diff --git a/src/ace.F90 b/src/ace.F90
index af256c9e2..b3f4fc09b 100644
--- a/src/ace.F90
+++ b/src/ace.F90
@@ -639,10 +639,11 @@ contains
 
     ! Store elastic scattering cross-section on reaction one
     rxn => nuc % reactions(1)
-    rxn % MT      = 2
-    rxn % Q_value = ZERO
-    rxn % TY      = 1
-    rxn % IE      = 1
+    rxn % MT            = 2
+    rxn % Q_value       = ZERO
+    rxn % multiplicity  = 1
+    rxn % IE            = 1
+    rxn % scatter_in_cm = .true.
     rxn % has_angle_dist = .false.
     rxn % has_energy_dist = .false.
     allocate(rxn % sigma(nuc % n_grid))
@@ -666,9 +667,10 @@ contains
        rxn % has_energy_dist = .false.
 
        ! read MT number, Q-value, and neutrons produced
-       rxn % MT      = int(XSS(LMT + i - 1))
-       rxn % Q_value = XSS(JXS4 + i - 1)
-       rxn % TY      = int(XSS(JXS5 + i - 1))
+       rxn % MT            = int(XSS(LMT + i - 1))
+       rxn % Q_value       = XSS(JXS4 + i - 1)
+       rxn % multiplicity  = abs(nint(XSS(JXS5 + i - 1)))
+       rxn % scatter_in_cm = (nint(XSS(JXS5 + i - 1)) < 0)
 
        ! read starting energy index
        LOCA = int(XSS(LXS + i - 1))
diff --git a/src/ace_header.F90 b/src/ace_header.F90
index f3e305c39..81635a68d 100644
--- a/src/ace_header.F90
+++ b/src/ace_header.F90
@@ -41,8 +41,9 @@ module ace_header
   type Reaction
      integer :: MT                      ! ENDF MT value
      real(8) :: Q_value                 ! Reaction Q value
-     integer :: TY                      ! Number of neutrons released
+     integer :: multiplicity            ! Number of neutrons released
      integer :: IE                      ! Starting energy grid index
+     logical :: scatter_in_cm           ! scattering system in center-of-mass?
      real(8), allocatable :: sigma(:)   ! Cross section values
      logical :: has_angle_dist          ! Angle distribution present?
      logical :: has_energy_dist         ! Energy distribution present?
diff --git a/src/output.F90 b/src/output.F90
index 389e7ca78..1e4054351 100644
--- a/src/output.F90
+++ b/src/output.F90
@@ -285,7 +285,7 @@ contains
     write(ou,*) 'Reaction ' // reaction_name(rxn % MT)
     write(ou,*) '    MT = ' // to_str(rxn % MT)
     write(ou,*) '    Q-value = ' // to_str(rxn % Q_value)
-    write(ou,*) '    TY = ' // to_str(rxn % TY)
+    write(ou,*) '    Multiplicity = ' // to_str(rxn % multiplicity)
     write(ou,*) '    Starting index = ' // to_str(rxn % IE)
     if (rxn % has_energy_dist) then
        write(ou,*) '    Energy: Law ' // to_str(rxn % edist % law)
@@ -829,8 +829,8 @@ contains
        end if
 
        write(unit_,'(3X,A11,1X,F8.3,2X,I4,2X,I6,1X,I11,1X,I11)') &
-            reaction_name(rxn % MT), rxn % Q_value, rxn % TY, rxn % IE, &
-            size_angle, size_energy
+            reaction_name(rxn % MT), rxn % Q_value, rxn % multiplicity, &
+            rxn % IE, size_angle, size_energy
 
        ! Accumulate data size
        size_total = size_total + size_angle + size_energy
diff --git a/src/physics.F90 b/src/physics.F90
index 9446609a0..65a4ede20 100644
--- a/src/physics.F90
+++ b/src/physics.F90
@@ -1059,7 +1059,6 @@ contains
     type(Nuclide),  pointer :: nuc
     type(Reaction), pointer :: rxn
 
-    integer :: n_secondary ! number of secondary particles
     integer :: law         ! secondary energy distribution law
     real(8) :: A           ! atomic weight ratio of nuclide
     real(8) :: E_in        ! incoming energy
@@ -1093,7 +1092,7 @@ contains
 
     ! if scattering system is in center-of-mass, transfer cosine of scattering
     ! angle and outgoing energy from CM to LAB
-    if (rxn % TY < 0) then
+    if (rxn % scatter_in_cm) then
        E_cm = E
 
        ! determine outgoing energy in lab
@@ -1120,8 +1119,7 @@ contains
     p % mu = mu
 
     ! change weight of particle based on multiplicity
-    n_secondary = abs(rxn % TY)
-    p % wgt = n_secondary * p % wgt
+    p % wgt = rxn % multiplicity * p % wgt
 
   end subroutine inelastic_scatter