Does uttering the triple divorce in one's imagination and through intrusive thoughts constitute a valid divorce according to Sharia?

Inner thoughts of divorce do not constitute divorce. This is the view of the majority of scholars, based on the Hadith: "Indeed, Allah has pardoned for my Ummah that which they whisper to themselves, as long as they do not act upon it or speak of it." So, as long as you have not uttered the words of divorce, nothing is binding upon you.