Calculation of the integrated fluence and radiation damage on the MNSR reactor aluminum vessel (LT-21)

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One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the reactor vessel (RV). In this study, the MCNP cross-sectional library (ENDF/B-VI) was modified to evaluate and analyze the radiation damage on the aluminum vessel of the MNSR research reactor. The neutron fluence, displacements per atom (DPA), gas production rate (He and H), heating rate and silicon production were calculated in the aluminum vessel. The result showed after 5000 h of operating time, the maximum integrated fluences on the vessel surface were 4.79 × 1017 and 5.83 × 1016 n.cm−2 in the thermal and fast regions, respectively. The total damage, gas production (H and He), heating rate and silicon production were 3.14 × 10−04 dpa, 8.46 × 10−04 appm and 1.20 × 10−04 appm, 1.20 × 10−04 J/g and 1.20 × 10−04 g−1, respectively. The contribution of the fast neutrons in the radiation damage, gas production (H and He) and heating rate was most effective. The radiation damage on the reactor vessel is less than the limits, and the reactor operation can be continued.