| 摘要 |
PURPOSE:To obviate a decrease of a thermal margin which an assembly has, and also, to raise the reactor core characteristic and the profitability by scraping the inside surface of a channel box of the assembly so that it becomes thinner toward the downstream side and the passage area is expanded. CONSTITUTION:As for a channel box 1 of an assembly, its external form is uniform in the axial direction of the channel box 1, wall thickness of the channel box material is thick in the upstream of a flow of cooling water, becomes thinner gradually toward the downstream except the downstream end part which the upper tie plate abuts on, and a cross-sectional area of the inside of the channel box 1 increases. Therefore,a pressure loss can be reduced effectively. This fact can reduce power of a pump and signifies to improve the profitability of power generation immediately. Also, on the contrary, by raising the flow rate of cooling water higher than its normal rate and lowering the void coefficient at the last stage of a cycle, the reactor core reactivity is raised, the cycle can be extended to a long period of time, and the profitability of power generation can be raised thereby, as well. |
