A laser leak detector for leakage monitoring of fuel channel closure plugs in pressurized heavy water reactors

Highlights: • A laser leak detector was developed for monitoring heavy water leakage in PHWRs. • The test at a PHWR was performed for leak detection at fuel channel closure plugs. • The detector has outstanding capability in sensitivity and in locating leaks. - Abstract: In light of a recent development in a coolant leakage detection method for pressurized heavy water reactors (PHWRs), which utilizes a novel leak detector based on laser absorption spectroscopy, we report the successful application of the said detection method for the detection and location of leaks in the fuel channel closure plug of the PHWRs. This paper contains the results of real-world performance tests performed on operational commercial PHWRs, and shows that the newly developed laser leak detector was fully capable of finding leak locations as well as detecting leaks with a sensitivity of less than ∼1 g/h. Based on these findings, we believe the laser leak detector can be a reliable apparatus for the early detection of heavy water leakage at fuel channel closure plugs during the normal operation of PHWRs