Nuclear research - the transition from a research reactor to an advanced research accelerator

Israel Research Reactor 1 (IRR-1) is a 5 MW pool-type reactor. It was donated by the USA in the framework of President Eisenhower's program ''Atoms for Peace'' and was first operated in 1960. It is mainly used today for neutron radiography and diffraction, activation analysis, production of radionuclides for medical R&D, geological dating, as well as for educational purposes. IRR-1 was successfully reviewed in 2013 for both safety (Integrated Safety Assessment for Research reactors – INSARR – mission by the IAEA) and nuclear security (Security Framework and Procedures for the Safeguarding of Nuclear Materials review by the USA). However, its age prompted a search for an alternative source of neutrons that already began fifteen years ago. It was decided to replace the reactor with a high-current accelerator of protons or deuterons. The advantages of accelerators over nuclear reactors for neutron production are multiple, among others the possibility of producing neutrons ranging in energy from sub-eV up to tens/hundreds of MeV, the decoupling of neutron moderation from neutron generation, the possibility to produce pulsed neutron beams, as well as to easily stop and restart neutron production, and the fact that no fissile materials are required and radioactive waste is therefore not produced. The Soreq Applied Research Accelerator Facility (SARAF) project was launched in 2001 to modernize the source of neutrons at Soreq NRC and extend neutron-based research and applications, as well as to modernize the experimental nuclear science infrastructure, promote nuclear physics research in Israel, and develop and produce radionuclides for bio-medical applications. It is planned to be used for research in particle physics and nuclear astrophysics, as well as for applications such as thermal neutron radiography. A liquid lithium target (LiLiT) has already been developed for very high neutron fluxes. Phase I of the SARAF project is completed and the accelerator operates at 4 MeV and 2 mA, generating world class research and development (publication of over 160 SARAF-related publications and hosting of a few international conferences). Phase II is being planned in cooperation with the French CEA, where the goal is to reach an energy of 40 MeV with a current of 5 mA. When completed, SARAF is intended to take over major tasks of IRR-1, when it reaches full capability