diff --git a/openmc/deplete/cram.py b/openmc/deplete/cram.py
index d0c868004c..184c411bf3 100644
--- a/openmc/deplete/cram.py
+++ b/openmc/deplete/cram.py
@@ -42,10 +42,14 @@ def deplete(chain, x, rates, dt, matrix_func=None):
         Updated atom number vectors for each material
     """
 
-    if not hasattr(chain, "fission_yields"):
-        fission_yields = repeat(chain.get_thermal_fission_yields())
-    else:
-        fission_yields = chain.fission_yields
+    fission_yields = chain.fission_yields
+    if len(fission_yields) == 1:
+        fission_yields = repeat(fission_yields[0])
+    elif len(fission_yields) != len(x):
+        raise ValueError(
+            "Number of material fission yield distributions {} is not equal "
+            "to the number of compositions {}".format(len(fission_yields),
+                len(x)))
 
     # Use multiprocessing pool to distribute work
     with Pool() as pool:
diff --git a/openmc/deplete/nuclide.py b/openmc/deplete/nuclide.py
index 615761cde9..5217831f49 100644
--- a/openmc/deplete/nuclide.py
+++ b/openmc/deplete/nuclide.py
@@ -86,9 +86,9 @@ class Nuclide(object):
     reactions : list of openmc.deplete.ReactionTuple
         Reaction information. Each element of the list is a named tuple with
         attribute 'type', 'target', 'Q', and 'branching_ratio'.
-    yield_data : dict of float to list
-        Maps tabulated energy to list of (product, yield) for all
-        neutron-induced fission products.
+    yield_data : dict of float to :class:`openmc.deplete.FissionYieldDistribution`
+        Fission product yields at tabulated energies for this nuclide. Can be
+        treated as a nested dictionary ``{energy: {product: yield}}``
     yield_energies : list of float
         Energies at which fission product yields exist
 
@@ -300,15 +300,15 @@ class FissionYieldDistribution(Mapping):
         -------
         FissionYieldDistribution
         """
-        yields = {}
+        all_yields = {}
         for elem_index, yield_elem in enumerate(element.iter("fission_yields")):
             energy = float(yield_elem.get("energy"))
             products = yield_elem.find("products").text.split()
-            yield_mapobj = map(float, yield_elem.find("data").text.split())
+            yields = map(float, yield_elem.find("data").text.split())
             # Get a map of products to their corresponding yield
-            yields[energy] = dict(zip(products, yield_mapobj))
+            all_yields[energy] = dict(zip(products, yields))
 
-        return cls.from_dict(yields)
+        return cls.from_dict(all_yields)
 
     @classmethod
     def from_dict(cls, fission_yields):
@@ -327,9 +327,7 @@ class FissionYieldDistribution(Mapping):
         energies = sorted(fission_yields)
 
         # Get a consistent set of products to produce a matrix of yields
-        shared_prod = set()
-        for prod_set in map(set, fission_yields.values()):
-            shared_prod |= prod_set
+        shared_prod = set.union(*(set(x) for x in fission_yields.values()))
         ordered_prod = sorted(shared_prod)
 
         yield_matrix = empty((len(energies), len(shared_prod)))
@@ -422,6 +420,9 @@ class FissionYield(Mapping):
     def __iter__(self):
         return iter(self.products)
 
+    def items(self):
+        return zip(self.products, self.yields)
+
     def __add__(self, other):
         new = self.copy()
         new += other
diff --git a/tests/unit_tests/test_deplete_chain.py b/tests/unit_tests/test_deplete_chain.py
index 2e5ad09832..dcb5127cba 100644
--- a/tests/unit_tests/test_deplete_chain.py
+++ b/tests/unit_tests/test_deplete_chain.py
@@ -7,7 +7,7 @@ from itertools import product
 
 import numpy as np
 from openmc.data import zam, ATOMIC_SYMBOL
-from openmc.deplete import comm, Chain, reaction_rates, nuclide
+from openmc.deplete import comm, Chain, reaction_rates, nuclide, cram
 import pytest
 
 from tests import cdtemp
@@ -359,3 +359,10 @@ def test_fission_yield_attribute(simple_chain):
     empty_chain.fission_yields = [thermal_yields] * 2
     assert empty_chain.fission_yields[0] == thermal_yields
     assert empty_chain.fission_yields[1] == thermal_yields
+
+    # test failure with deplete function
+    # number fission yields != number of materials
+    dummy_conc = [[1, 2]] * (len(empty_chain.fission_yields) + 1)
+    with pytest.raises(
+            ValueError, match="fission yield.*not equal.*compositions"):
+       cram.deplete(empty_chain, dummy_conc, None, 0.5)