The proposed spallation neutron source and modernized reactor as possible sites for a low temperature irradiation facility in Germany

Abstract

A feasibility study for a Spallation Neutron Source (SNQ) in Germany was completed in June 1981. In this project an intensity-modulated LINAC (100 pps) would provide a proton beam of energy 1100 MeV and time-average current I ̄ p = 5 mA . Spallation neutrons are produced in the lead material of a rotating target wheel and moderated in a hybrid arrangement consisting of both a small H 2O volume and a large D 2O tank. Here the maximum values of the peak and time-average thermal fluxes are \\ ̂ gf th ≈ 1.3 × 10 16 cm −2 s −1 and \\ ̄ gf th ≈ 6.5 × 10 14 cm −2 s −1 , respectively. A low temperature irradiation facility (LTIF) has been proposed to allow irradiations in the temperature range of 4.5 to 450 K with either thermal neutrons ( \\ ̄ gf th ≈ 1 × 10 14 cm −2 s −1 ) or fast neutrons ( \\ ̄ gf f ≈ 2 × 10 13 cm −2 s −1 ). The advantages and disadvantages of having this LTIF at the SNQ are discussed with respect to the alternative of installing it at a fission reactor. Finally, the example of a possible modernization and upgrading of the Munich research reactor FRM is used to discuss the performance of such a reactor and the concept of a LTIF in this case, and to point out the complementarity of an optimized SNQ (high- \\ ̂ gf applications) and such a modernized reactor (high- \\ ̄ gf applications).