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Areas of Activities
Top Products
Products & Services
INSPECTION OF BAFFLE TO FORMER BOLTS
The baffle to former bolts (BFB) fasten the vertical baffle plates to the horizontal former plates of the reactor pressure vessel lower internals.
The baffle bolts are manufactured from stainless steel and may be susceptible to irradiation-assisted stress corrosion cracking (I-ASCC)
Main characteristics of INETEC baffle to former bolt inspection
- Perform remote underwater, contact technique, ultrasonic inspection
- Provide reliable inspection
- Minimize radiation exposure to personnel
Main characteristics of INETEC baffle to former bolt inspection
- Remote controled central mast manipulator
- Manipulator provides accurate positioning of baffle bolt end effector
- All bolts can be reached
- Remote docking system
- Pneumatic system
- UT system
- Underwater video system
- UT examination:
Pulse – echo technique
Pitch – catch technique - Tomoscan III UT system (data acquisition and analysis)
Specially designed UT probes
Approach to BFB UT
Principle of the applied technique:
- each element works in pulse - echo mode
- two elements together work in pitch-catch mode
Drawing of the unflawed bolt and UT signal presentation:
Krsko NPP BFB Inspection
- The total of 728 BFB have been examined
- No bolts with flaw signals were found
- The technique applied showed high inspection reliability
- Fast examination performance - 71 hours have been spent for inspection including periodical system check
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