Monitoring system for plant operation condition and its in-situ electrochemical electrode

• US 5,203,984 A
• Filed: 08/28/1990
• Issued: 04/20/1993
• Est. Priority Date: 09/11/1989
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Suwa, Masateru, Akahori, Kimihiko, Hayashi, Makoto, Mabuchi, Katsumi, Takahashi, Takuya, Sakai, Masanori, Kojima, Yoshitaka, Sato, Fumio, Arato, Toshiaki, Inagaki, Masahisa, Ohsumi, Katsumi, Izumiya, Masakiyo, Masaoka, Isao
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Bell, Bruce F.
• Application Number:
  US07/573,780
• Time in Patent Office: 966 Days
• Field of Search: 204/153.1, 204/400, 204/433, 204/435
• US Class Current: 204/435
• CPC Class Codes: G01N 27/30 Electrodes, e.g. test electrodes; Half-cells G01N27/414 takes precedence
• CPC Class Codes: G01N 33/18 Water
• CPC Class Codes: G21C 17/022 for monitoring liquid coolants or moderators
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors
• CPC Class Codes: Y10S 706/906 Process plant

Abstract

A plant operational status monitoring supervisory system comprising; means for extracting information directly relating to water quality of an objective portion consecutively for a period of time by means of an electrochemical water quality sensor installed in an objective portion to monitor in-situ in a plant; means for evaluating water quality based on thus extracted information; means for comparing an obtained water quality evaluation result with a reference value for a predetermined plant operation procedure; and means for displaying or storing necessary portion out of said comparison results; is disclosed.

An electrochemical reference electrode used in this system being provided with an electrolyte layer containing ion of the electrode member; a porous ceramic layer surrounding the same without permeating liquid; and electrode member electrochemically contacting with said elec-trolyte layer; and a terminal electrically contacting with said electrode member; and further having a long life in high temperature water, various status of high temperature water in objective portions and that of nearby constituent members in a plant are possible to be monitored online by means of this reference electrode.

Further, because monitored data are processed by means of a neural network, the higher precision level of monitoring has been achieved.

Claims

1. A monitoring system for plant operating conditions comprising:

means for sampling consecutively information directly relating to high temperature water quality in an objective monitoring section of the plant for a certain period with an electrochemical water quality sensor disposed in said objective monitoring section;

means for evaluating the water quality based on the sampled information;

means for comparing the obtained results of the water quality evaluation with a predetermined reference value for the plant operation and manipulation; and

means for displaying or recording necessary portions of said comparison result;

wherein, said electrochemical water quality sensor is an electrochemical cell comprising a reference electrode member provided with an electrolyte layer containing ions of the reference electrode material, a porous layer which is made of ceramic or resin in contact with and surrounding the electrolyte layer and which is non-liquid-permeable but ion-permeable, a counter electrode member disposed in electrochemical relation with said electrolyte layer, said porous layer being in contact with and surrounding said reference electrode and said electrolyte so that said high temperature water does not directly contact said electrode and electrolyte, whereby dissolution of said reference electrode material into said high temperature water is substantially suppressed but said reference electrode is in electrochemical communication with said water, and terminals electrically contacting with said electrode members.

7. A monitoring system for plant operating conditions according to claim 1, wherein said porous layer is a ceramic layer with microscopic apertures covering a solid electrolyte or an electrochemical material formed over electrodes of supporting member.

8. A monitoring system for plant operating conditions according to claim 1, wherein said sensor comprises at least two kids of sensors for sensing dissolving hydrogen (DH), dissolving oxygen (DO), hydrogen ion concentration (pH), reference electrode (ECP), solution electric conductivity (S), dissolving hydrogen peroxide (DH₂ O₂) and crack (M).

