Radiator Leak

My car has been overheating and leaking radiator fluid from this damaged area. I first checked all the hoses, which were fine. So, I then pulled off the fan assembly and saw that the bottom corner, where the coolant had sprayed and leaked from looked very different than the bottom corner on the other side. I was wondering if this is something fixable with the K-Seal or JB Weld that I have or if I need to buy a new radiator? And if so, do I need to pull the radiator to get access to the bottom of it? And also, really wondering how damage like this can happen seeing as the area is protected by the fan shroud? Sorry the pictures are upside down I couldn't upload the ones I had taken from my library.