Essai de marche en puissance de la centrale nucléaire BR 3 en présence de bore dans le circuit primaire: Premiere partie: Marche avec 100 ppm de bore

The importance of chemical shim for power reactors is increasing, and so does the need for some experiments to solve the various problems associated with this type of reactor. Such an experiment is undertaken at the BR3 power reactor in the test program for the industry. Preliminary tests and calculations - the first ones on water chemistry under the special conditions of operation with boron (no ion exchanger in the purification system, lower pH than usual), the second ones on safety associated with the dynamic behaviour of the reactor in case of an accident - are achieved first. They show that the experiment is entirely practicable.
Then a first step (operation at power with 100ppm boron) is achieved. Boron is added progressively when the power station is at a power of 10 electrical MW (85 % of nominal power).
The evolution of chemical parameters and of core reactivity is followed during stable operation. Secondary load transients are then introduced and the Xe transients are followed by varying the boron concentration, without moving any control rod ; in this way, the primary water average temperature is maintained around 262° C with less than 1°C variation.
After complete boron dilution, no special phenomenon appears. A second step will be undertaken with 400 ppm boron at the end of this year 1963.