Characteristics of flow rate-limiting inserts in modeling emergency loss of integrity of a reactor loop

The relationship between the critical mass velocity of hot water on a number of operating and geometrical parameters is investigated. The greatest effect on (/rho/w)/sub cr/ is exerted by the pressure and underheating of the water at the nozzle inlet. The critical mass velocity of outflow of underheated or saturated water also depends on the length of the cylindrical throat of the nozzle. It has been established that (/rho/w)/sub cr/ decreases as l/sub th/ increases. However, this effect gradually attenuates as l/sub th/ increases. The greater the underheating of the water at the nozzle inlet, the sooner the effect of l/sub th/ attenuates. Investigation of the effect of throat diameter revealed that increasing d/sub th/ from 10 to 30 mm resulted in roughly a 5-8% increase in (/rho/w)/sub cr/. The effect of the aperture angle of the diffuser turned out to be negligible, at least for 3/less than equivalent to//alpha//less than equivalent to/180/degree/ and l/sub th//d/sub th//greater than equivalent to/1.5.