7 Neutronics of Lead and Bismuth
181
(a) Normal fuel rod “F” (1/8”p60EUEU) in Fig. 7.3
(b) “40” partial fuel rod (1/8”p40EUEU) in Fig. 7.3
(c) “14” partial fuel rod (1/8”p14EUEU) in Fig. 7.3
Poly. moderator (p)
(10.0”)
+
Poly. reflector (PE)
(1/2” 17 + 1/4”)
(8.75”)
Unit cell
(1/4”)
1/8”p
(1/8”)
1/16” EU 2
(1/8”)
Al plate
(20.00 mm)
2.0”Gr
(2”)
2.0” Gr (2”)
+ Void (1.71”)
60 times
(15”)
Reflector (21.54”)
(Lower)
Fuel (15”)
(Unit cell 60 times)
Reflector (23.46”)
(Upper)
Poly. moderator (p)
(10.0”)
+
Poly. reflector (PE)
(1/2” 19 + 1/4”)
(9.75”)
20 mm Al plate
+ 2.0”Gr (2”)
Al cell (23 cells;
((1/16”Al 2+1/8”p) 23 = 5.75”)
2.0”Gr (2”)
+ Void (1.71”)
14 times
(3.5”)
Reflector (27.29”)
(Lower)
Fuel (3.5”)
(Unit cell 14 times)
Reflector (29.21”)
(Upper)
Unit cell
(1/4”)
1/16” EU 2
(1/8”)
1/8”p
(1/8”)
Al cell
23
times
Al cell
23
times
Polyethylene
(10.0”p + PE)
(18.75”)
Polyethylene
(10.0”p + PE)
(19.75”)
Polyethylene
(10.0”p + PE)
(18.75”)
20 mm Al plate
+ 2.0”Gr (2”)
Al cell (10 cells;
(1/16”Al 2+1/8”p) 10 = 2.5”)
2.0”Gr (2”)
+ Void (1.71”)
40 times
(10”)
Reflector (24.04”)
(Lower)
Fuel (10”)
(Unit cell 40 times)
Reflector (25.96”)
(Upper)
Unit cell
(1/4”)
1/16” EU 2
(1/8”)
1/8”p
(1/8”)
Al cell
10
times
Al cell
10
times
Polyethylene
(10.0”p + PE)
(19.75”)
(d) Reference fuel rod “f” containing Al plates (1/8”Al40p20EUEU) in Fig. 7.3
10 times
(2.5”)
1/8”p
(1/8”)
1/16” EU 2
(1/8”)
20 mm Al plate
2.0”Gr
(2”)
2.0”Gr (2”)
+ Void (1.71”)
Reflector (21.54”)
(Lower)
Fuel (15”)
(Unit cell 60 times)
Reflector (23.46”)
(Upper)
1/16” EU 2
(1/8”)
1/16” Al 2
(1/8”)
40 times
(10”)
10 times
(2.5”)
1/16” EU 2
(1/8”)
1/8”p
(1/8”)
Polyethylene
(10.0”p + PE)
(18.75”)
Polyethylene
(10.0”p + PE)
(19.75”)
Fig. 7.4 Schematic drawing of fuel assemblies (Fig. 7.3) in the A-core (Ref. [3])