Zinc injection evaluation system based on corrosion product deposition influence and application
Patent Information
- Application Number
- CN202611166696.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-03
- Publication Date
- 2026-11-03
AI Technical Summary
Current research on the impact of zinc injection mainly relies on experience and local experimental conclusions, lacking multi-component modeling and systematic analysis of the impact of corrosion product deposition. This leads to an unclear understanding of the mechanism of CRUD and makes it difficult to optimize zinc injection water chemistry strategies.
By combining density functional theory (DFT) with a semi-empirical thermodynamic model, model building units, thermodynamic mapping units, equilibrium solution units, and evaluation output units are constructed. The phase transformation, stability, and dissolution-deposition equilibrium of CRUD under zinc injection are quantitatively evaluated through spin polarization DFT+U calculation and Gibbs free energy minimization method.
It enables quantitative assessment of CRUD under high temperature and high pressure environment, improves the predictability and controllability of zinc injection water chemistry strategy, reduces radiation dose, protects fuel assembly integrity, and ensures safe and stable reactor operation.
Smart Images
Figure CN123033600A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a technology in the field of pressurized water reactor control, specifically a zinc injection assessment system and its application based on the effects of corrosion product deposition. Background Technology
[0002] In the primary circuit of a pressurized water reactor (PWR), the Cruvium Surface Deposition (CRUD) on the fuel cladding surface is one of the key issues affecting reactor safety and economic operation. Thickening of the CRUD on the fuel surface significantly increases thermal resistance, causing an increase in near-surface temperature and potentially inducing localized corrosion (CILC) and corrosion instability-prone areas (CIPS). To reduce radiation dose and improve material corrosion resistance, the industry commonly employs a water chemistry control strategy of continuously injecting trace amounts of zinc ions into the primary circuit. By incorporating zinc into the oxide film and CRUD, zinc partially replaces cations such as Ni and Co, thereby reducing the radiation field and improving corrosion behavior. However, under zinc injection conditions, the solubility of corrosion products, the composition of precipitates, and the distribution of deposition sites all change. Currently, the engineering application of these changes still mainly relies on empirical knowledge and local experimental conclusions. Summary of the Invention
[0003] This invention addresses the shortcomings of existing technologies in the study of the effects of zinc injection, which remain at a macroscopic and empirical level and have significant deficiencies in multi-component modeling. It proposes a zinc injection evaluation system and its application based on the effects of corrosion product deposition. By combining precise calculations using density functional theory (DFT) with a semi-empirical thermodynamic model, it can systematically analyze the phase transformation, stability changes, and impact on the dissolution-deposition equilibrium of CRUD under zinc injection. This not only elucidates the mechanism of zinc injection's effect on CRUD but also provides crucial technical support for further optimizing zinc injection hydrochemical strategies.
[0004] This invention is achieved through the following technical solution:
[0005] This invention relates to a zinc injection evaluation system based on the effects of corrosion product deposition, comprising: a model building unit, a thermodynamic mapping unit, an equilibrium solution unit, and an evaluation output unit. The model building unit constructs solid solution models of nickel ferrite, zinc ferrite, and different ratios based on representative corrosion product components and calculates the ground-state energy of each CRUD component at 0 K based on spin-polarized DFT+U. The thermodynamic mapping unit collects enthalpy, entropy, heat capacity, and species-standard generation free energy data from relevant thermodynamic databases, maps the 0 K ground-state energy to the Gibbs free energy under the high-temperature and high-pressure environment of a pressurized water reactor, and establishes a system considering... The concentration, pH, and activity-corrected free energy functions of the CRUD components are used to form free energy functions. Under the constraints of preset temperature, pressure, total element content, and charge conservation, the equilibrium solution unit constructs the total Gibbs free energy expression for the CRUD-coolant multiphase multicomponent closed system and solves the mass distribution results of each phase and component under equilibrium conditions based on the Gibbs free energy minimization method. The evaluation output unit outputs the thermodynamic stability range, phase composition evolution law, local supersaturation, precipitation driving force, and evaluation results of the effect of zinc injection on corrosion product deposition of each phase of CRUD under different zinc injection conditions, based on the mass distribution results.
