NIS holds a range of information about British nuclear-powered and armed submarines; nuclear safety of Z & X Berths and the MoD’s proposals for the storage of nuclear sections of decommissioned submarines; the Interim Storage of Laid Up Submarines (ISOLUS).
You can also read position papers on ISOLUS from the Nuclear Submarine Forum (NsubF) and on "Z" berths from the Solent Coalition Against Nuclear Ships here(SCANS), plus further background information.
http://www.lancs.ac.uk/users/csec
/isolus2/isolus-homepage.htm and
http://www.royal-navy.mod.uk/static/
pages/content.php3?page=8882