Introduction
Lead-cooled Fast Reactors (LFR) are rather new concepts which have gathered increasing international attention after the Generation-IV International Forum selected them as promising candidates for a new generation of nuclear energy systems. Very limited operating experience exists to support the design, verification and licensing of LFRs. In particular, the lack of operating experience impacts the physics of the LFR core.
Under the guidance of the OECD NEA Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems, the OECD NEA Expert Group on Physics of Reactor Systems (EGPRS) is mandated to provide expert advice to the nuclear and accelerator community on the development needs in the domain of neutronics, radiation transport, reactor physics and nuclear fuel feedback along with uncertainty analysis of present and future nuclear power systems. EGPRS is currently monitoring benchmarks related to light-water cooled, molten-salt, sodium-cooled, and gas-cooled reactor systems and there is large interest to also address lead-cooled fast reactors. Parallel to further studies that will be proposed for assessing the impact of nuclear data uncertainties on integral parameters of design relevance, an introductory benchmark exercise under the auspices of EGPRS focuses on the physics of an LFR core. The specific purpose of the LFR physics benchmark is to: i) familiarise with the physics of an LFR core; ii) practice with the neutronics of an LFR core; and iii) assess confidence in the capability of simulating an LFR core.
The Advanced LFR European Demonstrator (ALFRED) is assumed as reference system for the LFR physics benchmark exercise. The ALFRED design is being carried out by the Fostering ALFRED Construction (FALCON) International Consortium, signed by Ansaldo Nucleare (IT), ENEA (IT) and RATEN-ICN (RO). Links with ENEA – the organisation responsible within FALCON for the core design of ALFRED – secure access to all the required information for the participants to the benchmark exercise.
The benchmark comprises three phases:
- PHASE 1 - Pin Cell: phase 1 consists of heterogeneous modelling of the cell of a fuel pin and of performing a criticality analysis of the cell in an infinite lattice.
- PHASE 2 - Sub Assembly/Super-Cell Simulations: for phase 2 of the benchmark, the simulation model is extended to the level of a whole Sub Assembly (S/A), or of a super-cell comprising several S/As.
- PHASE 3 - Whole Core Simulations: phase 3 addresses the modelling of the whole core, including control, shutdown and reflector/shield elements.
In previous MSc Theses, ALFRED models according to preliminary specifications and final PHASE 1 and PHASE 2 models were developed. Calculations for these two phases were completed and submitted to OECD/NEA.
The objective of this work is to develop de ALFRED core 3D model according to the final specifications and perform the neutronic calculations envisioned in the framework of the neutronics benchmark.
First, calculations requested in the specifications of the benchmark will be carried out using the reference nuclear data library JEFF-3.3. Afterwards, different nuclear data libraries will be used and sensitivity uncertainty quantification analyses will be performed. Full core depletion calculations will be also carried out, simulating the burnup of ALFRED’s MOX fuel according to core and loading scheme specifications, in order to obtain fuel composition at Beginning of Cycle and End of Cycle. The results from this calculations will be verified against SMR-LFR MOX database being developed at SCK CEN for waste management.
Objectives
This project envisages a six month workload where the following tasks must be achieved:
- familiarization with the physics of an LFR core;
- familiarization with Serpent 2 code;
- develop the model, perform neutronic calculations and repeat the calculations using different nuclear data libraries;
- sensitivity and uncertainty analyses;
- full core fuel depletion calculations;
- and, production of scientific outputs.
Le niveau de diplôme minimum du candidat
- Academic bachelor
Les connaissances préexistantes nécessaires
- Physics
Nuclear Engineering