Real-time Fusion Power Monitor via Neutron Activation of Circulating Fluid

Abstract

Much effort has been devoted to the concept of fusion reactors, both magnetic and inertial confinement, in pursuit of an alternative source of energy. The concept of tokamaks has shown the most promising in magnetic confinement fusion, and thus an international effort has combined the expertise of the scientific community to build the first test reactor in southern France. The International Thermonuclear Experimental Reactor (ITER) will employ a diagnostic tool which circulates a fluid that is activated by the fusion neutrons. The activated fluid is then monitored by a detector, whose resulting data is used to infer the fusion power.

This work set out to computationally apply the same design theory to the General Atomics DIII-D toroidal fusion reactor, located in La Jolla, California. With a careful choice for the irradiation site, the device should be able to both accurately infer fusion power and the neutron flux incident upon material samples. Monte Carlo simulations were employed to determine the activation yield, as well as the best detector geometry and resulting detection yield. Other components such as delay tank, heater, and pump are either discussed or investigated. A FORTRAN program was created to compute fusion power from detector output in such a way that the device can be operated in "near" real-time with minimal delays resulting from fluid circulation and numerical techniques. Computational analysis has shown that such a device is feasible, and thus has also laid a solid foundation for experimental application.