On capabilities and limitations of current fast neutron-flux monitoring instrumentation for the DEMO LFR ALFRED

Among Gen IV projects for future nuclear power plants, Lead cooled Fast Reactors (LFR) seem to be a very interesting solution due to its benefits in terms of fuel cycle, coolant-safety and waste management. The novelty of the matter causes some open issues about coolant chemical aspect, structural aspects, monitoring instrumentation, etc. Particularly hard neutron flux spectra would make traditional neutron instrumentation unfit to all reactor conditions, i.e. source, intermediate, and power range. Identification of new models of nuclear instrumentation specialized for LFR neutron flux monitoring asks for an accurate evaluation of the environment the sensor will work in. In this study, thermal-hydraulics and chemical conditions for LFR core environment will be assumed, as the neutron flux will be studied extensively by means of the Monte Carlo transport code MCNPX. The core coolant’s high temperature drastically reduces the candidate instrumentation, because only some kind of fission chambers and Self Powered Neutron Detectors can be operated in such an environment. This work aims at evaluating the capabilities of the available instrumentation (usually designed and tailored for Sodium cooled Fast Reactors, SFRs) when exposed to the neutron spectrum derived from ALFRED, a pool-type LFR project to demonstrate the feasibility of this technology into the European framework. This paper shows that such class of instrumentation does follow the power evolution, but is not completely suitable to detect the whole range of reactor power, due to excessive burn-up, damages or gamma interferences. Some improvements are possible in order to increase the signal-to-noise ratio, by optimizing each instrument in the range of reactor power, such to get the best solution. The design of some new detectors are here proposed, together with a possible approach for prototyping and testing them by means of a fast reactor

Considerations on reduction of indoor air pollution from radioactive emissions from building materials and the ground

The goal of this paper is to study the reduction of health risks from indoor radioactive pollutants, as thoron emissions from common building materials, and radon emission from both building materials and the ground. In particular, when dealing with the indoor environment, one of the most important hazard is represented by radon gas, considered by the World Health Organization (WHO) as the second largest cause of lung cancer, cigarette smoke being the first. Such a radioactive gas belongs to the natural radioactive background of radiation, and its presence all over the world is unavoidable. Radon gas density varies due to microclimatic factors such as temperature, air pressure, humidity and changes in ground layers. Radon gas emerges from the ground and penetrates building basements, accumulating itself into the indoor air, and being breathed in by people. Taking care of the airtightness of windows allows the radon concentration to build up, in some cases beyond reference levels, together with other chemical pollutants, i.e. combustion residues and solvents. The EU Basic Safety Standards, stated in the Council Directive 2013/59/Euratom, based on the last recommendations from the International Commission on Radiological Protection (ICRP) and from WHO, are focusing on risks related to radon gas concentration inside dwellings and working places. On considering that Council Directive 2013/59 Euratom has to be transposed into law by each EU Member State by February 2018, it is recommended that radon issues have to be considered during the design phase of the building construction. For NZEB applications a special attention is requested when energy consumption is reduced lower and lower by taking care of airtightness. In such a case, indoor pollutants (chemical, radioactive, particulate, etc.) can significantly accumulate beyond safe levels. This paper describes measurements and remedial actions of study cases, focusing on public and domestic environments

Radiation protection considerations on radon and building materials radioactivity in Near Zero Energy Buildings

