diff --git a/openmc/capi/math.py b/openmc/capi/math.py
index 4f8bb5cdb..390ee466f 100644
--- a/openmc/capi/math.py
+++ b/openmc/capi/math.py
@@ -157,8 +157,12 @@ def calc_zn(n, rho, phi):
     _dll.calc_zn_c(n, rho, phi, zn)
     return zn
 
+
 def calc_zn_rad(n, rho):
-    """ Calculate the even orders in n-th order modified Zernike polynomial moment with no azimuthal dependency (m=0) for a given radial location in the unit disk. The normalization of the polynomials is such that the integral of Z_pq*Z_pq over the unit disk is exactly pi
+    """ Calculate the even orders in n-th order modified Zernike polynomial
+    moment with no azimuthal dependency (m=0) for a given radial location in
+    the unit disk. The normalization of the polynomials is such that the
+    integral of Z_pq*Z_pq over the unit disk is exactly pi.
 
     Parameters
     ----------
@@ -178,6 +182,7 @@ def calc_zn_rad(n, rho):
     zn_rad = np.zeros(num_bins, dtype=np.float64)
     _dll.calc_zn_rad_c(n, rho, zn_rad)
     return zn_rad
+    
 
 def rotate_angle(uvw0, mu, phi=None):
     """ Rotates direction cosines through a polar angle whose cosine is
diff --git a/openmc/filter_expansion.py b/openmc/filter_expansion.py
index 842d03477..a756f7ba4 100644
--- a/openmc/filter_expansion.py
+++ b/openmc/filter_expansion.py
@@ -234,8 +234,8 @@ class SphericalHarmonicsFilter(ExpansionFilter):
     r"""Score spherical harmonic expansion moments up to specified order.
 
     This filter allows you to obtain real spherical harmonic moments of either
-    the particle's direction or the cosine of the scattering angle. Specifying a
-    filter with order :math:`\ell` tallies moments for all orders from 0 to
+    the particle's direction or the cosine of the scattering angle. Specifying
+    a filter with order :math:`\ell` tallies moments for all orders from 0 to
     :math:`\ell`.
 
     Parameters
@@ -342,11 +342,11 @@ class ZernikeFilter(ExpansionFilter):
         \frac{n+m}{2} - k)! (\frac{n-m}{2} - k)!} \rho^{n-2k}.
 
     With this definition, the integral of :math:`(Z_n^m)^2` over the unit disk
-    is :math:`\frac{\epsilon_m\pi}{2n+2}` for each polynomial where :math:`\epsilon_m` is
-    2 if :math:`m` equals 0 and 1 otherwise.
+    is :math:`\frac{\epsilon_m\pi}{2n+2}` for each polynomial where 
+    :math:`\epsilon_m` is 2 if :math:`m` equals 0 and 1 otherwise.
 
-    Specifying a filter with order N tallies moments for all :math:`n` from 0 to
-    N and each value of :math:`m`. The ordering of the Zernike polynomial
+    Specifying a filter with order N tallies moments for all :math:`n` from 0
+    to N and each value of :math:`m`. The ordering of the Zernike polynomial
     moments follows the ANSI Z80.28 standard, where the one-dimensional index
     :math:`j` corresponds to the :math:`n` and :math:`m` by
 
@@ -464,6 +464,7 @@ class ZernikeFilter(ExpansionFilter):
 
         return element
 
+
 class ZernikeRadialFilter(ExpansionFilter):
     r"""Score radial Zernike expansion moments in space up to specified order.
 
@@ -483,10 +484,14 @@ class ZernikeRadialFilter(ExpansionFilter):
         \frac{n+m}{2} - k)! (\frac{n-m}{2} - k)!} \rho^{n-2k}.
 
     With this definition, the integral of :math:`(Z_n^m)^2` over the unit disk
-    is :math:`\frac{\epsilon_m\pi}{2n+2}` for each polynomial where :math:`\epsilon_m` is
-    2 if :math:`m` equals 0 and 1 otherwise.
+    is :math:`\frac{\epsilon_m\pi}{2n+2}` for each polynomial where
+    :math:`\epsilon_m` is 2 if :math:`m` equals 0 and 1 otherwise.
 
-    If there is only radial dependency, the polynomials are integrated over the azimuthal angles. The only terms left are :math:`Z_n^{0}(\rho, \theta) = R_n^{0}(\rho)`. Note that :math:`n` could only be even orders. Therefore, for a radial Zernike polynomials up to order of :math:`n`, there are :math:`\frac{n}{2} + 1` terms in total.
+    If there is only radial dependency, the polynomials are integrated over
+    the azimuthal angles. The only terms left are :math:`Z_n^{0}(\rho, \theta) 
+    = R_n^{0}(\rho)`. Note that :math:`n` could only be even orders.
+    Therefore, for a radial Zernike polynomials up to order of :math:`n`,
+    there are :math:`\frac{n}{2} + 1` terms in total.
 
     Parameters
     ----------
diff --git a/src/math_functions.cpp b/src/math_functions.cpp
index 3d60ce4d0..8a36f7b92 100644
--- a/src/math_functions.cpp
+++ b/src/math_functions.cpp
@@ -601,10 +601,9 @@ void calc_zn_rad_c(int n, double rho, double zn_rad[]) {
     int index = int(p/2);
     if (p == 2) {
     // Setting up R_22 to calculate R_20 (Eq 3.10 in Chong)
-      double R_22 = std::pow(rho, 2);
+      double R_22 = rho * rho;
       zn_rad[index] = 2 * R_22 - zn_rad[0];
-    }
-    else {
+    } else {
       double k1 = ((p + q) * (p - q) * (p - 2)) / 2.;
       double k2 = 2 * p * (p - 1) * (p - 2);
       double k3 = -q * q * (p - 1) - p * (p - 1) * (p - 2);
diff --git a/src/tallies/tally_filter_zernike_radial.F90 b/src/tallies/tally_filter_zernike_radial.F90
index 6eaf97f53..1a4ed5ed5 100644
--- a/src/tallies/tally_filter_zernike_radial.F90
+++ b/src/tallies/tally_filter_zernike_radial.F90
@@ -98,18 +98,6 @@ contains
     character(MAX_LINE_LEN)         :: label
 
     label = "Zernike expansion, Z" // trim(to_str(2*bin)) // ",0"
-    ! integer :: n
-    ! integer :: first, last
-
-    ! do n = 0, this % order, -2
-      ! last = (n + 1)*(n + 2)/2
-      ! if (bin <= last) then
-      !   first = last - n
-      !   m = -n + (bin - first)*2
-        ! label = "Zernike expansion, Z" // trim(to_str(n)) // ",0"
-    !     exit
-    !   end if
-    ! end do
   end function text_label
 
 !===============================================================================