Reactor physics and dynamics (READY): READY summary report

As a result of upgrading, adapting, developing and validating several reactor physics and dynamics codes of VTT's code system more accurate calculations and predictions of physical phenomena can now be performed. Three-dimensional reactor physics codes have been introduced and validated for various applications, especially for out-of-core flux, criticality safety, and dose rate calculations. A multi-temperature MCNP cross section and scattering law library has been created. Most recently Monte Carlo technique has been applied in burnup calculations. Development of a new advanced nodal model has resulted in a highly promising new BWR simulator code, ensuring independent calculational capabilities for steady state and safety analyses. Validation of VTT's three-dimensional BWR dynamics code has been completed, and analyses with three-dimensional core models can be carried out for PWR, BWR and VVER type reactors. Until now, the transient analyses for BWRs have been done with one-dimensional models. Fuel models of the dynamics codes have been improved, and USNRC's fuel behaviour code has been coupled with VTT's advanced hydraulics model. The coupled code has been delivered to USA in agreement with USNRC. Development and application of a sophisticated hydraulics solver in reactor dynamics has resulted in a BWR circuit model that has been tested in steady state calculations.