I am frustrated about the progress on my project, and especially about issues in another department that seem to be holding up the release of important technical data. Can I blog about this tonight when I get home to release my stress over these matters?

It is not appropriate to discuss internal matters publicly, through blogs or any other public media.  Even if you consider that you are blogging in your personal capacity, a blog can reflect upon the reputation of CERN.  Blogging can also adversely impact work as well as professional relationships.  The lack of progress on a project and other internal issues should be handled through internal discussion and collaboration.