CREATE TABLE table_70004 ("Unit" TEXT, "Reactortype" TEXT, "Net capacity" TEXT, "Gross capacity" TEXT, "Construction started" TEXT, "Electricity Grid" TEXT, "Commercial Operation" TEXT, "Shutdown" TEXT)

When did the Electricity Grid 28.12.1972 officially shutdown?
SELECT "Shutdown" FROM table_70004 WHERE "Electricity Grid" = '28.12.1972'
SELECT "Shutdown" FROM "table_70004" WHERE "Electricity Grid" = '28.12.1972'