corium

Corium is a term with multiple meanings in different fields. In anatomy, it refers to the dermis, the thick, fibrous layer of connective tissue beneath the epidermis in vertebrate skin. The dermis contains collagen and elastin fibers, blood vessels, nerves, hair follicles, and sweat and sebaceous glands. It provides structural strength, nourishes the epidermis, and houses sensory receptors for touch, pressure, pain, and temperature. The dermis is classically divided into two layers: the superficial papillary dermis, which has loose tissue and dermal papillae that form fingerprints, and the deeper reticular dermis, a denser network of fibers that accounts for most of the skin’s strength and elasticity. The dermis also plays a key role in wound healing and thermoregulation through its vascular and glandular components.

In nuclear engineering, corium denotes the molten core material formed during a severe reactor accident when the fuel and cladding melt and relocate. This molten mixture can pool inside the reactor vessel or breach containment, interacting with coolant, structural materials, and surrounding concrete. Such interactions can generate hydrogen, release radioactive fission products, and pose significant safety challenges. Containment and mitigation strategies focus on cooling, stabilizing, and containing corium to prevent further damage and environmental release. The concept is central to analyses of meltdown phenomena and post-event debris characterization.

Etymology and usage: corium derives from Latin for skin or hide. In modern anatomy, the preferred term is dermis, though corium remains encountered in older texts and some clinical contexts.