HOUSTON, Sept 27 (Reuters) - Royal Dutch Shell Plc tentatively plans the first restart of a production unit at its 230,611 barrel-per-day (bpd) Norco, Louisiana, refinery for mid-October, sources familiar with plant operations said on Monday.

A Shell spokesman did not reply to a request for comment.

The refinery, located 21 miles (34 km) west of New Orleans, was shut on Aug.
28 ahead of the landfall of Hurricane Ida. The refinery was flooded and damaged as the powerful storm passed over the plant, the sources said.

Shell is working to restart the boiler at the refinery, which is necessary for internal power and to produce steam used in the production process, the sources said.

The refinery began attempting to restart the boilers over the weekend.

The Norco refinery was one of nine in Louisiana shut by Hurricane Ida.

All have returned to production except for the Shell refinery and Phillips 66's 255,600-bpd Alliance, Louisiana, refinery.
Sources familiar with operations at the Alliance plant have said it requires months of repairs

"U.S. refinery utilization jumped to 88% (of national capacity) from 82% as most Louisiana refineries resumed operations following Hurricane Ida," said Matthew Blair, analyst for Tudor Pickering Holt & Co in a research note on Monday.

(Reporting by Erwin Seba; editing by Richard Pullin )