PG-26 Results

The main variables of interest in this model were the temperatures recorded in the ceramic core block and helium coolant channels. The following plots and figure represent results obtained from the MultiApp HTTF model.

Note: many thermocouples were not able to handle the temperatures experienced in the HTTF during the experiment and temporarily failed. This resulted in large vertical variations in the experimental data which were unrealistic. However, these failures were brief enough for the overall trend to still be visible. Also, during the heat up, a slow coolant leak occurred in the primary system which caused a decrease in primary coolant inventory. HTTF operators were able to fix the leak during the test, however, the amount of coolant lost, amount of make-up coolant added, temperature of the make-up coolant, and the time of the make-up coolant addition were unknown during the making of this model.

Radial Temperature Distributions

Radial temperature distributions were plotted for core block 5 which is the mid-plane of the HTTF core. The core was divided into 3 radial sections, the inner ring (IR), middle ring (MR), and outer ring (OR). The temperatures in these plots represent the average of all Postprocessor temperature values within each radial region.

Radially averaged ceramic core temperatures in core block 5.

Radially averaged helium coolant temperatures in core block 5.

Axial Temperature Distributions

These plots represent temperatures recorded by Postprocessors located in the same x and y positions but at the 3 varying axial core block heights. These Postprocessors carry the same naming convention as their corresponding thermocouples in the HTTF core.

Axial distribution of ceramic core temperature at instrumentation position 05.

Axial distribution of helium coolant temperature at instrumentation position 18.

3-D Model Temperature Distribution

The 3-D model allowed for visualization of the temperature profile across the entire HTTF model. Below is an image of the HTTF model during the hottest point of the PG-26 transient.

Cutaway of the HTTF model during the hottest point of the PG-26 transient.