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Licensed Unlicensed Requires Authentication Published by De Gruyter August 27, 2019

Extension of nodal diffusion solver of Ants to hexagonal geometry

Erweiterung des in Ants enthaltenen nodalen Diffusionslösers auf hexagonale Geometrie
A. Rintala and V. Sahlberg
From the journal Kerntechnik

Abstract

The development of a new computational framework for core multi-physics problems, called Kraken, has been started at VTT Technical Research Centre of Finland Ltd. The framework consists of modular neutronics, thermal hydraulics and thermal mechanics solvers, and is based on the use of continuous-energy Monte Carlo reactor physics program Serpent. Ants is a new reduced order nodal neutronics program developed as a part of Kraken. The published methodology and first results of Ants has previously been limited to rectangular geometry steady state multigroup diffusion solutions. This work describes the solution methodology of Ants extended to hexagonal geometry steady state diffusion solutions. The first results using various two-dimensional and three-dimensional hexagonal geometry numerical benchmarks are presented. These benchmarks include the AER-FCM-001 and AER-FCM-101 three-dimensional VVER-440 and VVER-1000 mathematical benchmarks. The obtained effective multiplication factors of all considered benchmarks are within 18 pcm and the RMS relative assembly power relative differences are within 0.4% of the reference solutions.

Kurzfassung

Am finnischen VTT Forschungszentrum wurde mit der Entwicklung eines neuen Frameworks zur Berechnung von multiphysikalischen Reaktorkernaufgabenstellungen, genannt Kraken, begonnen. Das Framework besteht aus modularen Neutronenkinetik-, Thermohydraulik- und Thermomechanik-Lösern und basiert auf dem Monte-Carlo-Reaktorphysikprogramm Serpent. Dabei wurde als Teil von Kraken das Programm Ants zur Berechnung der Neutronenkinetik durch nodale Lösung von Differentialgleichungen reduzierter Ordnung entwickelt. Ants war bisher auf die Lösung der stationären Mehrgruppendiffusionsgleichung für rechteckige Geometrie beschränkt. In diesem Beitrag wird die Erweiterung der Lösungsmethodik von Ants beschrieben, mit der nun auch Diffusionslösungen in hexagonalen Kerngeometrien beschrieben und berechnet werden können. Die ersten Ergebnisse mit verschiedenen zweidimensionalen und dreidimensionalen numerischen Benchmarks für hexagonale Geometrie werden vorgestellt. Zu diesen Benchmarks gehören die dreidimensionalen mathematischen Benchmarks AER-FCM-001 und AER-FCM-101 für VVER-440 und VVER-1000. Die erhaltenen effektiven Multiplikationsfaktoren aller betrachteten Benchmarks liegen innerhalb von 18 pcm und die relativen Unterschiede der Brennelementleistung liegen innerhalb von 0,4% der Referenzlösungen.


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Received: 2019-02-12
Published Online: 2019-08-27
Published in Print: 2019-09-16

© 2019, Carl Hanser Verlag, München