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TCR Central Shutdown Rod Fine Motion Control...

by Eliott J Fountain, Earle E Burkhardt, Sacit Cetiner, Charles D Ottinger, Venugopal K Varma
Publication Type
Conference Paper
Journal Name
29th International Conference on Nuclear Engineering Nuclear Energy the Future Zero Carbon Power
Book Title
Proceedings of the 2022 29th International Conference on Nuclear Engineering (ICONE29)
Publication Date
Page Numbers
1 to 7
Publisher Location
New York, United States of America
Conference Name
29th International Conference on Nuclear Engineering (ICONE)
Conference Location
Shenzhen, China
Conference Sponsor
ASME's Nuclear Engineering division, the Japanese Society of Mechanical Engineers (JSME), and the Chinese Nuclear Society (CNS)
Conference Date

Transformational Challenge Reactor (TCR) is a Helium cooled 3 MWt test reactor that leverages advances in materials and manufacturing, computing, and AI in its design. Classical design of a shutdown rod uses either gravity, pneumatic, or springs to quickly release the Central Shutdown Rod (CSR) containing neutron absorber into the reactor core stopping nuclear reaction. Generally, the motor/actuator resides outside the reactor, but the motion is transmitted through a penetration into the pressure vessel. There are also designs where the control rod drive incorporates magnetic latches with coil residing outside the pressure boundary for precise position control of the rod.

We are proposing a magnetic coupling to position the shutdown rod without any penetration into the pressure vessel for the entire drive length of TCR shutdown rod. Electromagnets are currently used in non-power nuclear reactors for shutdown rods, but these electromagnets are resident inside the reactor pressure vessel. This paper will describe the use of an electromagnet outside the pressure vessel to position and release the shutdown rod. A prototype was developed at ORNL to demonstrate the concept, and a design optimization of the ferritic core and material was conducted to maximize the lift force of the electromagnet. An elevated temperature testing was also performed to ensure that the system will perform under the temperature conditions inside an operating reactor.