SYSTEM AND METHOD FOR DETECTING LEAKAGE OF NUCLEAR REACTOR COOLANT USING LASER INDUCED EMISSION SPECTRUM

• US 20110164715A1
• Filed: 12/08/2010
• Published: 07/07/2011
• Est. Priority Date: 12/09/2009
• Status: Active Grant

• Current Assignee: Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Original Assignee: Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Inventors: Jung, Euo-Chang, Song, Kyuseok, Yeon, Jei-Won
• Granted Patent: US 8,855,259 B2
• Time in Patent Office: Days
• US Class Current: 376/250
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G21C 17/002 Detection of leaks by testing the coolant or the moderator G21C17/04
• CPC Class Codes: G21C 17/02 Devices or arrangements for monitoring coolant or moderator
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

System and method for detecting and/or predicting in a field the leakage of nuclear reactor coolant that may occur at the pressure boundary of the primary system of a nuclear reactor. The system and method for detecting the leakage of nuclear reactor coolant uses a laser induced emission spectrum. The leakage of coolant is detected by detecting boron (B), a main component of the coolant, in corrosive products generated at the nuclear reactor pressure boundary on the basis of laser spectroscopy. An embodiment of the system for detecting leakage of nuclear reactor coolant may include a laser generator, a laser focusing lens, an emission collector, and emission spectrum analyzer.

Claims

1. An apparatus for detecting leakage of nuclear reactor coolant, comprising:

a laser generator for generating laser beam;

a laser focusing lens for focusing the laser beam generated by the laser generator;

an emission collector for inducing a plasma emission on a target material when the laser beam focused by the laser focusing lens is concentrated, and collecting light from the induced plasma emission; and

an emission spectrum analyzer for analyzing the light of the plasma emission collected by the emitted light collector.

2. The apparatus according to claim 1, wherein the laser generator comprises:

a laser generation unit;

an attenuator for adjusting intensity of the laser beam generated by the laser generation unit;

an energy meter for measuring energy intensity of the laser beam adjusted by the attenuator; and

a refraction unit for changing a path of the generated laser beam.

3. The apparatus according to claim 1, wherein the laser beam generated by the laser generator has a form of pulses.

4. The apparatus according to claim 2, wherein the laser generation unit is a laser having a power of 0.5 mJ or more.

5. The apparatus according to claim 1, wherein the laser beam focused by the laser focusing lens has a diameter that is greater than 0 and is equal to or less than 5 mm.

6. The apparatus according to claim 1, wherein the laser beam focused by the laser focusing lens has a diameter that is greater than 0 and is equal to or less than 3 mm.

7. The apparatus according to claim 1, wherein the emitted light collector is a lens or an optical fiber for collecting light.

8. The apparatus according to claim 1, wherein the emitted light collector is located within a range from 0.5 to 100 cm around the plasma emission induced on the target material.

9. The apparatus according to claim 1, wherein the emitted light collector is located within a range from 1 to 20 cm around the plasma emission induced on the target material.

10. The apparatus according to claim 1, wherein an analysis wavelength used to analyze boron in the emission spectrum analyzer ranges from 200 to 300 nm.

11. The apparatus according to claim 1, wherein an analysis wavelength used to analyze boron in the emission spectrum analyzer ranges from 249.0 to 251.0 nm.

12. An apparatus for detecting leakage of nuclear reactor coolant, comprising:

a laser generator for generating laser beam;

a laser focusing lens for focusing the laser beam generated by the laser generator;

an emission collector for inducing a plasma emission on a target material when the laser beam focused by the laser focusing lens is concentrated, and collecting light from the induced plasma emission;

an emission spectrum analyzer for analyzing the light of the plasma emission collected by the emitted light collector; and

an ultrasonic generation laser or a compressed air jetting device for temporarily eliminating water from surroundings of the target material.

13. The apparatus according to claim 12, further comprising a suction filter for eliminating impurities from surroundings of the emitted light collector.

14. The apparatus according to claim 13, wherein the impurities are volatile materials or separated fine particles generated during induction of the plasma emission.

15. A method of detecting leakage of nuclear reactor coolant, the method being performed using an apparatus for detecting leakage of nuclear reactor coolant, which includes a laser generator for generating laser beam;

a laser focusing lens for focusing the laser beam generated by the laser generator;

an emission collector for inducing a plasma emission on a target material when the laser beam focused by the laser focusing lens is concentrated, and collecting light from the induced plasma emission; and

an emission spectrum analyzer for analyzing the light collected by the emitted light collector, comprising;

a) causing at least the laser focusing lens and the emitted light collector of the apparatus to approach the target material;

b) controlling a focal distance of the laser beam with respect to the target material after a);

c) after the focal distance has been controlled, radiating the laser beam onto the target material;

d) collecting light of a plasma emission induced on the target material at c) by using the emitted light collector; and

e) analyzing the collected light.

16. The method according to claim 15, wherein e) is performed using a relative ratio of intensity of an emission line of only iron (Fe) in the emission spectrum to intensity of an overlapping emission line of boron (B) and iron.

17. The method according to claim 16, wherein e) is performed using a ratio of intensity at 249.773 nm of the emission line of boron with respect to intensity of the emission line of iron.

18. The method according to claim 17, wherein the emission line of iron uses wavelength range from about 249.0 to about 250.5 nm.