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Conference Article: Conceptual design of a passive, inherently safe emergency shutdown rod for High Temperature Reactor applications

Abstract

The concept of a passive, inherently safe, and fail-safe design for an emergency control rod is presented. The functioning of the rod is based solely on inexorable physical laws. The operation of the rod in its emergency function does not require the intervention of a human operator, nor does it rely on any signal from a monitoring or safety system. Although the concept could be applicable to a variety of reactors (provided a normal temperature range is specified), in this paper, the concept is applied to the emergency shutdown of a pebble-bed reactor. The preliminary study presented here demonstrates that the proposed Electro-Magnetic Optimally Scramming Control Rod (EM-OSCR) naturally operates when needed. The rod is held out of the core region by the force of an electromagnet. The force is generated by a current carried by a conductor, a portion of which passes near or through the reactor core region. When the temperature in the conductor increases because of an increase in temperature in the reactor, the conductor resistivity increases. This, in turn, leads to a current decrease. When the current decreases below the level necessary to hold the rod up, the rod is released and it falls into the core under the effect of gravity.

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Reference:

Proceedings of the Conference on High Temperature Reactors, Petten, NL, April 22-24, 2002
Organized by HTR-TN in cooperation with the European Nucler Society (ENS) and the IAEA

International Atomic Energy Agency, Vienna (Austria)

HTR-2002, pp:1-6