Solution quantitative analysis apparatus, quantitative analysis methods, and nuclear reactor water quality control system

• US 4,937,038 A
• Filed: 12/08/1988
• Issued: 06/26/1990
• Est. Priority Date: 12/11/1987
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mabuchi, Katsumi, Takahashi, Takuya, Sakai, Masanori, Kikuchi, Eiji, Ohsumi, Katsumi, Ohnaka, Noriyuki
• Primary Examiner(s): Wasil, Daniel
• Application Number:
  US07/281,212
• Time in Patent Office: 565 Days
• Field of Search: 376/245, 376/256, 204/1 T, 204/1 Y, 204/400, 204/412, 204/413, 204/434, 436/135, 436/153, 422/80, 73/26, 73/27 R, 73/61.1 R, 73/61.1 C, 73/863
• US Class Current: 376/245
• CPC Class Codes: G01N 27/42 Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte
• CPC Class Codes: Y10T 436/206664 Ozone or peroxide

Abstract

This invention comprises electrochemical analytical devices capable of performing electrolysis in multiple pulse modes. It relates to a method of quantitative analysis and equipment for performing quantitative analysis which uses a combinaiton of these pulse modes to realize the measurement of concentrations of multiple substances to be measured, occurring in the test solution to be measured and also a nuclear reactor water quality control system employing such a quantitative analysis method.

Claims

1. A quantitative analysis method for analysis of reactor water in a nuclear reactor which comprises the process for contacting three electrodes of a working electrode, a counter electrode, and a reference electrode in an electrolytic cell with the reactor water in at least one location in the primary water-based cooling system in a nuclear reactor;

a process for electrolyzing the reactor water by applying three types of different voltage-time waveform signals to the electrolytic cell;

a process for determining the limiting current or peak current values, according to the kind of voltammetry employed, from the electrolysis current resulting from said electrolysis process and the voltage required to produce the electrolysis current; and

a process for computing the concentrations of the H₂, O₂, and H₂ O₂ in reactor water, based on the limiting current or peak current values thus determined.

2. The quantitative analysis for analysis of reactor water in a nuclear reactor method of claim 1, wherein the reactor water is brought into contact with the three electrodes in the electrolytic cell through a hydrophobic gas-permeable membrane.

3. The quantitative analysis method for analysis of reactor water in a nuclear reactor of claim 1, wherein the three electrodes in the electrolytic cell is brought into contact with the reactor water in the reactor by installing them in an in-reactor instrumentation column in the nuclear reactor.

4. A nuclear reactor water quality control system in which comprises a means of performing quantitative analysis, based on electrolysis, on the reactor water from the primary water-based cooling system of a nuclear reactor, and a means of controlling the water quality of reactor water, based on the results obtained from said quantitative analysis means, wherein said water quality control system comprises the following components:

an electrode housing unit in an electrolytic cell, which is installed in at least one location in the said primary water-based cooling system so that the cell will come into contact with reactor water;

a signal discharge unit which applies voltage-time wave signals having specified parameters to a working electrode in the said electrolytic cell as a reference electrode standard voltage;

a signal input unit which inputs to the signal discharge unit voltage-time waveform signals having parameters which are determined by the type of voltammetry utilized, for each chemical species occurring in the primary water-based cooling system, and by changing the parameter for each chemical species involved;

a storage unit which stores in memory the results of the voltammetry performed according to the signals supplied by the signal discharge unit, as a relationship between the electrolysis current and the voltage required to produce the electrolysis current;

a current value determination unit which processes the data stored in the storage unit and which determines the limiting current or peak current, according to the type of voltammetry employed;

a concentration computation unit which calculates the concentrations of the desired chemical species in the reactor water, based on the limiting current or peak current values thus determined; and

a reactor water control means which regulates the water quality of the reactor water, based on the information produced by the concentration computation unit.

5. The nuclear reactor water quality control system of claim 4, wherein the voltage-time waveform signals which are input to the signal discharge unit comprises pulse mode waveform signals.

6. The nuclear reactor water quality control system of claim 4, wherein the chemical species computed by the concentration computation unit comprise at least one among H₂, O₂, and H₂ O₂.

7. The nuclear reactor water quality control system of claim 4, wherein the electrolytic cell electrode housing unit is installed in the reactor core in the nuclear reactor.

8. The nuclear reactor water quality control system of claim 4, wherein the electrolytic cell electrode housing unit is installed in an electrolytic cell electrode housing unit is installed in an in-reactor instrumentaion column in the nuclear reactor.

