Engineering feasibility of the beam window is one of the design issues in the accelerator-driven system (ADS). This study aims to perform the coupled analysis for the feasible beam window concept. To mitigate the design condition, namely to reduce the required proton beam current, subcriticality adjustment rod (SAR) was installed to the ADS core. The burnup analysis was performed for the ADS core with SAR and the results indicated that the maximum proton beam current during the burnup cycle was reduced from 20 to 13.5 mA. Based on the burnup analysis result, the coupled analysis; particle transport, thermal hydraulics and structural analyses, was performed. As the final result, the following design; the hemisphere shape, the outer radius = 180 mm, the thickness at the top of the beam window = 1.5 mm, and the factor of safety for the buckling = 3.8, was presented. The buckling pressure was almost same as the previous one and more feasible beam window concept was presented through this study.

In ESS, a 5 MW proton beam will hit a helium cooled tungsten target to generate neutrons by spallation. For the purpose of investigating various aspects of cooling with helium, an experimental system has been constructed at Lund University, Department of Energy Sciences. A helium flow of 3 g/s is circulated in a closed loop with pre-heater, cooler, filters and a test vessel. The vessel has windows for measurements and is designed for 10 bar and above 400 °C. In the test vessel, a tube forms a helium jet of up to 150 m/s onto a coin shaped material sample. One purpose of the system is to investigate erosion of sample surfaces. Drilling and attaching equipment to the surface had to be avoided, so the setup has been benchmarked and the comparison was used to tune a CFD model. Then the model is used to assess the conditions in the experiments. The setup, as well as the tests and calculations, are described and it is concluded that the temperature and velocity estimates are sufficient for the experiments to be performed.

In ESS, a pulsed proton beam of 5 MW mean power will hit a tungsten target to generate neutrons by spallation. The pulses are 2.86 ms long and occur with 14 Hz; the power within a pulse is 125 MW. Only centimeters from the target, the neutrons are moderated by liquid hydrogen in aluminium vessels. The deposited power heats the surrounding structures and fluids which are circulated and cooled. The hydrogen is operating at 15 bar and average temperature between 17 and 21 K, i.e. above the critical pressure 12.8 bar, but below the critical temperature 32.9 K. During the pulses, the peak heat deposition in the aluminium is 15 W/cm 3 and in the hydrogen 4 W/cm 3 . If the cooling of the aluminium is neglected during one pulse, the temperature increases to 34 K. That is above the critical temperature, where physical properties change strongly with temperature. Therefore the conjugate heat transfer has to be investigated in detail. This work includes 1D principal transient calculations of a general configuration as well as CFD simulations of the heating and cooling of a specific design. The 1D calculations are performed using GNU/Octave and the CFD using ANSYS/CFX. It is concluded that with an inlet temperature of 17 K, the wall temperature can be kept below the critical temperature in the general configuration and sufficient cooling can be ensured in the investigated specific design.

The conceptual design and basic engineering of a multipurpose ADS for R&D, named Chinese Initiative Accelerator Driven System (CIADS), have been carried out by Chinese Academy of Science. A lead-bismuth eutectic (LBE) spallation target with beam window is an alternative for the CIADS. In this work, by using the code system ANSYS, the static structure analysis of the spallation target beam window at the initial state was performed parametrically in conjunction with the thermal hydraulics to check the design compliance with the stress and the buckling design criteria. The static structure analysis of the target window was presented under the conditions of different window thicknesses, proton beam intensities and beam spot diameters. The results showed that all the parameters investigated in this work which meet the needs of thermal hydraulics design also compliance with the stress and the buckling design criteria. Also, the results were used to select the thickness of the beam window to maximize the engineering margins. More work will be done in the future for the structural analysis of target operating with certain dosage irradiated by the neutrons and the protons.

