NEA-1924 KRAKEN 1.2.X.

KRAKEN 1.2.X

Kraken is a computational framework for reactor analysis consisting of modular solvers for the different physics phenomena in the reactor core and a multi-physics driver package that handles the coupled solution flow. The framework is being developed for modelling nuclear reactors in stationary, operating cycle and transient analyses.

Kraken reactor analysis framework comprising of the following software components:

• The Ants nodal neutronics program.

• The Kharon thermal hydraulics solver.

• The libFluid fluid properties library.

• The SuperFINIX fuel behaviour manager program.

• The FINIX fuel performance code.

• The Cerberus multi-physics driver package.

• The Cetus multi-physics reactor simulator package.

• The KrakenTools package for pre- and post-processing in the Kraken framework.

• The Serpent Monte Carlo code

The Ants nodal neutronics program uses a combination of the analytic function expansion nodal method (AFEN) and flux expansion nodal method (FENM) to solve the multi group neutron diffusion equation. Kharon solves two phase thermal hydraulics in a time independent manner using the porous medium approach in closed channels. SuperFINIX distributes the fuel behaviour solution work to the necessary number of individual FINIX solvers. FINIX itself is based on a traditional 1.5 dimensional fuel performance code philosophy. The Cerberus multi-physics driver package for Python 3 communicates with the individual solvers using sockets, while offering a high level Python API for each solver and their fields.

Kraken framework is applicable for the modelling of full scale light water reactors (LWRs). The nodalization chosen for the discretization of the problem affects the runtime and memory demand of the solution.

Case-dependent.

The modular code-agnostic coupling approach in Kraken enables the easy use of higher fidelity solvers to verify the solution of reduced order solvers even in coupled simulations. The socket-based code-agnostic communication syntax allows the user to couple additional solvers to the framework as long as those solvers follow the communication syntax.

Serpent 2.2.X is included in the Kraken reactor analysis framework.

J. Leppänen, et al. "Current Status and On-Going Development of VTT’s Kraken Core Physics Computational Framework." Energies, 15 (2022).

More references at http://serpent.vtt.fi/kraken.html

Simple problems can be executed on a modern laptop. Dedicated computational resources such as computer clusters will reduce calculation time.

The reactor analysis framework has been developed mainly for use in the Linux operating system. The software components include Python 3, C and Fortran code under Linux operating system using the C programming language. Some software components have specific external dependencies:

• Ants requires the Intel oneApi Math Kernel Library.

• libFluid requires the Boost C++ library.

• SuperFINIX offers additional functionality if the GD graphics library is available.

• KrakenTools offers additional functionality if the serpentTools Python-package is available.

Some software components also function in the Windows operating system.

VTT Technical Research Centre of Finland, Ltd

Kivimiehentie 3

Espoo

FI-02044 VTT

Finland

Contact for commercial use: IP.agreements (at) vtt.fi