diff --git a/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_diameter.md b/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_diameter.md
new file mode 100644
index 0000000000000000000000000000000000000000..8571befee150c3cbe92fc502b4785792c238dc41
--- /dev/null
+++ b/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_diameter.md
@@ -0,0 +1 @@
+The diameter of the inlet pipe.
diff --git a/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_radius.md b/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_radius.md
deleted file mode 100644
index 6b81a97376fca2436c175007465ef50346e8c6af..0000000000000000000000000000000000000000
--- a/Documentation/ProjectFile/prj/processes/process/HEAT_TRANSPORT_BHE/borehole_heat_exchangers/borehole_heat_exchanger/pipes/inlet/t_radius.md
+++ /dev/null
@@ -1 +0,0 @@
-The radius of the inlet pipe.
diff --git a/ProcessLib/HeatTransportBHE/BHE/Pipe.cpp b/ProcessLib/HeatTransportBHE/BHE/Pipe.cpp
index 11986ed325805fc17d74634492a5f9daf5bd0da5..15ff7e87645f5771535e81b4ed566091b83a412b 100644
--- a/ProcessLib/HeatTransportBHE/BHE/Pipe.cpp
+++ b/ProcessLib/HeatTransportBHE/BHE/Pipe.cpp
@@ -20,15 +20,15 @@ namespace BHE
 {
 Pipe createPipe(BaseLib::ConfigTree const& config)
 {
-    //! \ogs_file_param{prj__processes__process__HEAT_TRANSPORT_BHE__borehole_heat_exchangers__borehole_heat_exchanger__pipes__inlet__radius}
-    const double radius = config.getConfigParameter<double>("radius");
+    //! \ogs_file_param{prj__processes__process__HEAT_TRANSPORT_BHE__borehole_heat_exchangers__borehole_heat_exchanger__pipes__inlet__diameter}
+    const double diameter = config.getConfigParameter<double>("diameter");
     const double wall_thickness =
         //! \ogs_file_param{prj__processes__process__HEAT_TRANSPORT_BHE__borehole_heat_exchangers__borehole_heat_exchanger__pipes__inlet__wall_thickness}
         config.getConfigParameter<double>("wall_thickness");
     const double wall_thermal_conductivity =
         //! \ogs_file_param{prj__processes__process__HEAT_TRANSPORT_BHE__borehole_heat_exchangers__borehole_heat_exchanger__pipes__inlet__wall_thermal_conductivity}
         config.getConfigParameter<double>("wall_thermal_conductivity");
-    return {radius, wall_thickness, wall_thermal_conductivity};
+    return {diameter, wall_thickness, wall_thermal_conductivity};
 }
 }  // namespace BHE
 }  // namespace HeatTransportBHE
diff --git a/Tests/Data/Parabolic/T/3D_Beier_sandbox/beier_sandbox.prj b/Tests/Data/Parabolic/T/3D_Beier_sandbox/beier_sandbox.prj
index 6c9750cfe94b23d331bb7a762a32ec244c9464b1..5899994915f62556fd96993df1ccf8d5c41c2055 100644
--- a/Tests/Data/Parabolic/T/3D_Beier_sandbox/beier_sandbox.prj
+++ b/Tests/Data/Parabolic/T/3D_Beier_sandbox/beier_sandbox.prj
@@ -45,12 +45,12 @@
                     </grout>
                     <pipes>
                         <inlet>
-                            <radius> 0.013665</radius>
+                            <diameter> 0.013665</diameter>
                             <wall_thickness>0.003035</wall_thickness>
                             <wall_thermal_conductivity>0.39</wall_thermal_conductivity>
                         </inlet>
                         <outlet>
-                            <radius>0.013665</radius>
+                            <diameter>0.013665</diameter>
                             <wall_thickness>0.003035</wall_thickness>
                             <wall_thermal_conductivity>0.39</wall_thermal_conductivity>
                         </outlet>
diff --git a/Tests/Data/Parabolic/T/3D_Beier_sandbox/fixed_power_constant_flow.prj b/Tests/Data/Parabolic/T/3D_Beier_sandbox/fixed_power_constant_flow.prj
index cc45512ed0537089c4f9bafae0bd0916d69606d2..cf26ce7ea2a851807703df0eb0248e339f5a3fb7 100644
--- a/Tests/Data/Parabolic/T/3D_Beier_sandbox/fixed_power_constant_flow.prj
+++ b/Tests/Data/Parabolic/T/3D_Beier_sandbox/fixed_power_constant_flow.prj
@@ -45,12 +45,12 @@
                     </grout>
                     <pipes>
                         <inlet>
-                            <radius> 0.013665</radius>
+                            <diameter> 0.013665</diameter>
                             <wall_thickness>0.003035</wall_thickness>
                             <wall_thermal_conductivity>0.39</wall_thermal_conductivity>
                         </inlet>
                         <outlet>
-                            <radius>0.013665</radius>
+                            <diameter>0.013665</diameter>
                             <wall_thickness>0.003035</wall_thickness>
                             <wall_thermal_conductivity>0.39</wall_thermal_conductivity>
                         </outlet>