CREATE TABLE table_143352_1 (construction_started VARCHAR, agr_power_station VARCHAR)

What year did construction start at Heysham 1
SELECT construction_started FROM table_143352_1 WHERE agr_power_station = "Heysham 1"
SELECT "construction_started" FROM "table_143352_1" WHERE "Heysham 1" = "agr_power_station"