Patent Number: 
Section: claims

1. A system for detecting an individual leaking fuel channel included in a reactor having an array of fuel channels arranged in columns and rows, each fuel channel including a pressure tube, a calandria tube surrounding the pressure tube, and an annulus space defined between the pressure tube and the calandria tube, the system comprising:a plurality of inlet lines, each of the plurality of inlet lines feeding annulus fluid in parallel to the annulus spaces of a corresponding plurality of fuel channels of a first grouping type;a plurality of detectors, each one positioned at an outlet of one of the plurality of outlet lines, each detector configured to detect moisture in annulus fluid;a plurality of outlet lines, each of the plurality of outlet lines collecting in parallel annulus fluid exiting the annulus spaces of a corresponding plurality of fuel channels of a second grouping type; anda plurality of isolation valves, each one positioned at an inlet of one of the plurality of inlet lines, each isolation valve operable to close and stop annulus fluid from circulating through one of the plurality of inlet lines,wherein the first grouping type is either one of a row or a column, and the second grouping type is the other one of a row or a column such that one of the plurality of detectors detecting moisture in the circulating annulus fluid is operable to identify a row or a column of an individual leaking fuel channel and sequential closing of the plurality of isolation valves is operable to identify the other of a row or a column of the individual leaking fuel channel. 2. The system of claim 1, further comprising a detector positioned at an outlet of each of the plurality of outlet lines, each detector configured to detect moisture in annulus fluid and to identify either the row or the column of an individual leaking fuel channel. 3. The system of claim 2, further comprising an isolation valve positioned at an inlet of each of the plurality of inlet lines, each isolation valve operable to stop annulus fluid from circulating through one of the plurality of inlet lines and to identify the individual leaking fuel channel. 4. The system of claim 1, wherein the annulus fluid includes a gas. 5. The system of claim 1, wherein the annulus fluid includes at least one of dry carbon dioxide, helium, nitrogen, and air. 6. The system of claim 1, wherein the plurality of inlet lines enter a vault of the reactor horizontally. 7. The system of claim 6, wherein the plurality of outlet lines exit the vault of the reactor vertically. 8. The system of claim 1, wherein the plurality of inlet lines enter a vault of the reactor vertically. 9. The system of claim 8, wherein the plurality of outlet lines exit the vault of the reactor horizontally. 10. The system of claim 1, wherein the first grouping type is a row and the second grouping type is a column. 11. The system of claim 1, wherein each of the plurality of fuel channels of the first grouping type fed annulus fluid by each of the plurality of inlet lines is located within a first section of the reactor. 12. The system of claim 11, wherein each of the plurality of fuel channels of the second grouping type from which each of the plurality of outlet lines collect annulus fluid is located with the first section of the reactor. 13. The system of claim 12, wherein the plurality of inlet lines is a first plurality of inlet lines and the plurality of outlet lines is a first plurality of outlet lines, the system further comprising a second plurality of inlet lines connected in series with the first plurality of outlet lines, each of the second plurality of inlet lines circulating annulus fluid in parallel through an annulus space of each of an additional plurality of fuel channels arranged in either a column or a row and located in a second section of the reactor, separate from the first section. 14. The system of claim 12, wherein the plurality of inlet lines is a first plurality of inlet lines and the plurality of outlet lines is a first plurality of outlet lines, the system further comprising a second plurality of outlet lines connected in series with the first plurality of inlet lines, each of the second plurality of outlet lines collecting in parallel annulus fluid exiting an annulus space of each of an additional plurality of fuel channels arranged in either a column or a row and located in a second section of the reactor, separate from the first section.