diff --git a/openmc/data/njoy.py b/openmc/data/njoy.py
index c9bbd9c85b..0ef77695b5 100644
--- a/openmc/data/njoy.py
+++ b/openmc/data/njoy.py
@@ -402,7 +402,6 @@ def make_ace(filename, temperatures=None, acer=True, xsdir=None,
     # acer
     if acer:
         nacer_in = nlast
-        fname = '{}_{:.1f}'
         for i, temperature in enumerate(temperatures):
             # Extend input with an ACER run for each temperature
             nace = nacer_in + 1 + 2*i
@@ -411,8 +410,8 @@ def make_ace(filename, temperatures=None, acer=True, xsdir=None,
             commands += _TEMPLATE_ACER.format(**locals())
 
             # Indicate tapes to save for each ACER run
-            tapeout[nace] = output_dir / fname.format("ace", temperature)
-            tapeout[ndir] = output_dir / fname.format("xsdir", temperature)
+            tapeout[nace] = output_dir / "ace_{:.1f}".format(temperature)
+            tapeout[ndir] = output_dir / "xsdir_{:.1f}".format(temperature)
     commands += 'stop\n'
     run(commands, tapein, tapeout, **kwargs)
 
@@ -422,7 +421,7 @@ def make_ace(filename, temperatures=None, acer=True, xsdir=None,
         with ace.open('w') as ace_file, xsdir.open('w') as xsdir_file:
             for temperature in temperatures:
                 # Get contents of ACE file
-                text = (output_dir / fname.format("ace", temperature)).read_text()
+                text = (output_dir / "ace_{:.1f}".format(temperature)).read_text()
 
                 # If the target is metastable, make sure that ZAID in the ACE
                 # file reflects this by adding 400
@@ -435,9 +434,14 @@ def make_ace(filename, temperatures=None, acer=True, xsdir=None,
                 ace_file.write(text)
 
                 # Concatenate into destination xsdir file
-                xsdir_in = output_dir / fname.format("xsdir", temperature)
+                xsdir_in = output_dir / "xsdir_{:.1f}".format(temperature)
                 xsdir_file.write(xsdir_in.read_text())
 
+        # Remove ACE/xsdir files for each temperature
+        for temperature in temperatures:
+            (output_dir / "ace_{:.1f}".format(temperature)).unlink()
+            (output_dir / "xsdir_{:.1f}".format(temperature)).unlink()
+
 
 def make_ace_thermal(filename, filename_thermal, temperatures=None,
                      ace='ace', xsdir=None, output_dir=None, error=0.001,
@@ -571,7 +575,6 @@ def make_ace_thermal(filename, filename_thermal, temperatures=None,
 
     # acer
     nthermal_acer_in = nlast
-    fname = '{}_{:.1f}'
     for i, temperature in enumerate(temperatures):
         # Extend input with an ACER run for each temperature
         nace = nthermal_acer_in + 1 + 2*i
@@ -580,18 +583,23 @@ def make_ace_thermal(filename, filename_thermal, temperatures=None,
         commands += _THERMAL_TEMPLATE_ACER.format(**locals())
 
         # Indicate tapes to save for each ACER run
-        tapeout[nace] = output_dir / fname.format(ace, temperature)
-        tapeout[ndir] = output_dir / fname.format(xsdir, temperature)
+        tapeout[nace] = output_dir / "ace_{:.1f}".format(temperature)
+        tapeout[ndir] = output_dir / "xsdir_{:.1f}".format(temperature)
     commands += 'stop\n'
     run(commands, tapein, tapeout, **kwargs)
 
-    ace_out = output_dir / ace
+    ace = output_dir / ace
     xsdir = (ace.parent / "xsdir") if xsdir is None else Path(xsdir)
-    with ace_out.open('w') as ace_file, xsdir.open('w') as xsdir_file:
+    with ace.open('w') as ace_file, xsdir.open('w') as xsdir_file:
         # Concatenate ACE and xsdir files together
         for temperature in temperatures:
-            ace_in = output_dir / fname.format(ace, temperature)
+            ace_in = output_dir / "ace_{:.1f}".format(temperature)
             ace_file.write(ace_in.read_text())
 
-            xsdir_in = output_dir / fname.format(xsdir, temperature)
+            xsdir_in = output_dir / "xsdir_{:.1f}".format(temperature)
             xsdir_file.write(xsdir_in.read_text())
+
+    # Remove ACE/xsdir files for each temperature
+    for temperature in temperatures:
+        (output_dir / "ace_{:.1f}".format(temperature)).unlink()
+        (output_dir / "xsdir_{:.1f}".format(temperature)).unlink()