Comment by semi-extrinsic

Anything that can explode if overheated in a refinery is covered with passive fire protection. This is designed to withstand jet fire exposure, meaning a heat load of at least 1100 °C and at least 250 kW/m2. Ordinary sunlight at peak is about 1 kW/m2, so your mirror needs to cover 250x the visual extent of the sun in the sky.