diff --git a/openmc/mgxs/library.py b/openmc/mgxs/library.py
index a38e42d245..c36d8d516e 100644
--- a/openmc/mgxs/library.py
+++ b/openmc/mgxs/library.py
@@ -426,7 +426,7 @@ class Library(object):
         ----------
         domain : Material or Cell or Universe or Integral
             The material, cell, or universe object of interest (or its ID)
-        mgxs_type : {'total', 'transport', 'absorption', 'capture', 'fission', 'nu-fission', 'scatter', 'nu-scatter', 'scatter matrix', 'nu-scatter matrix', 'chi'}
+        mgxs_type : {'total', 'transport', 'absorption', 'capture', 'fission', 'nu-fission', 'kappa-fission', 'scatter', 'nu-scatter', 'scatter matrix', 'nu-scatter matrix', 'chi'}
             The type of multi-group cross section object to return
 
         Returns
@@ -457,7 +457,7 @@ class Library(object):
                     break
             else:
                 msg = 'Unable to find MGXS for {0} "{1}" in ' \
-                      'library'.format(self.domain_type, domain)
+                      'library'.format(self.domain_type, domain_id)
                 raise ValueError(msg)
         else:
             domain_id = domain.id