[0006] The model building unit includes a component screening module, a unit cell model generation module, a calculation parameter configuration module, and a ground-state energy calculation module. Specifically: the component screening module determines the representative CRUD components to be calculated based on the composition information of the primary loop corrosion products of the pressurized water reactor and the chemical conditions of the zinc injection water, obtaining a set of candidate components including nickel ferrite, zinc ferrite, and nickel-zinc ferrite solid solutions; the unit cell model generation module, based on the candidate component set, performs crystal structure construction, cation occupancy setting, and different Zn / Ni ratio configuration processing to obtain the unit cell model corresponding to each CRUD component; the calculation parameter configuration module, based on the unit cell model and the electronic structure characteristics of transition metal ions, configures the spin-polarized DFT+U calculation parameters to obtain the first-principles calculation input file; the ground-state energy calculation module, based on the first-principles calculation input file, performs structural optimization and static energy calculation to obtain the ground-state energy results of each CRUD component at 0K.
[0007] The thermodynamic mapping unit includes: a thermodynamic data reading module, a temperature correction module, a chemical potential correction module, and a formation free energy construction module. Specifically: the thermodynamic data reading module reads parameters such as enthalpy, entropy, and heat capacity from the thermodynamic database based on the representative components of the CRUD and relevant species information in the coolant, obtaining fundamental thermodynamic data; the temperature correction module performs correction processing based on the ground-state energy result at 0K and the fundamental thermodynamic data, obtaining the Gibbs free energy correction term under high-temperature conditions; the chemical potential correction module calculates the Gibbs free energy correction term based on the temperature, pressure, pH, and other parameters of the pressurized water reactor's primary loop. Concentration and species activity information are used to perform chemical potential correction processing to obtain the chemical potential of each reactant species under different operating conditions; the formation free energy construction module constructs the formation free energy function of each CRUD component in the pressurized water reactor environment based on the ground state energy results, Gibbs free energy correction term and chemical potential.
[0008] The equilibrium solution unit includes: a constraint setting module, a total Gibbs free energy construction module, a GEM solution module, and an equilibrium result output module. Specifically: the constraint setting module establishes constraints for the multiphase, multi-component system based on preset temperature, pressure, total elemental content, charge conservation conditions, and zinc injection concentration conditions; the total Gibbs free energy construction module constructs the total Gibbs free energy expression for the CRUD-coolant system based on the formation free energy function and the constraints; the GEM solution module solves the multiphase, multi-component equilibrium system using the Gibbs free energy minimization method based on the total Gibbs free energy expression, obtaining the mass distribution of each phase and component under equilibrium conditions; and the equilibrium result output module outputs the equilibrium phase composition results under different zinc injection conditions based on the mass distribution.
[0009] The evaluation output unit includes: a phase stability analysis module, a phase composition evolution analysis module, a supersaturation calculation module, a precipitation driving force calculation module, and a zinc injection effect evaluation module. Specifically: the phase stability analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions; the phase composition evolution analysis module determines the thermodynamic stability range of different CRUD phases under different CRUD conditions based on the equilibrium phase composition results ... The equilibrium calculation results under concentration, pH, and temperature conditions are used to analyze the phase composition evolution of nickel ferrite, zinc ferrite, and nickel-zinc ferrite solid solutions. The supersaturation calculation module calculates the local supersaturation of each phase based on the concentration of the liquid phase component and the dissolution equilibrium relationship of the corresponding solid phase under equilibrium conditions. The precipitation driving force calculation module calculates the precipitation driving force of different CRUD phases based on the local supersaturation and the change in formation free energy. The zinc injection effect evaluation module outputs the evaluation results of the influence of zinc injection on the deposition behavior of corrosion products based on the thermodynamic stability range, phase composition evolution law, local supersaturation, and precipitation driving force.
