| 摘要 |
<p>PURPOSE:To measure gamma rays accurately and efficiently, by burying a collimator for introducing gamma rays into a shielding wall at a specified angle to eliminate such a troublesome work as angle adjustment of irradiation fuel assemblies. CONSTITUTION:A collimator 5 which focuses gamma rays from an irradiation fuel assembly 1 on a gamma ray detector 10 is buried into a shielding wall 4 as inclined in a range of 25 deg.-65 deg. on the level with respect to the side thereof 4 and the side thereof on the side pool water 2 is covered with a shielding front wall 7 made of stainless steel including the front of a through hole 6. With such an arrangement, when the assembly 1 is positioned on the front of the collimator 5 being held on the side of the wall 4 through a holding body 3 the amount of gamma rays of the assembly 1 is detected the angle thetamaintained at 25 deg.-65 deg. between the detector 10 and the assembly 1. This eliminates the need for troublesome angle adjustment of the assembly 1 and enables efficient and accurate measurement without causing changes in the gamma ray rate due to delicate angle difference of the assembly 1.</p> |
