Abstract: DESIGN AND SAFETY ANALYSIS OF ~(210)Po-Be START-UP SOURCE FOR 300 MW QINSHAN NUCLEAR POWER PLANT Cai Shanyu（China Institute of Atomic Energy,Beijing 102413）ABSTRACT Based on the general design principle of radioisotope neutron source，the elaborate design of ~(210)Po-Be star-up source for 300MW Qinshan Nuclear Power Plant is performed. Both neutron yields andmechanical strength have been taken into consideration in deriving the physical dimensions of sourcecapcule. The internal pressure built-up caused by the decay of ~(210)Po, the nuclear reaction：（n， 2n），（n，α），（n，γ）and（γ，n）of beryllium undergoing the neutron irradiation and the ambient temperaturecan be endured by capsule. The prototype testing indicate that the classification of prototype source performance is up to ISO／E66545．The designed ~(210)po-Be source can satisfy the requests of PWR start-upand ensure the safety and reliability of sources during the operation（≈450d）at reactor．Key words　~(210)po-Be neutron source“ primary”，start-up source“ primary”，source rodnuclear power station safety analysis prototype test