Recent updates of the E.U. Basic Safety Standards, stated in the Council Directive 2013/59/EURATOM, are focusing on risks related to radon gas concentration inside dwellings and working places, as well as radioactivity of building materials. In particular, the new E.U. Basic Safety Standards are based on last recommendations from the International Commission on Radiological Protection (ICRP), and from the World Health Organization (WHO), which consider that radon issues, and external irradiation from building material, as topic aspects to population’s health. Further, ICRP Publication 126, by using bio-kinetics models for estimating the effects of radon intakes, has drastically reduced the reference level for radon concentration in dwellings and working places. Radon issues have recently gained particular attention due to current orientations in constructing buildings with energy consumptions lower and lower. Radon gas emerges from the ground, penetrates building’s basements, and accumulates itself into the indoor air, being breathed by people. Taking care of windows’ airtightness allows the radon concentration to build up, in some cases beyond reference levels, together with other chemical pollutants, i.e. combustion residues and solvents. On considering that Council Directive 2013/59 EURATOM has to be transposed into law by each EU Member State by February 2018, it is recommended that radon issues have to be considered during the design phase of the building construction, particularly for NZEB applications. Further, external irradiation from building materials, i.e. tuff, marbles, tiles, pozzolana, coal ashes and so on, may be a reason of concern also. This paper describes radiation protection issues focusing on public and domestic environments, where people are supposed to spend a considerable amount of time. About radon, real measurements are shown, both in domestic and working scenarios. Dealing with external irradiation due to building materials, calculations and simulations have been performed and results are presented

Ottimizzazione della strumentazione di monitoraggio neutronico del nocciolo di un reattore LFR