The Accelerator Driven System (ADS) is a kind of nuclear reactor which can burn minor actinide waste products from conventional reactors with inherent safety. Because of the characteristics of a sub-critical reaction process, the fission chain reaction is maintained by additional neutrons generated by protons in spallation target. In this paper, a helium-cooled solid target is designed for a 10MW helium-cooled prismatic-type experimental ADS. The spallation material tungsten is modeled into the honeycomb structure, and high pressure helium flow in honeycomb holes remove heat deposited by the proton beam in the target. Since the complexity of geometry, if analysis the target with CFD code the computing time is unacceptable. Thus, a simple mathematical method was developed to solve the heat transfer problem in honeycomb structure, which avoids fine grid and the turbulent simulation, and gets a solution quickly. In order to analyze the transient characteristics of spallation target cooling system, a equivalent RELAP5 model for target and a RELAP5 model for cooling system are established. Results obtained indicate that the peak temperature in the target is lower than the limiting value under operating state and blockage condition as well as three typical transients with protected.

Pursuing a high minor actinide (MA) transmutation rate, this paper proposes a neutronics concept design of lead-bismuth (LBE) cooled accelerator-driven system (ADS) with burnup reactivity swing less than 1% and proton beam current smaller than 17mA. After a comparison with other types of fuels, Uranium-free metallic dispersion fuel (TRU-10Zr)-Zr* is selected to obtain a harder neutron spectrum to transmute MA. With a MA initial loading, the suitable proportion of initial Plutonium to transuranium element (TRU) is found around 33% to make sure that the burnup reactivity swing is less than 1%. The location of the spallation target is optimized to guarantee high external spallation neutron source efficiency and to lower proton beam current. For the subcritical system, initial effective multiplication factor is 0.97, and the thermal power is 1000 MW. For the accelerator, proton with energy of 1.5GeV and a parabolic spatial profile is provided by proton linac. It is demonstrated by the numerical results that the transmutation rate of MA is about 28% after 600 effective full power days (EFPD) while the support ratio for LWR units with the same power is about 46.

The double differential neutron yield generated by high energy proton beam bombarding on the targets of Tungsten, Lead and the Lead-Bismuth Eutectic (LBE) have been investigated based on FLUKA (Version 2011.2.8). Some FLUKA results have been checked with MCNPX and experimental data. Secondary neutron angular spectra are studied for cylinder and slab targets. The results show that the shape of the spectra are almost independent of angular bins while the yields in lateral and backward directions show a significant decrease as a results of the self-shielding effect in the slab target. The angular spectra of the photon and proton are also presented. The work is important for the shielding design of the target and the accelerator system.

Several distinct reactor strategies are proposed within the context of the IP Eurotrans framework programme for the transmutation of nuclear waste. A pool type reactor filled with liquid heavy metal and containing a subcritical core is one of the promising designs. Additional neutrons required for the nuclear reaction are generated by a spallation reaction inside the core. A high power proton beam is guided through a vacuum tube from an accelerator into the liquid heavy metal pool i.e. into the reactor core. At the point where the beam hits the metal surface special construction effort is indispensable to handle the high heat production. A specific target design is used to ensure a high fluid velocity and a stable surface at the beam entry. This design employs a concentric vertical feeder establishing a free conical surface with velocity up to 2.5 m/s ensuring stable surface flow and appropriate heat removal. The proposed target geometry has been constructed using underlying rules developed by the MYRRHA design group for the free surface target in the MYRRHA research reactor. A full scale model of this design using lead bismuth eutectic (LBE) has been set up and experimentally investigated at the of the Karlsruhe Institute of Technology (KIT). Measurements taken by high speed digital imaging visualize both conical inner and outer jet free surface. They show a stable surface in a wide range of operating conditions starting from 35% of the nominal flow rate and agree well with numerical investigations using commercial CFD code Star-CD and Star-CCM+. Previous concerns related to splashing or cavitation during the start-up or shut-down procedure proofed unjustified.