9. The nuclear reactor water quality control system of claim 4, wherein the electrolytic cell electrode housing unit is installed on the reactor core outlet side of the primary water-based cooling system.

10. The nuclear reactor water quality control system of claim 4, wherein the electrolytic cell electrode housing unit is installed in the water vapor separator unit in the reactor.

11. The nuclear reactor water quality control system of claim 6, wherein the reactor water control means comprise a means of regulating the amount of H₂ gas that is injected into the primary water-based cooling system.

12. The nuclear reactor water quality control system of claim 6, wherein the reactor water control means comprise a means of regulating the amount of N₂ H₄ that is injected into the water vapor generator in the reactor.

13. The nuclear reactor water quality control system of claim 12, wherein the quantity of N₂ H₄ that is injected into the vapor generator is based on the quantitative analysis of dissolved O₂ gas in the primary water-based cooling system, computed by the concentration computation unit.

14. The nuclear reactor water quality control system of claim 4, wherein said system comprises a comparison unit which converts concentration values produced by the concentration computation unit to conductivity values and compares them with standard values, and reactor water control means that regulates the water quality in the reactor water by maintaining said converted values below standard values.

15. The nuclear reactor water quality control system of claim 4, wherein said system comprises a function generator between the signal discharge unit and the signal input unit, and the waveform signals produced by the signal input unit are entered in the signal discharge unit through the function generator.

16. A nuclear reactor water quality control system which comprises a means of performing quantitative analysis, based on electrolysis, on the reactor water from the primary water-based cooling system of the nuclear reactor, and a means of controlling the water quality of reactor water, based on the results obtained from the above quantitative analysis means, wherein the said water quality control system comprises the following components:

an electrode housing unit in an electrolytic cell, which is installed in at least one location in the said primary water-based cooling system so that the cell will come into contact with reactor water;

a signal discharge unit which applies voltage-time wave signals having specified parameters to a working electrode in said electrolytic cell as a reference electrode standard voltage;

a signal input unit which inputs to the signal discharge unit voltage-time waveform signals having parameters which are determined by the kind of voltammetry utilized, for each chemical species occurring in the primary water-based cooling system, and by changing the parameter for each chemical species involved;

a storage unit which stores in memory the results of the voltammetry performed according to the signals supplied by the signal discharge unit, as a relationship between the electrolysis current and the voltage required to produce the electrolysis current;

a current value determination unit which processes the data stored in the storage unit and which determines the limiting current or peak current, according to the kind of voltammetry employed;

a concentration computation unit which calculates the concentrations of the desired chemical species int he reactor water, based on the limiting current or peak current values thus determined;

a comparison unit which compares the results of the said concentration computation unit with standard values; and

a reactor water control means which regulates the water quality of the reactor water, based on the information produced by the comparison unit.

17. The nuclear reactor water quality control system of claim 16, wherein the provision of a comparison unit which compares with standard values the quality of at least one dissolved gas from among H₂, O₂, and H₂ O.sub. 2 in the primary cooling water;

and a means of regulating the quantity of at least one of the gas H₂, O₂, and H₂ O₂ in the primary cooling water; and

a means of regulating the quantity of at least one of the gases H₂, O₂, H₂ O₂, that is injected into the reactor water, based on the information produced by the comparison unit.

18. The nuclear reactor water quality control system of claim 16, wherein the provided concentration computation unit generates equations in which the concentrations of the substances measured, and present in the reactor water, are treated as unknown variables, based on the limiting current or peak current values determined by the current determination unit;

and calculates the concentrations of the substances by solving the set of equations.

19. The nuclear reactor water quality control system of claim 16, wherein said system comprises a means of measuring at least one of the following:

reactor water conductivity, pH, or electric potential, at sampling points in the primary water-based cooling system;

a comparison unit which compares the results of measurements with standard values; and

the reactor water control means that regulates the water quality in the reactor water, based on the information produced by the said comparison unit and the said concentration comparison unit.

20. The nuclear reactor water quality control system of claim 16, wherein said system comprises a monitoring system which monitors the proper operation of the signal input unit, signal discharge unit, concentration computation unit, and comparison unit.

21. The nuclear reactor water quality control system of claim 20, wherein said system comprises a means of generating an alarm in the event that a malfunction is detected by the monitoring system.

