Study on the main design parameters of large scale fast breeder reactor(II); Evaluation of the plant transient behavior at the Loss of primary piping integrity accident

not registered; not registered ; not registered; not registered; Nakanishi, Seiji; not registered

As a series of the Study on the Main Design Parameters of Large Scale Fast Breeder Reactor (II) in 1987, the transient behavior at the loss of primary piping integrity accident of the loop-type plant of the Key Technological Design Study (II) in 1985 was analyzed by the FBR system code SSC-L, and then the effects of the coolant leakage on the core coolability were evaluated. (1)In case of the leakage from a crack opening area of 1cm, whieh was rationalized by fracture mechanics, at the cold leg piping near the inlet nozzle of the reactor vessel, the maximum leak mass flow rate was immediately reached to 3.6kg/sec after pipe break, and the saturated leak mass flow rate was reached to 0.9kg/sec at 300sec in the pump pony motor driving condition. (2)In case of the leakage from 1cm area as the originated event, with failure of the succeed of pony motor driving in two-loops due to failure of the starting of a emergency diesel generator as the single-failure criteria, the maximum cladding temperature was reached to 758C, therefore the reactor core was not damaged seriously, and the core coolability was secured sufficiently. (3)In order to compare the effects of the rationalization of crack opening area, in case of the enlargement of the leakage area from 1cm to 0.25Dt(25cm in this analysis), which was assumed in prototype reactor "MONJU", the maximum cladding temperature was increased only about 5C compared with that of the 1cm area. (4)Taking aim to get the setting ground of the source terms on the located evaluation, as a superposition of the obstruct condition on the core coolability, in case of the failure of the succeed of pony motor driving in three-loops except the accident loop, the maximum cladding temperature was reached to 847C (1cm area), and reached to 854C (25cm area) respectively, so both results were exceeded 830C, which was set up as the restriction temperat