Fast Ignition is recognized as the most promising approach to achieving the high energy gain target performance needed for commercial inertial confinement fusion (ICF). However, there are great difficulties related to the traditional approach of generating a relativistic electron beam and then focusing it on the hot “spark” region (hot spot) of the compressed target. One promising alternate approach that has been proposed by researchers at LLNL and LANL is the laser generation of a proton beam in an “interaction foil” to ignite the target. However, the total proton flux supplied from hydrogen adsorbed on the foil surface is too small to generate the desired proton flux threshold. In more recent studies it has been found that ions heavier than protons would provide better focusing on the hot spot if ways to efficiently generate them can be found. Here we propose to utilize a new “Deuterium Cluster ”type structure as the laser interaction foil to generate an energetic deuteron beam as the fast igniter. The ultra high density deuterium in the cluster structure promises much higher total flux for deuterons than for traditional protons. Also, deuterons will serve very important dual purposes — the deuteron deposition in the target hot spot will not only provide heating but also fuse with fuel as they slow down in the target. The resulting fusion alphas serve to provide added heating, reducing the input requirement. If the physics works as anticipated, this novel type of interaction foil can efficiently generate energetic deuterons during intense laser pulses. The massive yield of deuterons generated from our cluster material through laser acceleration, should turn out to be the most efficient way of FI of the DT fuel, and making the dream of near-term commercialization of FI fusion more achievable.

The Compact Pulsed Hadron Source (CPHS) of Tsinghua University will produce neutrons by the Be(n,p) reaction through bombarding a proton beam with 13MeV/50Hz/1.25mA from a LINAC system on a beryllium target. One of the purposes of this neutron source facility is to provide the neutron scattering capability for characterization of materials, especially soft matters and biological systems. Cold neutrons (wavelength > 4 Å) are essential to characterize the structure of these materials over the length scale of ∼100 nm with good resolution. We discuss the design and optimization of a cold neutron source (CNS) which employs a solid methane moderator for cold neutron generation. The moderator configuration, the associated cryogenic system, and operation conditions will be discussed.

A designed and constructed wire scanner is used to measure the 30 MeV Cyclotron proton beam profiles in both x- and y-directions prior to injection to another accelerator for Proton Therapy purposes. The position control and control of movement of the two orthogonal wire scanners are done through an interface board to the PC that communicates with both the photo-couple sensors and the designed driver board, mounted and connected to the step motor set up, respectively. The Win AGILE beam transport code is used to measure the beam profiles 407cm upstream from the wire scanner. The beam sigma’s are evaluated to be σ x = 2.234 cm 2 and σ y = 1.850 cm 2 . The beam emittance in both x- and y-directions obtained are ε x = 1.67×10 −5 m-rad and ε y = 5.64×10 −5 m-rad, respectively. The extract Twiss parameters are calculated as α x = −1.28, β x = 12.7, γ x = 0.21, α y = −0.55, β y = 3.28, and γ y = 0.10.

J-PARC (Japan Proton Accelerator Research Complex) is a multi-purpose research facility for materials and life sciences, nuclear and particle physics, and nuclear engineering with extremely high power proton beams of 1 MW. The accelerator complex consists of a 400-MeV linac, a 3-GeV Rapid Cycling Synchrotron (RCS), and a 50-GeV Main Ring synchrotron (MR). Its goals are to provide MW-class beams at 3 GeV and at several 10 GeV, while it is a challenge to localize and suppress beam loss to the level to allow hands-on maintenance of accelerator components. The RCS scheme is adopted to realize them, which is advantageous over conventional Accumulation Ring (AR) regarding less beam loss problems due to lower beam current and easier construction and operation of a linac. RCS, however, required various challenging technologies such as ceramic ducts to reduce eddy current effects, high field Radio Frequency (RF) system, and paint injection technique (an injection scheme to reduce phase space density of the beam) to reduce space charge effects. The linac has also unique technologies to minimize beam loss, such as compact electromagnet Drift Tube Quadrupoles (DTQ’s) to control beam envelopes precisely, and a fast beam suspending system in Machine Protection System (MPS) with Radio Frequency Quadrupole linac (RFQ). The beam commissioning of the linac started in Nov. 2006, and its design energy of 181 MeV in the first construction phase was achieved in Jan. 2007. RCS beam commissioning started in Sep. 2007 and the beam was accelerated to the designed energy of 3 GeV in Oct. 2007. MR beam commissioning started in May 2008, and the beam acceleration to 30 GeV was established in Dec. 2008. The first neutron and muon beams were produced in May and Sep. 2008, respectively, at Materials and Life science experimental Facility (MLF). The linac commissioning has resulted in very stable beam with short down time. RCS commissioning quickly achieved beam acceleration and extraction, and paint injections are being studied intensively. RCS recorded the highest beam power of 0.21 MW in Sep. 2008 with beam loss well localized at the collimators. The linac beam energy will be upgraded to 400 MeV with Annular Coupled Structure linac (ACS) in order to increase the beam power to 1 MW. In the second construction phase, upgrade of the linac with 600-MeV Super-Conducting Linac (SCL) for Accelerator-Driven nuclear waste transmutation System (ADS) and upgrade of MR energy from 30 to 50 GeV are planned.

