MODEL / DESIGN PARAMETERS
Design parameters¶
The main geometrical and design parameters of the GFMR reference model.
Main design parameters¶
| Parameter | Value |
|---|---|
| Power | 150 MW |
| Height | 3.6 m |
| Fuel temperature | 650 °C |
| Mass flow rate | 2300 kg s−1 |
| Enrichment | 2.12 % |
| Core diameter | 3.5 m |
| Fuel channel diameter | 4.0 cm |
| Graphite temperature | 800 °C |
| Hexagon pitch | 14 cm |
| Control rod insertion | 36 cm nominal |
The 3.5 m dimension is the reflector diameter in the geometry description and is labelled core diameter in the main design parameters.
Core configuration¶
The core contains 379 fuel channels arranged in a hexagonal lattice. Fuel flows through the graphite channels from the bottom of the reactor to the top.
The inner and outer regions differ only in fuel velocity. The higher inner-zone velocity enhances heat removal from the hotter central region of the core. See channel hydraulics for the specified values.
Control rod channel geometry¶
Nine control rods are placed directly inside the fuel channels. Each Hastelloy N guide tube separates the fuel salt from a hafnium absorber. A helium gap between the guide tube and absorber enables withdrawal and insertion.
| Parameter | Value |
|---|---|
| Control rod channel diameter | 4.0 cm |
| Absorber diameter | 1.3 cm |
| Guide tube thickness | 0.2 cm |
| Void gap thickness | 0.1 cm |
During nominal operation, the control rods are assumed to be inserted to a depth of 36 cm.