Il presente lavoro ha avuto come obiettivo lo studio di scelta ed ottimizzazione della strumentazione neutronica per il monitoraggio di flussi neutronici da reattori veloci, con particolare attenzione verso i Lead Fast Reactor, in ambienti ostili per la tecnologia, in cui i fattori limitanti per i rivelatori risultano essere l’alta temperatura (mediamente 400 ÷ 500 °C) ed un alto rateo di dose gamma. Partendo dalla strumentazione neutronica commercialmente disponibile, si sono proposti miglioramenti e soluzioni innovative al fine di ottimizzare l’efficacia e l’adeguatezza del sistema di strumentazione, monitoraggio e controllo di reattore. Un tale lavoro deve necessariamente affiancare la fase di progetto del reattore stesso cosicché la strumentazione prevista possa essere efficacemente integrata con le soluzioni progettuali concernenti il disegno neutronico e termoidraulico. L’identificazione di modelli innovativi per la strumentazione neutronica specializzata per reattori LFR, piuttosto recenti se confrontati con i fratelli maggiori Sodium Fast Reactor, richiede che sia ben identificato il tipo di ambiente in cui le sonde andranno ad operare. Non essendo presente, al momento, una sufficiente quantità di dati sperimentali in grado di fornire indicazioni precise riguardo il campo di radiazione o la strumentazione da impiegare in tali reattori, l’approccio più efficace e conveniente -almeno in fase preliminare- per colmare tali lacune è la simulazione mediante codici di calcolo. Focalizzandosi questo lavoro sull’aspetto del monitoraggio neutronico, saranno assunte le condizioni chimiche e termo-idrauliche dell’ambiente reattore, mentre saranno estensivamente studiati gli aspetti nucleari mediante il codice Monte Carlo di trasporto di radiazione MCNPX ver.2.7.0. Come reattore di riferimento è stato scelto il prototipo LFR dimostrativo nel panorama europeo, ALFRED, del quale si è simulato, tramite MCNPX, il pressure vessel e tutte le strutture interne a un elevato livello di dettaglio, al fine di ricavare il termine sorgente per la strumentazione, ovvero il flusso neutronico per le posizioni di reattore che possono verosimilmente alloggiare la strumentazione. Si sono dapprima valutate le prestazioni della strumentazione commercialmente disponibile, illustrandone criticamente le potenzialità e le problematiche d’impiego al caso in esame. Successivamente, sono stati proposti sviluppi e miglioramenti alle tecnologie in uso, con l’obiettivo di delineare modifiche potenzialmente attuabili al fine di ottimizzare la strumentazione per ambienti tipo LFR, prospettando così la possibilità di sviluppare e costruire rivelatori ad hoc, sia per il monitoraggio in-core che out-of-core, con possibilità di test in impianti sperimentali in grado di fornire spettri neutronici veloci. Il primo passo dello studio è consistito nell’analisi della strumentazione correntemente utilizzata per SFR, valutandone prestazioni e caratteristiche quando trasposta al reattore LFR ALFRED. Diversi modelli di camere a fissione ed Self-Powered Neutron Detectors, SPND, resistenti ad alte temperature sono stati analizzati dal punto di vista della risposta a diversi flussi neutronici, mostrandone limiti e criticità. La strumentazione commercialmente disponibile si è dimostrata applicabile, ma non completamente adeguata alle esigenze di monitoraggio del reattore studiato, evidenziando la necessità di studiare soluzioni progettuali innovative che siano corredate anche da esperienze sperimentali in flussi neutronici veloci. Per quanto concerne l’avviamento del reattore e la fase transitoria di salita in potenza, la strumentazione raccomandata consiste in camere e microcamere a fissione, sufficientemente sensibili per monitorare le decadi di flusso neutronico competenti allo start-up e all’intermediate range di reattore. Per quanto riguarda il livello di potenza nominale, gli alti ratei di flusso neutronico competenti al power range di ALFRED (300MWth), combinati con le elevate sensitività delle camere a fissione, non consentono a tale strumentazione di poter operare oltre 6÷12 mesi; i rivelatori di tipo prompt-SPND si dimostrano essere più appropriati in termini di affidabilità e durabilità nel tempo, sebbene vadano verificate le loro prestazioni, vista l’esiguità dei segnali elettrici prodotti, in alcuni casi anche alla potenza nominale del reattore. Un quadro verosimile della strumentazione applicabile al reattore ALFRED può riassumersi come segue: 1) start-up: quando il flusso neutronico risulta compreso tra 10E0 ÷ 10E6 n/(cm2 s) ed il fondo gamma di reattore è notevolmente intenso, solo le camere a fissione possono essere efficacemente utilizzate come strumentazione in-core, perché particolarmente sensibili al campo neutronico quando esercite in pulse mode; 2) intermediate range: quando il flusso neutronico risulta compreso tra10E6÷10E12 n/(cm2 s) e il fondo gamma di reattore assume -generalmente- lo stesso ordine di grandezza del campo neutronico e le camere a fissione possono continuare ad essere efficacemente impiegate, tipicamente in Mean Square Voltage mode; 3) power range: quando il flusso neutronico è compreso tra 10E12 ÷10E15 n/(cm2 s), il fondo gamma di reattore può essere considerato trascurabile per le camere a fissione, che dovranno essere esercite in current mode data l’abbondanza delle interazioni neutroniche all’interno del volume sensibile. Il campo neutronico è qui troppo intenso perché le camere a fissione durino a lungo nel tempo, a causa della loro intrinsecamente alta sensitività ai neutroni. Strumenti meno sensibili, gli SPND a risposta pronta, possono efficacemente prendere il posto delle camere a fissione come strumentazione in-core di monitoraggio e controllo del reattore. Si è fornita una concettualizzazione delle innovazioni applicabili alla strumentazione in generale, con particolare riguardo ai SPND a risposta pronta (oggi poco sperimentati perché non utili nell’attuale panorama reattoristico che si serve dei loro "fratelli maggiori", i SPND_ritardati), delineando possibilità innovative per la misura di flussi neutronici corrispondenti alla potenza nominale di reattore. L’intrinsecamente bassa sensitività della strumentazione SPND può difatti consentire una loro installazione fissa negli elementi di combustibile, essendo il loro rateo di burn-up sufficientemente basso da farli durare a lungo, anche se irraggiati con fluenze superiori a quelle limite per le camere a fissione di corrente uso. Nell’ottica di sviluppare quest’ultimo tipo di tecnologia strumentale, si è validata la simulazione Monte Carlo MCNPX per strumentazione SPND in monitoraggio di flussi neutronici veloci attraverso prove già svolte nel reattore veloce TAPIRO del Centro Ricerche ENEA Casaccia nell’ambito di progetti di ricerca riguardanti la fusione nucleare, identificando -così- uno strumento di calcolo che consenta di poter ottimizzare e ri-progettare al calcolatore tali rivelatori, migliorandone prestazioni, ottimizzandone caratteristiche e durata nel tempo. Nuovi materiali sensibili per tale classe di strumenti sono stati analizzati, insieme con lo studio del burn-up a seguito d’irraggiamento e la verifica della loro risposta dinamica alle variazioni di flusso neutronico. Si è studiata una concettualizzazione di una sonda innovativa basata su SPND che consenta, oltre che le convenzionali misure di flusso neutronico integrato in energia, anche una valutazione delle caratteristiche spettrali dei neutroni, combinando misure da diversi SPND e risolvendo matematicamente un problema di unfolding spettrale. La disponibilità del reattore TAPIRO di ENEA Casaccia può consentire lo studio sperimentale delle principali caratteristiche di prestazione degli strumenti detti, permettendo di acquisire una preziosa esperienza sul campo. Nel prossimo futuro, un SPND prototipo potrà esser costruito e testato, verificando sperimentalmente l’effettiva possibilità tecnica per tale strumentazione di monitorare flussi neutronici veloci. Il presente lavoro di tesi è il risultato di una collaborazione triennale con il Centro Ricerche ENEA Casaccia, nei laboratori UT-FISST/MEPING prima e FSN/FISS/CRGR poi, ed è stato inquadrato nei Piani Annuali di Ricerca 2013, 2014 e 2015 dell’Accordo di Programma Ministero dello Sviluppo Economico-ENEA