The European Facility for Industrial Transmutation (EFIT) is aimed at demonstrating the feasibility of transmutation process through the Accelerator Driven System (ADS) route on an industrial scale. The conceptual design of this reactor of about 400 MW thermal power is under development in the frame of the European EUROTRANS Integrated Project of the EURATOM Sixth Framework Program (FP6). EFIT is a pool-type reactor cooled by forced circulation of lead in the primary system where the heat is removed by steam generators installed inside the reactor vessel. The reactor power is sustained by a spallation neutron source supplied by a proton beam impinging on a lead target at the core centre. A safety-related Decay Heat Removal (DHR) system provided with four independent inherently safe loops is installed in the primary vessel to remove the decay heat in case of loss of secondary circuits heat removal capability. A quite detailed model of the EFIT reactor has been developed for the RELAP5 thermal-hydraulic code to be used in preliminary accidental transient analyses aimed at verifying the validity of the adopted solutions for the current reactor design with respect to the safety requirements, and confirm the inherent safety behavior of the reactor, such as decay heat removal in accidental conditions relying on natural circulation in the primary system. The accident analyses for the EFIT reactor include both protected and unprotected transients, on whether the reactor automatic trip, consisting in proton beam switch off, is actuated or not by the protection system. In this paper, the main results of the analyses of some protected transients with RELAP5 are presented. The analyzed transients concern the Protected Loss of Heat Sink (PLOHS), in which the DHR system plays a key role in bringing the reactor in safe conditions, and the Protected Loss of Flow (PLOF) transients with partial or total loss of forced circulation in the primary system.

A compact model of synchrotron accelerator facility is proposed for the treatment of deep seated tumors with proton therapy. The extracted beam from the existing C-30 cyclotron is first injected into the model of synchrotron. The injected beam is specified with its longitudinal plane as well as its horizontal and vertical emittances. For this design to be compatible with the cyclotron C-30 the synchrotron should be kept compact and the number of magnet components must be low. The modeled synchrotron layout is designed using the computer codes MADX and AGILE in order to accelerate the injection proton ions from 30 MeV to a maximum extraction energy of 250 MeV with magnetic rigidity of 2.433 Tm. In this lattice arrangement with phase advance of about 90 degrees in two horizontal and vertical planes doublet cells are utilized. This ring consists of two long straight sections for RF and injection/extraction equipment, as well as four short straight sections. For chromaticity correction two families of sextupoles are used. To prohibit emittance growth, a matching at injection in longitudinal plane was performed. The proton beam energy spread of 2% can be improved to 0.1% at injection by using the designed achromatic system. For the proton beam acceleration a RF cavity with an approximate voltage of 160 volts with a frequency in the range of 2.3 up to 14 MHz is used.

