NSUF 25-5535: Neutron Irradiation of a Johnson Noise Thermometry-Compensated Temperature Sensors
Small modular reactors and microreactors must be manufactured off-site, transportable to remote locations, and operate autonomously. Maintenance limitations of these reactors pose a significant survivability challenge for conventional instrumentation, in addition to the harsh high-radiation, high-temperature reactor environment. Simple, passive sensors, such as resistive temperature devices (RTDs), are used in SMR designs to balance cost and survivability. Though they survive the high temperature and radiation, the resistance of RTDs changes with the accumulation of radiation damage and must be compensated. In situ recalibration techniques enable RTD measurements to be re-based to account for sensor drift due to radiation by providing a complementary absolute temperature measurement using the same sensor and minimal additional instrumentation. Modern JNT measurements are typically performed using a pair of pre-amplifiers to perform a four-wire noise measurement across an RTD. The cross spectral density is taken from the outputs of the two independent amplifiers. Due to independence, the noise of the amplifiers is mitigated in the cross spectral density calculation, and the RTD Johnson noise spectra is recovered. While the RTD resistance varies with temperature and accumulated radiation damage, the JNT measurement is a function of temperature and instantaneous resistance and is agnostic to radiation-induced damage in the RTD. JNT measurements are most promising for periodically re-basing RTD-based temperature measurements to compensate for radiation-induced drift. To test this hypothesis, a JNT prototype system has been developed under the NEET-ASI program to utilize a commercial radiation-hardened integrated circuit featuring a pre-amplifier and analog-to-digital converter. This prototype has been demonstrated in a clean environment but remains to be validated in a reactor environment. The results of this RTE will elucidate the use of space-rated radiation-hardened devices for terrestrial reactor environments and provide a means of autonomously re-basing RTD temperature measurements to decrease maintenance needs.
Additional Info
| Field | Value |
|---|---|
| Awarded Institution | Idaho National Laboratory |
| DOI | 10.46936/NSUF/60015720 |
| Embargo End Date | 2028-01-22 |
| Facility Tech Lead | Kory Linton, Raymond Cao |
| Irradiation Facilities | Ohio State University Research Reactor |
| NSUF Call | FY 2025 Super RTE Call |
| PI | Nora Dianne Bull Ezell |
| PIE Facilities | Low Activation Materials Design and Analysis Laboratory |
| Prep Facilities | Low Activation Materials Design and Analysis Laboratory |
| Project Member | Dr. Nora Dianne Bull Ezell, R&D Engineer - Oak Ridge National Laboratory (https://orcid.org/0000-0001-9334-5822) |
| Project Member | Dr. Frederick Reed, R&D Associate - Oak Ridge National Laboratory (https://orcid.org/0000-0002-2280-4574) |
| Project Type | RTE |