22. A nuclear reactor preventive safety assurance system which comprises a means of performing quantitative analysis of reactor water in the primary water-based cooling system by electrolysis, and a means of generating an alarm when the results obtained by the quantitative analysis means exceeds a standard value;

wherein said nuclear reactor preventive safety assurance system comprises the following components;

an electrode housing unit in an electrolytic cell, which is installed in at least one location in the said primary water-based cooling system so that the cell comes into contact with reactor water;

a signal discharge unit which applies voltage-time wave signals having specified parameters to a working electrode in the said electrolytic cell as a reference electrode standard voltage;

a signal input unit which inputs to the signal discharge unit voltage-time waveform signals having parameters which are determined by the kind of voltammetry utilized, for each chemical species occurring in the primary water-based cooling system, and by changing the parameter for each chemical species involved;

a storage unit which stores in memory the results of the voltammetry performed according to the signals supplied by the signal discharge unit, as a relationship between electrolysis current and the voltage required to produce the electrolysis current;

a current value determination unit which processes the data stored in the storage unit and which determines the limiting current or peak current, according to the type of voltammetry employed;

a concentration computation unit which calculates the concentrations of the desired chemical species in the reactor water, based on the limiting current or peak current values thus determined;

a comparison unit which compares the results produced by the concentration computation unit with standard values; and

an alarm generation means which generated an alarm when the results from the concentration computation unit exceeds a standard value.

23. The nuclear reactor preventive safety assurance system of claim 22, wherein said system comprises a means of measuring the concentrations of SO₄^2-, SO₃ -, Cl-, and Na⁺ ions, which are breakdown products of the nuclear reactor cleaning chemical resins in the primary water-based cooling system;

and a means of generating an alarm when any one of the ionic concentrations exceeds a standard value.

24. A nuclear reactor water accident prevention system which comprises a means of performing quantitative analysis of reactor water in the primary water-based cooling system by electrolysis, and a means of predicting a reactor water accident, based on the results produced by the quantitative analysis means, wherein the said nuclear reactor water accident prevention system comprises following components and means:

an electrode housing unit in an electrolytic cell, which is installed in at least on location in the said primary water-based cooling system so that the electrodes will come into contact with the reactor water a signal discharge unit which applies voltage-time wave signals having specified parameters to a working electrode in said electrolytic cell as a reference electrode standard voltage;

a signal input unit which inputs to the signal discharge unit voltage-time waveform signals having parameters which are determined by the kind of voltammetry utilized, for each chemical species occurring in the primary water-based cooling system, and by changing the parameter for each chemical species involved;

a storage unit which stores in memory the results of the voltammetry performed according to the signals supplied by the signal discharge unit, as a relationship between the electrolysis current and the voltage required to produce the electrolysis current;

a current value determination unit which processes the data stored in the storage unit and which determines the limiting current or peak current, according to the kind of voltammetry employed;

a concentration computation unit which calculates the concentrations in reactor water of the desired chemical species, based on the limiting current or peak current values thus determined;

a comparison unit which compares the results produced by the concentration computation unit with standard values; and

the said nuclear reactor water accident prevention system capable of predicting potential accidents in the primary water-based cooling system, based on the information produced by the comparison unit.

25. A nuclear reactor water quality control system which comprises a means of performing quantitative analysis by electrolysis of reactor water, such as the water found in boilers in a boiling water nuclear reactor, pressurized water nuclear reactor, or thermal power generating plant;

and a means of regulating the quality of the reactor water, based on the results produced by the quantitative analysis means, wherein the said nuclear reactor water quality control system comprises the following components and means;

an electrode housing unit in an electrolytic cell, which is installed in at least one location in the said primary water-based cooling system so that the electrodes will come into contact with the reactor water;

a signal discharge unit which applies voltage-time wave signals having specified parameters to a working electrode in said electrolytic cell as a reference electrode standard voltage;

a signal input unit which inputs to the signal discharge unit voltage-time waveform signals having parameters which are determined by the kind of voltammetry utilized, for each chemical species occurring in the primary water-based cooling system, and by changing the parameter for each chemical species involved;

a storage unit which stores in memory the results of the voltammetry performed according to the signals supplied by the signal discharge unit, as a relationship between the electrolysis current and the voltage required to produce the electrolysis current;

a current value determination unit which processes the data stored in the storage unit and which determines the lifting current or peak current, according to the kind of voltammetry employed;

a concentration computation unit which calculates the concentrations of the desired chemical species in the reactor water, based on the limiting current or peak current values thus determined; and

the reactor water control means which regulates the reactor water quality, based on the information produced by the concentration computation unit.