Intense beams for muon colliders and neutrino facilities require high-performance target stations of 1–4 MW proton beams. The physics requirements for such a system push the envelope of our current knowledge as to how materials behave under high-power beams for both short and long exposure. The success of an adopted scheme that generates, captures and guides secondary particles depends on the useful life expectancy of this critical system. To address the key technical challenges around the target of these initiatives, a set of experimental studies have either been initiated or being planned that include (a) the response and survivability of target materials intercepting intense, energetic protons, (b) the integrity of beam windows for target enclosures, (c) the effects of irradiation on the long-term integrity of candidate target and focusing element materials, and (d) the performance of the integrated system and the assessment of its useful life. This paper presents an overview of what has been achieved during the various phases of the experimental effort including a tentative plan to continue the effort by expanding the material matrix. The paper also attempts to interpret what the experimental results are revealing and seeks for ways to extrapolate to the required intensities and anticipated levels of irradiation and it discusses the feasibility of the proposed approaches to achieving such high-performance systems. Further it explores the connection of accelerator target systems with reactor systems in order to utilize experience data that the nuclear reactor sector has acquired over the years.

This paper details the integration scheme as well as the induced activation by the proton beam clean-up system (collimation) in the accumulator ring section of the Spallation Neutron Source (SNS) accelerator complex. Specifically, the results of the optimization study in terms of satisfying both the optics of the proton beam and the minimization of activation of the accelerator components as well as of the surrounding structure have guided both the design of the components and their integration and are presented in this paper. The resulted collimation scheme is a two-stage clean-up system consisting of proton beam halo intercepting scrapers and appropriate fixed aperture absorbers. The accumulator ring structure consists of the High Energy Beam Transfer (HEBT) line which receives the 1 GeV proton beam from the SNS LINAC accelerator, the accumulator ring itself which compiles the micro-pulses into the final 60 Hz pulse, and the RTBT line that transfers the final proton pulse to the accelerator target. Collimation takes place in all three ring components and along respective straight sections with the exception of the off-momentum particle clean-up in the HEBT line in which off-momentum protons are guided to a stationary absorber outside the transfer line. Given that the activation issues of the collimating structures themselves as well as of the nearby accelerator components (mainly magnets) are similar in all sections of the ring, the activation of components in the ring clean-up system will be discussed in detail in the following sections.

A new type of liquid-metal target is designed for the Spallation Neutron Source in PSI. LBE is selected to be the target material and the primary coolant as well. RELAP5/MOD 3.2 is used to analyze the system thermal hydraulics. The nominal conditions are chosen based on temperature constraints from the design assessments. The steady state results are in the proximity of the design specifications and the heat removal capacity is adequately deployed. The normal thermal hydraulic transients, namely the proton beam and beam interrupt, are studied. A basic PID (Proportional, Integral, Derivative) control is implemented in the RELAP5 for regulating the target temperature. It is found that the control chain works very well for the beam trip in limiting the temperature fluctuations. In a beam interrupt, the proton beam is completely turned off without recovering. The transition from full power to hot-standby is quite smooth, but it becomes oscillatory in the long run due to the timelags in the cooling loops’ responses. An off normal case of target main coolant trip has also been studied. Without the main pump, the target can still be operated in the natural circulation mode, and the control can cope with the normal beam transients and restarting the target from hot standby.

