Disposal on Unqualified Items About Crape on Sealing Tube in Control Rod Driving System Suspended by Magnetic Force

Serious unacceptable scrapes on the ektexine of some sealing tubes were discovered during integrative capability test of control rod driving framework suspended by magnetic force. Heating and disasembling tests on control rod driving framework were carried out. The results show that rudimental bits during maching, impertinency in local configuration and improper chosen material of gliding parts are main reasons. Filtering nitrogen, disposing of maching rudimental matter, acute angle passivation, replacing material, increasing guide flowing holes were performed, after which run and downfall tests were carried out. It is shown that no new scrapes appear and rob downfall time decreases. The method and results can be conference for maching and maintenance of congener control rob driving framework.