Nuclear Energy for New Europe 2009

(This is a HTML version of the abstract for information only. It can differ from the original, submitted by the author(s). Special characters, formulas and figures are not properly reproduced here. Please, contact the author(s) or refer to the printed Book of Abstracts for the correct version.)

No: 212

Conference: Nuclear Energy for New Europe 2009

Title: Experimental and Computational Investigation of Coolability of Ballooned VVER bundles with Pellet Relocation

Theme: Thermal Hydraulics

Author(s): Péter Windberg, Imre Nagy, András Vimi, Zoltan Gregus

Contact : Péter Pál Windberg

E-mail: windberg@aeki.kfki.hu

Address: KFKI Atomic Energy Research Institute
H-1525 Budapest

Country: Hungary

During a LOCA incident the high pressure in the fuel rods can lead to clad ballooning. This enlarged section of fuel can collect the fuel debris. Of these are possible two consequences.
The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods.
The accumulated fuel pellet debris in the enlarged zone results a local power peak, which leads to further slowing down of quench front.
The evaluation of the role of these two effects on the coolability of VVER type fuel bundle was the main objective of the experimental series. The experimental results confirmed that a VVER bundle with even 86% blockage rate remains coolable after a LOCA event.
The coolability of ballooned VVER type bundle investigated also by the APROS code. The model of the studied system was built in the Finnish APROS thermohidraulic code. The APROS code was specially designed to simulate VVER reactors, so this code is the right choice to reproduce the examined cooling process on computer, and gives the opportunity to compare the measured and simulated results. The computational results showed also that a VVER bundle remains coolable after a LOCA event.

No:	212
Conference:	Nuclear Energy for New Europe 2009
Title:	Experimental and Computational Investigation of Coolability of Ballooned VVER bundles with Pellet Relocation
Theme:	Thermal Hydraulics
Author(s):	Péter Windberg, Imre Nagy, András Vimi, Zoltan Gregus
Contact :	Péter Pál Windberg
E-mail:	windberg@aeki.kfki.hu
Address:	KFKI Atomic Energy Research Institute H-1525 Budapest
Country:	Hungary

During a LOCA incident the high pressure in the fuel rods can lead to clad ballooning. This enlarged section of fuel can collect the fuel debris. Of these are possible two consequences. The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods. The accumulated fuel pellet debris in the enlarged zone results a local power peak, which leads to further slowing down of quench front. The evaluation of the role of these two effects on the coolability of VVER type fuel bundle was the main objective of the experimental series. The experimental results confirmed that a VVER bundle with even 86% blockage rate remains coolable after a LOCA event. The coolability of ballooned VVER type bundle investigated also by the APROS code. The model of the studied system was built in the Finnish APROS thermohidraulic code. The APROS code was specially designed to simulate VVER reactors, so this code is the right choice to reproduce the examined cooling process on computer, and gives the opportunity to compare the measured and simulated results. The computational results showed also that a VVER bundle remains coolable after a LOCA event.