Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_2189647_1 ( name_or_number VARCHAR, yield__megatons_ VARCHAR )

### Question ###
Name the name for 15 yield

### Accurate SQL ###

SELECT name_or_number FROM table_2189647_1 WHERE yield__megatons_ = "15"