerning the type-approval of the Automated Driving Systems of fully Automated Vehicles, opening the road to their introduction to the European market. The EU, in this way, becomes the first market in the world where this new generation of vehicles can be placed with a complete and unambiguous legislative framework. In order to define the conditions for the type-approval of vehicles operating without the presence of a driver, the EU Regulation 2022/1426 introduces a series of completely innovative elements that both industry and the Approval Authorities of the European Member States have the task to operationalise. In order to support this phase and to ensure the establishment of as harmonized as possible practices across the EU, the European Commission has launched in 2022 the process of drafting a first interpretation of some among the most innovative aspects of the Regulation. The present report is the result of this process. It has been drafted with the active contribution by the experts part of the Automated and Connected Vehicles sub-group of the Working Group on Motor Vehicles (MVWG-ACV). In its final form the report is composed by two parts. A first part of technical interpretation of the regulatory text and a second part composed by six appendixes providing examples and relevant resources to support the operationalization of different aspects of the legislation.JRC.C.4 - Sustainable, Smart and Safe Mobilit

Synthesis and evaluation of new Hsp90 inhibitors based on a 1,4,5-trisubstituted 1,2,3-triazole scaffold

Abstract: Ruthenium catalyzed 1,3-cycloaddition (click chemistry) of an azido moiety installed on dihydroxycumene scaffold with differently substituted aryl propiolates, gave a new family of 1,4,5-trisubstitued triazole carboxylic acid derivatives that showed high affinity towards Hsp90 associated with cell proliferation inhibition, both in nanomolar range. The 1,5 arrangement of the resorcinol, the aryl moieties, and the presence of an alkyl (secondary) amide in position 4 of the triazole ring, were essential to get high activity. Docking simulations suggested that the triazoles penetrate the Hsp90 ATP binding site. Some 1,4,5-trisubstitued triazole carboxamides induced dramatic depletion of the examined client proteins and a very strong increase in the expression levels of the chaperone Hsp70. In vitro metabolic stability and in vivo preliminary studies on selected compounds have shown promising results comparable to the potent Hsp90 inhibitor NVP-AUY922. One of them, (compound 18; SST0287CL1) was selected for further investigation as the most promising drug candidate

Cilostazol Activates Function of Bone Marrow-Derived Endothelial Progenitor Cell for Re-endothelialization in a Carotid Balloon Injury Model

BACKGROUND: Cilostazol(CLZ) has been used as a vasodilating anti-platelet drug clinically and demonstrated to inhibit proliferation of smooth muscle cells and effect on endothelial cells. However, the effect of CLZ on re-endothelialization including bone marrow (BM)-derived endothelial progenitor cell (EPC) contribution is unclear. We have investigated the hypothesis that CLZ might accelerate re-endothelialization with EPCs. METHODOLOGY/PRINCIPAL FINDINGS: Balloon carotid denudation was performed in male Sprague-Dawley rats. CLZ group was given CLZ mixed feed from 2 weeks before carotid injury. Control group was fed normal diet. CLZ accelerated re-endothelialization at 2 weeks after surgery and resulted in a significant reduction of neointima formation 4 weeks after surgery compared with that in control group. CLZ also increased the number of circulating EPCs throughout the time course. We examined the contribution of BM-derived EPCs to re-endothelialization by BM transplantation from Tie2/lacZ mice to nude rats. The number of Tie2-regulated X-gal positive cells on injured arterial luminal surface was increased at 2 weeks after surgery in CLZ group compared with that in control group. In vitro, CLZ enhanced proliferation, adhesion and migration activity, and differentiation with mRNA upregulation of adhesion molecule integrin αvβ3, chemokine receptor CXCR4 and growth factor VEGF assessed by real-time RT-PCR in rat BM-derived cultured EPCs. In addition, CLZ markedly increased the expression of SDF-1α that is a ligand of CXCR4 receptor in EPCs, in the media following vascular injury. CONCLUSIONS/SIGNIFICANCE: CLZ promotes EPC mobilization from BM and EPC recruitment to sites of arterial injury, and thereby inhibited neointima formation with acceleration of re-endothelialization with EPCs as well as pre-existing endothelial cells in a rat carotid balloon injury model. CLZ could be not only an anti-platelet agent but also a promising tool for endothelial regeneration, which is a key event for preventing atherosclerosis or restenosis after vascular intervention

RELAP5/MOD3 .2 Post Test Analysis and Accuracy Quantification of SPES Test SP-SB-04

The present document deals with the Relap5fMod3.2 analysis of the small br.!ak LOCA experiment SP-SB-04 performed in SPES facility. SPES is a PWR simulator (integral Test Facility) installed at SIET center in Pia::enza (IT). Volume scaling and core power scaling factors are 1/427, with respect to the Westinghouse 900 MWe standard reactor. The experiment is originated by a small break in the cold leg (2»> equivalent break area in the plant) without the actuation of the high pressure injection system. The test starts from full power and is the counterpart of the test SP-SB-03, that started at an initial power roughly equal to 10% of nominal power. Low pressure injection system actuation occurs after core dry-out. The Relap5 code has been extensively used at University of Pisa; the nodalizatic'n of SPES facility has, been qualified through the application of the version Relap5/Mod2 to the same experiment and another test performed in the same facility. Sensitivity analyses have been addressed to the influence of several parameters (like discharge break coefficient, time of accumulators start etc.) upon the predicted transient evolution. Qualitative and quantitative code calculation accuracy evaluation has been performed.