Prototype tomographic partial defect tester: Project status update

Passive Gamma Emission Tomography (PGET) has been extensively studied during the past years. The feasibility study and the tests performed show that the device is capable of detecting missing pins inside a PWR assembly. A construction project of the prototype device was enabled as IAEA Joint Support Program task: 'Prototype Tomographic Spent-Fuel detector system' (JNT A 1510). The participants to the task are: the Finnish Support Program to the IAEA Safeguards (FIN SP, construction of mechanical structures and coordination), Hungarian SP (system theory, analysis and control software, detection system specification and testing), Swedish SP (hosting the final testing and arranging additional analysis of the data) and the European Commission SP (facilitating the test campaign). The IAEA has defined the user requirements for the device. The IAEA expects that the device is capable of verifying fuel with a minimum burn-up of 15 GWd/t and a cooling time up to 40 years. Measurement time per assembly should be less than 10 minutes. The analysis software should automatically determine whether pins are missing or replaced by other than irradiated fuel material. Although dedicated training will be developed to train IAEA inspectors, no specific expertise should be needed to operate the equipment. Delivery of the detector arrays will take place in spring 2007. In the meanwhile, the mechanical components will be manufactured and the software written to the extent possible. After the delivery of the detector array the software will be finalized, and the detection system will be tested at a Co-60 facility, and the device will be assembled in final form. According to the project plan the final testing will take place in late 2007 at Ringhals NPP with spent fuel assemblies. Then the device will be ready for the IAEA. The PGET will be the first device for single rod verification by the IAEA, therefore greatly enhancing IAEA's verification capability. (author)