diff --git a/openmc/data/neutron.py b/openmc/data/neutron.py
index a53194aa7..22c9d0305 100644
--- a/openmc/data/neutron.py
+++ b/openmc/data/neutron.py
@@ -813,9 +813,8 @@ class IncidentNeutron(EqualityMixin):
         """
         with tempfile.TemporaryDirectory() as tmpdir:
             # Run NJOY to create an ACE library
-            kwargs.setdefault('ace', os.path.join(tmpdir, 'ace'))
-            kwargs.setdefault('xsdir', os.path.join(tmpdir, 'xsdir'))
-            kwargs.setdefault('pendf', os.path.join(tmpdir, 'pendf'))
+            for key in ["ace", "xsdir", "pendf", "heatr"]:
+                kwargs.setdefault(key, os.path.join(tmpdir, key))
             kwargs['evaluation'] = evaluation
             make_ace(filename, temperatures, **kwargs)
 
diff --git a/openmc/data/njoy.py b/openmc/data/njoy.py
index c8d630851..3fb75751f 100644
--- a/openmc/data/njoy.py
+++ b/openmc/data/njoy.py
@@ -1,10 +1,8 @@
-import argparse
 from collections import namedtuple
 from io import StringIO
 import os
 import shutil
 from subprocess import Popen, PIPE, STDOUT, CalledProcessError
-import sys
 import tempfile
 
 from . import endf
@@ -237,8 +235,9 @@ def make_ace(filename, temperatures=None, ace='ace', xsdir='xsdir', pendf=None,
         Fractional error tolerance for NJOY processing
     broadr : bool, optional
         Indicating whether to Doppler broaden XS when running NJOY
-    heatr : bool, optional
-        Indicating whether to add heating kerma when running NJOY
+    heatr : bool or str, optional
+        Indicating whether to add heating kerma when running NJOY. If string,
+        write the output tape to this file
     gaspr : bool, optional
         Indicating whether to add gas production data when running NJOY
     purr : bool, optional
@@ -292,6 +291,7 @@ def make_ace(filename, temperatures=None, ace='ace', xsdir='xsdir', pendf=None,
     if heatr:
         nheatr_in = nlast
         nheatr = nheatr_in + 1
+        tapeout[nheatr] = "heatr" if heatr is True else heatr
         commands += _TEMPLATE_HEATR
         nlast = nheatr