Powering Smarter Nuclear Fuel Management with CMS5
How utilities are gaining greater accuracy, flexibility, and confidence across the nuclear fuel lifecycle
For nuclear power operators, the challenge is no longer simply running a reliable plant. Today’s utilities must optimize fuel investments, manage evolving reactor designs, meet regulatory requirements, and respond quickly to changing operating conditions.
Studsvik’s Core Management System 5 (CMS5) was developed to help utilities meet those challenges.
Built on more than four decades of industry experience, CMS5 combines the advanced capabilities of CASMO5 and SIMULATE5 to provide a comprehensive platform for core design, analysis, and fuel management. The result is a powerful solution that enables engineering organizations to perform sophisticated reactor analyses with greater efficiency and accuracy while maintaining independence from fuel and reactor vendors.
Built on Proven Experience
CMS5 traces its heritage to technologies that have been used in more than 200 light water reactors worldwide. The platform incorporates lessons learned from decades of commercial reactor operations, allowing engineers to model complex reactor behavior with a high degree of confidence.
Unlike approaches that require specialized computing infrastructure, CMS5 leverages modern computational methods to deliver high-fidelity results while remaining practical for day-to-day engineering workflows.
Key Benefits
Greater Accuracy
High-fidelity core modeling and analysis
Pin-by-pin reconstruction capabilities
Precise fuel cycle performance predictions
Improved Engineering Efficiency
Rapid evaluation of design alternatives
Support for both routine and unplanned analyses
Streamlined workflows across engineering teams
Vendor Independence
Independent assessment of fuel suppliers
Greater control over fuel strategy and core design
Increased flexibility for procurement and planning decisions
Supporting Today’s Nuclear Fleet and Tomorrow’s
CMS5 supports a broad range of commercial light water reactor designs, including Pressurized Water Reactors (PWRs), Boiling Water Reactors (BWRs), Water-Water Energetic Reactor (VVERs), and Small Modular Reactors (SMRs). As the industry evolves, CMS5 evolves alongside it. New fuel technologies and operating strategies are incorporated into the platform, helping utilities stay prepared for future reactor and fuel developments.
A Complete Ecosystem for Advanced Core Analysis
CMS5 brings together a suite of integrated tools designed to support every stage of reactor core management with the flagship products of CASMO5 and SIMULATE5.
CASMO5
Advanced Lattice Physics Modeling
CASMO5 serves as the foundation for accurate fuel modeling and cross-section generation. Its advanced transport solutions and modern nuclear data libraries support critical applications such as:
Fuel management
Reload design
Core follow activities
Plant operations
Spent fuel management
SIMULATE5
High-Fidelity Core Analysis
SIMULATE5 provides three-dimensional steady-state core analysis for light water reactors. Designed specifically for reactor engineers and core designers, it supports:
Loading pattern evaluation
Startup physics testing
Thermal limit assessments
Shutdown margin calculations
Fuel cycle optimization
By validating and assessing fuel performance across the operating cycle, utilities can maximize the value of every fuel investment.
Extending the capabilities of CMS5, Studsvik provides additional integrated software solutions including – SIMULATE5-K, CMSBuilder, COPERNICUS, GARDEL, S3R, CASKLOAD, SNF, MARLA and CONCORS.
Partnership Beyond Software
Technology is only part of the equation.
Studsvik supports users with:
Rapid technical response
Online support resources
Access to technical documentation
User communities and knowledge sharing
Expert guidance from experienced nuclear professionals
As utilities seek higher performance, greater operational flexibility, and long-term fuel strategy confidence, CMS5 provides a proven platform for informed decision-making across the entire nuclear fuel lifecycle.
CMS5 Advances Support for Next-Generation Nuclear Technologies
In 2026, Studsvik achieved a significant regulatory milestone when the U.S. Nuclear Regulatory Commission (NRC) approved Supplement 1 to the CMS5 Generic PWR Topical Report. The approval expands CMS5 applicability beyond today’s operating reactor fleet to support emerging nuclear technologies and advanced reactor programs.
The NRC-approved enhancement supports:
Higher fuel enrichment levels
Increased fuel burnup strategies
Light water reactor-based Small Modular Reactor (SMR) designs
Plant life extension initiatives
Licensing and development activities for next-generation nuclear reactors
For utilities, reactor developers, and engineering organizations, this approval provides additional confidence that CMS5 can serve as a long-term platform supporting both current operational needs and future reactor innovation.
Why It Matters
As the nuclear industry increasingly focuses on life extension programs, advanced fuels, and SMR deployment, engineering teams require analysis tools that have both technical sophistication and regulatory credibility. The NRC approval demonstrates CMS5’s readiness to support the evolving demands of the nuclear sector, helping bridge the gap between today’s commercial reactors and tomorrow’s clean energy technologies.
Expanding Advanced Analysis Capabilities with Peacock and Nighthawk
Next-Generation Monte Carlo Simulation for Advanced Reactors
Complementing the CMS5 platform, Studsvik developed Peacock, a next-generation Monte Carlo analysis code designed to support both today’s operating reactors and emerging advanced reactor technologies. Peacock combines continuous-energy neutron transport, generalized 3D geometry modeling, and built-in depletion capabilities in a modern, user-friendly environment.
Key features include:
Continuous-energy Monte Carlo simulation
Flexible 3D geometry modeling for advanced fuel and reactor designs
Integrated depletion and isotope transmutation calculations
Simplified YAML-based user inputs
NQA-1 quality assurance and 10 CFR 50 Appendix B compliance objectives
Support for advanced reactors, SMRs, and conventional LWR applications
Nighthawk, Studsvik’s new 3D Diffusion Nodal simulator, is advancing the future of reactor modeling and simulation. Already benchmarked against a Fast-Spectrum reactor benchmark and featured in a publication presented at PHYSOR 2026, Nighthawk delivers proven capabilities for next-generation analysis. Together, Peacock and Nighthawk are building the foundation for a new era of high-fidelity nuclear modeling and simulation.
Collectively, CMS5, Peacock and Nighthawk provide a powerful combination of production-proven core analysis and next-generation high-fidelity simulation capabilities, helping nuclear organizations prepare for the future of reactor innovation.
Learn more: www.studsvik.com
Contact: cms-info@studsvik.com
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