Development and applications of a computer program for modeling the response to hydrogen burns in containment

In order to investigate all phases of hydrogen behavior during light water reactor accidents, the computer program called HECTR (Hydrogen Event: Containment Transient Response) was developed, which models hydrogen burns in containments and the associated important heat transfer mechanisms. HECTR can model a multicompartment containment building, assuming that the gases in each compartment are ideal and homogeneously mixed. Gas flow between compartments is driven by pressure differences and gravitational forces. Included in HECTR are models for hydrogen burns, radiative and convective heat transfer, heat transfer to sprays, wall heat conduction and inter-compartment fans. Steam and hydrogen source terms can be specified by the user. This paper describes HECTR and its constituent physical models in detail and presents some calculational results for the Grand Gulf Mark III BWR containment