Development of Diagnostics for High-Temperature High-Pressure Liquid Pb-16Li Applications

TL;DR

This paper presents the development and validation of non-contact level, pressure, and temperature diagnostics for high-temperature, high-pressure liquid Pb-16Li systems used in fusion reactor applications, ensuring reliable operation.

Contribution

It introduces indigenous calibration methods and long-term testing of sensors specifically designed for corrosive, high-temperature liquid metal environments, advancing diagnostic technology for fusion systems.

Findings

Radar level sensor deviation within [-3.36 mm, +13.64 mm]

Pressure sensor error within 1.1% of span

Sensors operated reliably over 1000 hours in liquid Pb-16Li

Abstract

Liquid lead-lithium (Pb-16Li) is of primary interest as one of the candidate materials for tritium breeder, neutron multiplier and coolant fluid in liquid metal blanket concepts relevant to fusion power plants. For an effective and reliable operation of such high temperature liquid metal systems, monitoring and control of critical process parameters is essential. However, limited operational experience coupled with high temperature operating conditions and corrosive nature of Pb-16Li severely limits application of commercially available diagnostic tools. This paper illustrates indigenous calibration test facility designs and experimental methods used to develop non-contact configuration level diagnostics using pulse radar level sensor, wetted configuration pressure diagnostics using diaphragm seal type pressure sensor and bulk temperature diagnostics with temperature profiling for high temperature, high pressure liquid Pb and Pb-16Li applications. Calibration check of these sensors was performed using analytical methods, at temperature between 380C-400C and pressure upto 1 MPa (g). Reliability and performance validation were achieved through long duration testing of sensors in liquid Pb and liquid Pb-16Li environment for over 1000 hour. Estimated deviation for radar level sensor lies within [-3.36 mm, +13.64 mm] and the estimated error for pressure sensor lies within 1.1% of calibrated span over the entire test duration. Results obtained and critical observations from these tests are presented in this paper.