TY - CHAP
T1 - The coupled code TRAB-3D-SMABRE for 3D transient and accident analyses
AU - Miettinen, Jaakko
AU - Räty, Hanna
PY - 2006
Y1 - 2006
N2 - VTT's three-dimensional TRAB-3D core dynamics code and
SMABRE thermal hydraulic system code have been coupled
together using an internal coupling scheme in order to
increase flexibility in the thermal hydraulics modelling
of the core calculation. VTT's reactor dynamics codes
have performed well in all the situations that they have
originally been designed for. The most important
limitation of the present code models is their inability
to handle coolant flow reversal in the core channel, a
phenomenon that can be encountered in e.g. BWR ATWS cases
or VVER power excursions. The new coupling of the two
codes is realized on the level of each node of each
channel in the core, with each fuel bundle described with
its own channel. TRAB-3D performs only the neutronics
calculation, SMABRE takes care of the hydraulics
calculation of the whole cooling circuit including the
reactor core, while heat transfer calculation can be
carried out optionally by either code. The codes have
earlier been coupled using a parallel coupling scheme.
Several modifications were necessary in SMABRE,
concerning modelling of hydraulics, heat transfer,
geometry and the matrix solution. The accuracy of the
steady state calculation in the coupled code has been
improved to a level suitable for both PWR and BWR
calculations, as compared against the SIMULATE and
reference TRAB-3D codes. Presently BWR dynamics
calculations are being tested with single disturbances,
such as control rod movements, pump coastdown etc.
Besides allowing modelling of reversed flow in the core,
the internally coupled code will make future modelling of
in-core cross-flows or even 3D flow in a PWR (such as
EPR) open core geometry possible, e.g. by using the
porous medium approach.
AB - VTT's three-dimensional TRAB-3D core dynamics code and
SMABRE thermal hydraulic system code have been coupled
together using an internal coupling scheme in order to
increase flexibility in the thermal hydraulics modelling
of the core calculation. VTT's reactor dynamics codes
have performed well in all the situations that they have
originally been designed for. The most important
limitation of the present code models is their inability
to handle coolant flow reversal in the core channel, a
phenomenon that can be encountered in e.g. BWR ATWS cases
or VVER power excursions. The new coupling of the two
codes is realized on the level of each node of each
channel in the core, with each fuel bundle described with
its own channel. TRAB-3D performs only the neutronics
calculation, SMABRE takes care of the hydraulics
calculation of the whole cooling circuit including the
reactor core, while heat transfer calculation can be
carried out optionally by either code. The codes have
earlier been coupled using a parallel coupling scheme.
Several modifications were necessary in SMABRE,
concerning modelling of hydraulics, heat transfer,
geometry and the matrix solution. The accuracy of the
steady state calculation in the coupled code has been
improved to a level suitable for both PWR and BWR
calculations, as compared against the SIMULATE and
reference TRAB-3D codes. Presently BWR dynamics
calculations are being tested with single disturbances,
such as control rod movements, pump coastdown etc.
Besides allowing modelling of reversed flow in the core,
the internally coupled code will make future modelling of
in-core cross-flows or even 3D flow in a PWR (such as
EPR) open core geometry possible, e.g. by using the
porous medium approach.
M3 - Chapter or book article
SN - 951-38-6886-9
T3 - VTT Tiedotteita - Research Notes
SP - 48
EP - 59
BT - SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006
PB - VTT Technical Research Centre of Finland
CY - Espoo
ER -