Mirion designed a detector assembly based on NaI(Tl) scintillation detector coupled to a photomultiplier tube specifically developed to perform 16N monitoring under severe environmental conditions. The SGLM (with or without shielding) is a non-intrusive system, providing fast measurements and minimizing the need of taking frequent samples for laboratory analysis. The estimation of the leak rate is then given by either a LPU, LPDU or DAK that processes the signal coming from the detector.
The SGLM 201K monitors steam generator leak rate in PWR nuclear power plants by measuring 16N volume activity.
The SGLM 202K monitors steam generator leak rate in VVER nuclear power plants by measuring 16N volume activity. The NaI scintillator is embedded in a 2 π 2’’ lead shield.