Atmospheric neutron can induce single event burnout (SEB) in thyristors

which threatens the reliable operation of UHVDC power transmission projects in high altitude areas. In this paper

the Atmospheric Neutron Irradiation Spectrometer (ANIS) of China Spallation Neutron Source (CSNS) is used to obtain the experimental data of the thyristor under atmospheric neutron irradiation

and the method of processing the experimental data

the radiation fault characteristics

and the deterioration characteristics of the thyristor are discussed. It is found that the time to failure of thyristor satisfies the three-parameter lognormal distribution

based on which the time to failure and its confidence interval can be estimated. There is a SEB threshold voltage. When the applied voltage of the thyristor is less than the threshold voltage

the SEB will not occur even if the thyristor is exposed to radiation for a long time. The relationship between the failure rate and applied voltage under atmospheric neutron irradiation satisfies the Zeller’s model and can also be described by a simple exponential model. It can also be obtained by fitting the data as a whole. The SEB failure rate under reverse bias voltage is lower than that under positive bias voltage. After neutron irradiation with a dose of 2.9×1010 n/cm2

the dynamic characteristics of thyristors change

with a 69% decrease in the stored charge of the pn junction

a 60.8% decrease in turn-on time

and a 36.4% increase in the maximum on state voltage. The research results of this paper can be used in the subsequent evaluation of atmospheric neutron irradiation failure rate and protection of converter valves.