UPDATE 1-Idemitsu shuts 60,000 bpd secondary unit after fire

* Fire breaks out as plant prepares for scheduled maintenance

* No other units at Aichi refinery affected

TOKYO, Sept 25 (Reuters) - Japan's third-biggest refiner, Idemitsu Kosan Co (5019.T), said it shut a 60,000 barrels per day (bpd) fuel oil desulphurisation unit at its Aichi refinery in western Japan on Thursday after a fire.

A company spokesman said the fire broke out at 3:50 p.m. (0650 GMT) while it was trying to shut the unit down for maintenance work, but it was extinguished about 20 minutes later and did not spread to any of the plant's other units.

The 160,000 bpd Aichi refinery is set to enter into turnaround from the end of September until the last 10 days of November, and any repairs needed on the desulphurisation unit are slated to be performed during that time. [ID:nT17853] (Reporting by James Topham; Writing by Osamu Tskimori)