From 45fb021e8906012c7c3f449c50ca4335cb66519e Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Mon, 8 Aug 2016 07:05:55 -0500
Subject: [PATCH] Strip metastable info when getting atomic mass

---
 openmc/data/data.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/openmc/data/data.py b/openmc/data/data.py
index da1406a9c..ebc2cba43 100644
--- a/openmc/data/data.py
+++ b/openmc/data/data.py
@@ -213,4 +213,8 @@ def atomic_mass(isotope):
                     line[100:106] + '.' + line[107:112])
                 _ATOMIC_MASS[name.lower()] = mass
 
+    # Get rid of metastable information
+    if '_' in isotope:
+        isotope = isotope[:isotope.find('_')]
+
     return _ATOMIC_MASS.get(isotope.lower())