Investigation of radiation damage in the aluminum structures of the German FRJ-2 research reactor

Radiation damage in the structures of the aluminum tank resulting from the reaction of fast and thermal neutrons with aluminum was simulated using the 3D MCNP Monte-Carlo code. Comparison of the local neutron flux with measurement showed a deviation less than 5%. Radiation damage in term of concentration of silicon was also determined for the front plate of the 4H-2 channel by the calculation of the total rate of Al(n,β)Si reaction. The results are in very good agreement with the measured Si-concentration obtained by chemical analysis. The results of calculation show that the tensile elongation of aluminum in the most irradiated segment of the 2TAN beam tube is reduced by 62% of the initial value. The content of Si is considerably lower than the end-of-life limit by 46% so that from the radiation damage point of view, the power operation of the reactor could be continued for additional 2.82E+6 MWh corresponding to approx. 20 years. (orig.)