CREATE TABLE table_24670 ("Date  ( GMT ) " TEXT, "Yield  ( megatons ) " TEXT, "Deployment" TEXT, "Country" TEXT, "Test Site" TEXT, "Name or Number" TEXT)

Name the name for 15 yield
SELECT "Name or Number" FROM table_24670 WHERE "Yield (megatons)" = '15'
SELECT "Name or Number" FROM "table_24670" WHERE "Yield (megatons)" = '15'