Analysis of ASTEC-Na capabilities for simulating a loss of flow CABRI experiment

Abstract This paper presents simulation results of the CABRI BI1 test using the code ASTEC-Na, currently under development, as well as a comparison of the results with available experimental data. The EU-JASMIN project (7th FP of EURATOM) centres on the development and validation of the new severe accident analysis code ASTEC-Na (Accident Source Term Evaluation Code) for sodium-cooled fast reactors whose owner and developer is IRSN. A series of experiments performed in the past (CABRI/SCARABEE experiments) and new experiments to be conducted in the new experimental sodium facility KASOLA have been chosen to validate the developed ASTEC-Na code. One of the in-pile experiments considered for the validation of ASTEC-Na thermal–hydraulic models is the CABRI BI1 test, a pure loss-of-flow transient using a low burnup MOX fuel pin. The experiment resulted in a channel voiding as a result of the flow coast-down leading to clad melting. Only some fuel melting took place. Results from the analysis of this test using SIMMER and SAS-SFR codes are also presented in this work to check their suitability for further code benchmarking purposes

Sudden neck swelling with rash as late manifestation of COVID-19: a case report

Background: Although there are reports of otolaryngological symptoms and manifestations of CoronaVirus Disease 19 (COVID-19), there have been no documented cases of sudden neck swelling with rash in patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection described in literature. Case presentation: We report a case of a sudden neck swelling and rash likely due to late SARS-CoV-2 in a 64-year-old woman. The patient reported COVID-19 symptoms over the previous three weeks. Computed Tomography (CT) revealed a diffuse soft-tissue swelling and edema of subcutaneous tissue, hypodermis, and muscular and deep fascial planes. All the differential diagnoses were ruled out. Both the anamnestic history of the patient’s husband who had died of COVID-19 with and the collateral findings of pneumonia and esophageal wall edema suggested the association with COVID-19. This was confirmed by nasopharyngeal swab polymerase chain reaction. The patient was treated with lopinavir/ritonavir, hydroxychloroquine and piperacillin/tazobactam for 7 days. The neck swelling resolved in less than 24 h, while the erythema was still present up to two days later. The patient was discharged after seven days in good clinical condition and with a negative swab. Conclusion: Sudden neck swelling with rash may be a coincidental presentation, but, in the pandemic context, it is most likely a direct or indirect complication of COVID-19

Extension of ASTEC-Na capabilities for simulating reactivity effects in Sodium Cooled Fast Reactor

The EU-JASMIN project (7th FP of EURATOM) has been centred on the development and validation of the new severe accident analysis code ASTEC-Na (Accident Source Term Evaluation Code) for Sodium-cooled Fast Reactors (SFR). The development of such computational tool being able to assist safety analysis of innovative reactor concepts is of crucial importance. One of the challenging issues when modelling SFRs is the neutronic reactivity feedbacks. This paper presents the model implemented in ASTEC-Na for representing the reactivity effects in SFR as well as the benchmarking results of a ULOF transient against SAS-SFR code results. It has been verified that the models are correctly implemented and that ASTEC-Na is now able to calculate reactivity feedbacks not only in the sodium single phase, but also after boiling onset and fuel in-pin relocation

Identification and categorisation of safety issues for ESNII reactor concepts. Part I: Common phenomena related to materials

International audience; With the aim to develop a joint proposal for a harmonised European methodology for safety assessment of advanced reactors with fast neutron spectrum, SARGEN-IV (Safety Assessment for Reactors of Gen IV) Euratom coordination action project gathered together twenty-two partners' safety experts from twelve EU Member States. The group consisted of eight European Technical Safety Organisations involved in the European Technical Safety Organisation Network (ETSON), European Commission's Joint Research Centre (JRC), system designers, industrial vendors as well as research and development (RandD) organisations. To support the methodology development, key safety features of four fast neutron spectrum reactor concepts considered in Deployment Strategy of the Sustainable Nuclear Energy Technology Platform (SNETP) were reviewed. In particular, outcomes from running European Sustainable Nuclear Industrial Initiative (ESNII) system projects and related Euratom collaborative projects for Sodium-cooled Fast Reactors, Lead-cooled Fast Reactors, Gas-cooled Fast Reactors, and the lead-bismuth eutectic cooled Fast Spectrum Transmutation Experimental Facility were gathered and critically assessed. To allow a consistent build-up of safety architecture for the ESNII reactor concepts, the safety issues were further categorised to identify common phenomena related to materials. Outcomes of the present work also provided guidance for the identification and prioritisation of further RandD needs respective to the identified safety issues. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-NDlicense

