LONDON, April 18 (Reuters) -
* Royal Dutch Shell said its Moerdijk petrochemical plant intheNetherlands was shutting down, but a planned maintenanceturnaround at the site was not yet confirmed
* A spokeswoman for the oil major said Shell was "carefullyoptimistic" at this point about the lower olefins unit shuttingdown "which will hopefully lead to the turnaround at some pointsoon"
* Workers have been on strike at the Moerdijk plant and thenearby404,000 barrel per day Pernis oil refinery, Europe's largest,since April 8(Reporting by Ahmad Ghaddar; Editing by Mark Potter)