The role of knowledge in water service coproduction and policy implications

More than 50 years after the seminal studies of Elinor Ostrom, the concept of water service “coproduction” is of interest due to its ability to achieve a delicate balance of governance in the sector. This novel analysis applies a systematic literature review to the water coproduction policies to identify the factors that promote their successful development. The results show that knowledge is the decisive element for newly shared governance. From this study, implications for water management and research are derived

Local Dermonecrosis with Generalized Urticaria Probably Due to Loxosceles rufescens Bite

BACKGROUND: The spiders of the Loxosceles genus, commonly denoted as “brown spiders” or “Mediterranean recluse” or “brown recluse,” belong to the spider family Sicariidae, suborder Labidognatha, order Araneida, class Arachnida, and phylum Arthropoda. This spider is widespread in Africa and South/Central America, but it is also distributed in North America, in the West Indies, in the Mediterranean Europe, and in China. CASE REPORT: Here, we report the case of a severe dermonecrotic loxoscelism identified in Southern Italy, probably due to the bite of Loxosceles rufescens. The patient was a women admitted at hospital ER because of a little skin erythema that evolved toward a severe necrosis and ulceration within 20 days. After clinical and laboratory data excluded other local and systemic diseases, she was treated with a systemic and local therapy using corticosteroids and antibiotics with the diagnosis of loxoscelism. The healing from the local skin lesion occurred within 2 months, but the local pain, weakness, and discomfort lasted for a long time. CONCLUSION: It is the fisrt time that a possible case of systemic loxoscelism with skin generalized urticaria is reported in Italy

Sperm ultra-structure and spermiogenesis in <i>Syllis krohni</i> (Polychaeta: Syllidae), with some observations on its reproductive biology

yllidae show a wide spectrum of both reproductive strategies and sperm types. Analysis of their reproductive patterns could drastically change the presently accepted taxonomic hierarchy of the group. To further contribute to the knowledge of Syllidae we have described the sperm ultra-structure and the spermiogenesis of Syllis krohni (Ehlers, 1864). Mature sperm has a cone-shaped acrosome whose distal end is notched by a trough that transversely encircles its anterior portion. During spermiogenesis, the acrosomal vesicle undergoes modifications leading to its final shape with a posterior opening. The nucleus appears flattened anteriorly and forms a cleft that surrounds the proximal centriole in its distal region. A 9+2 flagellar axoneme is observed. Up to five mitochondria surround the distal centriole. The spermatozoon of S. krohni can be ascribed to the ect-aquasperm type that is typical in species having external fertilisation and appears to be very similar in appearance to that of the congeneric species thus far investigated. The main difference is in the shape of the acrosome, which is more elongated and as long as the nucleus. Reproduction of syllids seems to be conservative within sub-families, and the sperm morphology can probably help in phylogenetic reconstruction. External fertilisation is a widespread strategy within the genus Syllis, probably leading to a substantial similarity in sperm morphology being maintained. It is hypothesised, however, that within the same sperm type linked to a particularly reproductive strategy, the acrosome ultra-structure can be indicative of phylogeny

