MONJU Shield plug gas blow-down test (II); Validation of COMMIX-PNC ver.MT and application to MONJU

not registered; Maekawa, I.*; Sato, Kazujiro*

The mass transport version (ver.MT) of three-dimensional thermal-hydraulic analysis code, COMMIX-PNC, has been developed to evaluate gas blow -down effects in the annulus between the MONJU closure head and plug port. The ver.MT has been validated through the analysis of the fundamental experiment of KCl transport and gas blow-down mock-up experiment. The fundamental experiments were carried out using a water cavity with 500 mm 500 mm 50 mm in size. The experiments began pouring KCl solution into the inlet of the cavity. The calculated histories of the KCl concentration transient agreed well with the experiment. For the mock-up gas blow-down experiment, three gas flowrate cases, 0.05m/min, 0.02m/min and 0.1m/min were calculated. Noble gas were predicted to reach the top part of the annulus only in the case with 0.1m/min flowrate. Through the application of the code to the MONJU configuration, the follwing have been effects of gas blow-down as obtained : [Normal gas blow condition] F.P. gases didn't enter into the annulus. [Half gas blow condition] The gases with 10% concentration reached the location of 3905 mm above the bottom of shielding plug, and [Gas blow trip condition] The gases with 13% concentration reached the door valve in 1000 sec. simulation. From the above results and their consistency with the evaluation of gas blow-down effects by the experimental correlation derived from the gas blow-down experiments, the correlation can be applicable to a complicated annulus like that of the MONJU.