| 摘要 |
PROBLEM TO BE SOLVED: To suppress a flow vibration in an instrumentation guide tube to prevent wear of the instrumentation guide tube. SOLUTION: An upper hole 37A and a lower hole 37B are formed at two upper and lower positions in a side face of the guide tube 27 and a thimble tube 22 is pressed against the inner peripheral surface of the guide tube 27 by a difference between pressures of a cooling material in the inside and outside of the upper and lower hole 37A, 37B. Further, an upper pressure regulation hole and a lower pressure regulation hole are formed at two upper and lower positions in a side face of an upper reactor core support column 21. A cooling material, having flown from the upper end of the guide tube into the guide tube, flows from the inside to the outside of the guide tube through a gap between the thimble tube and the upper hole, flows from the inside to the outside of the upper reactor core support column through the upper pressure regulating hole, flows from the lower end of the guide tube into the guide tube, flow from the inside to the outside of the guide tube through a gap between the thimble tube and the lower hole, and then flows from the inside to the outside of the upper core reactor support column through the lower pressure regulating hole. COPYRIGHT: (C)2009,JPO&INPIT |
