** Shares of KBR Inc up 5.1% at $58 premarket after WSJ reports activist investor Irenic Capital Management has built a stake in the government contractor

** Report says Irenic plans to push KBR, which delivers science and technology solutions to governments and companies, to separate its segment that serves the private sector

** Adds Irenic has accumulated a more than 1% stake in the company and plans to push management to spin off or sell its sustainable technology solutions segment

** Eight of nine brokerages rate the stock "buy" or higher, one "hold"; their median PT is $78

** Up to Wednesday's close, stock had fallen 1.3% YTD

(Reporting by Kannaki Deka)

((Kannaki.Deka@thomsonreuters.com))