Is there any good reference for conceptual problems for students which learn nuclear physics first time? I am not searching problems that involve difficult calculations. Quite the converse, they should be computational rather simple but conceptually difficult.
Try looking at the nuclear physics questions in the Physics GRE test. These are multiple choice questions that are supposed to be answered in a few minutes each. At this link: http://grephysics.net/ans/type/Advanced%20Topics