CREATE TABLE table_143352_1 (accounting_closure_date INT, agr_power_station VARCHAR)

What is the Closure date of Hunterston B
SELECT MIN(accounting_closure_date) FROM table_143352_1 WHERE agr_power_station = "Hunterston B"
SELECT MIN("accounting_closure_date") FROM "table_143352_1" WHERE "Hunterston B" = "agr_power_station"