OECD/NEA TVA Watts Bar Unit 1 Benchmark: Overview of R&D and Industrial French Solutions

Nuclear power plant safety analyses rely on accurate computational tools that are validated against comprehensive benchmarks. The Nuclear Energy Agency of the Organisation for Economic Co-operation and Development TVA (Tennessee Valley Authority) Watts Bar Unit 1 benchmark is an international benchmark covering conditions from start-up tests to multicycle depletion. The code-to-code comparisons and the measurements made available are used for consistent and comprehensive validation of both novel high-fidelity and legacy multiphysics computational tools. The paper provides an overview of research and development and industrial French solutions applied to hot zero power start-up test analysis. The solutions proposed by Commissariat à l’Energie Atomique (CEA) focus on numerical tool evolution and tests performed to support development of the codes and models. The comparison with industrial and advanced solutions provided by EDF and with measurements supports the analysis. Multicycle depletion analysis using EDF solutions is carried out and high accuracy is achieved when compared with measurements for the TVA Watts Bar Unit 1 cycle 1. Regarding CEA, only ongoing activities for neutronics/thermal-hydraulic couplings development are presented in the paper as a prerequisite to depletion analysis. The paper confirms that both legacy and new-generation French codes provide reliable predictions for reactor physics parameters, supporting their application in safety analyses. Results establish a comprehensive validation framework for multiphysics computational tools in nuclear reactor analysis.