Two ZR Marx generator operating configurations that make possible their rolling upgrade integration into Z

If the Sandia National Laboratories' Z-Machine Marx generators and the Z-refurbishment (ZR) Marx generators are mixed to drive like-modules in parallel, the ZR banks need to be temporarily reconfigured to closely match the output waveforms of the Z banks. Otherwise, there is significant module-to-module variations and a loss of consistency at the central target region. Sandia has explored two solutions for operating the ZR Marx generators to meet this requirement. One method involves charging the ZR banks to about 72 kV along with the 90-kV charge for the Z banks, thus requiring two power supplies and charge busses plus a different SF/sub 6/ pressure in the Marx switches. The other method is to short or bypass an appropriate number of ZR Marx stages so the remaining "reduced" Marx generator may be charged to the same 90-kV level. Some hardware, labor, and bank inductance tuning are needed to match output timing to the original pulsed power. This paper examines how to implement both solutions and compares their advantages and disadvantages with the goal of choosing only one of them. Models supporting this effort take into account measurements obtained from existing Marx generators that are reconfigured in similar ways.

I. Introduction

The transition of the Sandia Z machine into its refurbished upgrade, ZR, is planned to occur within a six-month window at the end of 2005. This transition includes new major pulsed power hardware and oil/water tank changes. The thirty-six 60-stage Marx generators are complicated, heavy (10 ton) systems in the energy storage section of Z. To become the ZR prime power source, they will undergo a few changes, the most important being the replacement of the present capacitors with new units. Rebuilding the Marx banks during the same period as the main renovations would require an off-site effort. Acquiring a staging facility, providing transportation, and managing all the related hardware and personnel logistics is not an attractive option.