CSNI1007 UPTF/TEST10B/RUN081.

1. NAME OR DESIGNATION:  UPTF/TEST10B-RUN081.

3. DESCRIPTION OF TEST FACILITY

The Upper Plenum Test Facility (UPTF) is a geometrical full-scale simulation of the primary system of the four-loop 1300 MWe Siemens/KWU pressurized water reactor (PWR) at Grafenrheinfeld. The test vessel, upper plenum and its internals, downcomer, primary loops, pressurizer and surge line are replicas of the reference plant. The core, coolant pumps, steam generators and containment of a PWR are replaced by simulators which simulate the boundary and initial conditions during end-of-blowdown, refill and reflood phase following a loss-of-coolant accident (LOCA) with a hot or cold leg break. The break size and location can be simulated in the broken loop.The emergency core coolant (ECC) injection systems at the UPTF are configurated to simulate the various ECC injection modes, such as hot leg, upper plenum, cold leg, downcomer or combined hot and cold leg injection of different ECC systems of German and US/Japan PWRs. Moreover, eight vent valves are mounted in the core barrel above the hot leg nozzle elevation for simulation of ABB and B&W PWRs.

The UPTF primary system is divided into the investigation and simulation areas. The investigation areas, which are the exact replicas of a GPWR, consist of the upper plenum with internals, hot legs, cold legs and downcomer. The realistic thermal-hydraulic behavior in the investigation areas is assured by appropriate initial and boundary conditions of the area interface. The boundary conditions are realized by above mentioned simulators, the setup and the operation of which are based on small-scale data and mathematical models. The simulation areas include core simulator, steam generator simulators, pump simulators and containment simulator. The steam production and entrainment in a real core during a LOCA are simulated by steam and water injection through the core simulator.

4. DESCRIPTION OF TEST

Investigation of steam/water flow phenomena at the upper tie plate and in the upper plenum and hot leg region of a PWR which may occur in the reflood phase during a large cold leg break LOCA with cold leg ECC injection.

Boundary Conditions:
There was no ECC injection. Steam and saturated water were injected into the core simulator. The cold leg break valve was open. The hot leg break valve and all pump simulators were partially open to establish the desired loop flow resistances.

Significant Findings:
During an initial time period - about 40 s - the water that was injected into the core simulator was distributed within the upper plenum and the adjacent loops. After these regions were "saturated" with water, the water was carried by the steam into the steam generator simulator inlet plenum and into the cyclones of these simulators where it was separated. The amount of water separated by the cyclones in the steam generator simulators was in good agreement with the amount of water injected into the core simulator after the initial time period of about 40 s. After termination of the steam injection into the core simulator, the water flow back into the core region was in quantitative agreement with the amount of water that was distributed during the initial time periods. During the entire test phase there was no significant pool formation above the tie plate.

5. EXPERIMENTAL LIMITATIONS OR SHORTCOMINGS

The system operating pressure was limited to 20 bar. So for some experiments pressure scaling was necessary.

6. PHENOMENA TESTED

The test focuses on entrainment, deentrainment and water fall back in the tie plate and upper plenum region, the hot legs and the steam generator simulator inlet plenum. Of special interest was the water entrainment into the cyclones of the steam generator simulators (steam binding effects).

7. SPECIAL FEATURES OF EXPERIMENT

Investigation of multi-dimensional flow behavior in a full-scale primary system of a 1300 MWe PWR.

8. COUNTERPART EXPERIMENTS:  CCTF/SCTF.

- K. Riedle, H. Watzinger:
Test No.10, Tie Plate Countercurrent Flow Test Experimental Data Report
U9 316/88/1, Siemens UB KWU, February 1988
- Emmerling et al.:
UPTF: Program and System Description, Siemens AG, KWU, U9 414/88/023, November
1988
- J. Sarkar, J. Liebert, R. Laufer:
Work Report, UPTF Test Instrumentation, Engineering Units and Computed
Parameters, Siemens AG, KWU, S554/92/013, November 26, 1992
- 2D/3D Program Work Summary Report
NUREG/IA-0126 - GRS-100 - MPR-1345 (June 1993)
- Reactor Safety Issues Resolved by the 2D/3D Program
NUREG/IA-0127 - GRS-101 - MPR-1346 (July 1993)

11. TEST DESIGNATION:  TEST10B-RUN081.

15. ESTABLISHMENT

     Siemens AG, KWU,
     Postfach 3220, 91050 Erlangen, FRG
     Germany

CCVM Data