ABU DHABI- Saudi Arabia plans to prequalify for bidding firms from two or three countries by April or May for the first nuclear reactors it wants to build, a consultant for the government body working on the nuclear plans said on Monday.

Saudi Arabia, the world's top oil exporter, wants nuclear power to diversify its energy supply mix, enabling it to export more crude rather than burning it to generate electricity.

It plans to build 17.6 gigawatts (GW) of nuclear capacity by 2032, the equivalent of around 16 reactors, making it one of the biggest prospects for an industry struggling after the 2011 nuclear disaster in Japan.

"Currently we are in the evaluation process for RFI (request for information) and we will hold discussions with them (suppliers) next month," Abdul Malik al-Sabery, a consultant at the King Abdullah City for Atomic and Renewable Energy told reporters in Abu Dhabi.

Sabery said a joint venture between the Saudi government and the winning developers would be signed in 2019 after the shortlisting by end of 2018. Commissioning of the first plant, which will have two reactors with a total a capacity between 2 and 3.2 GW, is expected in 2027.

Saudi Arabia's energy minister, Khalid al-Falih, said last month that he expected to sign contracts to build two nuclear reactors by the end of 2018.

Saudi Arabia has sent a request for information to international suppliers to build two reactors, the first step towards a formal tendering competition.

Sabery said Riyadh was currently evaluating requirements from five countries; China, Russia, South Korea, France and the United States.

Russian and South Korean companies have said they plan to bid and sources have told Reuters that Toshiba-owned U.S. company Westinghouse is in talks with U.S. rivals to form a bidding consortium. French state-controlled utility EDF also intends to take part in the tender.

Saudi Arabia is interested in reaching a civilian nuclear cooperation agreement with Washington, and Riyadh has invited U.S. firms to take part in developing the kingdom's first atomic energy programme.

(Reporting by Stanley Carvalho; Writing by Reem Shamseddine; Editing by Rania El Gamal and Louise Heavens) ((Reem.Shamseddine@thomsonreuters.com; +966503335202; Reuters Messaging: reem.shamseddine.thomsonreuters.com@reuters.net))