[0010] This invention relates to the application of the zinc injection assessment system based on the effects of corrosion product deposition. After constructing a unit cell model based on the CRUD components and performing DFT+U calculations to obtain the ground-state energy at 0K, the 0K DFT energy is combined with enthalpy, entropy, and heat capacity data at high temperatures to construct an expression for the formation free energy of the CRUD components. By correcting the chemical potential of each substance under different operating conditions, the formation free energy of each CRUD component in a pressurized water reactor environment is obtained, and then the total Gibbs free energy expression of the system is constructed. Finally, the GEM method is used to solve the mass distribution of each component under equilibrium conditions, and the local supersaturation and precipitation driving force of each phase are calculated.
[0011] Technical effect
[0012] This invention utilizes an integrated technology chain of "DFT+U ground state energy calculation -> high-temperature formation free energy construction -> GEM equilibrium solution," and... Concentration, pH, and activity corrections are explicitly incorporated into the chemical potential expression of CRUD components to establish a quantitative correlation between zinc injection conditions and the driving forces of CRUD phase formation, transformation, and deposition. Compared with existing technologies that mainly rely on loop tests, empirical judgment, or comparison of the total amount of CRUD before and after zinc injection, this invention can systematically and quantitatively evaluate the impact of different zinc injection schemes on the dissolution-migration-deposition behavior of corrosion products under the high temperature and high pressure environment of a typical pressurized water reactor primary loop. Verification by examples shows that the relative error between the calculated zinc mass fraction in the CRUD and the experimental EDS detection results is only 3%. This invention is not only applicable to the evaluation of the growth behavior of corrosion product deposits (CRUD) on the surface of pressurized water reactor fuel cladding, but can also be extended to deposition problems under zinc injection conditions, such as fouling deposition on steam generator heat exchanger tubes and corrosion product deposition on the inner wall of main pipes. The application of this invention can provide evaluation of zinc injection concentration and timing, significantly improving the predictability and controllability of CRUD risks in reactors under zinc injection water chemistry conditions, and has important engineering value for protecting fuel assembly integrity, reducing radiation dose, and ensuring the long-term safe and stable operation of the unit. Attached Figure Description
[0013] Figure 1 This is a flowchart of an implementation example;
[0014] Figure 2 This is a schematic diagram of the CRUD component unit cell model;
[0015] In the diagram: a represents NiFe2O4, and b represents Zn. 0.5 Ni 0.5 Fe2O4, c is ZnFe2O4;
[0016] Figure 3 This is a schematic diagram of the CRUD-coolant system;
[0017] Figure 4 This is a graph showing the relationship between the Zn mass fraction in the sediment layer and temperature. Detailed Implementation
[0018] like Figure 1 As shown in the figure, this embodiment relates to an application of a zinc injection evaluation system, which includes a model building unit, a thermodynamic mapping unit, an equilibrium solution unit, and an evaluation output unit.
[0019] Step 1, construct as follows Figure 2 The unit cell model of the CRUD composition shown includes and several different proportions Solid solution.
[0020] Step 2: Based on first-principles calculations, spin-polarized DFT+U calculations are performed using VASP software in conjunction with pseudopotentials and plane-wave basis sets to obtain the ground-state energy at 0K. Specifically, the Brillouin zone (BZ) is sampled using the Monkhorst-Pack scheme, and the convergence criterion for the electronic iterative self-consistent process is set to 10. -5 eV, the force threshold for the ion relaxation process is set to 10 eV. -4 eV / Å, to ensure that the results are in a true local minimum energy state.
