Patent ZA-200703554-B (ZA)
Title: Method for regulations of operational parameters of the core of a pressurised water nuclear reactor
Inventor: ALAIN GROSSETETE
IPC: G21C/
Filed: 2007-05-16
Abstract: The method for controlling operating parameters of a nuclear reactor core (10) in pressurized water, comprises evaluating the actual values of operating parameters according to the acquired quantities of operating conditions of the reactor core, selecting a control law of an absorbent compound concentration and insertion positions of rods between first and second control laws, and controlling operating parameters using control laws according to a record regarding the parameters and actual evaluated values of the operating parameters. The method for controlling operating parameters of a nuclear reactor core (10) in pressurized water, comprises evaluating the actual values of operating parameters according to the acquired quantities of operating conditions of the reactor core, selecting a control law of an absorbent compound concentration and insertion positions of rods between first and second control laws, controlling operating parameters using control laws according to a record regarding the parameters and actual evaluated values of the operating parameters, calculating an average temperature record of a primary cooling of liquid in the core from a quantity of a power supplied to an electrical network through the reactor, distributing the rods in a sub-set for controlling the primary cooling of the liquid average temperature in the core and in a heavy subset, which ensures the control of the axial distribution of power, calculating displacements of the rods in a control sub-set according to a record and an actual value of the average temperature of primary cooling of the liquid in the core, modifying the insertion position of the rods in control sub-set according to the calculated displacements of the rod for regulating the average temperature of primary cooling of the liquid in the core, calculating displacements of the rods in a heavy sub-set according to a record and an actual value of the axial distribution of thermal power, and modifying the insertion position of the rods in heavy sub-set according to the calculated displacements for regulating the axial distribution of thermal output. The nuclear reactor comprises a reactor core divided into an upper and a lower zone and producing a thermal power, control rods of the core to immerse a multiple racked insertion positions vertically from a higher position in the core, unit for inserting rods in the core vertically, a primary circuit (30) ensuring a circulation of a liquid for primary cooling through the core, unit for adjusting a concentration of a neutron absorbing compound in the primary cooling, and unit for acquiring representative quantities of operating conditions of the reactor core. The controlled operating parameters comprise an average temperature of primary cooling of the liquid in the core, an axial distribution of thermal power between upper and lower zones of the core, and a parameter represents a reactor power increasing capacity, which is corresponds to a thermal power to be produced by the core. The first law is selected when a group of rods is in an insertion position, which is lower than a predetermined position of the rods, and the second law is selected reversely. The reactor power increasing capacity is determined from insertion positions of rods of the control sub-set. The controlling stage using the second control law comprises calculating a concentration of absorbent compound depending on the record value of operating parameters and the actual value of the axial distribution of thermal power, adjusting the concentration of absorbent compound in the primary cooling of the liquid to the calculated concentration for regulating the axial distribution of thermal power as the record value of the operating parameters, calculating the displacement to be performed for the rods of control subset and heavy subset according to the record and the actual value of insertion positions of the rods of control subset, and modifying the insertion positions of the rods of control subset and/or heavy subset according to the calculated displacement to maintain the rods of control subset in a deadband around the insertion position. The rods of control sub-set are sequentially inserted or extracted when a heating power produced by the core varies.