Index: Ringtoets/Common/src/Ringtoets.Common.Forms/TypeConverters/NoProbabilityValueDoubleConverter.cs
===================================================================
diff -u -r2d104a54ab378eea92fd946b40cff2bd79ca39b0 -rbec135dd51ffb5a9beb8cc848d7f38731c5fe5e0
--- Ringtoets/Common/src/Ringtoets.Common.Forms/TypeConverters/NoProbabilityValueDoubleConverter.cs	(.../NoProbabilityValueDoubleConverter.cs)	(revision 2d104a54ab378eea92fd946b40cff2bd79ca39b0)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/TypeConverters/NoProbabilityValueDoubleConverter.cs	(.../NoProbabilityValueDoubleConverter.cs)	(revision bec135dd51ffb5a9beb8cc848d7f38731c5fe5e0)
@@ -75,7 +75,12 @@
                 {
                     if (text.StartsWith(returnPeriodNotation))
                     {
-                        return 1 / Convert.ToDouble(text.Substring(2));
+                        string returnPeriodValue = text.Substring(2).ToLower();
+                        if (returnPeriodValue == CommonBaseResources.RoundedDouble_ToString_PositiveInfinity.ToLower())
+                        {
+                            return 0.0;
+                        }
+                        return 1 / Convert.ToDouble(returnPeriodValue);
                     }
 
                     return Convert.ToDouble(text);
Index: Ringtoets/Common/test/Ringtoets.Common.Forms.Test/TypeConverters/NoProbabilityValueDoubleConverterTest.cs
===================================================================
diff -u -re71b611930c2ed5cea2117df1fd1effd3d45f4f4 -rbec135dd51ffb5a9beb8cc848d7f38731c5fe5e0
--- Ringtoets/Common/test/Ringtoets.Common.Forms.Test/TypeConverters/NoProbabilityValueDoubleConverterTest.cs	(.../NoProbabilityValueDoubleConverterTest.cs)	(revision e71b611930c2ed5cea2117df1fd1effd3d45f4f4)
+++ Ringtoets/Common/test/Ringtoets.Common.Forms.Test/TypeConverters/NoProbabilityValueDoubleConverterTest.cs	(.../NoProbabilityValueDoubleConverterTest.cs)	(revision bec135dd51ffb5a9beb8cc848d7f38731c5fe5e0)
@@ -124,6 +124,8 @@
         [TestCase("1e-3", 0.001)]
         [TestCase("1/1.000", 0.001)]
         [TestCase("1/0", double.PositiveInfinity)]
+        [TestCase("1/Oneindig", 0.0)]
+        [TestCase("1/oneINdig", 0.0)]
         [TestCase("1/-1.000", -0.001)]
         [TestCase("1/-10", -0.1)]
         [TestCase("1/-2,5", -0.4)]
@@ -154,6 +156,8 @@
         [TestCase("1e-3", 0.001)]
         [TestCase("1/1,000", 0.001)]
         [TestCase("1/0", double.PositiveInfinity)]
+        [TestCase("1/Oneindig", 0.0)]
+        [TestCase("1/oneINdig", 0.0)]
         [TestCase("1/-1,000", -0.001)]
         [TestCase("1/-10", -0.1)]
         [TestCase("1/-2.5", -0.4)]