diff --git a/news/PR-0665.rst b/news/PR-0665.rst
new file mode 100644
index 0000000000..3d512ecaf4
--- /dev/null
+++ b/news/PR-0665.rst
@@ -0,0 +1,16 @@
+**Added:** None
+
+**Changed:** None
+- Applied changes from PullRequest-Agent to MCNP related files:
+    - using std::err for errors
+    - update to C++11 standards for converting ints to strings
+    - removed unnecessary comments
+    - moved Graveyard and Vacuum strings to variables
+
+**Deprecated:** None
+
+**Removed:** None
+
+**Fixed:** None
+
+**Security:** None
diff --git a/src/mcnp/mcnp5/CMakeLists.txt b/src/mcnp/mcnp5/CMakeLists.txt
index ca13c7d2ea..af9213ce5f 100644
--- a/src/mcnp/mcnp5/CMakeLists.txt
+++ b/src/mcnp/mcnp5/CMakeLists.txt
@@ -52,7 +52,6 @@ set(CMAKE_Fortran_FLAGS_RELWITHDEBINFO "-O1 -g")
 
 # C compiler flags
 if (CMAKE_C_COMPILER_ID STREQUAL "Intel")
-  #set(CMAKE_C_FLAGS "${CMAKE_Fortran_FLAGS} -mcmodel=medium")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pc64")
 else ()
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -m64")
@@ -63,7 +62,6 @@ if (CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
   set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -no-vec")
   set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -heap-arrays 1024")
   set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -traceback")
-  #set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -mcmodel=medium")
   set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -pc64")
   set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -r8")
 else ()
diff --git a/src/mcnp/mcnp_funcs.cpp b/src/mcnp/mcnp_funcs.cpp
index 2544fc2633..88feed27f8 100644
--- a/src/mcnp/mcnp_funcs.cpp
+++ b/src/mcnp/mcnp_funcs.cpp
@@ -46,6 +46,9 @@ static bool visited_surface = false;
 static bool use_dist_limit = false;
 static double dist_limit; // needs to be thread-local
 
+static std::string graveyard_str = "Graveyard";
+static std::string vacuum_str = "Vacuum";
+
 
 void dagmcinit_(char* cfile, int* clen,  // geom
                 char* ftol,  int* ftlen, // faceting tolerance
@@ -198,36 +201,36 @@ void write_cell_cards(std::ostringstream& lcadfile, const char* mcnp_version_maj
       // that material numbers are assigned
       mat_num = DMD->volume_material_data_eh[entity];
       // if we cant make an int from the mat_num
-      if (mat_num.find("Graveyard") == std::string::npos &&
-          mat_num.find("Vacuum") == std::string::npos) {
+      if (mat_num.find(graveyard_str) == std::string::npos &&
+          mat_num.find(vacuum_str) == std::string::npos) {
         if (!DMD->try_to_make_int(mat_num)) {
-          std::cout << "Failed to cast material number to an integer"  << std::endl;
-          std::cout << "volume with ID " << cellid << " has material assignment" << std::endl;
-          std::cout << mat_num << " which appears to be a name rather than an integer" << std::endl;
-          std::cout << "Did you forget to run uwuw_preproc?" << std::endl;
+          std::cerr << "Failed to cast material number to an integer"  << std::endl;
+          std::cerr << "volume with ID " << cellid << " has material assignment" << std::endl;
+          std::cerr << mat_num << " which appears to be a name rather than an integer" << std::endl;
+          std::cerr << "Did you forget to run uwuw_preproc?" << std::endl;
           exit(EXIT_FAILURE);
         }
       }
 
       density = DMD->volume_density_data_eh[entity];
       // if we have a vacuum problem
-      if (mat_num == "Graveyard" || mat_num == "Vacuum") {
+      if (mat_num == graveyard_str || mat_num == vacuum_str) {
         mat_num = "0";
         density = "";
       }
     } else {
       std::string mat_name = DMD->volume_material_property_data_eh[entity];
       // if we not vacuum or graveyard
-      if (mat_name.find("Vacuum") == std::string::npos && mat_name.find("Graveyard") == std::string::npos) {
+      if (mat_name.find(vacuum_str) == std::string::npos && mat_name.find(graveyard_str) == std::string::npos) {
         if (workflow_data->material_library.count(mat_name) == 0) {
-          std::cout << "Material with name " << mat_name <<  " not found " << std::endl;
-          std::cout << "In the material library" << std::endl;
+          std::cerr << "Material with name " << mat_name <<  " not found " << std::endl;
+          std::cerr << "In the material library" << std::endl;
           exit(EXIT_FAILURE);
         }
 
