STU - Helium Loop

A part of the research of the Gas Cooled Fast Reactors generation IV is experimental support for evaluation of natural circulation in decay heat removal system (DHR).

The purpose of this experimental helium loop is investigation and testing of the decay heat removal system of the gas-cooled fast reactors and demonstrator ALLEGRO. The STU - Helium Loop can simulate diverse modes of decay heat removal in natural circulation under extended spectrum of boundary conditions. It is possible to continuously control the electrical input power in design range. The heat source, represented by vertical electrically heated rods, assures a heating up of helium in the loop up to 520 °C during the maximum heat power. For the helium cooling a decay heat removal system has been designed.
The DHR system consists of horizontal gas‑water recuperation heat exchanger with U-tubes where cooling water flows through the pipes and helium flows in the inter-pipe space of exchanger. The whole facility is designed for pressures up to 7 MPa.

Installed and operational parameters of the experimental helium loop are as follows:

Helium temperature at the output 400 ºC to 520 ºC
Helium temperature at the input 150 ºC to 250 ºC
Helium operational pressure 3 MPa to 7 MPa
Installed input power 500 kW
Designed heat power of the DHR 220 kW


The owner of STU - Helium Loop is Slovak University of Technology in Bratislava - Faculty of Mechanical Engineering. The experimental loop was commissioned in autumn 2016 and is located in Trnava.




František URBAN
Slovak University of Technology - Faculty of Mechanical Engineering, Slovakia

Branislav HATALA
VUJE, Slovakia