Results of validation and cross-verification of the ROK/B design code on the problem of loss of cooling in the spent fuel pool *

The procedures of validation and cross-verification the newly developed computational code ROK/B are described. main problem solved using is substantiation by calculation coolant density in spent fuel pool (SFP) temperature regime assemblies during a protracted shutdown cooling systems (break supply water). In addition to above, it possible use carry out an accident with discharge from SFP simultaneous prolonged systems. allows carrying calculations for various types designs VVER reactors, particular, VVER-1000, VVER-1200 VVER-440 power units single- two-tiered assembly arrangement, clad pipes racks (for compacted storage) without cladding, cased caseless ones. During reloading, high level maintained, which makes do “wet” transportation reactor SFP. mathematical model heat mass transfer calculation, including boiling model, implemented code, includes: motion equation, equations calculating enthalpy along height section natural circulation within channel containing (lifting section) inter-channel space (lowering section), equation balance between channels inter-assembly amount evaporated (and outflowed) water, rod steam environment. system supplemented closing relations thermal physics properties water steam, cladding materials, as well coefficients wall hydraulic resistance steam-water mixture channels, released reaction zirconium. Validation was carried on basis data ALADIN experiment performed German specialists JSC OKB Gidropress. Cross-verification comparison results KORSAR/GP SOKRAT/B1 codes. Based validation, has been concluded that deviation experimental not more than 2 10% (10% option 20 W). cross-verification, discrepancy codes 0.5% SOKRAT/V1) less KORSAR/GP).