From 63c13cddd69dbac48670578a613a0f67962b1ac7 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Tue, 23 Jun 2020 22:18:10 -0500
Subject: [PATCH] Copy hidden _fpy attribute when reducing depletion chain

---
 openmc/deplete/chain.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/openmc/deplete/chain.py b/openmc/deplete/chain.py
index 27e253d306..040a28cbfc 100644
--- a/openmc/deplete/chain.py
+++ b/openmc/deplete/chain.py
@@ -965,6 +965,8 @@ class Chain:
             new_nuclide = Nuclide(previous.name)
             new_nuclide.half_life = previous.half_life
             new_nuclide.decay_energy = previous.decay_energy
+            if hasattr(previous, '_fpy'):
+                new_nuclide._fpy = previous._fpy
 
             new_decay = []
             for mode in previous.decay_modes: