3 Reactor Kinetics
55
(a) Standard fuel assembly (3/8”P36EU)
(b) SV fuel assembly
(c) Partial fuel assembly (26)
Polyethylene
(19”PE)
Unit cell
(7/16”)
1/8”PE+1/4”PE
(3/8”)
1/16” EU
(1/16”)
Polyethylene
(19”PE+1/2PE 2 = 20”)
20 mm Al plate 1/2“PE 2 (1“)
1/2“PE 5+1/8“P 5
(25/8“) + Void (1/3“)
Reflector 20.784”
(Lower)
Fuel 15.75”
(Unit cell 36 times)
Reflector 23.462”
(Upper)
Polyethylene
(19PE”)
50 50 mm Void
16 unit cells
(1—16 Fuels)
(3/8” 16 = 6”)
Polyethylene
(19”PE+1/2”PE 4 = 21”)
16 unit cells
(17—32 Fuels)
(3/8” 16“ = 6”)
20 mm Al plate 1/2“PE 2 = 1”
1/2“PE 5+1/8“PE 5
(25/8“) + Void (10/9“)
Reflector 20.787”
(Lower)
Fuel 13.969”
(16 cells + Void + 16 cells)
Reflector 25.244”
(Upper)
Polyethylene
(19”PE)
Unit cell
(7/16”)
1/8”PE+1/4”PE
(3/8”)
1/16“ EU
(1/16”)
Polyethylene
(19”PE+1/2”PE
4 = 21”)
20 mm Al plate
+1/2”PE 2 plates
(1.787“)
Al cell
(1/16”Al+1/8”PE
+1/4“PE = 3/8“)
1/2“PE 5+1/8“PE 5
(25/8“) + Void (1/3“)
Al cell
5 times
Al cell
5 times
(15/8”)
Reflector 22.662”
(Lower)
Fuel 11.375”
(Unit cell 26 times)
Reflector 25.963”
(Upper)
Fig. 3.2 Fuel assemblies (Ref. [2])