Here is a list of Nuclear Physics reseach institutes -
http://www.rarf.riken.go.jp/rarf/np/nplab.html
I would recommend one investigate various programs and their specialties.
Center for Experimental Nuclear Physics and Astrophysics (CENPA)
University of Washington, Seattle, Washington, USA
http://www.npl.washington.edu/
Nuclear Theory Group in the Physics Department
University of Wisconsin, Madison, WI.
http://nucth.physics.wisc.edu/
U of Wisc also has a very good nuclear engineering program.
http://www.engr.wisc.edu/ep/neep/
UIUC Nuclear Physics Lab, University of Illinois, Urbana-Champaign
http://www.npl.uiuc.edu/newnpl/index.html
U of Illinois also has a very good nuclear engineering program.
http://www.ne.uiuc.edu/
Purdue University's Nuclear Engineering department has a really interesting program in computational physics. They are working with Argonne National Laboratory on the next generation of reactor simulator.
Triangle Universities Nuclear Laboratory (Duke University / North Carolina State University / University of North Carolina ) NCSU has a good nuclear engineering program as well.
http://www.tunl.duke.edu/ at Duke University