For the life of me, I cannot figure out where I get the RSS URL after selecting the "deliver to RSS Feed" option in Google Alerts (https://www.google.com/alerts)
What I find is that if you use the deliver by email option, the email you receive will have the RSS Feed URL. At the bottom of the email:
If you click on the RSS option, you will get the RSS url that you can use to add the feed to your RSS reader (like Feedly for example).