Publications: Internal Task note

Author(s) :Karel Samec et al. (CERN, IPUL, ITN and PSI)

Advances in nano-technology, bio-technology, nuclear medicine and the fundamental sciences require a facility to continue improving current capabilities in Europe beyond the year 2010. European competitiveness could benefit greatly from a unique research facility, flexible enough to satisfy users from many different fields of science and technology. The facility would be a valuable asset enabling economies of scale and giving Europe access to cutting-edge technology at the heart of future technological advances of major economic importance. Specialised facilities already operating at full capacity such as SINQ in Switzerland, ILL in France, have demonstrated the benefits of bringing together users from different scientific backgrounds and different countries. Such a research policy may be reinforced by the improved performance and greater reach of the EURISOL project which is aimed at a larger research community. Beneficiaries include the medical sciences such as oncology, medical imagery or studies of protein, as well as physics, astrophysics and cosmology, not forgetting nano-technology, supra-conductivity and general material technology. An initial Design Study funded by the European FP6 research framework program was able to establish the case for the project on a well-founded scientific and technical basis in terms of user cost-benefit analysis, risk identification and mitigation. Two major risk items were identified early on in the EURISOL program: the proton beam LINAC driver and the Multi-Megawatt target station. The current summary addresses the latter task which was assigned to a project group headed by CERN in Geneva and comprising PSI in Switzerland for the liquid metal converter target development, INFN in Italy for the fission targets and IPUL in Latvia for essential liquid metal technology testing.

Author(s) :Karel Samec et al. (CERN, IPUL, ITN, PSI)

The Eurisol initiative seeks to develop an isotope production facility to provide the scientific community with the means to achieving high yields of isotopes and extending the variety of isotopes thus produced towards more exotic types rarely seen in existing facilities. The Multi-MW converter target at the heart of the projected facility is designed to create isotopes by fissioning uranium carbide (UC) target arranged coaxially around a 4 MW converter target. It is therefore essential that the target be as compact as possible to avoid losing neutrons to capture whilst maximising the neutron flux to enhance the number of fissions per second in the UC targets. The proposed ISOL facility would use both (a) several 100 kW proton beams on a thick solid target to produce RIBs directly, and (b) a liquid metal 4 MW ‘converter’ target to release high fluxes of spallation neutrons which would then produce RIBs by fission in a secondary uranium carbide (UCx) target. An alternative windowless liquid mercury-jet ‘converter’ target to generate the neutrons has also been proposed for this Multi-MW target station.

Author(s) :Y. Romanets and R. Luís (ITN)

The objective of this work was to carry out a detailed study and analysis of all aspects related to radioprotection and radiation safety of the spallation target area and the whole spaces reserved for the fission targets and spallation target maintenance. Operational and no‐operational conditions were considered for an evaluation of the radiation safety conditions. An analysis of the proposed shielding dimensions and configuration was performed for the system during operation time. Parameters as activation, dose rate, energy deposition, etc. are more important for the no‐operation period, in order to evaluate the hazard level and determine the staff access type to the maintenance areas (direct or remote control). Such elements as the fission targets and the whole structure involved on it were studied in more detail because of the disposal issues, after operation. Activation, dose rate and residual nuclides were studied for each element of the assembly. All parameters were analyzed according to their time evolution after the shutdown of the facility. The studies were carried out using the state‐of‐the‐art Monte Carlo programs FLUKA and MCNPX.

Author(s) :Olivier Choisnet, Cyril Kharoua, Yacine Kadi, Karel Samec (CERN)

The EURISOL Design Study investigated the feasibility of a complex instrument to push back the boundaries of current physics knowledge amidst today’s ever-increasing need for realism due to constraints imposed by safety, performance and, not least, budgetary responsibility. In order to attend to these concerns, the EURISOL Multi-Megawatt converter target, its associated fission targets and the three 100 kW direct targets are all integrated into a single facility housing the ancillary equipment as well. The overall layout of the facility, its functional break-down and the main modes of operation are presented in the current report.