A Requirement for Zic2 in the Regulation of Nodal Expression Underlies the Establishment of Left-Sided Identity

ZIC2 mutation is known to cause holoprosencephaly (HPE). A subset of ZIC2 HPE probands harbour cardiovascular and visceral anomalies suggestive of laterality defects. 3D-imaging of novel mouse Zic2 mutants uncovers, in addition to HPE, laterality defects in lungs, heart, vasculature and viscera. A strong bias towards right isomerism indicates a failure to establish left identity in the lateral plate mesoderm (LPM), a phenotype that cannot be explained simply by the defective ciliogenesis previously noted in Zic2 mutants. Gene expression analysis showed that the left-determining NODAL-dependent signalling cascade fails to be activated in the LPM, and that the expression of Nodal at the node, which normally triggers this event, is itself defective in these embryos. Analysis of ChiP-seq data, in vitro transcriptional assays and mutagenesis reveals a requirement for a low-affinity ZIC2 binding site for the activation of the Nodal enhancer HBE, which is normally active in node precursor cells. These data show that ZIC2 is required for correct Nodal expression at the node and suggest a model in which ZIC2 acts at different levels to establish LR asymmetry, promoting both the production of the signal that induces left side identity and the morphogenesis of the cilia that bias its distribution

Multi-pin modelling of PWR fuel pin ballooning during post-LOCA reflood

Abstract Experiments investigating post-LOCA reflood generally indicate little coherence to fuel pin ballooning, and an absence of significant blockages and un-coolable regions of the core. Computational modelling is unable to predict this; the usual 'representative pin' models neither take into account the heterogeneity of the core, nor incorporate the dynamic coupling between the changing core geometry, and the flow paths taken by the coolant. In this paper we present a composite model, able to treat distinct pins mechanistically, and able to incorporate their (distinct) swelling behaviour into the thermal-hydraulic model of the reflood, allowing the cooling of a pin to be directly affected by the deformation of itself and its neighbours. INTRODUCTION In this paper we describe the development and initial application of a new computational model to analyse the ballooning of multiple fuel pins in the re-flood phase of loss of coolant accidents in PWRs. The main objectives of this new model are: (i) To allow proper incorporation of the many and significant systematic and stochastic differences between pins, and (ii) To allow the modelling of the coolant flow to take account of the dynamically changing geometry as pins begin to balloon. Such improved modelling is important to help reduce conservatisms in safety-case development, thereby widening operational envelopes. It will also be necessary whe

Extension of ASTEC-Na capabilities for simulating reactivity effects in Sodium Cooled Fast Reactor

The EU-JASMIN project (7th FP of EURATOM) has been centred on the development and validation of the new severe accident analysis code ASTEC Na (Accident Source Term Evaluation Code) for Sodium-cooled fast reactors (SFR). The development of such computational tools being able to assist safety analysis of innovative reactor concepts is of crucial importance. One of the challenging issues when modelling SFRs is the neutronic reactivity feedbacks. This paper presents the model implemented in ASTEC-Na for representing the reactivity effects in SFR as well as the benchmarking results of a ULOF transient against SAS-SFR code results. It has been verified that the models are correctly implemented and that ASTEC-Na is now able to calculate reactivity feedbacks not only in the sodium single phase, but also after boiling onset and fuel in-pin relocation.JRC.G.I.4-Nuclear Reactor Safety and Emergency Preparednes