diff --git a/openmc/clean_xml.py b/openmc/clean_xml.py
index 619475fa07..2bb3f39f1b 100644
--- a/openmc/clean_xml.py
+++ b/openmc/clean_xml.py
@@ -82,11 +82,11 @@ def clean_xml_indentation(element, level=0):
         if not element.tail or not element.tail.strip():
             element.tail = i
 
-        for element in element:
-            clean_xml_indentation(element, level+1)
+        for sub_element in element:
+            clean_xml_indentation(sub_element, level+1)
 
-            if not element.tail or not element.tail.strip():
-                element.tail = i
+        if not sub_element.tail or not sub_element.tail.strip():
+            sub_element.tail = i
 
     else:
         if level and (not element.tail or not element.tail.strip()):