As defined in Title 10, Section 20.1003, of the Code of Federal Regulations (10 CFR 20.1003), the CEDE (HE,50) is the sum of the products of the committed dose equivalents for each of the body organs or tissues that are irradiated multiplied by the weighting factors (WT) applicable to each of those organs or tissues (HE,50 = ΣWTHT.50).

An event or sequence of events that result in the melting of part of the fuel in the reactor core.

An expression of the likelihood that, given the way a reactor is designed and operated, an accident could cause the fuel in the reactor to be damaged.