O. Cabellos

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• Professor
• Full Professor at Universidad Politécnica de Madrid

The WIMSD-5B transport code is a deterministic tool for nuclear reactor core design and fuel management. It can efficiently handle pin-cell and supercell models and calculate homogenized cross sections, which are essential for reactor physics calculations. It is used by core design packages such as the CORD-2 package, developed at the Jožef Stefan...

This paper summarized the efforts performed to understand decay heat estimation from existing spent nuclear fuel (SNF), under the auspices of the Working Party on Nuclear Criticality Safety (WPNCS) of the OECD Nuclear Energy Agency. Needs for precise estimations are related to safety, cost, and optimization of SNF handling, storage, and repository....

The uranium-233 neutron capture cross section between 3 keV and 1 MeV was evaluated with the new alpha value recently measured at the Los Alamos National Laboratory LANCE facility and compiled in the EXFOR library. The obtained capture cross section is systematically lower than those in the latest versions of the major general purpose nuclear data...

GRE@T-PIONEeR is a Horizon 2020 project coordinated by Chalmers University of Technology, running over the period 2020-2024. 18 university teachers from 8 different universities located in 6 different countries gathered forces to develop and offer advanced courses in computational and experimental nuclear reactor physics and safety. All courses are...

The Target Accuracy Requirements (TAR) exercise was launched in the framework of the WPEC/S46 (2018-2022) on “Efficient and Effective Use of Integral Experiments for Nuclear Data Validation” [1]. This Exercise aims to quantify priority nuclear data needs or uncertainties reduction to meet design integral parameters target accuracies. To perform thi...

Within the frame of the EU H2020 program SANDA project, sensitivity and uncertainty analyses have been performed for the ESFR, ASTRID and ALFRED reactor concepts and the multipurpose flexible irradiation facility MYRRHA. Relevant reactor parameters, namely the effective multiplication factor, the effective delayed neutron fraction, the Doppler reac...

Radiotherapy using accelerated-protons has increasing potential in dealing with some tumors, and consequently, in the last decade proton-therapy centers have grown rapidly throughout the world. In these facilities, prompt radiation attenuation is essential to achieve legal dose limits, but not enough to develop efficient radiation protection. Activ...

One of the main drawbacks of current nuclear energy is the generation of high-level radioactive waste. On the other hand, the composition of the used nuclear fuel would still allow a very high amount of energy to be obtained from it. Advanced fuel cycles look for a better use of nuclear fuel while reducing the amount of waste generated by closing t...

This paper provides a summary of results of the WPNCS Subgroup on Bias and Correlated Data. The objective of this subgroup is to achieve comparisons between different validation methodologies (statistical models and numerical procedures) to compute keff predictions and their uncertainties based on given covariance information. In this context, the...

GRE@T-PIONEeR - GRaduate Education Alliance for Teaching the PhysIcs and safety Of NuclEar Reactors - is a project funded by the Euratom – Horizon 2020 Framework Programme which aims at developing and providing specialised and advanced courses in computational and experimental reactor physics at the graduate level (MSc and PhD levels) and post-grad...

The Working Party on International Nuclear Data Evaluation Co-operation Subgroup 47 (WPECSG47) entitled "Use of Shielding Integral Benchmark Archive and Database for Nuclear Data Validation" was organised from 2019 and 2022 with the objectives to promote more systematic and wider use of shielding benchmark experiments in nuclear data (ND) and trans...

In the last years, a new version of the Joint Evaluated Fission and Fusion File (JEFF) data library, namely JEFF-3.3, has been released with relevant updates in the neutron reaction, thermal neutron scattering and covariance sub-libraries. In the frame of the EU H2020 SANDA project, severale efforts have been made to enable the use of JEFF nuclear...

Recently, a second Target Accuracy Requirements (TAR) exercise is launched in the framework of the WPEC/S46 on “Efficient and Effective Use of Integral Experiments for Nuclear Data Validation”. The TAR exercise aims at quantifying nuclear data needs, in terms of uncertainty reduction, to meet target accuracies on specific integral parameters. These...

The development of advanced nuclear systems and optimization of current reactor designs relies to a large extent upon computer simulations. Accurate computational simulations are then required to provide reliable predictions. These predictions should be accompanied by the corresponding quantification of uncertainties, which may come from material p...

The preliminary assessment of the performance and safety of advanced reactors, as well as the identification of R&D needs, rely on computer simulations due to lack of operational experience. Those simulations should be based on verified and validated computational tools, calculation schemes, and nuclear data libraries, and should be accompanied of...

