The two agreements, including a letter of intent between Romania's Nuclearelectrica company and CGN, were signed in the presence of the Romanian and Chinese premiers, Victor Ponta and Li Keqiang.
Government and Nuclearelectrica officials declined to answer AFP questions on the content of the agreements.
Romanian authorities announced in October 2012 that CGN was interested in the construction of two new reactors at Romania's nuclear plant in Cernavoda (south-east), a project estimated to cost more than USD 5.4 billion.
"As far as the European Union's rules of competition are concerned, Romania will certainly observe them," Ponta said.
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"But today, under conditions of equal, European competition, there are numerous fields where the Chinese companies' bids are better from a technical and financial point of view.
"So I assured the (Chinese) prime minister that, if a Chinese company's bid is better, it will be declared the winner," he added.
Romania has been looking for private investors to finance the extension of Cernavoda since four shareholders of the project company, including CEZ (Czech Republic) and GDF Suez (France), pulled out in 2011, complaining of a lack of predictability.