Background: The accident classification method and acceptance criteria of spent fuel reprocessing facility used in China come from the regulatory requirements and the engineering experience of the USA about 40 years ago. Nowadays

these engineering projects have not been in operation

and part of former regulatory requirements have been withdrawn and replaced by newly issued documents. Purpose: Through comparison of the current regulatory requirements and previous engineering experience on the accident classification method and acceptance criteria of spent reprocessing facility in the USA

we aimed to offer some suggestions or advice for the development of accident analysis method ology in China. Methods: Investigation of the current regulatory requirements of the accident classification method and acceptance criteria for spent fuel reprocessing facility in the USA was carried out

and their comparison with the previous engineering practice was implemented. Results: On the basis of the historical engineering experience

the current regulatory requirements have introduced the risk assessment method into the accident classification and acceptance judgment. The current regulations require the license applicants to identify the hazards of concern through hazard risk analysis of the whole facility

and further

to assess both the likelihood of occurrence and the consequence of accidents by risk matrix. The marginal accidents in the whole accident scope consist of not only the design basis accidents

which were usually discussed as the accident margin for accident analysis in historical engineering experience

but also the incidents with low-level consequence but high-level likelihood of occurrence. The risk boundary in the risk matrix serves as the accident acceptance criteria; while in the historical engineering experience

the accident acceptance criteria only focused on the limit of individual total radiation dose on the boundary of the exclusion area. Conclusion: The current regulatory requirements of the accident classification method and acceptance criteria for spent fuel reprocessing facility in the USA have made a remarkable development from previous engineering experience. These requirements include the evaluation of effectiveness of engineering measures

and the assessment of the safety balance of the facility design

which might be a good reference for future development of accident analysis methodology in China. Abstract