(ES) El sistema de códigos SCALE, desarrollado por Oak Ridge National Laboratory, se presenta como una potente herramienta para el análisis neutrónico de reactores nucleares avanzados gracias a su amplio e integrado conjunto de códigos computacionales. SCALE está dotado de códigos para diferentes aplicaciones, desde el procesamiento de datos nuclea...

There is a long-standing controversy on nuclear data uncertainty assessment for general purpose nuclear data libraries. On the one hand, nuclear data users would like the libraries to predict uncertainties for selected integral quantities consistent with the integral experimental uncertainties, while on the other hand, doing so could make evaluatio...

Sodium-cooled Fast Reactors and Lead-cooled Fast Reactors have been selected by the Sustainable Nuclear Energy Technology Platform as technologies that can meet future European energy needs. To achieve the requested level of safety for these reactor technologies and to minimize the increase in the costs due to additional safety measures, accurate a...

The problem of calculating sensitivity coefficients to nuclear data in burnup problems is addressed. A non-intrusive method based on the random sampling of nuclear data and on linear regression is proposed to overcome the limitations of dealing with a complex coupled problem. Sensitivity plots are reported for the actinide concentrations that build...

In proton therapy centers stray neutron radiation of up to 230–250 MeV is yielded by (p, Xn) nuclear reactions. To monitor ambient dose in such facilities, extended-range rem-meters are needed. The aim of this project was to characterize the response of two extended-range rem-meters, WENDI-II and LUPIN-II, by Monte Carlo methods, for energies rangi...

Background: Information from differential nuclear-physics experiments and theory is often too uncertain to accurately define nuclear-physics observables such as cross sections or energy spectra. Integral experimental data, representing the applications of these observables, are often more precise but depend simultaneously on too many of them to una...

It is shown here that 14-MeV D+T LLNL pulsed-sphere experiments bring complementary information into the process of validating nuclear data compared to experiments that are traditionally used for this purpose—such as critical assemblies. To be more specific, the 14-MeV D+T LLNL pulsed-sphere neutron-leakage spectra enable to validate scattering and...

The Horizon 2020 ESFR-SMART project investigates the behaviour of the commercial-size European Sodium-cooled Fast Reactor (ESFR) throughout its lifetime. This paper reports work focused on the End of Equilibrium Cycle (EOEC) loading of the ESFR, including neutronic analysis, core- and zone-wise reactivity coefficients, and more detailed local mappi...

Monte Carlo neutron transport codes can be used for high-fidelity predictions of the performance of nuclear systems. However, validation against experiments is required in order to establish the credibility in the results and identify the inaccuracies due to the used calculation scheme and associated databases. The International Handbook of Evaluat...

The ESFR-SMART project is the latest iteration of research into the behaviour of a commercial-size SFR core throughout its lifetime. As part of this project the ESFR core has been modelled by a range of different reactor physics simulation codes at its end of cycle state, and the important safety relevant parameters evaluated. These parameters are...

La actualización y mejora continua en la dosimetría de neutrones y benchmarking es una de las actividades desarrolladas en el Laboratorio de Medidas Neutrónicas de la Universidad Politécnica de Madrid. En este laboratorio se emplea un contenedor Howitzer para alojar las fuentes de neutrones de 241Am/9Be empleadas en dicho laboratorio para activació...

The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides \(^{235}\hbox {U}\), \(^{238}\hbox {U}\) and \(^{239}\hbox {Pu}\), on \(^{241}\hbox {Am}\) and \(^{23}\hbox {Na}\), \(^{59}\hbox {Ni}\), Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includ...

The ESFR-SMART project is the latest iteration of research into the behaviour of a commercial-size SFR core throughout its lifetime. As part of this project the ESFR core has been modelled by a range of different reactor physics simulation codes at its end of cycle state, and the important safety relevant parameters evaluated. These parameters are...

Monte Carlo neutron transport codes can be used for high-fidelity predictions of the performance of nuclear systems. However, validation against experiments is required in order to establish the credibility in the results and identify the inaccuracies due to the used calculation scheme and associated databases. The International Handbook of Evaluat...

Shielding benchmarks were extensively used for the validation and improvement of nuclear data since many years. Recent evaluations however mostly rely on the validation using critical benchmarks, which can introduce biases and compensation effects. A new Working Party on International Nuclear Data Evaluation Co-operation Subgroup 47 (WPEC SG47) ent...

The aim of this work is to review different Monte Carlo techniques used to propagate nuclear data uncertainties. Firstly, we introduced Monte Carlo technique applied for Uncertainty Quantification studies in safety calculations of large scale systems. As an example, the impact of nuclear data uncertainty of JEFF-3.3 ²³⁵ U, ²³⁸ U and ²³⁹ Pu is demon...

