CSNI0035 LOBI/A1-06.

1. NAME OR DESIGNATION:  LOBI/A1-06.

3. DESCRIPTION OF TEST FACILITY

The LOBI facility is a 1/700 scale model of a four loop PWR and has two primary loops, the intact loop representing three loops and the broken loop representing one loop of a four-loop PWR.  The reactor pressure vessel model contains an electrically heated rod-bundle with 64 rods and a heated length of 3.9 m. The nominal heating power is 5.3 MW. The downcomer is of annular shape.  An upper head simulator is connected to the vessel. Each of the two primary loops contains a pump and a steam generator. The different mass flows in the loops are established by the pump speeds, since the two pumps are identical. Heat is removed from the  steam generators by a secondary system. ECC water can be supplied from two accumulators, one for each loop.  Cold or hot leg as well as combined injection can be simulated.
     The LOBI test facility is the only high pressure integral test facility within the European Communities (1982), built and operated in the Joint Research Centre, Ispra, ITALY. In the LOBI experiments  the thermal-hydraulic behavior of the facility during a transient, caused by a simulated loss of coolant accident (LOCA), is investigated to provide an experimental basis for analytical model development and code verification.

4. DESCRIPTION OF TEST

The Test A1-06 is one of a series of three LOBI tests in which the ECC injection mode was studied.  In all experiments, a double-ended 2A break in the cold leg was simulated. The downcomer gap width was 12 mm.
  In test A1-06, ECC water was injected from the intact loop accumulator into the hot leg and the cold leg and from the broken loop accumulator into the hot leg only. The pressurizer was connected to the intact loop.
  At break initiation, the core power stayed at 5.29 MW (100%) during 2.9 seconds and was then stepwise reduced and reached zero at 30 seconds.
  After blowdown initiation, the intact loop pump speed decreased to 71% after 8.0 seconds and remained constant. The broken loop pump speed diminished to 10.4% after 3.0 seconds and reached zero speed after 27.0 seconds.

5. EXPERIMENTAL LIMITATIONS OR SHORTCOMINGS

LOBI experiments cover only the blowdown phase of a transient.  The available downcomer gaps result in either unrealistic core flows or too large a hot-wall effect and unrealistic ECC delivery.

6. PHENOMENA TESTED

Natural circulation in 1- and 2-phase flow; asymmetric loop behaviour; phase separation; ECC mixing and condensation; heat transfer; 1- and 2-phase pump behaviour.

7. SPECIAL FEATURES OF EXPERIMENT

LOBI's large size and full height components are considered an advantage.

8. COUNTERPART EXPERIMENTS:  Semiscale.

- L. Regel and E. Ohlmer:
Experimental Data Report on LOBI Test A1-06
ISPRA LEC 82-17, Communication No. 3952, September 1982
- L. Piplies and N. Granner:
Quick Look Report on LOBI Test A1-06
ISPRA LQC 82-15 Communication No. 3955, September 1982
- H. Staedke:
Pre-Test Prediction for LOBI TEST A1-06
ISPRA LPC 82-14 Communication No. 3968, July 1983
- W. Kolar and W. Brewka:
LOBI Experimental Data Tape - Format Description
Technical Note No.I.06.C1.85.49 (May 1985)
- LOBI Project - RELAP5 Base Input Data for LOBI-MOD2
LPC 85-18 (February 1985)

11. TEST DESIGNATION:  A1-06

15. ESTABLISHMENT

        Commission of the European Communities
        Joint Research Centre
        Ispra Establishment
        I-21020 Ispra
        ITALY

CCVM data        mag tape2A BREAK PUMP-VESSEL, DC 12 MM  4,086KbytesCVMTP