INTERPRETATION OF DIII-D EDGE PHYSICS & ROTATION DATA
The Georgia Tech Fusion Research Center (FRC) is a collaborating member of the DIII-D National Tokamak Facility Team, which provides faculty and students with access to DIII-D data and processing tools. The FRC presently concentrates on development of theory and computational tools for and interpretation of plasma edge and rotation data. Recent and ongoing research include the development and application of theories for a particle pinch, ion orbit loss of particles and energy, intrinsic rotation, the radial electric field, etc. and the interpretation of diffusive transport coefficients from measured data, the interpretation of how ion orbit loss and the pinch velocity change at the L-H mode transition, comparison of gyroviscous predictions with measured toroidal velocities, etc. Representative recent papers are: a) Contrib. Plasma Phys. 56, 495 (2016); b) Phys. Plasmas 23, 122505 (2016); and c) Phys. Plasmas 24,012505 (2017).
BURN CONTROL IN ITER
There are various internal (e.g. plasma instabilities) and external (e.g. accidental turn-on of a plasma heating unit) which could produce an increase in plasma temperature, which would cause an increase in the plasma fusion heating rate and a further increase in temperature, etc. in ITER. We are searching for mechanisms in the plasma edge that would respond to an increase in temperature with an increase in radiative cooling or a decrease in energy confinement, which would thus stabilize such a runaway temperature increase. A burn control code is being assembled to enable us to investigate ion orbit loss, impurity seeding and other edge phenomena that could effectively control the burning plasma power output, without causing deleterious effects such as disruptions.
SUBCRITICAL ADVANCED BURNER REACTOR
The long-lived, highly radioactive transuranics in spent nuclear fuel are fissionable in a fast reactor, which means they can be burned (fissioned) to produce additional energy rather than buried in long-term High Level Waste Repositories. Subcritical operation of such “burner” or “transmutation” reactors would appear to offer some significant advantages. Students and faculty at Georgia Tech NRE have developed a design for such a SABR, based on coupling an IFR metal-fueled/Na-cooled fission reactor and an ITER-level superconducting tokamak fusion neutron source, and have performed fuel cycle and safety analyses. Fuel cycle analysis shows that such SABRs operating with LWRs in a 1-to-3 power ratio could burn all the transuranics produced in the LWRs. Dynamic safety analyses indicate that the SABRs can survive loss-of-flow, loss-of-heat-sink and loss-of-power accidents without core damage. We propose to continue these fuel cycle and dynamic analyses and to optimize the design. Representative papers are: a) Nucl. Techn. 162, 53 (2008); and Nucl. Techn. 187, 15 (2014).