Modeling the Tokamak Exhaust Processing System in a Commercial Simulator for Process Monitoring Purposes

Abstract

Nuclear fusion depends on tritium breeding and self-sufficiency. Tritium represents a hazard due to its radioactivity and migration properties. Because of these difficulties, ITER, the largest fusion experiment so far, relies on a conservative static procedure to monitor the tritium inventory. Future commercial fusion plants can avoid operation halts if a dynamic monitoring strategy proves itself valid. Tritium plant models have been developed for this kind of monitoring and analysis task, but sensor accuracy and reliability are an issue still to be addressed, and the path to dynamic monitoring remains unclear. The present work shows the modeling procedure of the Tokamak Exhaust Processing system in a commercial simulator, Aspen HYSYS, to reproduce the inventories, streams, process conditions, and compositions of this subsystem during operation. The model is verified in a steady-state scenario using data from the available literature. A demonstration of such a tritium plant subsystem shows meaningful value for several reasons. First, this process has not been modeled before in commercial dynamic simulators, which are typically used in the process industry. It will also allow new stakeholders to participate in future fusion-related projects. Second, it will play a key role in industry-like tritium process monitoring, in which the new model will act as a digital twin of the plant. Data-driven diagnostics can be fueled by model data, helping engineers to generate additional data that could otherwise be expensive to get directly from the plant. For these reasons, models will represent an essential part of a dynamic monitoring system, necessary for feasible fusion projects.

Keywords:

• Tritium processing
• tokamak exhaust processing
• dynamic modeling
• Aspen HYSYS
• isotopic database

Acronyms

ADS:	=	Atmosphere Detritiation System
ANS:	=	Analytical System
DF:	=	Decontamination Factor
DS:	=	Detritiation System
GDC:	=	Glow Discharge Cleaning
ISS:	=	Isotope Separation System
NBI:	=	Neutral Beam Injector
PERMCAT:	=	PERMeator CATalytic reactor
PI:	=	proportional-integral
SDS:	=	Storage and Delivery System
SRK:	=	Soave-Redlich-Kwong
TEP:	=	Tokamak Exhaust Processing
TLK:	=	Tritium Laboratory Karlsruhe
VDS:	=	Vent Detritiation System
WDS:	=	Water Detritiation System

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Notes

^a DF is defined for the TEP system as the ratio between input tritium flow rate to output tritium flow rate.^[10]

Additional information

Funding

This work has been possible thanks to co-funding of the Centro para el Desarrollo Tecnológico Industrial of the Spanish Ministry of Science and Innovation [IDI-20200750] and to the Industrial Doctorates Plan of the Government of Catalonia [2018 DI 0048].