HELIOS-2

World-Class Solvers: Method of Characteristics

HELIOS-2 includes an all new Method of Characteristics solver which allows larger models - such as multiple fuel bundles and fractional cores - to be calculated with fewer required computing resources. The same robust calculation method that powers CASMO is now native to HELIOS-2, providing increased speed and accuracy for solutions to even the most complicated geometric problems.

Users have the option to use the traditional collision probabilities solver for transport calculations when appropriate for the problem being solved. Resonance self-shielding is calculated via the subgroup method, with a transport-based Dancoff calculation. The predictor-corrector method is used for depletion, and the depletion path allows arbitrary state changes, generalized decay capabilities, and branch-off calculations at any point in the solution path.

HELIOS-2 has been extensively validated against measured critical experiments, continuous-energy Monte Carlo calculations, and international isotopic benchmarks - delivering exceptional accuracy for traditional, non-traditional, and experimental fuel designs.

Cutting-Edge Data: ENDF/B-VII Cross-Section Library

Lattice physics calculations are only as good as the underlying cross-section data, and HELIOS-2 has been updated with the latest available neutron and gamma data, fine-tuned to provide the most accurate solutions possible. Using the most recent ENDF/B-VII nuclear data available, Studsvik has developed a high-resolution, 177-group neutron library for use with HELIOS-2.

This extensive update from the previous HELIOS library improves accuracy and enhances resonance treatments. HELIOS-2 also includes an updated 48-group gamma library for gamma transport and smearing calculations. Cross-section data is available for over 350 nuclides and materials including more than 175 fission products, 40 heavy nuclides, and expanded depletion chains.

Easy to Use: Geometry Viewing Modules

HELIOS-2 is built on a centralized database system with advanced input and output processors. A flexible graphical geometry display assists in developing input for even the most complicated fuel designs. Users can view geometry, material and temperature assignments, and edit areas of both the full problem and individual structures before beginning the calculation, to be sure the model is correct.

The HELIOS-2 input processor allows datasets to be stored in the database and be accessed in the main input - allowing fixed or common data to be centrally available and accessible without the need to re-enter input data. HELIOS-2 allows stacking of multiple cases in a single input, which can be simultaneously analyzed and compared. With appropriate input, calculations can be stopped and restarted, allowing the user to perform mid-calculation geometry alteration.

The output processing module allows manipulation of flux, reaction rate, and current edits, B1 calculations for subsets of the defined calculation geometry, and comparison of results from multiple calculation paths. Data may be displayed in tables or two-dimensional data maps; options also exist to write data to the database or to formatted external text files. HELIOS-2 can even create “data banks” of previously burned fuel bundles for spent fuel pool analysis, shuffling and core management, or reinsertion into the core.