2. A monitoring system for plant operating conditions comprising:

means for sampling consecutively information directly relating to high temperature water quality in an objective monitoring section of the plant in a period from one inspection to the next inspection of the plant with an electrochemical water quality sensor disposed in said objective monitoring section of the plant;

means for evaluating the water quality based on the sampled information;

means for comparing the obtained results of water quality evaluation with a predetermined reference value for the plant operation and manipulation; and

means for displaying or recording necessary portions of said comparison result;

wherein said electrochemical water quality sensor comprises an electrochemical reference electrode provided with a solid electrolyte layer containing ions of the reference electrode member, a porous ceramic layer in contact with and surrounding the electrolyte layer, a counter electrode member disposed in electrochemical relation with said electrolyte layer, a heat resistant porous ceramic overcoat layer surrounding said ceramic layer which is non-liquid-permeable but ion-permeable, said porous layer being in contact with surrounding said reference electrode and said electrolyte so that said high temperature water does not directly contact said electrode and electrolyte, whereby dissolution of said reference electrode material into said high temperature water is substantially suppressed but said reference electrode is in electrochemical communication with said water, and terminals electrically contacting said electrode members.

13. A monitoring system for plant operating conditions according to claim 2, wherein said porous ceramic layer is a ceramic layer with microscopic apertures covering a solid electrolyte formed over said electrodes.

14. A monitoring system for plant operating conditions according to claim 2, wherein said sensor comprises at least two kinds of sensors for sensing dissolved hydrogen (DH), dissolved oxygen (DO), hydrogen ion concentration (pH), reference electrodes (ECP), solution electric conductivity (S), dissolved peroxide (DH₂ O₂) and crack length (M).

3. A monitoring system for plant operating conditions comprising:

means for sampling consecutively information directly relating to high temperature water quality in an objective monitoring section of the plant in a predetermined period with a electrochemical water quality sensor disposed in said objective monitoring section of the plant and in which the high temperature water in said objective monitoring sections contacts electrochemically with electrolyte through a porous material, said electrochemical water quality sensor comprising a reference electrode, an electrolyte body in contact with said reference electrode, a counter electrode disposed in electrochemical relation with said reference electrode, a porous layer of water-impermeable, ion-permeable and heat resistant material, and terminal electrically contacting with said electrodes, said porous layer being in contact with and surrounding said reference electrode and said electrolyte so that said high temperature water does not directly contact said electrode and electrolyte, whereby dissolution of said reference electrode material into said high temperature water is substantially suppressed but said reference electrode is in electrochemical communication with said water;

means for analyzing the water quality based on the sampled information;

means for comparing the obtained results of water quality analyzation with a predetermined reference value for the plant operation and manipulation; and

means for displaying or recording necessary portions of the resulting comparison.

15. A monitoring system for plant operating conditions according to claim 3, wherein said porous layer is a ceramic layer with microscopic apertures covering a solid electrolyte formed over said electrodes.

16. A monitoring system for plant operating conditions according to claim 3, wherein said sensor comprises at least two kinds of sensors for sensing dissolved hydrogen (DH), dissolved oxygen (DO), hydrogen ion concentration (pH), reference electrode (ECP), solution electric conductivity (S), dissolved peroxide (DH₂ O₂) and crack length (M).

4. A monitoring system for plant operating conditions comprising:

means for sampling consecutively information directly relating to water quality of high temperature water in an objective monitoring section of the plant in a predetermined period with an electrochemical water quality sensor disposed in said objective monitoring section of the plant and in which the high temperature water in said objective monitoring section contacts electrochemically with an electrolyte through a porous material substantially suppressing dissolution of the electrolyte to the high temperature water, said electrochemical water quality sensor comprising a reference electrode in contact with an electrolyte material, a heat resistant, insoluble, a porous material layer in contact with and a surrounding said reference electrode and said electrolyte material so as to substantially isolate the electrode and electrolyte from the water, a terminal electrically contacting said reference electrode, a pH electrode disposed in electrochemical relation with said reference electrode and surrounded by the heat resistant, insoluble, porous material, and a terminal electrically contacting said pH electrode, whereby dissolution of said reference electrode and pH electrode into high temperature water is substantially suppressed but said electrodes are electrochemically communicated with said high temperature water;

means for analyzing the water quality based on the sampled information;

means for comparing the obtained results of water quality analyzation result with a predetermined reference value for the plant operation and manipulation; and

means for displaying and/or recording necessary portions of the resulting comparison information.

