Law reviews are publications that are generally written by law students. They are usually scholarly. Some may be peer-reviewed but the "peers" reviewing law review articles are often other students. Since this is different from the usual definition of peer-review, you will want to check with your professor to see if you can use law review articles in your assignment.
There are some law journals that are peer reviewed in the more traditional definition of the term, such as the American Bar Association's Business Lawyer and the American Indian Law Review. Check the journal's website (Google the journal's title to find the website) submission guidelines to verify how their review process is handled.
However, law reviews are considered secondary sources because the articles are providing analyses and commentary on legal issues. The Harvard Law School Library provides a good definition of law reviews on their secondary sources web page.
