FRIDGe Example

Single Assembly

An few example fuel assemblies can be seen in fridge/data/assembly. This example will look at the EBRII_MKII assembly. This assembly has the following attributes, which can be seen in Table 1.

Table 1. Variables for Fuel Assembly YAML file.

Variable Name	EBRII MKII Assembly
Assembly Type	Fuel
Assembly Pitch	5.887
Duct Thickness	0.2032
Duct Inside Flat to Flat	5.6134
Assembly Height	164.386
Coolant	LiquidNa
Assembly Material	SS316
Pins Per Assembly	91
Pin Diameter	0.4420
Clad Thickness	0.0305
Fuel Diameter	0.3302
Pitch	0.566
Wire Wrap Diameter	0.124
Wire Wrap Axial Pitch	15.24
Fuel Height	34.29
Fuel	U
Clad	SS316
Bond	LiquidNa
Bond Above Fuel	1.31
Plenum Height	28.3
Plenum Smear	{LiquidNa: 0.50, Void: 0.25, SS316: 0.25}
Reflector Height	61.3537
Reflector Smear	{LiquidNa: 0.116, 0.884}

The inputs from Table 1 create an assembly similar to the MK-II driver assemblies found in EBRII, as referenced in [1], which can be seen in Figure 1. In Figure 1 the regions are, from bottom to top; lower reflector, fuel, plenum, and upper reflector. Along with this, a blown up section where the fuel meets the plenum region shows how the variable Bond Above Fuel adds addition bond above the fuel. Figure 2 shows the 91 pins in the assembly; there is fuel (purple), bond (blue), clad (yellow), wire wrap + coolant mixture (green), excess coolant (light blue), and the hex duct (maroon).

Figure 1. EBR-II MKII assembly.

Figure 2. Plan view of EBR-II fuel section.

Full Core

Utilizing the EBR-II MKII assembly from above and creating reflector and blanket assemblies, a simplified full core model of EBR-II was created. This model only has three types of assemblies (driver, reflector, and blanket assemblies), but it provides a proof of concept for building full core models with varying assemblies. Figure 3 shows the EBR-II full core model, where it should be noted that not all of the blanket assemblies were added to reduce the size of the figure and input file. The input files for the core and assemblies can be seen in data/core and data/assembly, respectively.

Figure 3. Simplified EBR-II Core.

[1] E. Lum, C. Pope, R. Stewart, B. Byambadorj, Q. Beaulieu, “Evaluation of Run 138B at Experimental Breeder Reactor II”, EBR2-LMFR-RESR-001-CRIT, International Handbook of Evaluated Reactor Physics Benchmark Experiments, 2018.