diff --git a/src/main/java/neqsim/processSimulation/processEquipment/stream/Stream.java b/src/main/java/neqsim/processSimulation/processEquipment/stream/Stream.java
index 24bdf0e809..e03b25f49a 100644
--- a/src/main/java/neqsim/processSimulation/processEquipment/stream/Stream.java
+++ b/src/main/java/neqsim/processSimulation/processEquipment/stream/Stream.java
@@ -192,7 +192,11 @@ public Stream clone() {
     if (stream != null) {
       clonedSystem.setStream((Stream) stream.clone());
     }
-    clonedSystem.thermoSystem = thermoSystem.clone();
+    if (thermoSystem != null) {
+      clonedSystem.thermoSystem = thermoSystem.clone();
+    }
+
+
     return clonedSystem;
   }