[0021] Step 3: Based on the SUPRT database, assuming the proton's chemical potential is 0 at a reference pH of 0, and by linking pH with hydrogen ion activity, a reaction simulation is performed under non-reference conditions. The reaction is then calculated based on the relationship between pH and H+. + The relationship between ionic strength and activity coefficient was used to derive the chemical potential of each substance under different operating conditions, and the formation free energy expressions for each component of CRUD in a pressurized water reactor environment were constructed, specifically as follows: ,in: Let x be the chemical potential of species x at temperature T. Let R be the standard chemical potential of species x at temperature T, and R be the gas constant. Let be the activity of species x, and pH be the acidity or alkalinity of the system. Let T be the standard Gibbs free energy of formation at temperature T. Let n be the total ground-state energy at 0 K, and n be the stoichiometric coefficient of the substance. Let i be the stoichiometric coefficient of the i-th product. Let be the stoichiometric coefficient of the j-th substance.
[0022] Step 4: Using the GEM equilibrium calculation method based on the principle of minimizing Gibbs free energy, the CRUD-coolant system is considered as a multiphase, multi-component closed system composed of water, solute, precipitated solid phase, and gas phase, such as... Figure 3 As shown. Under given temperature T, pressure P, and constraints on the total elemental content and charge conservation of the system, the amount of matter distribution of each phase and component in equilibrium is determined by solving for the minimum Gibbs free energy of the overall system. An expression for the total Gibbs free energy of the system is constructed, thereby obtaining the thermodynamic stability range and phase composition evolution law of each phase in CRUD under different zinc injection conditions. Specifically: , , , ,in: Let P be the total Gibbs free energy of the system under pressure P and temperature T. Let be the amount of substance of the k-th component. For identification purposes, Let be the chemical potential of the k-th component under given temperature, pressure, and activity conditions. Let be the standard chemical potential of the k-th component at a given temperature and pressure, A be the element conservation and charge conservation constraint matrix, n be the column vector consisting of the amounts of substance of each component, and b be the column vector consisting of the total element content and net charge constraints of the system. Let be the stoichiometric coefficient of the k-th component in the r-th independent reaction.
[0023] Step 5: The GEM method is used to solve for the mass distribution of each component under equilibrium conditions, and the local supersaturation and precipitation driving force of each phase are calculated. Specifically, in the CRUD-coolant multiphase multicomponent closed system established in Step 4, the equilibrium mass distribution of each component in the liquid, solid, and gas phases is obtained by minimizing the Gibbs free energy, with temperature T, pressure P, total element content, and charge conservation as constraints. Based on this, the local supersaturation and precipitation driving force of each potential precipitating phase are further calculated based on the equilibrium calculation results. The local supersaturation is used to characterize the degree of deviation of the system from the corresponding solid phase precipitation equilibrium state, and the precipitation driving force is characterized by the change in Gibbs free energy of the relevant precipitation reaction. When the change in Gibbs free energy of the reaction is less than 0, it indicates that the corresponding precipitation process has a thermodynamic tendency to proceed spontaneously. By comparing the calculation results under different zinc injection concentrations, pH values, and temperature and pressure conditions, the evolution law of phase composition, the change law of local supersaturation, and the change law of precipitation driving force of each phase in CRUD are obtained, thereby realizing a quantitative assessment of the influence of zinc injection on the deposition behavior of corrosion products.
[0024] Through practical application experiments, under typical pressurized water reactor (PWR) operating conditions, the VASP software completed the CRUD component 0K ground-state energy calculation described in step 2, the SUPRT thermodynamic database was used to complete the standard thermodynamic data reading and chemical potential correction described in step 3, and the GEM equilibrium solver was used to complete the multiphase and multicomponent equilibrium calculations and precipitation trend analysis described in steps 4 and 5. Using the typical high-temperature and high-pressure operating conditions of the primary loop of a PWR as input conditions, and setting the total amounts of Zn, Ni, Fe, and other elements and corresponding hydrochemical conditions under different temperature conditions, the zinc injection evaluation system based on the influence of corrosion product deposition of this invention was run to obtain the results of the Zn mass fraction in the deposition layer changing with temperature, such as... Figure 4 As shown in the figure. The results indicate that the Zn mass fraction in the deposition layer first increases and then decreases with increasing temperature: at approximately 425 K, the Zn mass fraction is approximately 0.11%; it reaches a peak of approximately 0.24% at approximately 490 K; and then gradually decreases with further temperature increases, dropping to approximately 0.21% at approximately 600 K. Furthermore, comparing the calculated zinc mass fraction in the CRUD with the experimental EDS detection results shows that the relative error between the two is only 3%, indicating that the present invention can accurately reflect the compositional changes and deposition behavior of the CRUD under zinc injection conditions, and has good evaluation accuracy.
