Adaptation of the ASTEC code system to accident scenarios in fusion installations

Progress on source term evaluation of accidental events in the experimental fusion installation ITER

“…In ITER, safety systems are designed to face such a situation in order to keep safe the integrity of the VV: 2 by-pass valves open at a VV target pressure and additional rupture disks open at another target pressure in order to activate the Vacuum Vessel Pressure Suppression System (VVPSS). The obtained results [3] showed a good agreement between ASTEC and the MELCOR code currently used by ITER/Organization (ITER/Org. in the rest of the paper) on the pressure evolutions in VV and in VVPSS and on break mass flow rate.…”

“…Since 2009 [2], a large effort has been undertaken to investigate the key items and extend the capabilities of the ASTEC code [3] to address the main accident sequences which may occur in the fusion installations, in particular in ITER, an experimental installation for which IRSN provides assistance to the French Nuclear Safety Authority (ASN) regarding nuclear safety and radiation protection. First analysis of accidental scenarios led to identify the gaps of knowledge and to focus the efforts to improve the modelling for some issues related on one hand to reference accidental situations that may lead to the loss of confinement and on the other hand to the evaluation of their consequences in terms of potential releases to the environment.…”

“…In the representative LOCA scenarios in ITER, coolant that can be flashed inside or outside the vacuum vessel can be water from a failed cooling pipe. As an example, the present ASTEC version was used [3] for the study of a design basis accident where a double-ended rupture of 128 pipes of FW/BLK (first wall/blanket) coolant loop was assumed due to a plasma disruption. In ITER, safety systems are designed to face such a situation in order to keep safe the integrity of the VV: 2 by-pass valves open at a VV target pressure and additional rupture disks open at another target pressure in order to activate the Vacuum Vessel Pressure Suppression System (VVPSS).…”

Methodology for accident analyses of fusion breeder blankets and its application to helium-cooled pebble bed blanket

“…Some of these codes have been modified, and have additional physical models to treat fusion-relevant phenomena [9][10][11][12][13]. For example, fusion-adapted versions of MELCOR are widely applied for fusion accident analyses [3,12,14,15].…”

Modelling of Ingress of Coolant Event into Vacuum Experiments with ASTEC Code

“…Application of computer code RELAP5 for modelling of the ingress of coolant events is presented in [7]. Recently IRSN (France) presented results of adaption of ASTEC computer code for fusion installations [8]. Comparison of ASTEC results with measured pressures during ICE P1 test is presented there as well.…”