NSUF 24-4987: Temperature effects of rhodium self-powered neutron detectors in a gamma field

Self-powered neutron detectors (SPND) have often been used as a part of the in-core power monitoring and control system for traditional light water reactors. The rhodium-based SPND is often chosen for reactor flux mapping given its linearity in response to neutron flux and low background gamma contribution through (n, β-) reactions in the emitter. Based on the material composition as well as its fabrication process, the Rh-SPNDs have temperature compatibility of up to 900 °C making the sensor a candidate for high-temperature advanced reactor concepts. However, limited data is available for SPND for separate field (pure gamma or neutron) testing at temperatures beyond PWR temperatures, especially at temperatures above 500 °C where significant temporal nonlinearity – signal overshoot or undershoot – is observed for mix-field in-core demonstrations. Therefore, this project aims to supplement the knowledge gap by characterizing the temperature effects of gamma-contributed signals in the Rh-SPND above 500 °C. This project will leverage INL’s design of the temperature qualification device (TQD) that is compatible with the ATR gamma facility to provide a well-controlled temperature environment. Rh-SPNDs inserted into the TQD will be irradiated in a Co-60 equivalent gamma field of ~1E6 Rad/hr. This is expected to generate a minimum signal of 10 pA in the Rh-SPND: more than enough for detection with 3-digit resolution using the Keithley 6517B electrometer. Signal output will be measured as function of temperature with a focus on the onset temperature of signal drift, magnitude of signal overshoot per ΔT, and heating rate effects at 600, 750, and 900 °C – relevant temperatures to advanced reactor concepts. The overall experiment is expected to take 8 individual working days to characterize each temperature and associated heating rates. Successful completion of this project will provide better insight into the gamma-contributed signal at temperature. This allows for a more direct treatment such as compensation, redesign, or shielding to enable deployments of Rh-SPNDs in advanced reactors without compromising its functionality.

추가 정보

필드	값
Award Announced Date	2024-05-28T17:17:25.003
Awarded Institution	Idaho National Laboratory
Facility Tech Lead	Alina Montrose
Irradiation Facility	ATR Canal
PI	Kevin Tsai
PI Email	[email protected]
Project Type	RTE
RTE Number	None