A repetitive 800 kA linear transformer drivers stage for Z-pinch driven fusion-fission hybrid reactor

Abstract

This paper presents the design and tests of a repetitive 800 kA fast linear transformer driver (LTD) stage aimed for the Zpinch driven fusion-fission hybrid reactor (Z-FFR).The LTD stage consists of 34 parallel basic resistor R, inductor L, and capacitor C (RLC) circuits each made up of two 100 kV/40 nF capacitors, a multi-stage gas switch and Metglas magnetic cores. The stage can deliver about 800 kA current pulse with rise time of 100 ns into the matched liquid resistive load at a repetitive frequency 0.1 Hz. A novel method to trigger the stage via a continuous internal trigger bus composed by a single cable has been proposed and demonstrated. The experimental results show that the new trigger method is feasible and reliable. A 140 kV, 25 ns rising time trigger pulse, and a 5.2 kA, 30 μs width pre-magnetization current pulse which can operate at a repetition rate 0.1 Hz were used in this stage to insure the LTD stage generating a 80 kV/800 kA current pulse every 10 s. A multi-stage gas switch that has a lifetime in excess of 10,000 shots and a jitter less than 3 ns one sigma agrees well with the demand of Z-FFR. The electrical behavior of the stage can be predicted from a simple RLC circuit, which can simplify the design of various LTD-based accelerators.

A trigger source for linear transformer driver

“…The trigger source was applied to trigger themulti-spark gap switch [1] using in the LTD stage, shown in figure 8. Two 40 nF capacitors charged to plus and minus 100 kV are connected the LTD switch.…”

“…In future linear transformer drivers (LTD) may be an optimal choice for Z-Pinch driven fusionfission hybrid reactor (Z-FFR) and inertial fusion energy (IFE) where the required repetition rate is estimated to be 0.1 Hz [1,2]. So the high voltage pulses used to trigger the switches in the LTD stage should be continuously generated with the same repetition rate.…”