[en] We have examined the dominant mechanisms of energy flow in a fusion-fission hybrid reactor, which is based on a magnetically confined thermonuclear D-T plasma. D-T fusion provides a source of high energy neutrons which are absorbed in a blanket outside the reactor. The blanket combines the functions of energy multiplication by fission of U²³⁸, Pu²³⁹ and U²³³, and tritium breeding. The fusion driver produces 100 MW of neutron power while the blanket provides energy multiplication of about 50. The hybrid can produce about 2000 MW of electrical power. The plasma is contained in the space between two concentric cylinders. There is uniformity in the direction parallel to the curved surfaces of the cylinders, and the confining field is purely toroidal. The plasma has a rectangular cross-section bounded by a planar electrode at one end and a thermionic emitter at the other, and cylindrical walls inside and outside. There is a modest pressure gradient, i.e., nT ∼ constant. The temperature is high in the core of the plasma, where fusion occurs, but falls to low values near the walls and end-plates. He has have found a class of sustainable MHD equilibria with Q ∼ 0.3. The inner and outer radii and height of the reactor are 31, 38 and 7 metres respectively. A high magnetic field is required, in the range 200-400 kG. T rises from 200 eV at the walls to 2.7 keV in the fusion zone, where n, ∼ 1.5 x 10¹⁴ cm^-3. There is a small vertical flow velocity to provide fueling. He has studied alpha-particle slowing down, electron-cyclotron radiation transport, inelastic reactions, bremsstrahlung, conduction, convection, and heat exchange between electrons and ions in the reactor