Complex sentence: Nobel laureate Carlo Rubbia at CERN (European Organization for Nuclear Research), has worked on developing thorium reactors and has stated that a tonne of thorium can produce as much energy as 200 tonnes of uranium, or 3,500,000 tonnes of coal.
Split into simpler sentences: Nobel laureate Carlo Rubbia at CERN (European Organization for Nuclear Research), has worked on developing the use of thorium as an alternative to uranium in reactors. Rubbia states that a tonne of thorium can produce as much energy as 200 tonnes of uranium, or 3,500,000 tonnes of coal.