NEPTUN/5007, PWR LOCA Cooling Heat Transfer Tests for Loft, Boil-Off Experiments

1 - Description of test facility: NEPTUN is designed to perform PWR LOCA simulation experiments, which provide the full length emergency cooling heat transfer tests for LOFT. Therefore the NEPTUN heater bundle with 33 electrical heater elements and 4 guide tubes simulates a section of the LOFT nuclear core. The main test loop also contains measuring systems for the carry-over rate and for the steam expelled, and a back-pressure control system. A water loop brings the water to the initial reflooding conditions. In addition, auxiliary systems maintain normal operating conditions. 2 - Description of test: Test 5007 was one of ten core boil-off experiments. It was chosen as the 'base case', because it was conducted at high pressure and intermediate power. The power is increased at about 50 secs and a rapid drop in the core fluid level occurs at about 100 secs. Between 100 and 110 secs, large voids are formed expelling some of the liquid from the core. At about 800 secs the power is shut off and the rods are allowed to cool down before the system is re-flooded. 3 - Status: CSNI1011/01, 21-Jul-1993 Arrived at NEADB