Improved Reactor Vessel and Bottom Nozzle UT Inspection Experience

摘要

Framatome ANP, an AREVA and Siemens company, recently completed a combined ten-year reactor pressure vessel (RPV) in-service inspection (ISI) and a volumetric ultrasonic (UT) examination of all bottom-mounted nozzles (BMNs) at Florida Power & Light's (FPL) Turkey Point-3 nuclear station. Both the 10-year RPV robot and the BMN tool had undergone significant improvements since their last deployment. The enhancements focused primarily on reducing inspection times. The new tools were also designed to minimize the in-containment lay-down area and utility support during the inspection period. This latter aspect was particularly critical for FPL during this outage because of the busy refuel floor schedule that included both vessel examination and head replacement tasks. It was logical to combine these two examinations since they are both performed with the internals completely removed. The vessel examination required approximately 4 days (95.5 hours) and the BMN examination required 1.5 days (36 hours). Total "hook-to-hook" time was 5.75 days (138 hours) - more than 1 day ahead of schedule. The dose savings over alternate inspection approaches for the BMN examination was also very significant. This paper discusses the tool improvements and new techniques used for the examinations of the RPV and the BMNs as well as the field experience during the FPL examination.