From 3c25a2a4b3e28ca026ed00a52bd39baa9e2e1d24 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Wed, 17 Jun 2020 06:59:31 -0500
Subject: [PATCH] Add note in Chain.from_endf docstring about missing FPY

---
 openmc/deplete/chain.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/openmc/deplete/chain.py b/openmc/deplete/chain.py
index 2405a67a27..27e253d306 100644
--- a/openmc/deplete/chain.py
+++ b/openmc/deplete/chain.py
@@ -264,6 +264,16 @@ class Chain:
         -------
         Chain
 
+        Notes
+        -----
+        When an actinide is missing fission product yield (FPY) data, yields will
+        copied from a parent isotope, found according to:
+
+        1. If the nuclide is in a ground state and a metastable state exists with
+           fission yields, copy the yields from the metastable
+        2. Find an isotone (same number of neutrons) and copy those yields
+        3. Copy the yields of U235 if the previous two checks fail
+
         """
         chain = cls()