[0025] Through calculation and comparative verification, the thermodynamic calculation results obtained by the above steps can reasonably predict the equilibrium composition and precipitation trend of each phase in the CRUD under zinc injection conditions. The prediction results are in good agreement with the high temperature solubility test and the unit shutdown sampling analysis data: under typical zinc injection conditions, the relative error between the calculated zinc mass fraction in the CRUD and the experimental EDS detection results is only 3%.
[0026] Compared with existing technologies that mainly rely on empirical analysis based on changes in total CRUD before and after zinc injection or loop test phenomena, making it difficult to quantitatively characterize the effects of zinc injection from the perspectives of phase composition and thermodynamic driving forces, this invention uses coupled DFT calculations, semi-empirical thermodynamic models, and GEM equilibrium solutions, and explicitly introduces chemical potential into the expression. By varying the injection volume and pH, the system can output the equilibrium composition, local supersaturation, and precipitation trends of the CRUD phases at different locations under various zinc injection conditions, enabling a quantitative assessment of the impact of zinc injection on corrosion product deposition behavior. Verification through examples shows that the relative error between the calculated zinc mass fraction within the CRUD and the experimental EDS detection results is only 3%, indicating that the invention has good assessment accuracy. Furthermore, the phase composition and thermodynamic driving force obtained by this invention can be directly used as input boundary conditions for CFD programs or subchannel programs, thereby improving the predictability of zinc injection water chemistry scheme design optimization.
[0027] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.
Claims
1. A zinc injection evaluation system based on the influence of corrosion product deposition, characterized in that, include: The system comprises a model building unit, a thermodynamic mapping unit, an equilibrium solution unit, and an evaluation output unit. Specifically: the model building unit constructs solid solution models for nickel ferrite, zinc ferrite, and different ratios based on representative corrosion product components, and calculates the ground-state energy of each CRUD component at 0 K using spin-polarized DFT+U. The thermodynamic mapping unit collects enthalpy, entropy, heat capacity, and species-standard generation free energy data from relevant thermodynamic databases, maps the 0 K ground-state energy to the Gibbs free energy under the high-temperature and high-pressure environment of a pressurized water reactor, and establishes a system considering... The concentration, pH, and activity-corrected free energy functions of the CRUD components are used to form free energy functions. Under the constraints of preset temperature, pressure, total element content, and charge conservation, the equilibrium solution unit constructs the total Gibbs free energy expression for the CRUD-coolant multiphase multicomponent closed system and solves the mass distribution results of each phase and component under equilibrium conditions based on the Gibbs free energy minimization method. The evaluation output unit outputs the thermodynamic stability range, phase composition evolution law, local supersaturation, precipitation driving force, and evaluation results of the effect of zinc injection on corrosion product deposition of each phase of CRUD under different zinc injection conditions, based on the mass distribution results.
2. The zinc injection evaluation system based on the influence of corrosion product deposition according to claim 1, characterized in that, The model building unit includes a component screening module, a unit cell model generation module, a calculation parameter configuration module, and a ground-state energy calculation module. Specifically: the component screening module determines the representative CRUD components to be calculated based on the composition information of the primary loop corrosion products of the pressurized water reactor and the chemical conditions of the zinc injection water, obtaining a set of candidate components including nickel ferrite, zinc ferrite, and nickel-zinc ferrite solid solutions; the unit cell model generation module performs crystal structure construction, cation occupancy setting, and different Zn / Ni ratio configuration processing based on the candidate component set to obtain the unit cell model corresponding to each CRUD component; the calculation parameter configuration module configures the spin-polarized DFT+U calculation parameters based on the unit cell model and the electronic structure characteristics of transition metal ions, obtaining the first-principles calculation input file; and the ground-state energy calculation module performs structural optimization and static energy calculation based on the first-principles calculation input file to obtain the ground-state energy results of each CRUD component at 0K.
