A numerical calculation based on point defect kinetics under stress wa
s carried out to evaluate radiation-induced stress relaxation in a sol
ution-annealed 316 stainless steel at low and medium temperatures (60
and 300 degrees C). The calculation shows that the stress relaxation r
elative to the initial stress is almost independent of the initial str
ess under irradiation. At 1x10(-6) dpa/s, stress relaxation at 60 degr
ees C is greater than that at 300 degrees C and the stress almost disa
ppears in a month of continuous irradiation. Even with a low damage ra
te of 1x10(-8) dpa/s, the stress relaxation at 60 degrees C is conside
rable and exceeding that at 300 degrees C and 1 x 10(-6) dpa/s during
the first several months of irradiation. The results indicate the impo
rtance of the radiation-induced stress relaxation in experimental fusi
on reactors.