Patent Number: 
Section: claims

1. A method for in situ passivation of steel surfaces of a nuclear reactor, comprising the steps of:forming a protective film on a surface of the nuclear reactor primary circuit elements by introduction of a substance interacting with a material of the primary circuit elements into a primary circuit coolant, thus forming the protective film;wherein, during installation of the nuclear reactor prior to its filling with a reactor coolant, a core simulator is installed in place of a core, the nuclear reactor is filled with a reactor coolant that is heated to temperatures ensuring passivation conditions and then the core simulator is removed and replaced with a standard core. 2. The method according to claim 1, wherein a liquid metal coolant is used as the primary circuit coolant. 3. The method according to claim 2, wherein the in situ passivation is carried out in two stages, wherein the first stage is carried out under isothermal passivation conditions where oxygen is introduced into the liquid metal coolant, and the second stage is conducted under non-isothermal passivation conditions. 4. The method according to claim 3, wherein the isothermal passivation is carried out at T=300° C.-330° C. 5. The method according to claim 4, wherein oxygen is introduced in the liquid metal coolant with a thermodynamic activity a=10−1÷10−3. 6. The method according to claim 5, wherein the oxygen thermodynamic is maintained fort=220 (±20) hours. 7. The method according to claim 3, wherein the non-isothermal passivation is performed with at least one pump on. 8. The method according to claim 7, wherein a power of the pump amounts to at least 30 percent of a rated value. 9. The method according to claim 7, wherein an oxygen concentration is maintained at a level of Co2=(1-4)*10−6 wt %. 10. The method according to claim 7, wherein the oxygen thermodynamic activity a is increased to a=10−2÷ 10−4. 11. The method according to claim 7, wherein the power of the pump is at least 30 percent of the rated value, the oxygen concentration Co2=(1-4)*10−6 wt % and the oxygen thermodynamic activity a=10−2÷10−4 are maintained for t=550 (±50) hours. 12. The method according to claim 1, wherein the core simulator is a core model simulating its shape, relative position of core elements, and their masses and dimensions.