Abstract
Helium gas loops are essential for understanding the thermal-hydraulics phenomenain helium systems and for validating and testing components for high-temperature gas-
cooled reactors (HTGRs). However, current helium loops in the US operate at lower pres-
sures and temperatures than required for HTGR components, limiting their effectiveness.
Additionally, these loops cannot achieve the necessary Reynolds and Nusselt numbers for
testing high-temperature and high-pressure HTGR components, constraining their ability
to accurately replicate HTGR operating conditions.
In response to these limitations, Idaho National Laboratory (INL) has designed the
Helium Component Testing Out-of-pile Research (HECTOR) facility, a high-pressure,
high-temperature helium loop capable of testing components at pressures up to 8 MPa
and temperatures up to 800°C. The HECTOR facility aims to reduce the uncertainty asso-
ciated with the performance of HTGR components during reactor operation by providing
a comprehensive testing infrastructure.
This thesis provides an overview of the system design, detailing the design capabilities
of the loop. It includes an examination of the non-dimensional parameters calculated
for the system and a comprehensive thermodynamic analysis exploring the irreversibility
and reversible work of the overall system. A parametric study on the effects of ambi-
ent temperature and humidity on the systems heat removal via the chiller subsection is
also presented. The final chapter offers a comparative analysis of three types of heat ex-
changers shell-and-tube, Printed Circuit Heat Exchanger (PCHE), and Offset-Strip Fin
Heat Exchanger (OSFHE) evaluating their overall heat transfer coefficient, required heat
transfer surface area, and pressure drops. The HECTOR facility represents a significant
advancement in the experimental infrastructure for HTGR component validation and
testing.