Experiments to investigate the effect of flight path on direct containment heating (DCH) in the Surtsey test facility

Abstract

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Results of an experiment in a Zion-like geometry to investigate the effect of water on the containment basement floor on direct containment heating (DCH) in the Surtsey Test Facility: The IET-4 test

“…This was quickly followed by molten debris particles. Debris velocity was calculated to be ---14m/s at level 3, similar to the 16 m/s calculated from the breakwire array data obtained in the LFP-8A experiment [Allen et al 1991]. Figure 19 shows the absolute pressure measured inside the seal table room and the pressure measured in Surtsey plotted against time.…”

“…This was a small steam explosion, as was observed in IET-1 [Allen et al 1992d]. There is previous evidence [Allen et al 1992a] that small steam explosions in the reactor cavity have little effect on the HPME/DCH event. The third broad peak, which occurred between =0.4 and =0.8 s, was due to thermite entrainment from the cavity caused by the steam blowdown; thus the debris entrainment interval lasted =0.4 s.…”

“…In previous Surtsey experiments with a 3.5 cm exit hole (LFP-1A, LFP-2A, LFP-8A, [Allen et al 1991] and WC-1 [Allen et al 1992a]), the debris entrainment interval was =1 s. In lET-1, IET-3 and IET-4 the debris entrainment intervai was =0.45 s. Differences in the debris entrainment interval observed in the lET experiments compared to earlier Surtsey tests are probably due to the new melt generator/crucible design. The present design used a 1:10 linear scaled hemispherical bottom head, whereas the melt generator used in previous experiments had a relatively long, narrow cylindrical shape, and the molten thermite was pushed out with a piston-like motion.…”

“…In the lET tests, it is more difficult to distinguish single-phase thermite ejection and steam blowthrough from the changes in shape and inflection points in the blowdown curve ( Figure 11) than in earlier experiments [Allen et al 1991[Allen et al , 1992a[Allen et al , 1992b. The IET tests used a melt generator that was a 1:10 linear scale model of the hemispherical bottom head of a RPV.…”

An Evaluation Methodology Development and Application Process for Severe Accident Safety Issue Resolution

“…The credibility of an evaluation methodology relies on the associated verification and validation through code [8] (2) Core melt progression (i) Zr melt breakout temperature (ii) Fuel rod collapse temperature (iii) Core material melt temperatures PHEBUS (CEA) [9,10] QUENCH (FZK) [12] LOFT (OECD) [13] (3) Core melt relocation to lower head (i) Melt relocation heat transfer coefficient Lower head failure program (NRC) [14] (4) In-vessel oxide/metal separation RASPLAV/MASCA (OECD) [ [21] TROI (KAERI) [22] (10) High pressure melt ejection (i) Particle size (ii) Obstructions DCH/TDS/LFP/WC (SNL) [23][24][25][26][27] IET-Zion/IET-surry/U (SNL/ANL) [28,29] CWTI (ANL) [31] DCH (FAI) [32] (11) Steam/hydrogen transport (i) Containment transition to single convective volume HDR (Germany) [33] NUPEC large scale test facility (MITI, Japan) [34] Battelle model containment (USA) [35] (12) Hydrogen recombination (i) PAR efficiency…”