Late-phase melt conditions affecting the potential for in-vessel retention in high power reactors

In-vessel Retention Strategy for High Power Reactors - K-INERI Final Report (includes SBLB Test Results for Task 3 on External Reactor Vessel Cooling (ERVC) Boiling Data and CHF Enhancement Correlations)

“…The aspect ratio H/R of the oxidic layer is about 06 ~ 0.7. From the BALI experiment, [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] thermal splitting defined as upward heat flow to total power of heat generation is in the range of 0.52 ~ 0.54 for these pool configurations. The calculated results using LP code are summarized in Table 5 Compared to the oxidic layers, the metallic layers are in the low Rayleigh number natural convection regime.…”

“…The right side of Equation (4-14) represents the absorbed energy for evaporation of a certain amount of steam at the surface plus the energy removed convectively for vapor heating. Equation (4-14) may be rewritten in terms of the differential terms for the azimuthal angle and the vapor film thickness as The total heat transfer from the downward-facing hemisphere is given by (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) Defining the average Nusselt number as , it follows that (4-23)…”

“…Peyayopanakul and Westwater [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] suggested that the thickness of the copper vessel was 3 cm so that data from the quenching experiment would be similar to those from the steady state experiment. If the time to traverse the top 10% of the boiling curve were greater than 1 sec, the boiling process would be in a quasi-steady state (Dhir [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] ). The test section's inner cavity was filled with bulk fiber and covered on top with the Fire Stop disk for thermal insulation.…”

“…It is thought that these results are physically reasonable because the melting temperature of the metallic mixture of the upper layer is about 1,000 K lower than oxidic material of the lower layer. Results from the BALI experiment [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] suggest that the lower oxidic pool is fully surrounded by the oxidic crust.…”

Generation III pressurized water reactors and China’s nuclear power

“…For severe accidents, a passive containment cooling system, in-vessel retention (IVR, Fig. 8) (Rempe et al, 2002;Knudson et al, 2004), and a Passive core cooling system ADS: automatic depressurization system; IRWST: in-containment refueling water storage tank; PRHR HX: passive residual heat removal heat exchanger; DVI: direct vessel injection; RNS: normal residual heat removal system containment hydrogen control system (including passive hydrogen recombiner and igniters) have been designed. A passive main control room emergency habitability system is designed to provide a suitable environment for plant personnel in main control room.…”