CREATE TABLE table_name_69 (yield VARCHAR, purpose VARCHAR, location VARCHAR)

What is the yield in NTS Area U2R when the purpose is weapons development?
SELECT yield FROM table_name_69 WHERE purpose = "weapons development" AND location = "nts area u2r"
SELECT "yield" FROM "table_name_69" WHERE "location" = "nts area u2r" AND "purpose" = "weapons development"