Analysis of C/E results of fission rate ratio measurements in several fast lead VENUS-F cores

During the GUINEVERE FP6 European project (2006-2011), the zero-power VENUS water-moderated reactor was modified into VENUS-F, a mockup of lead cooled fast spectrum system with solid components that can be operated in both critical and subcritical mode. The Fast Reactor Experiments for hybrid Applications (FREYA) FP7 project was launched in 2011 to support the designs of the MYRRHA Accelerator Driven System (ADS) and the ALFRED Lead Fast Reactor (LFR). Three VENUS-F critical core configurations, simulating the complex MYRRHA core design and one configuration devoted to the LFR ALFRED core conditions were investigated in 2015. The MYRRHA related cores simulated step by step design peculiarities like the BeO reflector and in pile sections. For all of these cores the fuel assemblies were of a simple design consisting of 30 % enriched metallic uranium, lead rodlets to simulate the coolant and Al2O3 rodlets to simulate the oxide fuel. Fission rate ratios of minor actinides such as Np-237, Am-241 as well as Pu-239, Pu-240, Pu-242 and U-238 to U-235 were measured in these VENUS-F critical assemblies with small fission chambers in specially designed locations, to determine the spectral indices in the different neutron spectrum conditions. The measurements have been analyzed using advanced computational tools including deterministic and stochastic codes and different nuclear data sets like JEFF-3.1, JEFF-3.2, ENDF/B7.1, ENDF/B6.8, JENDL-4.0 and TENDL-2014. The analysis of the C/E discrepancies will help to improve the nuclear data in the specific energy region of fast neutron reactor spectra

The Industrial Development Areas.The case of Caserta

The volume presents the results of the multi-disciplinary research project PURE - Productive and Urban metabolism Resources. Eco-solutions for new lands, funded by our University with the funds of the V:ALERE project. This funding is intended to support the work of our researchers, promoting their role as principal investigators in research projects. The PURE project, led by a research group of the Department of Architecture and Industrial Design - DADI coordinated by Giuseppe Guida, has started from some research hypotheses according to which starting from what of active or abandoned remains from the phenomenon of the Industrial Development Areas there are conditions to propose redevelopment strategies and to reinterpret their role in the territory. For the DADI research team these areas can be redesigned as containers for environmental infrastructure, urban and metropolitan equipment, slow mobility routes, even wooded areas able to coexist with the production realities still present or to be installed

Monte Carlo Assessment of Spatial and Energy Effects in the VENUS-F Subcritical Configurations and Application for Reactivity Determination

International audienceExperiments with a subcritical core and an external pulsed neutron source (PNS) have been performed at the VENUS-F reactor of theSCK-CEN during the year 2012 within the frame of the FREYA project of the 7th European Framework Programme. Different reactivity levels,obtained by varying the position of the control rods and the safety rods, have been investigated, with values of kef f ranging between 0.9and 0.96. The area-ratio and the prompt decay constant techniques are well-known techniques to determine the reactivity of the systemfrom the results of PNS experiments. However, both techniques are based on the point kinetics model and hence they are affected by thespatial and energy effects present in real systems, which will cause them to produce biased values of the reactivity. In this work, we applya methodology based on Monte Carlo simulations to assess the spatial and energy effects present in the VENUS-F core and to determinerelationships between the reactivity and the measured parameters (area-ratio and prompt decay constant) that take into account these effects and allow the application of the reactivity determination techniques to obtain accurate reactivity values beyond the limits of the point kinetics model. The results of the validation of this methodology against the experimental results obtained in the VENUS-F reactor will also be discussed

Estimate of the reactivity of the VENUS-F subcritical configuration using a Monte Carlo MSM method

International audienceThe GUINEVERE project was launched in 2006 in order to study the feasibility of transmutation in Accelerator Driven subcritical Systems (ADS). This facility, hosted at the Belgian Nuclear Research Center SCK·CEN, couples the fast subcritical lead reactor VENUS-F with an external neutron source provided by the GENEPI-3C accelerator.In order to test on-line subcriticality monitoring techniques, an independent measurement of the reactivity of VENUS-F was achieved using the Modified Source Multiplication Method (MSM). The unknown reactivity of the subcritical configuration of interest was determined by comparing detector count rates driven by an external neutron source in this configuration with those obtained in a slightly subcritical configuration whose reactivity was determined by rod drop experiments. To account for spatial effects, MSM correction factors were calculated for all the detectors using the Monte Carlo neutron transport code MCNP. The corrected reactivity values of all the detectors were found to be consistent. This led to a final estimate of −5.28 ± 0.13 $ for the reactivity of VENUS-F.The MSM factors calculated with MCNP were found to be insensitive to the assumptions made for modeling the reactor and the detectors. Thus the MSM method appears to be a robust technique for measuring large subcriticality values with good accuracy

Monte Carlo Assessment of Spatial and Energy Effects in the VENUS-F Subcritical Configurations and Application for Reactivity Determination

International audienceExperiments with a subcritical core and an external pulsed neutron source (PNS) have been performed at the VENUS-F reactor of theSCK-CEN during the year 2012 within the frame of the FREYA project of the 7th European Framework Programme. Different reactivity levels,obtained by varying the position of the control rods and the safety rods, have been investigated, with values of kef f ranging between 0.9and 0.96. The area-ratio and the prompt decay constant techniques are well-known techniques to determine the reactivity of the systemfrom the results of PNS experiments. However, both techniques are based on the point kinetics model and hence they are affected by thespatial and energy effects present in real systems, which will cause them to produce biased values of the reactivity. In this work, we applya methodology based on Monte Carlo simulations to assess the spatial and energy effects present in the VENUS-F core and to determinerelationships between the reactivity and the measured parameters (area-ratio and prompt decay constant) that take into account these effects and allow the application of the reactivity determination techniques to obtain accurate reactivity values beyond the limits of the point kinetics model. The results of the validation of this methodology against the experimental results obtained in the VENUS-F reactor will also be discussed

Reactivity Measurement of the Lead Fast Subcritical VENUS-F Reactor Using Beam Interruption Experiments

International audienceIn order to incinerate minor actinides and thus to reduce the issues linked to nuclear waste management, Accelerator-Driven Systems(ADS) are being under study. An ADS consists in the coupling of a particle accelerator with a sub-critical fast reactor. The on-line reactivitymonitoring is a serious issue regarding safety, therefore several methods to estimate the reactivity of such sub-critical systems have tobe investigated. Here, we present one method based on the study of the neutron population evolution during beam interruption experimentscarried out in the framework of the FREYA FP7 program [1,2] at the GUINEVERE facility, which couples the fast lead sub-critical reactorVENUS-F with the deuteron accelerator GENEPI-3C at SCK-CEN in Mol, Belgium. After describing the facility, the analysis based on pointkinetics theory and preliminary results of the reactivity measurements will be presented. Then, spatial effects that are not taken into accountby point kinetics theory will be highlighted using MCNP simulations, and correction factors to raw results will be calculated. In the end, finalresults will be compared to reference reactivity values obtained with the Modified Source Multiplication (MSM) method