diff --git a/openmc/model/triso.py b/openmc/model/triso.py
index 1e27e126aa..2552623a0c 100644
--- a/openmc/model/triso.py
+++ b/openmc/model/triso.py
@@ -41,8 +41,6 @@ class TRISO(openmc.Cell):
         Name of the TRISO cell
     center : numpy.ndarray
         Cartesian coordinates of the center of the TRISO particle in cm
-    outer_radius : float
-        Outer radius of TRISO particle
     fill : openmc.Universe
         Universe that contains the TRISO layers
     region : openmc.Region