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possibility and no improvement can be expected. This is not the same with a pulsed pile, where important new advances can be expected. It seems that SORA is of considerable interest.”
Maier-Leibnitz shared this view, and had great esteem for Walter Kley who was deeply involved in SORA. It was necessary to choose; Jules Horowitz’s doubts on Euratom, and the absence both in France and Germany of expertise on pulsed reactors condemned the SORA30 project.
However, the value of pulsed reactors was demonstrated a little later by the start of operations in 1984 at Dubna of the pulsed reactor IBR-2. The concept and performance are close to that foreseen for SORA. Nonetheless the steady-state reactor of the ILL would amply prove the reliability and efficiency of this approach, whereas a pulsed reactor would be more fragile, less safe and more difficult to defend against the rising anti-nuclear sensitivity at the end of the 1970s. In other ways the technology of pulsed sources change direction towards more promising paths, like spallation31 sources or pulsed reactors coupled to an accelerator.
With hindsight, the choice of a constant high flux reactor optimised for the production of intense neutron beams was certainly the best at that time. In contrast, the next generation of
30 In contradiction to what Néel writes on p 216 of his memoirs, “Un siècle de physique”, Jacob, Paris, (1991), Horowitz never supported the SORA project. It is doubtful that he could have predicted a demise of plans for the Grenoble reactor because this project was being developed by Robert Dautray, one of his best employees.
31 These sources are not based on the nuclear reaction of fission as in a nuclear reactor but on the spallation pro- cess. In other words a powerful accelerator bombards a heavy metal target with high energy protons which emits a pulsed flux of fast neutrons.
Chapter 1 - Pre-history
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