* S.Korea state utility seen likeliest NuGen suitor
* KEPCO in talks, but needs "considerable time" -source
* Up to NuGen group to determine partner - British minister
* Britain, Toshiba seek to accelerate chase for deal (Adds British minister, KEPCO spokesman comments)
By Jane Chung
SEOUL, April 5 (Reuters) - As Britain steps up the hunt for a new partner for a stalled nuclear power project, South Korea's KEPCO remains the most likely suitor, but two people with direct knowledge of the matter said the giant utility won't be rushed to the altar.
With British business minister Greg Clark in Seoul for talks, the status of KEPCO - Korea Electric Power Corp (KEPCO) - as likely buyer was enhanced this week by troubled Japanese group Toshiba Corp having to take on full ownership of the NuGen project after France's Engie backed out. Strapped for cash, Toshiba needs a sale.
One of few utilities to retain global nuclear ambitions, KEPCO said last month that it was in talks over a potential stake purchase in NuGen, a three-reactor, up-to-3,800 megawatt project in northwest England that London needs on stream in 2025 to meet projected power demand, but has suffered significant setbacks since it was set up in 2010.
But while both Britain and Toshiba seek to accelerate progress towards a deal, state-owned KEPCO will not be able to move faster, the people with direct knowledge of the matter said on Wednesday. They declined to be identified because they were not authorised to discuss the matter publicly.
"Both Britain and Toshiba, they seem to be in a greater hurry than we thought and pushing KEPCO. In fact, it requires considerable time to review a project, so it is not a matter that can be done hastily," one of the people said.
At a briefing in Seoul on Wednesday, Britain's Clark offered no evidence of concrete progress in negotiations with KEPCO. The minister said he had travelled for talks with KEPCO and energy ministry officials in order to deepen relationships, but said the choice of a partner is for NuGen to decide, not the British government.
"It would be a positive partnership that we feel that the UK and Korea can have in nuclear, but on the particular project of Moorside, that is for the developers to make a proposal," Clark said.
A KEPCO spokesman said the firm will make its position clear once it has reviewed terms and conditions of any potential investment carefully.
Toshiba's U.S. nuclear construction arm Westinghouse filed for bankruptcy last week, and the company is selling a majority stake in its prized memory chips business to raise cash.
One key issue for KEPCO will be the technology used for the Moorside project - Toshiba's AP1000 reactor, as planned, or its own APR1400. While Toshiba previously received the green light from Britain for the Westinghouse design, KEPCO could make approval for its own technology that a condition.
"KEPCO is working and studying hard which type of nuclear reactors would suit better for them, given the current market situation," the second person with knowledge of the matter said.
Using KEPCO's own reactors could "give a better reason to join the project", the person said. (Reporting by Jane Chung; Editing by Kenneth Maxwell)