diff --git a/docs/source/conf.py b/docs/source/conf.py
index 9330315903..b97ff782d9 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -27,8 +27,9 @@ except ImportError:
 MOCK_MODULES = ['numpy', 'numpy.polynomial', 'numpy.polynomial.polynomial',
                 'numpy.ctypeslib', 'scipy', 'scipy.sparse', 'scipy.interpolate',
                 'scipy.integrate', 'scipy.optimize', 'scipy.special',
-                'scipy.stats', 'h5py', 'pandas', 'uncertainties', 'matplotlib',
-                'matplotlib.pyplot','openmoc', 'openmc.data.reconstruct']
+                'scipy.stats', 'scipy.spatial', 'h5py', 'pandas', 'uncertainties',
+                'matplotlib', 'matplotlib.pyplot','openmoc',
+                'openmc.data.reconstruct']
 sys.modules.update((mod_name, MagicMock()) for mod_name in MOCK_MODULES)
 
 import numpy as np
diff --git a/openmc/lattice.py b/openmc/lattice.py
index 730d7dc4a9..89cfcfe52c 100644
--- a/openmc/lattice.py
+++ b/openmc/lattice.py
@@ -607,12 +607,12 @@ class RectLattice(Lattice):
             element coordinate system
 
         """
-        ix = floor((point[0] - self.lower_left[0])/self.pitch[0])
-        iy = floor((point[1] - self.lower_left[1])/self.pitch[1])
+        ix = int(floor((point[0] - self.lower_left[0])/self.pitch[0]))
+        iy = int(floor((point[1] - self.lower_left[1])/self.pitch[1]))
         if self.ndim == 2:
             idx = (ix, iy)
         else:
-            iz = floor((point[2] - self.lower_left[2])/self.pitch[2])
+            iz = int(floor((point[2] - self.lower_left[2])/self.pitch[2]))
             idx = (ix, iy, iz)
         return idx, self.get_local_coordinates(point, idx)
 
@@ -1019,10 +1019,10 @@ class HexLattice(Lattice):
             iz = 1
         else:
             z = point[2] - self.center[2]
-            iz = floor(z/self.pitch[1] + 0.5*self.num_axial)
+            iz = int(floor(z/self.pitch[1] + 0.5*self.num_axial))
         alpha = y - x/sqrt(3.)
-        ix = floor(x/(sqrt(0.75) * self.pitch[0]))
-        ia = floor(alpha/self.pitch[0])
+        ix = int(floor(x/(sqrt(0.75) * self.pitch[0])))
+        ia = int(floor(alpha/self.pitch[0]))
 
         # Check four lattice elements to see which one is closest based on local
         # coordinates
diff --git a/openmc/mgxs/mgxs.py b/openmc/mgxs/mgxs.py
index a557e51cc1..0c0b15ad9d 100644
--- a/openmc/mgxs/mgxs.py
+++ b/openmc/mgxs/mgxs.py
@@ -10,6 +10,7 @@ import itertools
 
 from six import add_metaclass, string_types
 import numpy as np
+import h5py
 
 import openmc
 import openmc.checkvalue as cv
@@ -1682,13 +1683,8 @@ class MGXS(object):
         ValueError
             When this method is called before the multi-group cross section is
             computed from tally data.
-        ImportError
-            When h5py is not installed.
 
         """
-
-        import h5py
-
         # Make directory if it does not exist
         if not os.path.exists(directory):
             os.makedirs(directory)
diff --git a/openmc/model/triso.py b/openmc/model/triso.py
index 67bf3bc442..7258a86f21 100644
--- a/openmc/model/triso.py
+++ b/openmc/model/triso.py
@@ -12,11 +12,7 @@ from abc import ABCMeta, abstractproperty, abstractmethod
 
 from six import add_metaclass
 import numpy as np
-try:
-    import scipy.spatial
-    _SCIPY_AVAILABLE = True
-except ImportError:
-    _SCIPY_AVAILABLE = False
+import scipy.spatial
 
 import openmc
 import openmc.checkvalue as cv
@@ -742,7 +738,7 @@ def _close_random_pack(domain, particles, contraction_rate):
         outer_pf = (4/3 * pi * (outer_diameter[0]/2)**3 * n_particles /
                     domain.volume)
 
-        j = floor(-log10(outer_pf - inner_pf))
+        j = int(floor(-log10(outer_pf - inner_pf)))
         outer_diameter[0] = (outer_diameter[0] - 0.5**j * contraction_rate *
                              initial_outer_diameter / n_particles)
 
@@ -837,10 +833,6 @@ def _close_random_pack(domain, particles, contraction_rate):
         if rods:
             inner_diameter[0] = rods[0][0]
 
-    if not _SCIPY_AVAILABLE:
-        raise ImportError('SciPy must be installed to perform '
-                          'close random packing.')
-
     n_particles = len(particles)
     diameter = 2*domain.particle_radius
 
diff --git a/openmc/tallies.py b/openmc/tallies.py
index 235ad2472e..b685dcae39 100644
--- a/openmc/tallies.py
+++ b/openmc/tallies.py
@@ -1508,8 +1508,6 @@ class Tally(IDManagerMixin):
         ------
         KeyError
             When this method is called before the Tally is populated with data
-        ImportError
-            When Pandas can not be found on the caller's system
 
         """