         pyne::Material material = workflow_data->material_library[mat_name];
         int matnumber = material.metadata["mat_number"].asInt();
-        mat_num = _to_string(matnumber);
+        mat_num = std::to_string(matnumber);
         density = "-" + _to_string(material.density);
       } else {
         mat_num = "0";
@@ -251,15 +254,15 @@ void write_cell_cards(std::ostringstream& lcadfile, const char* mcnp_version_maj
       } else if (mcnp_version_major[0] == '6') {
         mcnp_name = pyne::particle::mcnp6(particle_name);
       } else {
-        std::cout << "Unknown MCNP verison: " << mcnp_version_major << std::endl;
+        std::cerr << "Unknown MCNP verison: " << mcnp_version_major << std::endl;
         exit(EXIT_FAILURE);
       }
       double imp = 1.0;
       // if we find graveyard always have importance 0.0
-      if (mat_name.find("Graveyard") != std::string::npos) {
+      if (mat_name.find(graveyard_str) != std::string::npos) {
         imp = 0.0;
         // no splitting can happenin vacuum set to 1
-      } else if (mat_name.find("Vacuum") != std::string::npos) {
+      } else if (mat_name.find(vacuum_str) != std::string::npos) {
         imp = 1.0;
         // otherwise as the map says
       } else {
@@ -269,7 +272,7 @@ void write_cell_cards(std::ostringstream& lcadfile, const char* mcnp_version_maj
     }
     // its possible no importances were assigned
     if (set.size() == 0) {
-      if (mat_name.find("Graveyard") == std::string::npos) {
+      if (mat_name.find(graveyard_str) == std::string::npos) {
         importances = "imp:n=1";
       } else {
         importances = "imp:n=0";
@@ -277,7 +280,7 @@ void write_cell_cards(std::ostringstream& lcadfile, const char* mcnp_version_maj
     }
 
     // add descriptive comments for special volumes
-    if (mat_name.find("Graveyard") != std::string::npos) {
+    if (mat_name.find(graveyard_str) != std::string::npos) {
       importances += "  $ graveyard";
     } else if (DAG->is_implicit_complement(entity)) {
       importances += "  $ implicit complement";
@@ -307,7 +310,7 @@ void write_surface_cards(std::ostringstream& lcadfile) {
       surface_property = "+";
     else
       surface_property = "";
-    lcadfile  << surface_property << _to_string(surfid) << std::endl;
+    lcadfile  << surface_property << std::to_string(surfid) << std::endl;
   }
   return;
 }
@@ -787,15 +790,6 @@ void dagmc_teardown_() {
   delete DAG;
 }
 
-// these functions should be replaced when we adopt C++11
-// int to string
-std::string _to_string(int var) {
-  std::ostringstream outstr;
-  outstr << var;
-  std::string ret_string = outstr.str();
-  return ret_string;
-}
-
 // double to string
 std::string _to_string(double var) {
   std::ostringstream outstr;
diff --git a/src/mcnp/mcnp_funcs.h b/src/mcnp/mcnp_funcs.h
index 09a2bf1d8c..bc79f824b8 100644
--- a/src/mcnp/mcnp_funcs.h
+++ b/src/mcnp/mcnp_funcs.h
@@ -147,9 +147,6 @@ void write_surface_cards(std::ostringstream& lcad_string);
 void write_material_data(std::ostringstream& lcad_string);
 void write_tally_data(std::ostringstream& lcad_string);
 
-// until we adopt C++11 - makes life easy
-// convenience functions for c++ int to string
-std::string _to_string(int val);
 // convenience functions for c++ double to string
 std::string _to_string(double val);