Research on Release Calculation of Fission Product from Defect Fuel Rod to Reactor Coolant

The calculation model was established according to the research on the release mechanism of fission product from defect fuel rod to reactor coolant. The sensitivity analysis was carried out for fuel rod defect rate, fuel rod defect size and burnup base on the design date of CPR1000 nuclear power plant, and the calculated equivalent escape rate was compared with the escape rate described in AP1000 design control document. The sensitivity analysis and comparison results show that the calculation model is sensitive for fuel rod defect size but not sensitive for fuel rod defect rate and burn up. The calculated equivalent escape rate of part nuclides is similar as the escape rate of AP1000 design control document base on the calculation model and the 34μm fuel rod defect size.