Method and system for detection and prevention of stress corrosion cracking in buried structures

A system for detecting stress corrosion cracking in a structure, comprising:

• a) a plurality of test cells, each test cell comprising:
• i) a test coupon constructed of the same material as said structure and having a first end and a second end;
• ii) a temperature monitoring device for monitoring the temperature of said test coupon;
• iii) a heating element affixed to said test coupon;
• iv) an impressed current anode;
• v) a reference electrode;
• vi) a means of applying a stress to said test coupon which is at least as great as the maximum stress which can occur in said structure;
• vii) a shunt resistor having a first end and a second end, wherein the second end of said resistor is connected to the first end of said test coupon;
• viii) a current source connected to the first end of said shunt resistor and the second end of said test coupon;
• ix) a first voltage measuring device for measuring the voltage drop across said shunt resistor;
• x) a second voltage measuring device for measuring the voltage drop across said test coupon;
• b) a temperature monitoring device affixed to said structure which monitors the temperature of said structure;
• c) a temperature control system which controls each of said heating elements so that the temperature of each of said test coupons is regulated at the temperature of said structure;
• d) a plurality of potentiostat circuits, wherein each said potentiostat circuit regulates the current passing from said test coupon to said anode in one of said test cells, whereby said test coupon is held at a fixed potential with respect to said reference electrode, and wherein each of said test coupons is held a different fixed potential;
• wherein the resistance of each of said test coupons is calculated from the current provided by each said current source and said voltage drop across each said test coupon and wherein the presence of stress corrosion cracking in one of said test coupons is detected as an increase in the resistance of said test coupon.

A sensor for detecting stress corrosion cracking in buried pipelines, comprising:

• a) a three-dimensional framework constructed of a sturdy, non-conductive structural material;
• b) a plurality of C-ring coupons supported by said framework, each C-ring coupon having associated therewith:
• i) a temperature monitoring device for monitoring the temperature of test C-ring coupon;
• ii) a heating element affixed to said C-ring coupon;
• iii) an impressed current anode affixed to said framework in the vicinity of said C-ring coupon;
• iv) a reference electrode affixed to said framework in the vicinity of said C-ring coupon;
• v) a mechanism for applying a stress to said C-ring coupon.