Speaker
Description
The Optical Fiber Radiation Probe System (OFPS), which utilizes an optical fiber-based scintillation detector, has been employed by inspectors from the International Atomic Energy Agency (IAEA) and South Korea to verify spent fuel bundles from CANDU-type heavy water reactors. To address challenges identified in previous studies, the OFPS is currently undergoing enhancements to improve its performance. As part of these upgrades, two new optical fiber-based scintillation detectors have been designed and manufactured. A field test was conducted at the Wolseong Nuclear Power Plant, a CANDU-type facility in South Korea, to evaluate and compare the performance of the existing detector with the newly developed detectors. The primary objectives of this study were to assess the detection sensitivity and dynamic range of the optical fiber-based scintillation detectors. Four different radiation detectors?one existing OFPS detector and three newly developed detectors for the Improved Optical Fiber-based VErification System (IOVES)?were evaluated during the field tests. These detectors varied in terms of optical fiber diameter, radiation scintillator material, and scintillator size. The tests were performed at the spent fuel storage pool of Wolseong Unit 3. Experimental results indicated that the IOVES detector featuring a 0.6 mm optical fiber diameter and a 2.5 mm x 2.5 mm x 10 mm p-Terphenyl organic scintillator exhibited the highest performance among all tested detectors. Unlike the other three detectors, this detector clearly differentiated spent fuel bundle layers with both long and short cooling periods, and notably avoided signal saturation even with shorter cooling periods. These findings demonstrate that the newly developed scintillation detector has superior sensitivity and a significantly enhanced dynamic range. Consequently, this optical fiber-based radiation detector is expected to improve the efficiency and effectiveness of inspection activities by the IAEA and national authorities because it can reliably measure spent fuel bundles regardless of their cooling periods.
| Workshop topics | Applications |
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