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_name_25 ( reactor_type VARCHAR, commercial_operation VARCHAR, unit VARCHAR )

### Question ###
What reactor type that has a commercial operation of , and a tianwan-7 unit?

### Accurate SQL ###

SELECT reactor_type FROM table_name_25 WHERE commercial_operation = "—" AND unit = "tianwan-7"