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The increasing worldwide interest in Lead-cooled Fast Reactors (LFRs) substantiates the need to validate the analytical codes and methods used to support their design. For neutronic analyses, this is chiefly reflected in assessing the impact of nuclear data uncertainties on the integral and local parameters resulting from such analyses. The aim of refining nuclear data moves continuous efforts for more accurate measurements, be them differential or integral, for which adequate facilities are required. The availability at the ENEA's Casaccia research center of a fast source reactor – RSV TAPIRO – provides a unique opportunity to perform new integral experiments in support of fast reactors, including LFRs, owing to the well-characterized neutron spectrum of the thermal column. A series of experiments has been envisaged, dealing with the use of Lead in a reactor. The experiments concern the propagation of neutrons through blocks of materials representing relevant elements of a reactor core, and ranging from pure Lead to mixtures reproducing portions of the reflector and shield in LFRs. The paper is focused on the feasibility study of some of these experiments in which Lead and mixture blocks are inserted in the so-called thermal column of the RSV TAPIRO reactor and irradiated by the neutron flux emerging from the Copper reflector surrounding the reactor core.

This paper presents the results of neutron flux measurements at two irradiation facilities of the TRIGA Mark II reactor at ENEA Casaccia Research Center, Italy. The goal of these measurements is to provide a complete characterization of neutron irradiation facilities for accurate and precise dose evaluation in radiation damage tests and, more generally, for all applications that need a good knowledge of neutron flux in terms of intensity, energy spectrum and spatial distribution. The neutron activation technique is used to measure the activation rates of several reactions, chosen so to cover the whole energy range of neutron flux spectrum. A multi-group neutron flux measurement is obtained through an unfolding algorithm based on a Bayesian statistical model. The obtained results prove that this experimental method allows to measure the total neutron flux within 2% statistical uncertainty, and to get at the same time a good description of its energy spectrum and spatial distribution.

A simplified Fusion-Fission Hybrid System (FFHS) deterministic calculation model has been developed in order to study the coupling be- tween a fusion machine and a subcritical fission system. Monte-Carlo (MC) codes are very flexible and they have to be considered as refer- ence calculation tools for complex systems like FFHS. On the other hand, deterministic codes can provide, in shorter calculation time respect to MC codes, parametric and sensitivity analysis, also by exploiting General Perturbation Theory (GPT) methodologies, which can usefully support the global FFHS theoretical analysis. This work describes the comparison between the results obtained for a simplified FFHS model by using a MC code (MCNP6.1, MC N-Particle) and a deterministic code (ERANOS). In particular, in this preliminary study, integral pa- rameters like keff, thermal power, neutron fluxes and some key reaction rate profiles, will be compared. If the comparison between the two mentioned codes will give encouraging results further, more refined, studies will be performed in order to consider deterministic codes as a powerful workhorse for the FFHS analysis, including time dependent analysis devoted to transient and reactivity monitoring issues.

In this work a user-friendly, digital monitoring system for supervision of process variables coming from a fission nuclear reactor of TRIGA type (1-MW TRIGA reactor RC-1) is presented. The system, developed on the basis of COTS tools, can easily interface the control room instrumentation and display the typical monitoring parameters (e.g. nuclear power, temperatures, flow rates, radiological variables) in an intuitive, user-adjustable way for plant operators. A front panel of a virtual instrument allows for a direct measure while the acquisition system, for signals coming from the reactor, can process the data and generate a detailed representation of the results, whose statistics can be interpreted to optimize the reactor management parameters. This system has been also designed so as to include a simulation tool able to predict specific performances and investigate critical phenomena, and to optimize overall plant performances. In particular, it allows to have a feedback control and to perform several predictive statistical surveys of all main process parameters. The proposed system could help operators in training and continuous learning activities, and serve as a basis for an advanced decision support system and for a remote training tool for students and trainees not authorized to work in a radiation environment. © 2016 Elsevier B.V. All rights reserved.

