Preliminary Comparison of Wet Bypass Accident Consequences Between ITER and a Helium-Cooled Fusion Power Plant

Probabilistic risk assessment model for released tritium into the environment for CFETR

“…The pressure of the volume V 2 is approximated by the equation of state of ideal gas (equation ( 9)) assuming the temperature is constant within the very short period during which the pressure rapidly reaches the equilibrium state. This simplification was also adopted in the rapid assessment method of tritium released from accidents in fusion NPPs proposed in [24]. The volume V 2 expands from the volume V i 2 of the first pressure relief room until the equilibrium pressure is lower than the pressure opening limit of the next relief room.…”

“…We used the developed ATACC1.0 code to perform the estimation of radioactivity of released tritium into the environment caused by LOCAs. In the calculation, we assumed that the mobile tritium inventory in the VV and TES is 1 kg [24] and 0.5 kg, respectively; and the permeability of tritium of the coolant system is 0.005 g m −3 , and a loop with a volume of 130 m 3 contains a tritium mass of 1.3 g. It is reasonable to categorize a series of sequences into a release category based on the similarity of the PIE, accident process, ultimate confinement failure mode, release pathway, and source term. The consequences of the most severe accident sequence in the release category conservatively envelop the consequences of all sequences in the category.…”

“…Tritium distribution and potential release path under LOCAs condition are shown in figure 18. Based on the main parameters of the tritium confinements [5,6,23,24] given in table 11, the mass and the radioactivity of released tritium were estimated for each TRC using the ATACC1.0 code, and the results are shown in table 12.…”