Comparison of melt penetration models

Melt-penetration and gas release following a core disruptive accident in a large LMFBR plant as predicted by two existing mechanistic codes (CORCON-MOD1 and GROWS-2) were compared. The results indicate that the total gas release from the limestone concrete cavity predicted by both codes was about the same whereas the melt-penetration predicted by CORCON-MOD1 was a factor of about 2.6 higher than for GROWS-2 at the end of a 104 s time period. Indications are that the discrepancy is related to the manner in which heat flux from the melt to the concrete is being utilized to calculate penetration rate. The CORCON-MOD1 code is recommended for short term (< 103 s) melt-penetration problems and GROWS-2 for longer term problems. (orig.)