new core param + change to createAssemblyOfType

Summary:
- adding a reactor.core parameter to store the geometric axial mesh (_not_ the neutronics mesh that is currently stored on reactor.core.axialMesh). This new parameter is: `core.p.currentGeometryAxialMesh`
-  ensuring that when new assemblies are created from blueprint assemblies that the geometric block mesh on the assembly is set to align with the `core.p.currentGeometryAxialMesh` if `detailedAxialExpansion: False`.

armi/reactor/reactorParameters.py

@@ -217,6 +217,13 @@ def detailedNucKeys(self, value):
 
     with pDefs.createBuilder(default=0.0, location="N/A") as pb:
 
+        pb.defParam(
+            "currentGeometryAxialMesh",
+            units="cm",
+            description="Current core axial mesh.",
+            default=None,
+        )
+
         pb.defParam(
             "breedingRatio2",
             units="N/A",

armi/reactor/reactors.py

@@ -216,6 +216,7 @@ def __init__(self, name):
         self._automaticVariableMesh = False
         self._minMeshSizeRatio = 0.15
         self._inputHeightsConsideredHot = True
+        self._detailedAxialExpansion = False
 
     def setOptionsFromCs(self, cs):
         # these are really "user modifiable modeling constants"
@@ -227,6 +228,7 @@ def setOptionsFromCs(self, cs):
         self._automaticVariableMesh = cs["automaticVariableMesh"]
         self._minMeshSizeRatio = cs["minMeshSizeRatio"]
         self._inputHeightsConsideredHot = cs["inputHeightsConsideredHot"]
+        self._detailedAxialExpansion = cs["detailedAxialExpansion"]
 
     def __getstate__(self):
         """Applies a settings and parent to the core and components."""
@@ -1688,6 +1690,12 @@ def createAssemblyOfType(self, assemType=None, enrichList=None, cs=None):
                     # therefore breaks the burnup metric.
                     b.adjustUEnrich(enrich)
 
+        if not self._detailedAxialExpansion:
+            # if detailedAxialExpansion: False, make sure that the assembly being created has the correct core mesh
+            a.setBlockMesh(
+                self.p.currentGeometryAxialMesh[1:], conserveMassFlag="auto"
+            )  # pass [1:] to skip 0.0
+
         return a
 
     def saveAllFlux(self, fName="allFlux.txt"):
@@ -2221,6 +2229,9 @@ def processLoading(self, cs):
                 "Please make sure that this is intended and not a input error."
             )
 
+        self.p.currentGeometryAxialMesh = self.findAllAxialMeshPoints(
+            applySubMesh=False
+        )
         self.p.axialMesh = self.findAllAxialMeshPoints()
         refAssem = self.refAssem
 

armi/reactor/tests/test_reactors.py

@@ -740,6 +740,13 @@ def test_createAssemblyOfType(self):
         aNew = self.r.core.createAssemblyOfType(aOld.getType())
         self.assertAlmostEqual(aOld.getMass(), aNew.getMass())
 
+        # test axial mesh alignment
+        aNewMesh = aNew.getAxialMesh()
+        for i, meshValue in enumerate(aNewMesh):
+            self.assertAlmostEqual(
+                meshValue, self.r.core.p.currentGeometryAxialMesh[i + 1]
+            )  # use i+1 to skip 0.0
+
         # creation with modified enrichment
         aNew2 = self.r.core.createAssemblyOfType(aOld.getType(), 0.195)
         fuelBlock = aNew2.getFirstBlock(Flags.FUEL)