CREATE TABLE table_14738 ("Unit" CLOB, "Reactor type" CLOB, "Net capacity" CLOB, "Gross capacity" CLOB, "Construction started" CLOB, "Electricity grid" CLOB, "Commercial operation" CLOB, "Shutdown" CLOB)

What commercial operation that has a gross capacity of 1,126 mw, and a unit of tianwan-4?
SELECT "Commercial operation" FROM table_14738 WHERE "Gross capacity" = '1,126 mw' AND "Unit" = 'tianwan-4'
SELECT "Commercial operation" FROM "table_14738" WHERE "Gross capacity" = '1,126 mw' AND "Unit" = 'tianwan-4'