diff --git a/armi/reactor/tests/test_components.py b/armi/reactor/tests/test_components.py
index 13cbe6996..6cbc1e696 100644
--- a/armi/reactor/tests/test_components.py
+++ b/armi/reactor/tests/test_components.py
@@ -621,7 +621,7 @@ def test_ExpansionConservationHotHeightDefined(self):
 
         self.assertAlmostEqual(
             circle1.getMassDensity(),
-            circle1.material.density3(Tc=circle2.temperatureInC),
+            circle1.material.density3(Tc=circle1.temperatureInC),
         )
         # change back to old temp
         circle1.changeNDensByFactor(circle1.getThermalExpansionFactor())