diff --git a/300s School/NUCE 2100 - Fundamentals of Nuclear Engineering/2024-09-17 Module 5 Nuclear Fission Basics.md b/300s School/NUCE 2100 - Fundamentals of Nuclear Engineering/2024-09-17 Module 5 Nuclear Fission Basics.md
index 26939384..25666846 100644
--- a/300s School/NUCE 2100 - Fundamentals of Nuclear Engineering/2024-09-17 Module 5 Nuclear Fission Basics.md	
+++ b/300s School/NUCE 2100 - Fundamentals of Nuclear Engineering/2024-09-17 Module 5 Nuclear Fission Basics.md	
@@ -44,3 +44,4 @@ Different neutron moderators require a different number of collisions to bring t
 Fuel pellots. Small boys. Stacked into fuel elements 12 feet high. about 300 per rod
 14x14 lattice or 17x17. That is one fuel assembly.
 Zirconium is used as the cladding. Low neutron absorbtion cross section.
+Not all of the rods in the lattice are fuel. Sometimes they are, but also, sometimes they're control rods or instrumentation rods.