Advanced Reactors and Nuclear Data

Advanced Fission Reactors Physics

An original methodology for PWR reactor core design and analysis has been developed.

The codes integrated into SEANAP (Sistema Español de Análisis de Núcleos de Agua a Presión) System are:

  • WIMS-MARIA: Cell and fuel assembly cross sections libraries generation.
  • COBAYA3-ANDES: Fine mesh 3D (pin-by-pin) and multigroup core calculations.
  • SIMULA: Nodal 3D core calculations.
  • SIMTRAN: Coupled neutronic-thermohydraulics 3D core calculations.
  • COBRA: 3D channels and subchannels analysis.

SEANAP system can be used to simulate a number of applications, such as:

  • Optimized PWR refueling calculations.
  • Nuclear cycles design analysis.
  • Online monitoring for operational surveillance.
  • Operational optimization such as changes in power level, reactor startups and reactor shutdowns.
  • Neutronic-thermohydraulic transients core calculations.
  • Operational plant transient calculations, such as a main steam line break.
  • Uncertainties cuantification.



This system has been developed in collaboration with: ENDESA, Unión Eléctrica Fenosa Ingeniería, Centrales Nucleares Asco y Vandellós II, y Consejo de Seguridad Nuclear. SEANAP system has been used by the Spanish PWR plants during more than 30 years, and to follow the operation in Ascó I, Ascó II y Vandellós.

NURESIM is a common European platform of advanced simulation for present and next PWR nuclear reactor generations. In this project platform development take part 18 institutions from different countries such as laboratories, institutes and universities with renowned prestige in the development of nuclear reactors simulation methods.

The Spanish participation in the FP6-NURESIM, FP7-NURISP and FP7-NURESAFE Euratom projects have been focused in the development of new integrated codes for reliable and detailed reactor core simulation, including neutron kinetics and 3D coupled thermohydraulics (multiphysics) in relevant multiscales. These scales are: pin-by-pin scale, and quarter fuel assembly scale, including reflectors and other relevant components in vessel and thermohydraulic scale.

The following Multiphysics codes have been included in the NURESIM European platform, using SALOME platform for multiscale scale coupling schemes:

  • ANDES (Analytical Nodal Diffusion Equation Solver).
  • COBAYA-3 (Multi-scale and multigroup fine-mesh/nodal kinetics solver).
  • COBRA-TF ( Thermalhydraulic subchannel and channel twophase calculations).

Uncertainties determinations in LWR modelling (OECD/NEA-CSN)

Best Estimates Methods with uncertainties: Best Estimate Plus Uncertainties (BEPU) Project

Methodology for uncertainties quantification with COBAYA/COBRA-TF calculations:

  • 2 for cross sections calculations in few groups.
  • Uncertainties calculations with COBAYA: Perturbation theory and stochastic method

Methodology for uncertainties quantification with SEANAP whole cycle calculations:

  • WIMS for Cross sections calculations
  • Uncertainties calculations with SIMULA

Uncertainty and sensitivity analysis to nuclear data, and core specifications, and relevance in integral core parameters results (critical boron, reactivity coefficients, power distribution…).

Naval nuclear Propulsion

State-of-the-art of the nuclear reactors technology for naval propulsion in military submarines, military aircraft carriers, civil icebreakers, cargo ships, and nuclear reactors in offshore platforms. Past, present, and under development nowdays.

Space Nuclear Propulsion

State-of-the-art of the Radioisotope Thermal Generators, and Nuclear reactors technology for space exploration. Past, present, and under development nowdays.


Nuclear Data. Uncertainty Propagation

The research group on “Nuclear Data Analysis & Processing, Activation-Source Term Calculation and Uncertainty Propagation” has many years of research experience in reactor simulation, covering the following areas: Nuclear Data Analysis and Processing, Neutronics, Isotopic Inventory Characterization and Uncertainty Analysis and Quantification.

Research activities have been applied in many different nuclear systems: PWR and BWR NNPPs, ADS, GEN-IV, IFMIF-ITER, IFE, NIF, … The group has been involved, among others, in the following European project in the 6th Framework Programme “European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System (EUROTRANS)”. And in the 7th Framework Programme “Accurate Nuclear Data for Nuclear Energy Sustainability (ANDES)”.

At present, the group is involved in “Solving Challengues in Nuclear Data for the Safety of European Nuclear Facilities (CHANDA)”.

For more information, download O. Cabellos Presentation