section of the machine has been reduced to about half the previous size while the oil section has been expanded significantly in order to house larger intermediate storage lines (i-stores) and new laser towers, which used to sit in the water section. The refurbishment was completed in October 2007. The newer Z machine can now shoot around 26 million amperes (instead of 18 million amperes previously) in 95 nanoseconds. The radiated power has been raised to 350 terawatts and the X-ray energy output to 2.7 megajoules. However the maximum temperature the new version may reach with the same record holder stainless steel wire-array liner used in 2005 is not yet known. The ultra-high temperatures reached in 2006 (2.66 to 3.7 billion kelvins) are much higher than those required for the classical hydrogen, deuterium and tritium fusion previously considered. They could allow, in theory if not in practice, the fusion of light hydrogen atoms with heavier atoms such as lithium or boron. These two possible fusion reactions do not produce neutrons, and thus no radioactivity or nuclear waste, so they open the possibility of human-made clean aneutronic fusion. Sandia's roadmap includes another Z machine version called ZN (Z Neutron) to test higher yields in fusion power and automation systems. ZN is planned to give between 20 and 30 MJ of hydrogen fusion power with a shot per hour using a Russian Linear Transformer Driver (LTD) replacing the current Marx generators. After 8 to 10 years of operation, ZN would become a transmutation pilot plant capable of a fusion shot every 100 seconds. The next step planned would be the Z-IFE (Z-inertial fusion energy) test facility, the first true z-pinch driven prototype fusion power plant. It is suggested it would integrate Sandia's latest designs using LTDs. Sandia Labs recently proposed a conceptual 1 petawatt (1015 watts) LTD Z-pinch power plant, where the electric discharge would reach 70 million amperes. As of 2012, fusion shot simulations at 60 to 70 million amperes are showing a 100 to 1000 fold return on input energy. Tests at the Z machine's current design maximum of 26-27 million amperes were set to begin in 2013. Z-Pinch Inertial Fusion Energy program The Sandia Laboratories Z-IFE project aims to solve the practical difficulties in harnessing fusion power. Major problems include producing energy in a single Z-pinch shot, and quickly reloading the reactor after each shot. By their early estimates,