一、前言研究性重水堆改建工程在完成设计和施工准务后于1978年11月起停堆进行改建,1980年6月反应堆重新达到临界。整个反应堆的改建,是以提高堆的中子通量等指标为中心进行的。根据改建的物理及热工水力设计,反应堆的栅格作了重新布置,需更换已经微漏及磨损的旧内壳。同时,为提高堆功率,增加一回路流量和散热能力,需将一回路作重要变更。改建实施包括堆本体和一回路的改建,二回路的改建,反应堆直属工艺系统的大 I. INTRODUCTION The reconstruction of the research heavy water reactor started with the reconstruction of the reactor in November 1978 after completion of the design and construction standards. In June 1980, the reactor reached the critical point again. The reconstruction of the entire reactor is based on the improvement of reactor neutron flux and other indicators as the center. According to the rebuilt physical and thermal hydraulic design, the grid of the reactor was rearranged and the old inner shell, which had been slightly leaky and worn, had to be replaced. At the same time, in order to increase the reactor power and increase the capacity and cooling capacity of the primary circuit, an important change of the primary circuit is required. Reconstruction, including the reconstruction of the reactor body and the primary circuit, the secondary circuit reconstruction, the reactor directly under the large-scale process system