Author(s) :Cyril Kharoua, Olivier Choisnet, Yacine Kadi, Karel Samec (CERN)

The design proposed within Task #2 of the EURISOL Design Study for the remote handling of the mercury converter target and its associated loop is presented with particular emphasis on achieving rapid turn-around during routine maintenance. The converter target needs to be completely exchanged every four months due to the high irradiation damage sustained. Other components are less susceptible to damage but may need periodic maintenance; in particular the on-line isotopic separation unit in the mercury loop.

Author(s) :Cyril Kharoua, Olivier Choisnet, Yacine Kadi, Karel Samec (CERN)

The design proposed within Task #2 of the EURISOL Design Study for the remote handling of the mercury converter target and its associated loop is presented with particular emphasis on achieving rapid turn-around during routine maintenance. The converter target needs to be completely exchanged every four months due to the high irradiation damage sustained. Other components are less susceptible to damage but may need periodic maintenance; in particular the on-line isotopic separation unit in the mercury loop.

Author(s) :Karel Samec, Mats Lindroos, Yacine Kadi, Etam Noah, Jacques Lettry (CERN) Werner Wagner, Knud Thomsen, Jacek Patorski, Sergej Dementevjs, (PSI) Anatoli Zik, Erik Platacis (IPUL)

The EURISOL Design Study has reached final completion and the three institutes, CERN, IPUL and PSI, participating in the development of the Multi-Megawatt target station have met the objective of a reliable, affordable and credible design. The costs involved in the full development of such a target are forecast to reach 200 million €, approximately 15% of the total costs of the EURISOL facility. A breakdown of the costs is presented as well as an outline of future possible R&D efforts aimed at improving reliability and safety of the facility. Another important goal of the proposed R&D is to minimise development risk by focusing resources, early on in the project, on areas identified as presenting a particular risk. An example clearly identified in the study would be the conditioning of the contaminated Mercury, both during the lifetime of the facility and after decommissioning.

Author(s) :K. Samec et al.

Early on in the EURISOL-DS study the converter target was identified as a major component on the critical path to demonstrating the overall concept of such a facility; without the target the entire project would not be feasible. The very harsh environment under which a target is to operate under irradiation is best summed by its governing parameters listed in Table 1. Obtaining experimental proof of two independent target designs; one featuring a beam window, the other without, was therefore instrumental to proving a viable concept for the overall EURISOL facility. Considerable effort was expended on ensuring adequate testing of the designs for which all participants, in particular IPUL, devoted much time and effort.

Author(s) :K. Samec et al.

The development of high-power converter targets otherwise known as neutron sources is today the focus of much attention, driven by the need for ever greater densities of neutron fluxes which are required in the fundamental sciences such as neutron imagery, isotope production and also for the more long-term goal of realising a hybrid sub-critical nuclear reactor. The neutrons in a converter target are produced by a process known in physics as spallation whereby a heavy Z atom releases neutrons below 20 [MeV] when hit by an incoming proton. The Eurisol initiative seeks to develop such an isotope production facility to provide the scientific community with the means to achieving high yields of isotopes and extending the variety of isotopes thus produced towards more exotic types rarely seen in existing facilities. The proposed ISOL facility would use both (a) several 100 kW proton beams on a thick solid target to produce RIBs directly, and (b) a liquid metal 1–5 MW ‘converter’ target to release high fluxes of spallation neutrons which would then produce RIBs by fission in a secondary uranium carbide (UCx) target. An alternative windowless liquid mercury-jet ‘converter’ target to generate the neutrons has also been proposed for this Multi-MW target station. The Multi-MW converter target at the heart of the projected facility is designed to create isotopes by fissioning uranium carbide (UC) target arranged coaxially around a 4 MW converter target. It is therefore essential that the target be as compact as possible to avoid losing neutrons to capture whilst maximising the neutron flux to enhance the number of fissions per second in the UC targets.

Author(s) :Cyril Kharoua, Yacine Kadi, Karel Samec (CERN)

This technical note summarizes the design calculations performed within Task#2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL-DS) on the safety hull of the CGS design of the mercury converter. A study was carried out in order to propose a configuration for the safety hull and the connection between the target and the accelerator. The results of these calculations show a layout and a design proposal for the safety barrier of the EURISOL DS target design.