Achievements and Status of Research Activities in the Source Term Area
Congress title :ERMSAR 2007 2nd European Review Meeting on Severe Accident Research
Congress town :Karsruhe
Congress date :16/06/2007
In the SARNET Source Term area, 23 organisations harmonise their experimental and theoretical research into 20 safety-related phenomena that may occur in a light water reactor severe accident, relevant to potential release of fission products to the environment.
Given their radiological importance, particular attention is being given to iodine and ruthenium. Iodine transport and speciation in the primary circuit and containment are being explored to improve predictability of the in-containment gaseous iodine source. Aspects such as chemical reactions with other elements (i.e., silver), mass transport processes (i.e., sump-to-atmosphere transfer), physico-chemical interactions with safety systems (i.e., passive autocatalytic recombiners), etc., are investigated. With ruthenium, enhanced release under air ingress is studied, with its behaviour in the circuit and containment. Aerosol studies aim to quantify the source term following steam generator tube rupture, which leads to containment by-pass; aerosol leakages through containment concrete wall cracks and revaporisation phenomena that could lead to a late source term are also investigated.
This paper summarises experimental and theoretical work in the first three years, noting successful collaboration with international projects such as Phebus FP, ISTP, ISTC and FZK QUENCH. Indications are given on the progress towards defining/improving models and towards resolving the associated safety issues.