Abstract: Disclosed herein is a method including: performing eddy current testing on a steam generator tube material by using a motorized rotating pancake coil (MRPC) probe, evaluating a test signal measured using the eddy current testing, and predicting the corrosion rate of the steam generator tube material from a noise value in the MRPC inspection signal of the steam generator tube obtained from the evaluating. When the prediction method of a corrosion rate of a steam generator tube according to the present invention is used, the steam generator tube material which has low corrosion rate can be selected at the material selecting step because the corrosion rate can be predicted and the criterions on the corrosion rate of the steam generator tube can be established as the requirements through an eddy current MRPC noise inspection of the steam generator tube material.

Abstract: Provided are a tube sheet of a steam generator installed to support a tube of the steam generator, and a manufacturing method thereof, particularly, a tube sheet of a steam generator having an anticorrosive layer and a manufacturing method thereof.

Abstract: Disclosed herein is a method including: performing eddy current testing on a steam generator tube material by using a motorized rotating pancake coil (MRPC) probe, evaluating a test signal measured using the eddy current testing, and predicting the corrosion rate of the steam generator tube material from a noise value in the MRPC inspection signal of the steam generator tube obtained from the evaluating. When the prediction method of a corrosion rate of a steam generator tube according to the present invention is used, the steam generator tube material which has low corrosion rate can be selected at the material selecting step because the corrosion rate can be predicted and the criterions on the corrosion rate of the steam generator tube can be established as the requirements through an eddy current MRPC noise inspection of the steam generator tube material.

Abstract: Provided is an apparatus for concurrently detecting a defect occurring in a heat exchanger tube and a geometric transition of the heat exchanger tube. The apparatus for detecting the state of a heat exchanger tube, including: the first detection unit detecting a defect of the heat exchanger tube; and the second detection unit detecting a geometric transition of the heat exchanger tube, in which the first detection unit and the second detection unit are disposed at the same circumferential position of a cylindrical body separately, installed to have a certain distance in the lengthwise direction of the cylindrical body, and inserted inside the heat exchanger tube. According to the present invention, not only a defect but also the type of geometric transition, which may accelerate the initiation and growth of a defect, is identified and the size of the geometric transition is concurrently measured, thereby improving the reliability in early detection of a defect.

Abstract: Provided is an apparatus for concurrently detecting a defect occurring in a heat exchanger tube and a geometric transition of the heat exchanger tube. The apparatus for detecting the state of a heat exchanger tube, including: the first detection unit detecting a defect of the heat exchanger tube; and the second detection unit detecting a geometric transition of the heat exchanger tube, in which the first detection unit and the second detection unit are disposed at the same circumferential position of a cylindrical body separately, installed to have a certain distance in the lengthwise direction of the cylindrical body, and inserted inside the heat exchanger tube. According to the present invention, not only a defect but also the type of geometric transition, which may accelerate the initiation and growth of a defect, is identified and the size of the geometric transition is concurrently measured, thereby improving the reliability in early detection of a defect.

Abstract: The present invention relates to a method for inhibiting stress corrosion cracking occurring on steam generator tubes in the secondary side of nuclear power plants and an inhibitor therefor. The method comprises supplying lanthanum boride as an inhibitor for stress corrosion cracking into the secondary feed water of the nuclear power plants. The method according to the present invention improves the resistance of stress corrosion cracking ten times or higher than no inhibitor, and five times or higher than the conventional inhibitor. In particular, the method according to the present invention shows a superior inhibiting effect in the lead-contaminated environment such that the complete inhibition of stress corrosion cracking can be achieved. As thus, the method can reduce the unexpected stop of operating nuclear power plants caused by the stress corrosion cracking on steam generator tubes, thereby reducing the cost required for maintaining and repairing the tubes.

Abstract: Disclosed herein is a method of discriminating a through-wall crack and measuring the through-wall length of the crack in a steam generator tube of a nuclear power plant. The method of the present invention is characterized in that the through-wall crack is discriminated and the through-wall length of the crack is measured in such a way that there are measured the number and positions of inflection points of a graph that is plotted by relating characteristic amplitude values of eddy current signals, which are generated whenever a coil of a motorized rotating probe passes the crack while being spirally rotated, to the positions in the length of the crack.

Abstract: The present invention relates to a method for inhibiting stress corrosion cracking occurring on steam generator tubes in the secondary side of nuclear power plants and an inhibitor therefor. The method comprises supplying cerium boride as an inhibitor for stress corrosion cracking into the secondary feed water of the nuclear power plants. The method according to the present invention improves resistance of stress corrosion cracking three times or higher than no inhibitor, and two times or higher than the conventional inhibitor. In particular, the method according to the present invention shows a superior inhibiting effect in the lead-contaminated environment such that the complete inhibition of stress corrosion cracking can be achieved. As thus, the method can reduce the unexpected stop of operating nuclear power plants caused by the stress corrosion cracking on steam generator tubes, thereby reducing the cost required for maintaining and repairing the tubes.

Abstract: Disclosed herein is a method of detecting a through-wall crack and measuring the through-wall length of the crack in a steam generator tube of a nuclear power plant. The method of the present invention is characterized in that the through-wall crack is detected and the through-wall length of the crack is measured in such a way that there are measured the number and positions of inflection points of a graph that is plotted by relating characteristic amplitude values of eddy current signals, which are generated whenever a coil of a motorized rotating probe passes the crack while being spirally rotated, to the positions in the length of the crack.

Abstract: The present invention relates to a method for inhibiting stress corrosion cracking occurring on steam generator tubes in the secondary side of nuclear power plants and an inhibitor therefor. The method comprises supplying lanthanum boride as an inhibitor for stress corrosion cracking into the secondary feed water of the nuclear power plants. The method according to the present invention improves the resistance of stress corrosion cracking ten times or higher than no inhibitor, and five times or higher than the conventional inhibitor. In particular, the method according to the present invention shows a superior inhibiting effect in the lead-contaminated environment such that the complete inhibition of stress corrosion cracking can be achieved. As thus, the method can reduce the unexpected stop of operating nuclear power plants caused by the stress corrosion cracking on steam generator tubes, thereby reducing the cost required for maintaining and repairing the tubes.

Abstract: The present invention relates to a method for inhibiting stress corrosion cracking occurring on steam generator tubes in the secondary side of nuclear power plants and an inhibitor therefor. The method comprises supplying cerium boride as an inhibitor for stress corrosion cracking into the secondary feed water of the nuclear power plants. The method according to the present invention improves resistance of stress corrosion cracking three times or higher than no inhibitor, and two times or higher than the conventional inhibitor. In particular, the method according to the present invention shows a superior inhibiting effect in the lead-contaminated environment such that the complete inhibition of stress corrosion cracking can be achieved. As thus, the method can reduce the unexpected stop of operating nuclear power plants caused by the stress corrosion cracking on steam generator tubes, thereby reducing the cost required for maintaining and repairing the tubes.