Abstract
Advancements in nuclear reactor core modeling and computational capability have encouraged further development of in-core neutron sensors. Measurement of the neutron-flux distribution within the reactor core provides a more complete understanding of the operating conditions in the reactor than typical ex-core sensors. Micro-Pocket Fission Detectors have been developed and tested previously but have been limited to single-node operation and have utilized highly specialized designs. The development of a widely deployable, multi-node Micro-Pocket Fission Detector assembly will enhance nuclear research capabilities. A modular, four-node Micro-Pocket Fission Detector array was designed, fabricated, and tested at Kansas State University. The array was constructed from materials that do not significantly perturb the neutron flux in the reactor core. All four sensor nodes were equally spaced axially in the array to span the fuel-region of the reactor core. The array was filled with neon gas, serving as an ionization medium in the small cavities of the Micro-Pocket Fission Detectors. The modular design of the instrument facilitates the testing and deployment of numerous sensor arrays. The unified design drastically improved device ruggedness and simplified construction from previous designs. Five 8-mm penetrations in the upper grid plate of the Kansas State University TRIGA Mk. II research nuclear reactor were utilized to deploy the array between fuel elements in the core. The Micro-Pocket Fission Detector array was coupled to an electronic support system which has been specially developed to support pulse-mode operation. The Micro-Pocket Fission Detector array composed of four sensors was used to monitor local neutron flux at a constant reactor power of 100 kWth at different axial locations simultaneously. The array was positioned at five different radial locations within the core to emulate the deployment of multiple arrays and develop a 2-dimensional measurement of neutron flux in the reactor core.
Highlights
Research nuclear reactors commonly utilize neutronsensitive radiation detectors located external to the reactor core to monitor reactor power [1, 2]
Each of the four Micro-Pocket Fission Detectors (MPFDs) responded to changes in the neutron flux in the reactor core and maintained a stable response with constant reactor power
A different raw count rate was expected for each sensor due to the axial distribution of MPFDs in the reactor and the different amount of fissile material present in each detector, the mass normalized response was expected to be very similar for opposing nodes
Summary
Research nuclear reactors commonly utilize neutronsensitive radiation detectors located external to the reactor core to monitor reactor power [1, 2]. Advancements in nuclear reactor core modeling and computational capability have encouraged further development of in-core neutron sensors. This work, presented at the International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, June 19-23, 2017, was supported in part by the U.S Department of Energy under Grants DE-NE0008408 and NE0008305. S. McGregor are part of the S.M.A.R.T
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
