Background: Initial event analysis is the beginning of the reactor nuclear safety analysis and probabilistic safety assessment

and plays a key role in these analyses. At present

the initial event analysis evaluation method and experience are mainly used for the water reactors. There is hardly any analysis method and theory for the initial event analysis of the solid thorium molten salt reactor. However

with the research of molten salt reactor and the reactor progress of probabilistic safety assessment (PSA)

initial event analysis has become increasingly important. Purpose: On the one hand

by carrying on the preliminary exploration research for the TMSR-SF1 (Thorium Molten Salt Reactor

Solid Fuel #1) initial event analysis

to determine TMSR-SF1 initial events of potential

causes radioactive release

and give the TMSR-SF1 initial event lists. On the other hand

the aim is to group the determinate initial events. Methods: First of all

we used the master logic diagram (MLD) analysis method

and referenced the initial event lists of pressurized water reactor

the fluoride-salt-cooled high-temperature reactor (FHR)

the high temperature gas cooled reactor and the sodium cooled fast reactor

to carry on the TMSR-SF1 preliminary analysis and research of initial events and main external events. Then

the accident type classification method was applied to group theTMSR-SF1 preliminary determinate initial events. Results: Through the MLD analysis

we determined the preliminary initial event lists for TMSR-SF1 which contain 37 initial events

and given 6 class accident types of TMSR-SF1 initial events. Conclusion: This study provides basic foundation for the TMSR-SF1 PSA accident sequence analysis of the next step

and gives an important support for the integrity of the molten salt reactor safety analysis. Abstract