Effect of Particle Recycling on Burn Control by Compression-Decompression

As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function for detector signals and a real time evaluation function of the α value with the Feynman-α method was established, with which the kinetic parameter (α value) was measured at the STACY heterogeneous core. Hashimoto's difference filter was implemented in the system, enabling the measurement in a critical condition. The measurement result of the new system agreed with the pulsed neutron method. The α value was also evaluated by the newly developed algorithm of α-mode calculations for the Monte Carlo method, which was compared with the experimental value. Those computational and experimental α values show agreement within their uncertainties.     

Thermal Stability of Pure and Catalyzed D-D Fusion Reactor Plasmas

The thermal stabilities of the D-D fusion reactor plasmas operating on the pure- deuterium and the catalyzed-deuterium cycles have been analyzed by the first-order perturbation method in order to make clear the steady-state operating conditions.

When the constant or trapped-ion mode scaling of the confinement-time is used, the critical temperature of the self-heated plasma lies in the vicinity of the minimum point for the confinement parameter nτ. Bohm scaling gives the lowest value for the critical temperature, while neo-classical scaling does the highest one. With increasing fuel injection energy, the growth rate of the instability at low temperature decreases, whereas it does not always decreases at high temperature.

In the D-D fusion plasma, the subsidiary reaction ³He(d, p)⁴ He makes dominant contribution to the plasma heating and the instability at low temperature. The cyclotron radiation, the dominant power loss mechanism at high temperature, plays a significant role in determining the critical temperatures. Calculations neglecting the cyclotron radiation yield the inadequate, considerably higher values for them.

The validity of the above results has been confirmed by the non-linear dynamic simulations.