1,720,984 research outputs found
Simulation tools and approaches for the compliance with performance-based ECCS cladding acceptance criteria (10 CFR50.46c)
No full textThe Nuclear Regulatory Commission (NRC) is currently considering a revision of the requirements in 10 CFR 50.46C, rules, focused on the ECCS rule in LOCA scenarios. The new approach modifies the analysis strategy in order to take into account also the effects of the burn-up rate. The maximum temperature and the oxidation of the cladding must be casted as function of the fuel exposure in order to find the limiting conditions in the history of the reactor, with its different design and different reloading patterns. This new analysis requires new tools and capabilities in order to have reasonable computational times and good accuracy, taking in account the dynamic phenomena of multi-physics systems. In order to perform such analysis, a rigorous Probabilistic Risk Assessment (PRA) strategy needs to be employed. This work is a proof of concept for illustrating a new proposed approach that will be required in the next years, in order to face the challenges posed by the new rule
RAVEN: a GUI and an Artificial Intelligence Engine in a Dynamic PRA Framework
Full text linkIncreases in computational power and pressure for
more accurate simulations and estimations of accident scenario consequences are driving the need for Dynamic
Probabilistic Risk Assessment (PRA) [1] of very complex models. While more sophisticated algorithms and
computational power address the back end of this challenge, the front end is still handled by engineers that
need to extract meaningful information from the large amount of data and build these complex models.
Compounding this problem is the difficulty in knowledge transfer and retention, and the increasing speed of
software development. The above-described issues would have negatively
impacted deployment of the new high fidelity plant simulator RELAP-7 (Reactor Excursion and Leak
Analysis Program) at Idaho National Laboratory. Therefore, RAVEN that was initially focused to be the
plant controller for RELAP-7 will help mitigate future
RELAP-7 software engineering risks. In order to accomplish such a task Reactor Analysis
and V
Uncertainty quantification method for RELAP5-3D© using RAVEN and application on NACIE experiments
Full text linkThe best estimate plus uncertainty (BEPU) method plays a key role in the development of the innovative Generation IV nuclear reactors, for the improvement of knowledge and the good evaluation of the safety margins for new phenomena. The aim of this paper is to validate an uncertainty quantification (UQ) approach using RAVEN code. RAVEN, developed at the Idaho National Laboratory, is a multipurpose probabilistic and uncertainty quantification framework, capable to communicate with any system code, implemented with an integrated validation methodology involving several different metrics. In this activity, a coupled calculation RELAP5-3D/RAVEN has been performed to assess the validity of the embedded UQ approach. The simulations have concerned two tests conducted on NACIE (NAtural CIrculation Experiment) facility, a non-nuclear loop-type system using Lead-Bismuth Eutectic (LBE) as coolant, realized at the ENEA Brasimone Research Centre (Italy) to support the development of the GEN-IV reactors. The experimental tests are aimed to investigate the phenomena related to the natural and gas enhanced circulation flow regimes of heavy liquid metals (HLM), and to test and validate the main components in a LBE environment. A numerical 1D model of NACIE facility has been realized and the post-test analysis has been carried out using RELAP5-3D© ver. 4.3.4. Based on these results, a statistical analysis has been performed using RAVEN computer code, investigating the capability of three probabilistic comparison metrics fully integrated in the code
Mathematical Framework for the Analysis of Dynamic Stochastic Systems with the RAVEN code
No full textRAVEN (Reactor Analysis and Virtual control Environment) is a software code under
development at Idaho National Laboratory aimed at performing probabilistic risk assessment and uncertainty quantification using RELAP-7, for which it acts also as a simulation controller. In this paper we will present the equations characterizing a dynamic stochastic system and we will then discuss the behavior of each stochastic term and how it is accounted for in the RAVEN software design. Moreover we will present preliminary results of the implementatio
Enhanced shuffling and fuel management capability in PHISICS code
No full textThe paper is aimed to report the improvements of the shufflling and fuel management module within the PHISICS code
Performing Probabilist Risk Assessment Through RAVEN
No full textRAVEN (Reactor Analysis and Virtual control
ENviroment) [1, 2] is a software framework that acts
as the control logic driver for the Thermo-Hydraylic code
RELAP-7, a newly developed software at Idaho National
Laboratory. The aim of this paper is to provide an overview
of the software structure and its utilization in conjunction
with RELAP-7/MOOSE [3, 4]. RAVEN is a multi-purpose
Probabilistic Risk Assement (PRA) code that allows
dispatching different functionalities. It is designed to derive
and actuate the control logic required to simulate the plant
control system and operator actions (guided procedures) and
to performboth Monte-Carlo sampling ofrandom distributed
events and dynamic event tree based analysis [5]. In order to
assist the user in the input/output handling, a Graphical User
Interface (GUI) and a post-processing data mining module,
based on dimensionality and cardinality reduction [6], are
available. This paper wants to point up the link between the
software layout and the mathematical framework from which
its structure is derived. In order to show some capabilities, a
demo of a Station Black Out (SBO) analysis of a simplified
Pressurized Water Reactor (PWR) model is reported.RAVEN (Reactor Analysis and Virtual control
ENviroment) [1, 2] is a software framework that acts
as the control logic driver for the Thermo-Hydraylic code
RELAP-7, a newly developed software at Idaho National
Laboratory. The aim of this paper is to provide an overview
of the software structure and its utilization in conjunction
with RELAP-7/MOOSE [3, 4]. RAVEN is a multi-purpose
Probabilistic Risk Assement (PRA) code that allows
dispatching different functionalities. It is designed to derive
and actuate the control logic required to simulate the plant
control system and operator actions (guided procedures) and
to performboth Monte-Carlo sampling ofrandom distributed
events and dynamic event tree based analysis [5]. In order to
assist the user in the input/output handling, a Graphical User
Interface (GUI) and a post-processing data mining module,
based on dimensionality and cardinality reduction [6], are
available. This paper wants to point up the link between the
software layout and th
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
New RELAP5-3D Lead and LBE Thermophysical Properties Implementation for Safety Analysis of Gen IV Reactors
Full text linkThe latest versions of RELAP5-3D© code allow the simulation of thermodynamic system, using different type of working fluids, that is, liquid metals, molten salt, diathermic oil, and so forth, thanks to the ATHENA code integration. The RELAP5-3D© water thermophysical properties are largely verified and validated; however there are not so many experiments to generate the liquid metals ones in particular for the Lead and the Lead Bismuth Eutectic. Recently, new and more accurate experimental data are available for liquid metals. The comparison between these state-of-the-art data and the RELAP5-3D© default thermophysical properties shows some discrepancy; therefore a tool for the generation of new properties binary files has been developed. All the available data came from experiments performed at atmospheric pressure. Therefore, to extend the pressure domain below and above this pressure, the tool fits a semiempirical model (soft sphere model with inverse-power-law potential), specific for the liquid metals. New binary files of thermophysical properties, with a detailed mesh grid of point to reduce the code mass error (especially for the Lead), were generated with this tool. Finally, calculations using a simple natural circulation loop were performed to understand the differences between the default and the new properties
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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