Joule heated ceramic melter (JHCM) vitrification is the baseline treatment technology for US high level radioactive waste and has been adopted in Japan, Germany, and China. The Vitreous State laboratory (VSL) operates the largest array of JHCM test systems in the US, with five platforms spanning scale-up of 60X, including the largest such test platform in the US. These systems have supported vitrification facilities at West Valley, DWPF and M-Area at Savannah River, WTP HLW and LAW at Hanford, as well Rokkasho in Japan. Melter bubbler technology invented at VSL is central to the performance of the Hanford HLW and LAW systems and was recently successfully retro fitted into DWPF, producing a near doubling of throughput. Results from many thousands of days of melter testing have produced significant enhancements in production rates and waste loadings through optimization and integration of glass formulations, design and operating conditions, and cold cap management.