atw - International Journal for Nuclear Power | 05.2022

atw Vol. 67 (2022) | Ausgabe 5 ı September
| Young Scientist‘s Workshop award ceremony
from left to right: Dr. Katharina Stummeyer, Frank Apel, Julia Krieger, Marc Kirsch, Nelson Felipe Rincón Soto, Eduard Diaz-Pescador,
Souad Pederzani, Prof. Dr. Jörg Starflinger, Markus Brodoch.
Silicate Concrete and Applying then to Simulations
of Several Experiments with AC²-COCOSYS”.
As part of the external validation of the AC² model
basis, simulations of Molten Core-Concrete Interactions
(MCCI) are conducted, in particular BETA,
MOCKA and OECD-CCI tests. The focus of this
work is the calculation of the decomposition parameter
of silicate concrete and the modelling of the
heat transfer between melt and concrete. An
approach for calculating the decomposition parameters
of concrete is presented and the influences
of the individual components are shown. Depending
on the calculated decomposition properties
of the concrete and the heating power, the effective
heat transfer coefficients can be determined.
M. Kirsch reported about “Experimental investigation
on the long-term operational behaviour of
two-phase closed thermosyphon bundles for
passive heat transfer from spent fuel pools under
normal, abnormal, and accident conditions”. Twophase
closed thermosiphons (TPCT) are passive
heat transfer devices that can ensure the safe
operation of nuclear facilities in the event of a
power failure or other malfunction. In the present
investigations at the ATHOS (Atmospheric Thermosiphon
cOoling System) test facility at University
of Stuttgart, the long-term operation of TPCTs
under different heat transfer rates, temperatures
and cooling airflow conditions were investigated.
The investigations show that a reliable long-term
operation is feasible. Maximum heat transfer rates
of up to 900 W per TPCT were achieved.
J. Krieger talked about the „Simulation of the
OSU-MASLWR Test Facility with the system Code
AC ² ”. To evaluate the applicability of AC ² -ATHLET
for the simulation of SMRs, the experimental test
facility OSU-MASLWR (Oregon State University-
Multi Application Small Light Water Reactor) is
simulated and compared with experimental
results. The focus is on the primary loop driven by
natural convection and the heat transfer in the
helically coiled steam generator. The currently
available data of the ICSP 3 (International Collaborative
Standard Problem) test serve as a basis
for the input deck modelling. The results show that
AC ² -ATHLET is able to model the natural circulation
in good agreement, but that deviations of the
temperature and mass flow course occur. By
increasing the heat transfer, qualitative as well as
quantitative improvements are achieved on the
secondary side.
F. Krist performed an “Analysis of the AC ² Models
regarding Fission Product Release using PHÉBUS
experiments.” For the analysis and validation of
the accident analysis code AC ² – ATHLET-CD,
simulations of the experiments Phébus FPT1 and
FPT3 are presented and discussed. The release
KERNTECHNIK 2022 · 21. – 22. JUNI · LEIPZIG 71
Special | KERNTECHNIK 2022
BEST PAPER AWARD YSW ı Conference Report ı Jörg Starflinger