Numerical simulation of jet breakup phenomenon during severe accident of sodium-cooled fast reactor using MPS method

Characteristics and Mechanisms of Debris Bed Formation Behavior in Severe Accidents of Sodium-Cooled Fast Reactors: Experimental and Modeling Studies

“…Therefore, it is crucial and necessary to assess the CDAs of SFRs from a safety standpoint. In a typical CDA of an SFR, the progression of the accidental event can be divided into four phases, including (1) the initiating phase [8][9][10], (2) the transition phase [11][12][13], (3) the post-accident material relocation (PAMR) phase [14][15][16][17], and (4) the post-accident heat 2 of 35 removal (PAHR) phase [18][19][20][21][22]. During the PAMR phase, in a subcooled sodium pool, the molten fuel, structural components, and other materials may be discharged from the reactor core, rapidly quenched, and fragmented into solid debris due to interactions with the sodium coolant.…”

“…Sci. 2023, 13, x FOR PEER REVIEW post-accident material relocation (PAMR) phase [14][15][16][17], and (4) the post-accid removal (PAHR) phase [18][19][20][21][22]. During the PAMR phase, in a subcooled sodium p molten fuel, structural components, and other materials may be discharged from actor core, rapidly quenched, and fragmented into solid debris due to interactio the sodium coolant.…”

“…In these investigations, in general, the initial debris bed sh supposed to be homothetically piled [37], cylindrical [38], heap-like [40,41], and G shaped [39] or conical [16,[42][43][44]. Nevertheless, it was found that the geometries o beds (such as their heights) also significantly affect their heat removal capacity [4 the past few years, by assuming that the bed was initially conical (or convex), e investigations on the relocation phenomena of debris beds (termed as self-leveli gered by sodium boiling were performed [14,15,43,44,[47][48][49][50]. Based on these in tions, the self-leveling mechanisms (e.g., bubble-particle interactions within partic and characteristics (e.g., parametric influence on the leveling rate) were clarifie ever, it should be noted that the complex multiphase flows, including solid debri coolant, and sodium vapor, involved in the DBF process can result in varyin shapes of the debris bed, which in turn can influence the progression of severe a in SFRs.…”

“…Nevertheless, it was found that the geometries of debris beds (such as their heights) also significantly affect their heat removal capacity [45,46]. In the past few years, by assuming that the bed was initially conical (or convex), extensive investigations on the relocation phenomena of debris beds (termed as self-leveling) triggered by sodium boiling were performed [14,15,43,44,[47][48][49][50]. Based on these investigations, the self-leveling mechanisms (e.g., bubble-particle interactions within particle beds) and characteristics (e.g., parametric influence on the leveling rate) were clarified.…”