3. The zinc injection evaluation system based on the influence of corrosion product deposition according to claim 1, characterized in that, The thermodynamic mapping unit includes: a thermodynamic data reading module, a temperature correction module, a chemical potential correction module, and a formation free energy construction module. Specifically: the thermodynamic data reading module reads parameters such as enthalpy, entropy, and heat capacity from the thermodynamic database based on CRUD representative components and relevant species information in the coolant, obtaining fundamental thermodynamic data; the temperature correction module performs correction processing based on the ground-state energy result at 0K and the fundamental thermodynamic data, obtaining the Gibbs free energy correction term under high-temperature conditions; the chemical potential correction module, based on the temperature, pressure, pH, and other parameters of the pressurized water reactor's primary loop... Concentration and species activity information are used to correct chemical potentials to obtain the chemical potentials of each reactant species under different operating conditions. The formation free energy construction module constructs the formation free energy function of each CRUD component in a pressurized water reactor environment based on the ground state energy results, Gibbs free energy correction terms, and chemical potentials.
4. The zinc injection evaluation system based on the influence of corrosion product deposition according to claim 1, characterized in that, The equilibrium solution unit includes: a constraint setting module, a total Gibbs free energy construction module, a GEM solution module, and an equilibrium result output module. Specifically: the constraint setting module establishes constraints for the multiphase, multi-component system based on preset temperature, pressure, total elemental content, charge conservation conditions, and zinc injection concentration conditions; the total Gibbs free energy construction module constructs the total Gibbs free energy expression for the CRUD-coolant system based on the formation free energy function and constraints; the GEM solution module solves the multiphase, multi-component equilibrium system using the Gibbs free energy minimization method based on the total Gibbs free energy expression, obtaining the mass distribution of each phase and component under equilibrium conditions; and the equilibrium result output module outputs the equilibrium phase composition results under different zinc injection conditions based on the mass distribution.
5. The zinc injection evaluation system based on the influence of corrosion product deposition according to claim 1, characterized in that, The evaluation output unit includes: a phase stability analysis module, a phase composition evolution analysis module, a supersaturation calculation module, a precipitation driving force calculation module, and a zinc injection effect evaluation module. Specifically: the phase stability analysis module determines the thermodynamic stability range of different CRUD phases under different zinc injection conditions based on the equilibrium phase composition results; the phase composition evolution ... The equilibrium calculation results under concentration, pH, and temperature conditions are used to analyze the phase composition evolution of nickel ferrite, zinc ferrite, and nickel-zinc ferrite solid solutions. The supersaturation calculation module calculates the local supersaturation of each phase based on the concentration of liquid phase components and the dissolution equilibrium relationship of the corresponding solid phase under equilibrium conditions. The precipitation driving force calculation module calculates the precipitation driving force of different CRUD phases based on the local supersaturation and the change in formation free energy. The zinc injection effect evaluation module outputs the evaluation results of the impact of zinc injection on the deposition behavior of corrosion products based on the thermodynamic stability range, phase composition evolution law, local supersaturation, and precipitation driving force.
6. An application of the system according to any one of claims 1-5, characterized in that, After constructing a unit cell model based on the CRUD components and performing DFT+U calculations to obtain the ground state energy at 0K, the 0K DFT energy is combined with enthalpy, entropy, and heat capacity data at high temperatures to construct the formation free energy expression for the CRUD components. By correcting the chemical potential of each substance under different operating conditions, the formation free energy of each CRUD component in a pressurized water reactor environment is obtained, and then the total Gibbs free energy expression of the system is constructed. Finally, the GEM method is used to solve the mass distribution of each component in equilibrium state and to calculate the local supersaturation and precipitation driving force of each phase.