Evaluation and Management of Patients with Methomyl Poisoning – A Case Report

The Apulian Poison Centre (PC) of Foggia, Italy, annually manages numerous consultations concerning certain or suspected poisonings from pesticides, starting at the same time a careful activity related to the risk assessment phase. The management of the exposure to pesticides and to other chemicals, and the alerting of the “National center for chemicals, cosmetics and consumer protection” at the Istituto Superiore di Sanità (ISS), actively contributes to the improvement of products quality and safety. Thus, leading to a reduction in the number of intoxications - and therefore of the accesses to the emergency services - allows greater protection for workers, bystanders, residents and consumers. The reported case of methomyl poisoning has been of fundamental importance both from the medical point of view and for the management of the intoxicated patient, both for the risk assessment actions, and for cooperation with the competent authorities, generating discussion points on the regulations in force between PCs and National Competent Authority. It follows that the feedback of intoxication in an emergency can lead to improvements in the management and risk mitigation measures in order to reach a greater protection of human, animal, and environmental health. In addition, the regulatory feedback deriving from these reports is an input to the increase product quality improvement (mixtures, labels, packaging, and risk communication) leading to a greater protection of potential exposed subjects. The importance of creating an information and management network that allows the optimization of the flow of information deriving from PCs arises. The actions taken are therefore described, both relating to the management of the emergency, and relating to the subsequent information flow and to the measures for containing the consequent risks

Secondary metabolite profile in induced tetraploids of wild Solanum commersonii Dun.

The main aim of this work was to study the leaf secondary metabolite profiles of artificially induced tetraploids (2n1⁄44x1⁄448) of Solanum commersonii, a diploid (2n1⁄42x1⁄424) wild potato species. The tetraploid genotypes of S. commersonii were produced by oryzalin treatment. Both HPLC-UV and LC/ MS analyses revealed that there were no qualitative differences in the metabolite profiles between the diploid S. commersonii and its tetraploids. By contrast, the results showed that the phenylpropanoid content was generally significantly higher in the tetraploids than in the diploid S. commersonii. Concerning the glycoalkaloids (GAs), the results provided evidence that the content of minor GAs (solanidenediol triose, solanidadienol lycotetraose, and solanidenol lycotetraose) was higher in tetraploids than in the diploid progenitor, while the content of major GAs (dehydrodemissine and dehydrocommersonine) was significantly higher in diploid S. commersonii than in its tetraploid genotypes. The results are discussed from the practical perspective of potato biodiversity enhancement

Biological and geochemical markers of the geographical origin and genetic identity of potatoes

There is a growing interest in agriculture productions combining safety and quality attributes with clear regional identity. In the last few years several methods have been employed for food authentication and traceability. In this study we tested geochemical data for elemental concentrations of Mn, Cu, Zn, Rb, Stand Cd and strontium isotope ratio in combination with biological data of 11 secondary metabolites and DNA as markers for the authentication of the origin of early potatoes at small geographical scale levels in Italy. DNA fingerprints through 12 SSR (simple sequence repeat) primer pairs allowed cultivar identification, confirming the discrimination power of molecular markers. Element concentrations, strontium isotope ratio and secondary metabolite data, through multivariate statistics (partial least squares discriminant analysis. PLS-DA), made it possible to clearly assign all the potato samples to the respective administrative regions of cultivation. The validation of the models was successful. It included external prediction tests on 20% of the data randomly selected from each administrative province and a study on the robustness of these multivariate data treatments to uncertainties on measurement results