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Comparative thermohydraulic analyses of VVER 1000 active core for two different construction types of assemblies

Thermohydraulische Analysen eines VVER-1000 Kerns für zwei verschiedene Brennelement-Typen
  • Y. Perin , S. Nikonov , R. Henry , I. Pasichnyk and K. Velkov
From the journal Kerntechnik


The OECD/NEA Benchmark on NPP Kalinin Unit 3 “Switching-off of one of the four operating main circulation pumps at nominal power” based on measurements is at its end phase. A new benchmark is starting based on measurements from the NPP Rostov Unit 2 “Reactivity compensation with diluted boron by stepwise insertion of control rod cluster into the VVER-1000 core”. The Rostov-2 core is loaded with assemblies of a new modern type “TVS-2M” which differs in construction in comparison with the “TVSA”-type implemented in the Kalinin-3 core. The goal of the performed study is to determine the thermohydraulic differences, during steady-state operation, between the two cores based on loads with different assembly types. Results of steady-state simulations are compared for Kalinin-3 and Rostov-2 cores, taken from the respective Benchmarks specifications. To ensure that the observed differences are coming only from the fuel assembly construction, the same axial power density is used for all cases. Calculations are done with an under-development version of the GRS system code ATHLET, which has sub-channel modeling capabilities. Thus, in addition to the typical assembly-wise models, calculations with seven assemblies modeled at the sub-channel (pin-by-pin) level were also performed and analyzed. This work will help the Benchmarks' Rostov-2 participants to set up more accurate core thermohydraulic models.


Der OECD/NEA-Benchmark „Switching-off of one of the four operating main circulation pumps at nominal power“, der auf experimentellen Daten des KKWs Kalinin Block 3 basiert, befindet sich in der Endphase der Auswertung. Ein neuer Benchmark „Reactivity compensation with diluted boron by stepwise insertion of control rod cluster into the VVER-1000 core“, der auf experimentellen Daten aus dem KKW Rostov Block 2 basiert, startet derzeit. Der Rostov-2-Kern wird mit Brennelementen des neuen modernen Typs „TVS-2M“ beladen. Dieser Typ unterscheidet sich in der Konstruktion vom „TVSA“-Typ im Kalinin-3-Kern. Das Ziel der durchgeführten Studie ist, die thermohydraulischen Unterschiede zwischen den Kernen im stationären Zustand aufgrund der Implementierung des neuen Brennelementtyps zu ermitteln. Die Ergebnisse von stationären Rechnungen werden für die beiden Kerne (Kalinin-3 und Rostov-2) verglichen. Um sicherzustellen, dass die beobachteten Unterschiede nur von der Brennelementkonstruktion stammen, wird für beide Fälle die gleiche axiale Leistungsverteilung verwendet. Berechnungen werden mit einer Version des GRS-Systemcodes ATHLET, die Entwicklungen zur Unterkanalmodellierung enthält, durchgeführt. Deshalb wurden zusätzlich zu den üblichen brennelementweisen Modellen auch Berechnungen mit sieben Brennelemente, die auf Unterkanalebene (brennstabweise) modelliert werden, durchgeführt. Diese Arbeit soll den Teilnehmern des Rostov-2 Benchmarks helfen, genauere thermohydraulische Kernmodelle zu erstellen.



1 Ivanov, B.; et al.: OECD/DOE/CEA VVER-1000 coolant transient (V1000CT) benchmark – A consistent approach for assessing coupled codes for RIA analysis. Progress in Nuclear Energy48 (2006) 72874510.1016/j.pnucene.2006.06.002Search in Google Scholar

2 Kolev, N.; Petrov, N.; Ivanov, B.; Ivanov, K.: Simulation of the VVER-1000 pump start-up experiment of the OECD V1000CT benchmark with CATHARE and TRAC-PF1. Progess in Nuclear Energy48 (2006) 92293610.1016/j.pnucene.2006.07.003Search in Google Scholar

