Tests were performed in a high pressure heat transfer loop to determine the behavior of transient DNB during pressure blowdown in rod bundles. Water flowed along a 21 rod, 5-ft-long electrically heated rod bundle with a radially nonuniform heat flux distribution. Both steady-state and transient DNB tests were conducted over the following range of operating parameters: 1 Pressure—750 to 1500 psia; 2 Inlet temperature—480 to 540 deg F; 3 Mass velocity—1 × 106 to 3 × 106 lb/hr ft2; 4 Grid configurations—2. The data were analyzed using calculated subchannel local velocity and enthalpy as a function of time with proper allowance for the mixing and cross flow within the bundle. Results show that the inception of transient DNB during pressure blowdown can be predicted on the basis of steady-state data.

This content is only available via PDF.
You do not currently have access to this content.