In the paper a possibility of using a lead isotope, pure Pb-208, as a coolant for a subcritical core of 80 MW thermal capacity of the PDS-XADS type facility is considered. Calculations of neutronic characteristics were performed using Monte Carlo technique. The following initial data were chosen: an annular core with a target, as a neutron source, at its centre; the core coolant — Pb-208 (100%); a fuel — a mix of mono nitrides of depleted uranium and power plutonium with a small share of neptunium and americium; the target coolant — a modified lead and bismuth eutectic, Pb-208(80%)-Bi(20%); proton beam energy — 600 MeV; effective multiplication factor of the core under operation — K eff = 0.97; thermal capacity of the core — N = 80 MW. From calculations performed it follows that in using Pb-208 as the core coolant the necessary intensity of the external source of neutrons to deliver 80 MW thermal capacity is equal to S = 2.29−10 17 n/s that corresponds to proton beam current I p = 2.8 mA and beam capacity P p = 1.68 MW. In using natural lead instead of Pb-208 as the core coolant, effective multiplication factor of the core in normal operating regime falls down to the value equal to K eff = 0.95. In these conditions multiplication of external neutrons in the core and thermal capacity of the subcritical core are below nominal by 1.55 times. For achievement the rated core power N = 80 MW it is required on ∼20–30% to increase the fuel loading and volume of the core, or by 1.55 times to increase intensity of the external source of neutrons. In the last case, the required parameters of the neutron source and of the corresponding proton beam are following: intensity of the neutron source S = 3.55·10 17 n/s., beam current I p = 4.32 mA, beam capacity P p = 2.59 MW. To exploit the accelerator with the reduced proton beam current it will be required about 56 tons of Pb-208, as a minimum, for the core coolant. Charges for its obtaining can be recovered at the expense of the economy of the proton accelerator construction cost. In this case, the acceptable price of the lead isotope Pb-208 must be less than $2,860/kg.

One of the most famous radioisotopes used in nuclear medicine is Iodine-123. Among the various types of nuclear reactions for producing I-123, the following reactions are favored due to the absence of I-124 and I-125 impurities: 54 124 Xe ( P , 2 n ) 55 123 Cs 5.9 min β + 54 123 Xe 2.08 hr β + 53 123 I 54 124 Xe ( P , pn ) 54 123 Xe 2.08 hr β + 53 123 I Recently in Cyclotron and Nuclear Medicine Department of NRCAM, at Atomic Energy organization of Iran (AEOI), a system for producing I-123 via Xe-124 gas target technology, has been constructed and installed. One of the major problems in this system is the highly expensive cost of the enriched Xenon-124 gas. Therefore, saving this gas inside the system is very important. Unfortunately, by accidental rupture of the window foil or bad function of O-rings, the whole Xenon gas will escape from the system immediately. In this paper, by using computer codes; ALICE91, SRIM and doing some calculations we are going to demonstrate our latest effort for feasibility study of producing I-123 with the above mentioned reactions, but using Xe-124 solid target instead. According to our suggested design, a conical shaped irradiation vessel made of copper with 1mm thickness, 1cm outlet diameter, 5cm length and 12° angle at summit can be fixed inside a liquid nitrogen housing chamber. The Xenon-124 gas will be sent to the inside of this very cold conical trap and eventually deposited on its surface in solid form. Our calculation shows that during bombardment with 17–28 MeV proton energy, the thickness of solidified Xenon layer will remain around .28 mm. Likewise; thermo-dynamical calculation shows that in order to prevent the evaporation of solidified Xenon, the maximum permissible proton beam current for this system should be less than 1.4 μA. According to these working conditions, the production yield of I-123 can be predicted to be around 150 mCi/μAh.

Iodine-123 is one of the most famous radioisotopes for Single Photon Emission Computed Tomography (SPECT) use, so, for 123 I production, the 123 Te has been chosen as a target through 123 Te (p,n) 123 I reaction. The various enriched targets (%99.9, %91, %85.4 and %70.1) have been used for the present calculations. In the current work, by using computer codes; ALICE & SRIM and doing a sort of calculations, we are going to demonstrate our latest effort for feasibility study of producing 123 I by the above mentioned reaction. By using proton beam energy of less than 30 MeV, the mentioned codes give more accurate results. The cross section of all Tellurium reactions with proton has been calculated at 0–30 MeV proton beam energy with ALICE code. In the present work, the yield of 123 I has been calculated by analytical methods. Our prediction for producing 123 I yield via bombardment of 123 Te (%99.9) with proton beam energy at 5–15 MeV is about 7.2 mCi/μAh. The present work shows that, the 123 I yield is proportional to abundance of 123 Te. Thermodynamical calculations with various current beams of up to 900 μA have been done, and the proper cooling system for the above purpose has been designed.