| 摘要 |
A closure insert assembly (10) for a control rod drive mechanism (72) for a nuclear reactor has incorporated therein a vent valve arrangement. The vent valve is of the ball type comprising a ball (66) which engages two oppositely disposed conical ball seats (44, 70), one of wich is allowed to move lateraily with respect to tne other, causing the ball (66) and ball seats (44, 70) to be <<self-centering>> and resulting in a uniform compressive force being aplied over minor circumferences on the ball (66). |
