Several possible ways to prevent the log filling:

Insert the records in batches and take log backups between the batches.

Switch the DB to 'Simple' recovery mode, insert in batches, switch back to 'Full' recovery mode, take an immediate full backup (this may not be advisable if you need to maintain point in time recoverability for the DB)

Allow the log to grow, or add space to the log to cover the amount of data. Remove other files from the drive if possible to free up space.

Without more information about the situation, it's tough to give meaningful advice.