Debris flows represent dangerous occurrences in many parts of the world. Several disasters are documented due to this type of fast-moving landslides; therefore, natural-hazard assessment of debris flows is crucial for safety of life and property. To this aim, much current work is being directed toward developing geotechnical-hydraulic models for the evaluation of debris flow susceptibility. A common base for such current models is parameterization of background predisposing and triggering factors such as inherent characteristics of geo-materials, topography, landscape and vegetation cover, rainfall regime, human activities, etc. which influence the occurrence of these processes on slopes. The same factors are also taken into account in soil erosion prediction models. Consequently, it seems worth investigating the effectiveness of the soil erosion index as debris flows susceptibility indicator. To this aim, a logistic regression analysis was carried out between the erosion index assessed by means of the Revised Universal Soil Loss Equation (RUSLE) model and the inventory of debris flows that have occurred in an area in Sicily (Southern Italy). Model assumptions were verified and validated by means of a series of statistical tools. Different possible scenarios were also evaluated by considering hypothetical changes in soil erosion rate under different rain erosivity conditions. Notwithstanding the rough approximations in model data collection, the outcomes appear encouraging. © 2014, Springer-Verlag Berlin Heidelberg.

Messina area (Italy) range stretches along the coast and have high relief energy. Huge rainfall events cause rapid gravitational phenomena classified as debris flows. The rampant urbanization developed in the last decades in the Messina Municipality has determined a fragile territorial settlement, prone to be heavily damaged by debris flows, as in October 2009. In order to support the community in tackling the risk conditions which it is subjected to, it is necessary to develop “non-structural” measures, characterized by a high level of environmental sustainability. The scientific community and the public authorities responsible for land management and involved in the mitigation of the geomorphological risk are paying a specialattention to the development of monitoring and alarm systems able to improve the current civil defence plans. Based on the historical information on rainfall, this study deals with the triggering thresholds of debris flows. The results provide additional elements to the knowledge of the critical rainfall, useful for developing effective early warning systems. . © Springer International Publishing Switzerland 2015.

October 1st 2009 a heavy rainfall caused more than one thousand debris flows in two small basins south of Messina town (North–East Sicily, Italy). After the disaster Messina Municipality entrusted the risk assessment of its whole territory to a geomorphology and GIS team, led by ENEA, that applied and improved a heuristic method aimed at the identification of the areas prone to landslide triggering, based on the recognition of physical and dynamical characteristics of phenomena. This landslide susceptibility method is a GIS based process that consists in four steps: Field Survey, Site Analysis, Macro-Area Analysis and Susceptibility Analysis. Through the Field Survey of natural and anthropic conditions of past and recent phenomena a landslide inventory is generated, and each thematic map is stored in a GIS database. In the Site Analysis a univariate statistical analysis of the inventory leads to classify each causative factor as a discriminating parameter (condition necessary for slope instability) or as a pr edisposing factor (condition that works together in worsening slope stability). In the Macro-Area Analysis the GIS overlay of all thematic maps is performed to recognize, in surrounding areas, features similar to those of past events. Finally a susceptibility function runs the weighted sum of Predisposing Factors in zones where all Discriminating Parameters are present, deriving the Susceptibility Map. The here discussed heuristic GIS method allows the integration of multidisciplinary knowledge, both quantitative and qualitative, thus exploiting field experience. . © Springer International Publishing Switzerland 2015.

Favignana island (Sicily, Italy) is a historical and environmental attraction site frequented by tourists during the long warm season of the year. For several centuries the calcareous sandstone outcropping in the east side of the island has been extracted and used as building stone. Actually the quarries and the caves are undergoing to erosional and gravitational processes that are influencing the touristic use. As well as putting at risk the safety of people attending the area, the diffused rock falls are likely to jeopardize sites of great anthropological value that, once destroyed, can no longer be reconstructed. An integrated monitoring project of the cliffs is aimed to identify the most active areas and to provide support to the local government’s policies in the implementation of mitigation measures. If adequate measures will be taken in the future, operators and users of the tourist circuit will have the opportunity to enjoy these amazing areas with lower level of landslide risk. © Springer International Publishing Switzerland 2015.