Thermal Hydraulic Analysis
ISL’s staff of experienced analysts use open source and proprietary techniques to perform fluid systems and thermal hydraulic analyses. Where existing software lacks sufficient capabilities to perform the required analysis, ISL’s software developers can provide the tools needed to do the job. ISL’s analysis and code development expertise covers the full range of fluid-thermal systems, computational fluid dynamics, nuclear thermal-hydraulics and thermal analysis. Services range from expert consulting to the performance of complete analyses using software developed specifically for the work assignment. ISL is currently developing computer software and analysis systems to simulate thermal-hydraulic and neutronic responses of complex nuclear power systems. The work includes updating and maintaining Reactor Excursion and Leak Analysis Program 5 (RELAP5) and related computer codes, as well as participating in the development of next generation advanced analytical techniques, including TRAC/RELAP Advanced Computational Engine (TRACE). ISL covers the complete range of analysis methodology development activities including preparation of software requirements specifications, code design, programming, testing and assessment, code distribution, help desk, training, and user support. Thermal-Hydraulics Capability Overview (285KB)
Simulation of Complex Systems Behavior
ISL applies large computer programs to simulate the physical behavior of commercial nuclear power plant systems during accident conditions. These activities address the phenomenological aspects of thermal-hydraulics such as:
- boiling and condensation
- fluid flow and heat transfer, including details of convective heat transfer
- nucleate boiling, transition boiling/quench front advance, and dispersed flow film boiling
- detailed coupling of the flow regimes and associated heat transfer mechanisms
- multi-surface models for radiation heat transfer
- multi-dimensional drift-flux and two-fluid models of two-phase flow for bubbly, slug annular, and droplet/mist flow
- condensation in the presence of non-condensable gases
Typical problems addressed by ISL include: thermal design analysis, nuclear plant accident simulation, fluid system simulation to support design, nuclear plant performance analysis, analysis of operational transients, test program reviews, simulator benchmarking, containment analysis, severe accident analysis, hydrodynamic force calculations, control system studies, spent fuel cooling analysis, and safety analysis.
Computational Fluid Dynamics
Recognizing the tremendous potential of Computational Fluid Dynamics (CFD) methods in support of complex systems analysis, ISL has developed techniques and quality standards for CFD applications that significantly extend the capabilities of traditional methods in the area of thermal-hydraulics. ISL’s research staff has CFD expertise in the following areas:
- Generation of structured, unstructured and hybrid grids.
- Modeling of laminar and turbulent single-phase flow.
- Computational Multiphase Flow Dynamics (CMFD).
- Coupling of CFD methods with neutronic/thermal-hydraulic system codes for safety analysis of nuclear power plants.
- Implementation of specific physical models in commercial CFD software through external software routines.
- Parallel computing.
- Validation and Verification (V&V) of CFD analyses (Quality Assurance).
- Effective data post-processing and visualization.