Evaluation of Blowdown and Condensation (B and C) Loop Behavior During Air Clearing Phase with a Prototypic Sparger Using the RELAP Code: CPT-3 Test

KAERI has performed a series of blowdown tests to evaluate the performance of the prototypic sparger which will be used in the APR1400. Among the tests, the CPT-3 test is one of the fundamental blowdown tests and the objective of CPT-3 test was to determine the effect of air mass inside the piping on the IRWST boundary during an operation of SDVS (Safety Depressurization and Vent System). The test is conducted from the initial system pressure of 15.2 MPa and steam temperature of 343.2 deg. C. In the paper, the transient thermal-hydraulic behavior in the discharge line observed in the CPT-3 test is evaluated using the RELAP5/MOD3.1 code. The result shows that RELAP5/MOD3.1 can predict the blowdown behavior of the test facility properly and the code can be used as an evaluation tool for the verification of SDVS design of the APR 1400. (authors)