CREATE TABLE table_14736 ("Unit" CLOB, "Reactor type" CLOB, "Net capacity" CLOB, "Gross capacity" CLOB, "Construction started" CLOB, "Electricity grid" CLOB, "Commercial operation" CLOB, "Shutdown" CLOB)

What reactor type that has a commercial operation of , and a tianwan-7 unit?
SELECT "Reactor type" FROM table_14736 WHERE "Commercial operation" = '—' AND "Unit" = 'tianwan-7'
SELECT "Reactor type" FROM "table_14736" WHERE "Commercial operation" = '—' AND "Unit" = 'tianwan-7'