Nuclear power plant having a water chemistry control system for a primary cooling system thereof and an operation method thereof

A primary cooling system of a boiling water nuclear reactor, characterized by comprising:

• means for sensing a physical quantity of a specific factor of factors determining a water chemistry around at least one first specific portion of the primary cooling system;
• means for estimating the water chemistry at at least one second specific portion of the primary cooling system different from said first specific portion on basis of the measured value and data base stored in a memory device;
• and
• means for injecting an agent for mitigating corrosion damage of structural material of the primary cooling system into the primary cooling system so that a conjectural value obtained by said estimating means will be within a target range.

A primary cooling system of a boiling water nuclear reactor, characterized by a water chemistry control system comprising:

• a plurality of water chemistry sensors provided in flow passages of water or steam of the primary cooling system at different portions;
• means for detecting or estimating a water chemistry at least one specific portion of said primary cooling system;
• and
• at least one injection device for injecting an agent for improvement of the water chemistry to mitigate corrosion damage of said primary cooling system.

A water chemistry control method of a nuclear power plant, comprising the steps of:

• measuring at least a physical quantity representative of water chemistry at a first portion of a primary cooling system of the nuclear power plant;
• estimating a value representative of water chemistry at a second portion of said primary cooling system different from said first portion on the basis of a measures value in said measuring step and data stored in a memory device obtain a estimated value concerning the water chemistry around said second portion;
• and
• controlling the water chemistry around said second portion according to said estimated value.

A water chemistry control method of a nuclear power plant, comprising the steps of:

• monitoring, on the basis of water chemistry information and radiolysis production concentration distribution around structural material at various portions of the primary cooling system and on the basis of flow rate distribution, dose rate distribution at the various portions of the primary cooling system, electro-chemical potential of the structural material under water chemistry conditions of each the portion of the primary cooling system in the reactor;
• comparing the electro-chemical potential with a standard electro-chemical potential value set in advance;
• and
• controlling the water chemistry on the basis of the compared results.

A water chemistry control method of a nuclear power plant, comprising the steps of:

• monitoring, on the basis of water chemistry information and radiolysis production concentration distribution around structural material at various portions of the primary cooling system and on the basis of flow rate distribution, dose rate distribution at the various portions of the primary cooling system, electro-chemical potential distribution and SCC sensibility distribution of the structural material under water chemistry conditions of each the portion of the primary cooling system in the reactor;
• comparing monitored values with a standard electro-chemical potential value and a standard SCC sensibility value set in advance;
• and
• controlling the water chemistry on the basis of the compared results.