The materials for making normal heat are generally sufficient.
The problem is pushing it hotter and hotter because excess heat doesn’t show up, resulting in exceeding the materials limits, breakage, etc.
If LENR were to show up at the edge of materials abilities, the device will fail almost certainly.
Better to build something sufficiently strong, durable, and with at least 50% more heat capabilities than the normal maximum conditions. Then when LENR happens, the experiment can continue and the anomaly investigated without a panic.