Loss Of Coolant Accident analyses for coolant leak from the primary circuit through a hole 30 mm equivalent diameter. Pt. 2

Coolant leaks from the hot and cold branches near a reactor with an inaccessible high-pressure aftercooling system and with two emergency storage tanks were analyzed. Variants without operator intervention and with operator intervention during the opening of the by-pass station to the condenser 30 min after initiation of the accident and cooling of the primary circuit by means of the secondary circuit were treated. Included was the effect on the accident patterns, of disconnecting the emergency storage tanks during the cooling. The calculation was fitted to the Dukovany NPP. The time development of the accident was analyzed for the two variants. Taking into account the analysis involving the availability of 4 and 2 emergency storage tanks during a leak through an equivalent hole 30 mm in diameter and without the use of high-pressure pumps it is concluded that the reactor can only be kept in a safe condition by aftercooling from the secondary circuit at a rate of 30 degC/hr. The aftercooling must be started no later than 30 min after the accident outbreak. (J.B.). 2 tabs., 126 figs., 1 ref