WARSAW (Reuters) -Polish mining group KGHM and nuclear technology firm NuScale Power on Monday signed a deal to start deploying small modular reactors in Poland, aiming to have the first operational as soon as 2029. Poland relies on coal for around 80% of its electricity production, but it is banking on nuclear power to help it cut emissions and diversify its energy sources as tensions with major gas producer Russia mount. KGHM Chief Executive Marcin Chludzinski and John Hopkins, the CEO of NuScale Power, signed the deal in Washington on Monday in the presence of U.S. and Polish government off…