| In this paper, research and development on PWR's high performance fuel rod both in China and in the world is introduced. Transient experiment is introduced, whose research method is that absorber is moved down and up with different speed, power of fuel rod changes with different speed as well, so behavior of fuel rod will be studied.Physics design is most important in transient experiment. MCNP/3B is used in physics calculation. Two kinds of absorber, boron carbide and silver, are calculated respectively. Boron, whose absorption cross section aa is bigger, is unsuitable for its irradiation brittleness and 10B(n,ct) reaction. Silver is studied in detail. Its weight is 750g. Power of experiment fuel rod increases about 50%, as absorber is lifted up 400mm, which is its full track distance, vertically. Reactivity value of absorber is -2.859%Ak/k. The maximum heating rate of absorber is O.SkW. h/ inside experiment fuel rod is much lower than that outside experiment device. Influence of absorber movement on thermal neutron flux decreases, as radial distance between absorber and measuring point increases. At the same time, experiment has been done to validate calculation. Experiment results show that calculation matches well with experiment. In the end, safety analysis is done. |
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