diff --git a/armi/physics/thermalHydraulics/settings.py b/armi/physics/thermalHydraulics/settings.py
index a8df91ed2..3975a35e7 100644
--- a/armi/physics/thermalHydraulics/settings.py
+++ b/armi/physics/thermalHydraulics/settings.py
@@ -34,7 +34,7 @@ def defineSettings():
         ),
         setting.Setting(
             CONF_TH_KERNEL,
-            default=False,
+            default="",
             label="Thermal Hydraulics Kernel",
             description="Name of primary T/H solver in this run",
         ),
diff --git a/armi/physics/thermalHydraulics/tests/__init__.py b/armi/physics/thermalHydraulics/tests/__init__.py
new file mode 100644
index 000000000..84776603f
--- /dev/null
+++ b/armi/physics/thermalHydraulics/tests/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2024 TerraPower, LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/armi/physics/thermalHydraulics/tests/test_thermalHydraulicsPlugin.py b/armi/physics/thermalHydraulics/tests/test_thermalHydraulicsPlugin.py
new file mode 100644
index 000000000..3c9938abc
--- /dev/null
+++ b/armi/physics/thermalHydraulics/tests/test_thermalHydraulicsPlugin.py
@@ -0,0 +1,41 @@
+# Copyright 2024 TerraPower, LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for the thermal hydraulics plugin."""
+from armi.physics import thermalHydraulics
+from armi.physics.thermalHydraulics.settings import CONF_DO_TH, CONF_TH_KERNEL
+from armi.settings import caseSettings
+from armi.tests.test_plugins import TestPlugin
+
+
+class TestThermalHydraulicsPlugin(TestPlugin):
+    plugin = thermalHydraulics.ThermalHydraulicsPlugin
+
+    def test_thermalHydraulicsSettingsLoaded(self):
+        """Test that the thermal hydraulics case settings are loaded."""
+        cs = caseSettings.Settings()
+
+        self.assertIn(CONF_DO_TH, cs)
+        self.assertIn(CONF_TH_KERNEL, cs)
+
+    def test_thermalHydraulicsSettingsSet(self):
+        """Test that the thermal hydraulics case settings are applied correctly."""
+        cs = caseSettings.Settings()
+        thKernelName = "testKernel"
+
+        cs[CONF_DO_TH] = True
+        cs[CONF_TH_KERNEL] = thKernelName
+
+        self.assertTrue(cs[CONF_DO_TH])
+        self.assertEqual(cs[CONF_TH_KERNEL], thKernelName)
diff --git a/doc/release/0.4.rst b/doc/release/0.4.rst
index 2b69760ac..9151fd113 100644
--- a/doc/release/0.4.rst
+++ b/doc/release/0.4.rst
@@ -25,6 +25,7 @@ Bug Fixes
 ---------
 #. Fixed ``DerivedShape.getArea`` for ``cold=True``. (`PR#1831 <https://github.com/terrapower/armi/pull/1831>`_)
 #. Fixed error parsing command line integers in ``ReportsEntryPoint``. (`PR#1824 <https://github.com/terrapower/armi/pull/1824>`_)
+#. Changed data type of ``thKernel`` setting from ``bool`` to ``str`` in ``ThermalHydraulicsPlugin``. (`PR#1855 <https://github.com/terrapower/armi/pull/1855>`_)
 #. TBD
 
 Quality Work