7. The application according to claim 6, characterized in that, The ground state energy at 0K was obtained by spin-polarized DFT+U calculation using VASP software in combination with pseudopotential and plane-wave basis set. Specifically, the Brillouin zone (BZ) was sampled using the Monkhorst-Pack scheme, and the convergence criterion of the electronic iterative self-consistent process was set to 10. -5 eV, the force threshold for the ion relaxation process is set to 10 eV. -4 eV / Å, to ensure that the results are in a true local minimum energy state.
8. The application according to claim 6, characterized in that, The aforementioned expression for the formation free energy of the CRUD component refers to: based on the SUCRT database, assuming the proton chemical potential is 0 at a reference pH of 0, and by relating pH to hydrogen ion activity, performing reaction simulations under non-reference conditions, and based on pH and H... + The relationship between ionic strength and activity coefficient was used to derive the chemical potential of each substance under different operating conditions, and the formation free energy expressions of each component of CRUD in a pressurized water reactor environment were constructed, specifically as follows: ,in: Let x be the chemical potential of species x at temperature T. Let R be the standard chemical potential of species x at temperature T, and R be the gas constant. Let be the activity of species x, and pH be the acidity or alkalinity of the system. Let T be the standard Gibbs free energy of formation at temperature T. Let n be the total ground-state energy at 0 K, and n be the stoichiometric coefficient of the substance. Let i be the stoichiometric coefficient of the i-th product. Let be the stoichiometric coefficient of the j-th substance.
9. The application according to claim 6, characterized in that, The aforementioned expression for the total Gibbs free energy of the system refers to: using the GEM equilibrium calculation method based on the principle of minimizing Gibbs free energy, the CRUD-coolant system is considered as a multiphase, multi-component closed system composed of water, solute, precipitated solid phase, and gas phase. Under given temperature T, pressure P, and constraints on the total element content and charge conservation of the system, the amount of matter distribution of each phase and component in equilibrium is determined by solving for the minimum value of the overall system's Gibbs free energy, thus constructing the expression for the total Gibbs free energy of the system. This allows for the acquisition of the thermodynamic stability range and phase composition evolution law of each phase of CRUD under different zinc injection conditions. Specifically: , , , ,in: Let P be the total Gibbs free energy of the system under pressure P and temperature T. Let be the amount of substance of the kth component. For identification purposes, Let be the chemical potential of the k-th component under given temperature, pressure, and activity conditions. Let be the standard chemical potential of the k-th component at a given temperature and pressure, A be the element conservation and charge conservation constraint matrix, n be the column vector consisting of the amounts of substance of each component, and b be the column vector consisting of the total element content and net charge constraints of the system. Let be the stoichiometric coefficient of the k-th component in the r-th independent reaction.
10. The application according to claim 6, characterized in that, The aforementioned method of using GEM to solve for the mass distribution of each component under equilibrium conditions refers to: in a CRUD-coolant multiphase multicomponent closed system, under the constraints of temperature T, pressure P, total element content of the system, and charge conservation, the equilibrium mass distribution of each component in the liquid, solid, and gas phases is obtained by minimizing the Gibbs free energy. Based on this, the local supersaturation and precipitation driving force of each potential precipitating phase are further calculated based on the equilibrium calculation results. The local supersaturation is used to characterize the degree of deviation of the system from the precipitation equilibrium state of the corresponding solid phase, and the precipitation driving force is characterized by the change of Gibbs free energy of the relevant precipitation reaction. When the change of Gibbs free energy of the reaction is less than 0, it indicates that the corresponding precipitation process has a thermodynamic tendency to proceed spontaneously. By comparing the calculation results under different zinc injection concentrations, different pH values, and different temperature and pressure conditions, the phase composition evolution law, local supersaturation change law, and precipitation driving force change law of each phase of CRUD are obtained, thereby achieving a quantitative assessment of the influence of zinc injection on the deposition behavior of corrosion products.