The aim of this paper is to present the activities carried out by NEA Data Bank on checking, processing and verification of JEFF-3.3T4 covariances. A picture of the completeness and status of the JEFF-3.3T4 covariances is addressed. The verification of JEFF-3.3T4 covariances is performed with nuclear data sensitivity tool providing the keff uncerta...

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 235,238U, 239Pu, 56Fe, 16O and 1H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Wor...

Uncertainty propagation to k eff using a Total Monte Carlo sampling process is commonly used to solve the issues associated with non-linear dependencies and non-Gaussian nuclear parameter distributions. We suggest that in general, k eff sensitivities to nuclear data perturbations are not problematic, and that they remain linear over a large range;...

SFCOMPO-2.0 is the new release of the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) database of experimental assay measurements. These measurements are isotopic concentrations from destructive radiochemical analyses of spent nuclear fuel (SNF) samples. The measurements are supplemented with design informa...

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies – 16O, 56Fe, 235,8U and 239Pu – with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working P...

The n_TOF neutron time-of-flight facility at CERN is used for high quality nuclear data measurements from thermal energy up to hundreds of MeV. In line with the CERN open data policy, the n_TOF Collaboration takes actions to preserve its unique data, facilitate access to them in standardised format, and allow their re-use by a wide community in the...

JANIS (JAva-based Nuclear Data Information System) software is developed by the OECD Nuclear Energy Agency (NEA) Data Bank to facilitate the visualization and manipulation of nuclear data, giving access to evaluated nuclear data libraries, such as ENDF, JEFF, JENDL, TENDL etc., and also to experimental nuclear data (EXFOR) and bibliographical refer...

The European approach for the development of nuclear data for fusion technology applications is presented. Related R&D activities are conducted by the Consortium on Nuclear Data Development and Analysis for Fusion to satisfy the nuclear data needs of the major projects including ITER, the Early Neutron Source (ENS) and DEMO. Recent achievements are...

A sensitivity and uncertainty analysis was carried out to estimate the uncertainty in the neutron multiplication factor keff and to identify the most important nuclear data for neutron induced reactions for criticality calculations of the latest MYRRHA designs. Sensitivity profiles, i.e. sensitivity to the nuclear data as a function of incoming neu...

The impact of the current nuclear data library covariances such as in ENDF/B-VII.1, JEFF-3.2, JENDL-4.0, SCALE and TENDL, for relevant current reactors is presented in this work. The uncertainties due to nuclear data are calculated for existing PWR and BWR fuel assemblies (with burn-up up to 40 GWd/tHM, followed by 10 years of cooling time) and for...

The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) concept is a flexible experimental lead-bismuth cooled and mixed-oxide (MOX) fueled fast spectrum facility designed to operate both in sub-critical (accelerator driven) and critical modes. One of the key issues for the safe operation of the reactor is the uncertainty asse...

The challenge for any nuclear data evaluation project is to periodically release a revised, fully consistent and complete library, with all needed data and covariances, and ensure that it is robust and reliable for a variety of applications. Within an evaluation effort, benchmarking activities play an important role in validating proposed libraries...

Members of the International Network of Nuclear Reaction Data Centres (NRDC) have collaborated since the 1960s on the worldwide collection, compilation and dissemination of experimental nuclear reaction data. New publications are systematically complied, and all agreed data assembled and incorporated within the EXFOR database. Recent upgrades to ac...

The TALYS Evaluated Nuclear Data Library (TENDL) has now 8 releases since 2008. Considerable experience has been acquired for the production of such general-purpose nuclear data library based on the feedback from users, evaluators and processing experts. The backbone of this achievement is simple and robust: completeness, quality and reproducibilit...

The European approach for the development of nuclear data for fusion technology applications is presented. Related R&D activities are conducted by the Consortium on Nuclear Data Development and Analysis for Fusion to satisfy the nuclear data needs of the major projects including ITER, the Early Neutron Source (ENS) and DEMO. Recent achievements are...

In the framework of the OECD/NEA WPEC subgroup 41, ways to improve neutron induced capture cross sections for 241Am and 237Np are being sought. Decay data, energy dependent cross section data and neutron spectrum averaged data are important for that purpose and were investigated. New time-of-flight measurements were performed and analyzed, and cons...

The selection, testing, verification and benchmarking of evaluated nuclear data consists, in practice, in putting an evaluated file through a number of checking steps where different computational codes verify that the file and the data it contains complies with different requirements. These requirements range from format compliance to good perform...

The objective of this work is for the verification of large experimental (EXFOR) and evaluated nuclear reaction databases (JEFF, ENDF, JENDL, TENDL…). The work is applied to neutron reactions in EXFOR data, including threshold reactions, isomeric transitions, angular distributions and data in the resonance region of both isotopes and natural elemen...

Benchmarking and Validation Activities within JEFF Project