SIMULATE5 is a 3D, steady state, multi-group, nodal code for the analysis of both PWRs and BWRs. SIMULATE5 delivers vendor independence and unparalleled accuracy for advanced core designers with increased heterogeneity and aggressive operating strategies.

Proven Results

Studsvik’s 30 years of experience producing flexible, highly accurate software solutions for the nuclear power industry is reflected in the state-of-the-art reactor physics methods and engineering features in SIMULATE5.

Fully capable of modeling all current and next generation PWRs, BWRs and SMRs with first-principle neutronic and thermal hydraulic calculations, SIMULATE5 provides a robust, single solution to core design and core analysis requirements.

Truly Advanced

Highly heterogeneous cores and aggressive operating strategies have pushed existing reactor analysis method to their limit.

Studsvik, the global leader in reactor analysis software, has developed SIMULATE5 to address these deficiencies and meet the demands of current and future core designs with cutting-edge neutronic and thermal-hydraulic methods not found in any other analysis package.

Driven by CASMO5

SIMULATE5’s advances neutronics engine demands more accurate physics models for assemblies containing high mixed-oxide(MOX) or burnable poison concentrations. CASMO5 has been developed specifically to support increased requirements of SIMULATE5. Together, they comprise the most advanced light water reactor physics analysis system in the world.



The newly designed SIMULATE5 neutronics engine solves the multi-group diffusion equations with a hybrid micro-macro depletion model that includes more than 50 explicitly defined actinide and fission product nuclides.

Radial and axial heterogeneities are treated using a proprietary submeshing scheme to overcome the shortfalls of spatially-averaged cross-sections and discontinuity factors. An improved, multi-group pin power reconstruction model, which combines homogenous power shapes with pin form factors straight from CASMO5, captures instantaneous spectral effects and exposure-induced pin power variations.

Ease of use

The SIMULATE5 input format is simple to use, allowing free-format input capable of modeling complex core layouts and includes automated functions to simplify tedious engineering calculations.

With practical defaults for PWRs and BWRs, robust error checking, and seamless interfaces to other Studsvik core analysis tools, SIMULATE5 allows engineers to spend their time analyzing, not troubleshooting software.

Fuel Management

SIMULATE5 efficiently and accurately verifies core loading pattern designs even with complicated core designs containing:

  • Reprocessed uranium and/or MOX
  • Integrated burnable poisons (gadolinia, erbia, IFBA), removable poisons (WABA, Pyrex), and combinations of both
  • Part-length fuel rods

In-core instrumentation for power monitoring, including 235U fission chambers, rhodium and platinum detectors, gamma and neutron TIPs, vandadium aeroballs, and gamma thermometers The SIMULATE5 model supports fuel studies and validates vendor-predicted cycle lengths, ensuring the maximum return on your fuel investment.

Core Follow and Operational Support

Once established, the SIMULATE5 core model can perform a variety of automated core follow calculations to support reactor operations, including reactivity coefficients and rod worth analysis, that would otherwise take hours of tedious user input.

Intelligent search routines allow the user to quickly search for quantities such as critical boron or rod position, based on a variety of bounding parameters.

Engineering Applications

SIMULATE5 is built to meet the needs of reactor engineers and core designers, with functionality to support startup physics testing, power maneuver guidance, thermal limit assessment, shutdown margin calculations, and much more.


SIMULATE5 is available for all standard computing platforms running most modern 32-and 64-bit operating systems. Linux, Windows and UNIX are all suitable environments for SIMULATE5.

SIMULATE5 Requirements

Advanced Thermo-Hydraulic Model

SIMULATE5 includes more complete thermal-hydraulic modeling outside of the core by extending the T-H model from lower to upper tie plates in PWRs and including the entire vessel loop in BWRs.

Many advanced BWR thermal-hydraulic models have been synthesized into a generic solver, ensuring accuracy even in complex scenarios, such as PWR voiding.

For further information, please contact us.