Study Of Added Mess The Containment Sump Strainer In Nuclear Plant

Containment sump strainer is an important part of a nuclear power plant safety system, and its domestical design and manufacturing are of great significance. In the process of containment sump strainer's design, its under-water added mass is an important parameter; however, few researches on the measurement have been made in published literatures. This paper mainly focuses on the measuring method of added mass in the thin-wall cylinder, which is the simplified model of containment sump strainer, and analysis of the parameters affecting added mass. The requirements of engineering applications will be met on the basis of conclusion of influence trends and experienced formula.This paper mainly investigates the following sections:1. Investigate on the policies, regulations and standards at home and abroad of security and reliability in containment sump strainer's design, manufacture and installation.2. Design an experimental method which indirectly measures added mass from the measurement of rotary inertia, according to the complex structure of containment sump strainer. Since the main part of containment sump strainer is strainer-surfaced cylinder, this paper simplifies the structure from two aspects, tube structure and the influence of strainer. There is experienced formula on added mass of solid cylinder, so we can indicate the reliability of the experimental method by measuring the added mass of this solid structure.3. Measure under-water added mass of solid cylinder with different length and radius. Firstly, mass of cylinder without water, i.e. inertial mass, is measured and compared with the value of cylinder weighing with the error less than 2%. Next, added mass of cylinder under water is tested and compared with theoretical value with the error less than 5%. The results indicate that the measurement we selected of added mass is reliable.4. Measure added mass of cylinder, and discuss the influence of vibration frequency, acceleration and object structure. It is found that added mass of cylinder increases with length and radius, and is independent on the vibration frequency. And the ratio of added mass between thin-wall and solid cylinder is a constant, approximately 1.9, which can be taken as added mass coefficient of cylinder based on the solid cylinder.5. Measure added mass of containment sump strainer of three types. Compared between the cylinder and sump strainer, added mass are found that strainer-surfaced structure has significant effects on the added mass under the same size. The added mass, compared with the cylinder, decreases to one third of the original. For the three different types of containment sump strainers, coefficient of correction is between 0.5 and 0.6.6. Measure added mass of six-rowed cylinder containment sump strainer in two directions. The results exhibit that the added mass increases with the area of the cross section in direction of motion. It indicates that the added mass of nonaxisymmetrical cylinder differs from disperate moving directions.