 BRITaIN'S plans for a new generation of nuclear power stations have suffered another setback after being delayed by at least a year.  The first of the new plants will not be built until 2019 because of extra safety checks following Japan's atomic disaster.  Ministers originally hoped to get the first nuclear power station built by 2017, before revising this to 2018.  Now there has been a further slippage, after an updated timetable showed the first station in Somerset is not expected until nearer the end of the decade.  The Government has placed its hope on nuclear power to stop Britain being vulnerable to energy shortages when coal power stations start retiring from 2015.  The Coalition's plans for building eight to 10 nuclear plants over the next decade were described last week as "simply lacking credibility" by peers in the House of Lords.  There have been concerns about the high cost and whether the plants can be built quickly enough to meet Britain's growing need for electricity.  EDF Energy, the company building the first plant, has refused to give a "firm and final completion date" for nuclear power. a spokesman for the company said the 2019 date was only "indicative".  The Government disclosed in its Carbon Plan yesterday that tripling the UK's nuclear power would be the cheapest way for the country to tackle climate change by reducing emissions.  Chris Huhne, the Energy Secretary, claimed that nuclear power and wind farms will be much cheaper for the consumer than relying on oil and gas.  He said going green would stop Britain being "vulnerable" to imported oil and gas.  The Government concedes that bills will have to rise sharply  