1,720,986 research outputs found
An Object Oriented Approach to Simulation of Triga Mark II Dynamic Response
No full textThis paper deals with the development of a model for the nuclear research reactor TRIGA Mark II operating at University of Pavia. The purpose of the modeling is to reproduce the dynamic behavior of the reactor on the entire operative power range, i.e. 0÷250 kW, using the object oriented approach, implemented by the Modelica language. The main advantage is the a-causal formulation of the model, based on equations instead of statement assignment
Valutazione dei costi esternali nella produzione di energia elettrica
No full text(Quadrimestrale Tecnico Scientifico - ENEA), Anno12- N.2- Maggio-Agosto 199
Characterization of a facility for the measurement of fission fragment transport effects : experimental determination of the fission rates for fissile and fissionable isotope
No full textA Zero Dimensional Model for Simulation of Triga Mark II Dynamic Response
No full textIn this paper the development of a model for the nuclear research reactor TRIGA Mark II operating at University of Pavia is presented. Purpose of the modeling is to reproduce the dynamic behavior of the reactor on the entire operative power range, i.e. 0÷250 kW. A zero dimensional approach is accounted for and the coupling between neutronics and thermal-hydraulics in natural circulation is considered
Benchmark evaluation of reactor critical parameters and neutron fluxes distributions at zero power for the TRIGA Mark II reactor of the University of Pavia using the Monte Carlo code MCNP
No full textThe aim of this work was to develop a methodological approach based on Monte Carlo code for the neutronic analysis of the first core configuration of the TRIGA Mark II research reactor of the University of Pavia and the validation of the results by benchmarking with the experimental and operational data reported in the reactor Fist Criticality Final Report.
The neutron analysis was realised by means of the 3-D continuous-energy Monte Carlo code MCNP4C. The reactor model implemented represents in good detail all core components and allows the description of different core and fuel configurations with good versatility. Continuous-energy cross section data from ENDF/B-VI and ENDF/B-V and S(α, β) scattering functions from the ENDF/B-VI library were used. The results of the MCNP simulations and the experimental values show a very good agreement proving the goodness of the model
Study of a new Automatic Reactor Power Control for the TRIGA Mark II Reactor at University of Pavia
No full textAbstract—The installation of a new Instrumentation and Control
(I&C) system for the TRIGA MARK II reactor at University of
Pavia has recently been completed in order to assure a safe and
continuous reactor operation for the future. The intervention
involved nearly the whole I&C system and required a channelby-
channel component substitution. One of the most sensitive
part of the intervention concerned the Automatic Reactor Power
Controller (ARPC) which permits to keep the reactor at an
operator-selected power level acting on the control rod devoted to
the fine regulation of system reactivity. This controller installed
can be set up using different control logics: currently the system
is working in relay mode. The main goal of the work presented in
this paper is to set up a Proportional-Integral-Derivative (PID)
configuration of the new controller installed on the TRIGA
reactor of Pavia so as to optimize the response to system
perturbations
Absolute Flux Measurement by NAA at the Pavia University TRIGA MARK II Reactor Facilities
No full textThe neutron flux is a crucial parameter to know in the analysis of a nuclear reactor, because it affects the reaction rate and thus the fuel burnup. Moreover, a very precise knowledge of the flux in the irradiation facilities is helpful for benchmarking the simulation models of the reactor. In this paper, we present the results of the measurements of the neutron flux in three irradiation facilities of the TRIGA Mark II reactor installed at the University of Pavia. The neutron activation analysis of samples containing a large number of elements was used to perform an absolute measurement of the flux. The -ray spectroscopy measurements were repeated on different HPGe detectors and GEANT4 Monte Carlo simulations were developed to evaluate the detection efficiency for every radioisotope of interest. The very good agreement among the results of the flux calculations from the many different activated isotopes confirms the reliability of the methodology
A zero dimensional model for simulation of TRIGA Mark II dynamic response
No full textAim of this work is to reproduce the dynamic behavior of the TRIGA Mark II reactor of the University of Pavia on the entire operative power range (i.e. 0–250 kW) using a zero dimensional approach. In this work the coupling between neutronics and thermal-hydraulics in natural circulation has been considered. In specific, a point reactor kinetics model with one energy group and six delayed neutron precursors groups has been adopted while for thermal-hydraulics modeling two regions have been defined (i.e. the fuel and the coolant). The nonlinear system of coupled Ordinary Differential Equations has been solved by means of MATLAB Simulink®, which represents a reliable tool for dynamic and control analysis. The model has then been validated through the comparison with a set of experimental data collected in four different reactor power transients, obtaining a very satisfying agreement. Finally, the linear stability analysis of the TRIGA reactor has been performed by means of the root locus, finding out that the power level at which reactor is operating deeply influences the position of the poles of the transfer function between control rod height and neutron density. These results can then be employed as a reliable starting point in designing an automatic device for reactor power control
Neutronic Analysis of the Pavia University Triga Mark II Reactor Core
No full textAn advanced computational tool based on Monte Carlo code was developed for the neutronic analysis of the TRIGA Mark II research reactor of the University of Pavia and the results from simulations were benchmarked with the experimental data. The neutron analysis was performed by means of the 3-D continuous-energy Monte Carlo codes MCNP4C and MCNP5. All core components were reproduced in good detail and the model allows the description of different core and fuel configurations with good versatility. In a first step, the results from the simulations with fresh fuel at room temperature were compared with the experimental data about critical core parameters at zero power level, quoted in the reactor First Criticality Final Report; a very good agreement was found and the goodness of the model was proved. Afterwards, neutron flux and reactivity dependence on the fuel and moderator temperature was studied in detail; all the available methods for the simulation of thermal effects were analyzed in order to model the reactor in the stationary operating condition at 250 kW. The model was updated to the present configuration and the use of specific S(α,β) cross sections was found to be of primary importance for a correct simulation of low-energy neutrons scattering within moderator
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