3 Kliem, S.; Kozmenkov, Y.; Hoehne, T.; Rohde, U.: Analyses of the V1000CT-1 Benchmark with the DYN3D/ATHLET and DYN3D/RELAP Coupled Code Systems Including a Coolant Mixing Model Validated Against CFD Calculations. Progress in Nuclear Energy48 (2006) 83084810.1016/j.pnucene.2006.06.008Search in Google Scholar

4 Kozmenkov, Y.; Kliem, S.; Grundmann, U.; Rohde, U.; Weiss, F.-P.: Calculation of the VVER-1000 coolant transient benchmark using the coupled code systems DYN3D/RELAP5 and DYN3D/ATHLET. Nucl. Eng. Design237 (2007) 1938195110.1016/j.nucengdes.2007.02.021Search in Google Scholar

5 Tereshonok, V. A.; Nikonov, S. P.; Lizorkin, M. P.; Velkov, K.; Pautz, A.; Ivanov, K.: International Benchmark for Coupled Codes and Uncertainty Analysis in Modelling: Switching-off of one of the four operating main circulation pumps at nominal power at NPP KALININ UNIT 3, 18th Symposium of AER on VVER Reactor Physics and Reactor Safety, Hungary, Eger, October 6–10, 2008Search in Google Scholar

6 Avramova, M.; Denisenko, A.; Denisova, M.; Gordienko, P.; Ivanov, K.; Nikonov, S.; Pasichnyk, I.; Shumskiy, B.; Sizov, R.; Velkov, K.: EGMPEBV Benchmark “Rostov-2”, 27th Symposium of AER on VVER Reactor Physics and Reactor Safety, Germany, Munich, October 17–20, 2017Search in Google Scholar

7 Lerchl, G.; Austregesilo, H.; Schöffel, P.; von der Cron, D.; Weyermann, F.: ATHLET Mod3.1 Cycle A. User's Manual, GRS 2016Search in Google Scholar

8 Row, D. S.: COBRA-II. A digital computer program for thermohydraulic subchannel analysis of rod bundles nuclear fuel elements. BHWL-1229 V.C-80, February, 197010.2172/4183936Search in Google Scholar

9 Nikonov, S.; Pasichnyk, I.; Velkov, K.: Multiscale Application of System Code Athlet for Detailed VVER Core Analysis, 26th Symposium of AER on VVER Reactor Physics and Reactor Safety, Finland, Helsinky, October 10–14, 2016Search in Google Scholar

10 Davis, T. A.: Umfpack user guide. Technical report, CISE – University of Florida, 2012Search in Google Scholar

11 Balay, S.; Brown, J.; Buschelman, K.; Eijkhout, V.; Gropp, W. D.; Kaushik, D.; Knepley, M. G.; McInnes, L. C.; Smith, B. F.; Zhang, H.: PETSc user's manual. Technical Report ANL-95/11 – Revision 3.3, Argonne National Laboratory, 2012PMid:24109792; 10.2172/1178102Search in Google Scholar

12 Nikonov, S.; Velkov, K.; Pautz, A.: Detailed modeling of Kalinin-3 NPP VVER-1000 reactor pressure vessel by the coupled system code ATHLET/BIPR-VVER, Proceedings of M&C 2011, Rio de Janeiro, RJ, Brazil, May 8–12, 2011Search in Google Scholar

13 Nikonov, S.; Pasichnyk, I.; Velkov, K.; Pautz, A.: Comparisons with Measured Data of the Simulated Local Core Parameters by the Coupled Code ATHLET-BIPR-VVER Applying a New Enhanced Model of the Reactor Pressure Vessel, 21th Symposium of AER on VVER Reactor Physics and Reactor Safety, Dresden, Germany, September 19–23, 2011Search in Google Scholar

Published Online: 2019-08-27
Published in Print: 2019-09-16

© 2019, Carl Hanser Verlag, München

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