"We expect the chip unit valuation will be at least 2 trillion yen ($18 billion), Satoshi Tsunakawa said at a news briefing in Tokyo after the company's U.S. Westinghouse nuclear unit filed for Chapter 11 protection from creditors.

Tsunakawa will seek approval for the sale of more than half the business at a gathering of shareholders in Tokyo on Thursday.

(Reporting by Makiko Yamazaki; Writing by Tim Kelly; Editing by Edwina Gibbs)