Michael D. Heibel

Nuclear Radiation-Tolerant Wireless Transmitter Irradiation Test Results

This paper describes the novel implementation of a vacuum-micro-electronic (VME) device configured as a wireless transmitter capable of transmitting, within a nuclear radiation environment, a radio-frequency signal proportional to a voltage input. The VME device discussed in this paper would enable key operating parameters of every fuel assembly in a commercial reactor core to be continuously monitored without adding vessel penetrations and cabling. The devices frequency and amplitude response to radiation are discussed, and the results of irradiation testing are presented. The results of the irradiation test show that the device described herein can withstand the exposure to a neutron fluence and gamma-ray dose substantially higher than previously achieved.

High Spatial Resolution Radiation Detection Using Distributed Fiber Sensing Technique

This paper studies perspectives on using optical fibers and distributed fiber sensing schemes to perform real-time-distributed gamma-ray radiation sensing with high spatial resolution. The radiation-induced optical property changes of aluminum-doped fibers were studied using cobalt-60 sources. The distributed optical loss of the aluminum-doped fiber was characterized using the Rayleigh backscattering optical frequency domain reflectometry (Rayleigh OFDR). The optical loss of unprotected fiber under various gamma dose rates remains linear up to 100 grays (Gy). Using the gamma radiation-sensitive fiber, the localized optical loss measured by the Rayleigh OFDR was used to map the accumulated gamma radiation dosage on the entire surface of the cylinder with a 1-cm spatial resolution. Using electrical cables as a ubiquitous sensor platforms for fiber sensor deployment, this paper explores the potential for multifunctional distributed fiber sensor by integrating distributed fiber temperature and gamma ionizing radiation sensors in electrical cables for multifunctional measurements to improve the safety of nuclear power systems at both the component and system levels. As sensors that can readily be embedded in a wide variety of materials and structures, radiation-sensitive fibers can be low-cost and highly flexible tool to gauge the performance degradation and longevity of materials and components used in the nuclear power systems.