Methodologies for an improved prediction of the isotopic content in high burnup samples. Application to Vandellos-II reactor core

Fuel cycles are designed with the aim of obtaining the highest amount of energy possible. Since higher burnup values are reached, it is necessary to improve our disposal designs, traditionally based on the conservative assumption that they contain fresh fuel. The criticality calculations involved must consider burnup by making the most of the experimental and computational capabilities developed, respectively, to measure and predict the isotopic content of the spent nuclear fuel. These high burnup scenarios encourage a review of the computational tools to find out possible weaknesses in the nuclear data libraries, in the methodologies applied and their applicability range. Experimental measurements of the spent nuclear fuel provide the perfect framework to benchmark the most well-known and established codes, both in the industry and academic research activity. For the present paper, SCALE 6.0/TRITON and MONTEBURNS 2.0 have been chosen to follow the isotopic content of four samples irradiated in the Spanish Vandellós-II pressurized water reactor up to burnup values ranging from 40 GWd/MTU to 75 GWd/MTU. By comparison with the experimental data reported for these samples, we can probe the applicability of these codes to deal with high burnup problems. We have developed new computational tools within MONTENBURNS 2.0. They make possible to handle an irradiation history that includes geometrical and positional changes of the samples within the reactor core. This paper describes the irradiation scenario against which the mentioned codes and our capabilities are to be benchmarked

Analysis of Different Uncertainty Activation Cross Section Data Libraries for LWR, ads and demo Neutron Spectra

This work is aimed to present the main differences of nuclear data uncertainties among three different nuclear data libraries: EAF-2007, EAF-2010 and SCALE-6.0, under different neutron spectra: LWR, ADS and DEMO (fusion

Anselmo de Cantorbery, 1109-2009

El 21 de abril del 2009 se cumplen 900 años de la entrada en la eternidad de Anselmo de Cantorbery, cuya influencia se proyecta de manera cada vez más ostensible en el futuro del pensamiento filosófico y teológico.April 21, 2009 is the 900th anniversary of Anselm de Cantorbery's entrance into eternity, whose influence is increasingly projected into the future of philosophical and theological thought

Vida e justiça

The following paper aims to work out the route from Life to Justice through three different moments: 1) it summarizes the structure of Michel Henry’s book C’est Moi la Vérite; 2) it provides a commentary on Meister Eckhart´s Sermon VI in which the author preaches about the verse of the Book of Wisdom (5, 16): “But the just shall live for evermore: and their reward is with the Lord, and the care of them with the most High”; 3) it offers two ways of presenting the idea of Justice in Saint Anselm of Canterbury in order to show that it does not differwith life and that it is the source from which the works that might contributeto build the personal ethics and the politics that gather the humans come.En este artículo intenta hacer el itinerario de la Vida a la Justicia a través de tres bloques de sentidos: 1º) sintetiza la estructura del libro de Michel Henry C´est Moi la Vérité; 2º) glosa el Sermón VI de M. Eckhart donde predica sobre la frasedel Libro de la Sabiduría (5,16): Los Justos vivirán eternamente y su recompensa está con Dios; 3º) se rescatan dos modos de exponer la Justicia en San Anselmo de Cantorbery para mostrar que no difiere de la vida y es la fuente de dondeemanan las obras con las que pueden edificarse la ética personal y la política que reúne a los hombres.Neste artigo se tenta fazer o itinerário da Vida à Justiça, através de três blocos de sentidos: 1º) sintetiza a estrutura do livro de Michel Henry C’est Moi la Vérité; 2º) glosa o Semão IV de M. Eckhart, no qual ele prega sobre a frase do Livro da Sabedoria (5,16): Os justos viverão eternamente e sua recompensa está com Deus; 3º) são resgatados dois modos de expor a Justiça, em Santo Anselmo de Canterbury, para mostrar que ela não difere da Vida e é a fonte de onde emanam as obras com as quais podem ser edificadas a ética pessoal e a política que reúne os homens

Electrically tunable photonic true-time-delay line

We present a new application of the acousto-optic superlattice modulation of a fiber Bragg grating based on the dynamic phase and group delay properties of this fiber-optic component. We demonstrate a tunable photonic true-time-delay line based on the group delay change of the light reflected from the grating sidebands. The delay is electrically tuned by adjusting the voltage applied to a piezoelectric transducer that generates the acoustic wave propagating along the grating. In our experiments, a truetime delay of 400 ps is continuously adjusted (300 ps within the 3 dB amplitude range of the first sideband), using a 12 cm long uniform grating

The kinematics of the quadrupolar nebula M1-75 and the identification of its central star

The link between the shaping of bipolar planetary nebulae and their central stars is still poorly understood. The kinematics and shaping of the multipolar nebula M 1-75 are hereby investigated, and the location and nature of its central star are briefly discussed. Fabry-Perot data from GHaFAS on the WHT sampling the Doppler shift of the [N II] 658.3 nm line are used to study the dynamics of the nebula, by means of a detailed 3-D spatio-kinematical model. Multi-wavelength images and spectra from the WFC and IDS on the INT, and from ACAM on the WHT, allowed us to constrain the parameters of the central star. The two pairs of lobes, angularly separated by ~22 degrees, were ejected simultaneously approx. ~3500-5000 years ago, at the adopted distance range from 3.5 to 5.0 kpc. The larger lobes show evidence of a slight degree of point symmetry. The shaping of the nebula could be explained by wind interaction in a system consisting of a post-AGB star surrounded by a disc warped by radiative instabilities. This requires the system to be a close binary or a single star which engulfed a planet as it died. On the other hand, we present broad- and narrow-band images and a low S/N optical spectrum of the highly-reddened, previously unnoticed star which is likely the nebular progenitor. Its estimated V-I colour allows us to derive a rough estimate of the parameters and nature of the central star.Comment: 8 pages, 6 figures, accepted for publication in Astronomy & Astrophysic