* Areva-supplied reactor a decade late in Finland
* TVO, Areva claim billions from each other
* Partial arbitration awards so far 3-0 for TVO
* Final decision seen in the coming months (Adds report on TVO stance, Areva comment)
By Jussi Rosendahl and Tuomas Forsell
HELSINKI, Nov 15 (Reuters) - Finnish utility Teollisuuden Voima (TVO) has won a third partial ruling from the International Chamber of Commerce (ICC) in its long-running nuclear reactor dispute with plant suppliers Areva and Siemens, TVO said on Wednesday.
TVO and the suppliers are claiming billions of euros from each other due to years of delays and cost overruns on the Olkiluoto 3 reactor project in southwest Finland. Its start was postponed last month to May 2019 - a decade later than planned.
Areva-Siemens, which started the dispute over delays, is claiming 3.6 billion euros ($4.3 billion) from TVO, while the Finnish company has filed a counter-claim of 2.6 billion euros.
TVO said the partial award resolved matters related to the construction works in its favour. It was the last partial decision before the final ruling on compensation, expected in the coming months.
TVO deputy CEO Risto Siilos said he was optimistic over the final outcome.
"We maintain our view that our case is stronger than the plant supplier's claims," he told Reuters by phone.
"The partial decisions are final and binding, and although no financial decisions have yet been made, they give an indication of what's coming."
An Areva spokesman said the firm disagreed with TVO's interpretation that the partial ruling was an indication of the final ruling as it did not cover the key issues at stake in the arbitration.
"We remain confident about the final sharing of responsibilities," he said.
French energy newsletter Enerpresse reported that TVO would be willing to end the litigation provided that Areva ensures that it has the financial means to finalise the reactor project.
A TVO spokesman declined to comment on that.
The Areva spokesman said Areva remains open to a balanced agreement to end the long arbitrage procedure.
"It is TVO's intransigence which led to the collapse of talks 18 months ago, at both parties' expense. The basis for a win-win agreement is on the table," he said.
TVO also filed an appeal in September to the European Commission over France's restructuring of its nuclear industry.
TVO argued the French plan to inject 4.5 billion euros into state-owned Areva was not enough and could leave the troubled company unable to meet its future liabilities.
A turnkey contract for Olkiluoto 3, signed in 2003, fixed the cost of the reactor at 3.2 billion euros. Areva has since estimated the overall cost at closer to 8.5 billion euros.
TVO's largest owner, Pohjolan Voima Oy (PVO), told Reuters on Tuesday it might seek further compensation from the suppliers.
PVO is majority-owned by Finnish paper makers UPM and Stora Enso, while utility Fortum owns a direct stake in TVO.
Olkiluoto 3, a European Pressurised Reactor (EPR), is set to become Finland's fifth and largest nuclear unit and provide about 10 percent of the country's power needs.
Analysts have estimated delays at the plant have translated into additional annual costs of hundreds of millions of euros for Finnish consumers through higher electricity prices. ($1 = 0.8462 euros) (Reporting by Jussi Rosendahl and Tuomas Forsell, additional reporting by Bate Felix and Geert De Clercq in Paris, Editing by Mark Potter and Adrian Croft)