5. A monitoring system for plant operating conditions comprising:

means for analyzing consecutively water quality in a circulation water line or a storage water line in a period from a periodic inspection to the next inspection of the plant with an electrochemical sensor disposed in said objective monitoring section of the plant including high temperature water, said electrochemical sensor comprising a reference electrode in contact with an electrolyte material, a heat resistant, insoluble, porous material layer in contact with an completely surrounding said reference electrode and said electrolyte material, a terminal electrically contacting said reference electrode, a pH electrode disposed in electrochemical relation with said reference electrode and surrounded by the heat resistant, insoluble, porous material, and a terminal electrically contacting said pH electrode, whereby dissolution of said reference electrode and pH electrode into high temperature water is substantially suppressed but said electrodes re electrochemically communicated with said high temperature water;

means for displaying the analyzed result;

means for selecting a predetermined reference value for the plant operation and manipulation in response to the analyzed water quality result;

means for predicting variation of said reference value based on the mutual relationship between the analyzed result and the reference value for the plant operation and manipulation; and

means for controlling water quality.

6. A monitoring system for plant operating conditions comprising:

means for analyzing consecutively water quality in a circulation water line or a storage water line in a period from a periodic inspection to the next inspection of the plant with an electrochemical sensor disposed in said objective monitoring section of the plant including high temperature water and for outputting data relating to at least pH, an amount dissolved oxygen and concentration of dissolved hydrogen, said electrochemical sensor comprising a reference electrode, an electrolyte body in contact with said reference electrode, a counter electrode disposed in electrochemical relation with said electrolyte a porous layer of water impermeable, ion-permeable and heat resistant material, and terminals electrically contacting said electrodes, said porous layer being in contact with and substantially isolating said electrode and electrolyte from the water, whereby dissolution of said reference electrode material into said high temperature water is substantially suppressed but said reference electrode is electrochemically communicated with said water;

means for displaying the analyzed result;

means for selecting a predetermined reference value for the plant operation and manipulation in response to the analyzed water quality result;

means for predicting variation of said reference value based on the mutual relationship between the analyzed result and the reference value for the plant operation and manipulation; and

means for controlling water quality.

9. An electrochemical reference electrode comprising:

a solid electrolyte layer containing ion of the electrode member, a porous ceramic layer or porous resin layer surrounding the same, which is non-liquid-permeable, an electrode member electro-chemically contacting with said electrolyte layer, a heat resistant porous overcoat layer surrounding said ceramic layer or resin layer, and a terminal electrically contacting with said electrode material.

10. An electrochemical electrode comprising an electrolyte layer composed of halogenated substance of the electrode, a porous ceramic layer or porous resin layer surrounding the same, which is non-liquid-permeable, an electrode member electrochemically contacting with said electrolyte layer, a sheath protecting said ceramic layer or resin layer and providing an aperture for communicating part of said ceramic layer or resin layer with a liquid to be tested, and a terminal electrically contacting with said electrode member.

11. An electrochemical electrode characterized by comprising a solid electrolyte layer containing positive ion and halogen ion of the electrode member, a porous ceramic layer or resin layer surrounding the same, a porous insulation layer surrounding said porous ceramic layer or resin layer preventing liquid permeance but allowing ion permeance, a metal electrode member electrochemically contacting with said electrolyte layer, a sheath protecting said ceramic layer or resin layer and providing an aperture for communicating part of said ceramic layer or resin layer with a liquid to test, and a terminal electrically contacting with said electrode member.

12. An electrochemical electrode comprising a solid electrolyte layer containing an oxide of the electrode member, a porous ceramic layer or resin layer surrounding the above, a porous insulation layer surrounding said porous ceramic layer or resin layer preventing liquid permeance but allowing ion permeance, a metal electrode member electrochemically contacting with said electrolyte layer, a sheath protecting said ceramic layer or resin layer and providing an aperture for communicating part of said ceramic layer or resin layer with a liquid to be tested, and a terminal electrically contacting with said electrode member.