| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the workability by fixing a magnet to a seal pipe arranged around a piping through hole and deflecting the upward radiation in the seal pipe by a field generated from the magnet thereby reducing the radiation leaking into the upper space. SOLUTION: A seal pipe 11 is arranged to surround the piping through a hole 2 at the lower mirror part 1 of a vessel a vessel through pipe 3 and a stub tube 4 while a sealing material is arranged at the contact part between the lower end of the seal pipe 11 and the inner face of the lower mirror part 1 of the vessel. Consequently, a sealing part 13 is formed and an atmosphere isolated from cooling water W for reactor is brought about in the seal pipe 11. The seal pipe 11 is fixed, to the outer circumferential surface thereof at a position lower than the level of the reactor cooling water W, with a pair of magnets 12 having N and S poles. The upward radiation in the inner space of the seal pipe 11 is deflected gradually to the direction intersecting the line of magnetic force perpendicularly. It is deviated from the seal pipe 11 and attenuated while intersecting the water W. Consequently, the radiation to be radiated directly upward can be reduced.</p> |
