Materials Irradiation Test Facility Research Articles

Conceptual Design of the IFMIF Target Facility

The lithium target facility design has been developed in the Conceptual Design Activities for the International Fusion Materials Irradiation Facility (IFMIF). As for the lithium target design, the replaceable backwall concept is selected as a reference design with the cell environment of 10{sup -1}Pa, and the free jet and Fusion Materials Irradiation Test Facility (FMIT) type design are carried as the option. In the lithium loop design the single loop is layed out to provide the lithium flow to the two targets with redundant components including tanks, heat exchangers, lithium purification systems, and lithium monitoring systems for high availability. Total lithium flow capability of 120 liter/s is provided by single electromagnetic pump, and the total lithium inventory is 22,300 liters. 9 refs., 5 figs., 2 tabs.

Materials development and testing aspects of IFMIF in the conceptual design stage

The conceptual design activity for the International Fusion Materials Irradiation Facility (IFMIF-CDA, 1995–1997) has recently attained its systems integration step incorporating three major subsystems, i.e. remote handling cell/irradiation test assembly, liquid metal target and accelerators. The mission is to provide a facility for testing candidate materials for fusion power reactors to full lifetime performance and also to provide scientific bases for calibration and validation of data from other radiation sources. The reference design considered to overcome the technical barriers has remained since the time of the early Fusion Materials Irradiation Test Facility (FMIT) design, and followed closely the ‘Users Requirements’ in terms of the test volume, flux, flux spatial distribution, energy spectrum, attainable annual fluence, etc. Implications of the interfaces between the requirements and the design approaches are discussed, and a perspective of the engineering validation to be done prior to construction and operation is presented.

A high-flux accelerator-based neutron source for fusion technology and materials testing

Advances in high-current linear-accelerator technology since the design of the Fusion Materials Irradiation Test (FMIT) Facility have increased the attractiveness of a deuteriumlithium neutron source for fusion materials and technology testing. This paper discusses the conceptual design of such a source that is aimed at meeting the near-term requirements of a high-flux high-energy International Fusion Materials Irradiation Facility (IFMIF). The concept employs multiple accelerator modules providing deuteron beams to two liquid-lithium jet targets oriented at right angles. This beam/target geometry provides much larger test volumes than can be attained with a single beam and target and produces significant regions of low neutron-flux gradient. A preliminary beam-dynamics design has been obtained for a 250-mA reference accelerator module. Neutron-flux levels and irradiation volumes were calculated for a neutron source incorporating two such modules, and interaction of the beam with the lithium jet was studied using a thermal-hydraulic computer simulation. Approximate cost estimates are provided for a range of beam currents and a possible facility staging sequence is suggested.

A beam penetration monitor and thickness gauge for the liquid lithium target in the FMIT facility

The fusion materials irradiation test (FMIT) facility was designed to provide very high fluxes of fusionlike neutrons to study irradiation properties of materials for fusion reactors. Neutrons would be produced by stopping a 0.1 A beam of 35 MeV deuterons in a liquid lithium target. The lithium was a falling jet which flowed in front of a thin backwall plate. Most of the 3.5 MW of energy in the beam was to be deposited in the lithium as heat near the depth of maximum beam penetration. If the lithium thinned too much deuterons would penetrate into the backwall and rapid melting might occur. A fast, on-line method was desired for detecting penetration of the beam through the lithium in time to limit melting by shutting it off. A method was found which is based upon observation of changes in the ratio of gamma rays to neutrons emitted from the lithium plus backwall. This method also provides a measure of the thickness of the jet at any moment. The basis of the method and experimental results are described. The technique may have wider applications.

IFMIF, an Accelerator-Based Neutron Source for Fusion Components Irradiation Testing Materials Testing Capabilities

The International Fusion Materials Irradiation Facility (IFMIF) is proposed as an advanced accelerator-based neutron source for high-flux irradiation testing of large-sized fusion reactor components. The facility would require only small extensions to existing accelerator and target technology originally developed for the Fusion Materials Irradiation Test (FMIT) facility. At the extended facility, neutrons would be produced by a 0.1-A beam of 35-MeV deuterons incident upon a liquid lithium target. The volume available for high-flux (>10/sup 15/ n/cm/sup 2/-s) testing in the base version of IFMIF would be 40 cm/sup 3/, a factor of over five larger than in the FMIT facility. This is because the effective beam current of 35-MeV deuterons on target can be increased by a factor of 2.5. Such an increase can be accomplished by funnelling beams of deuterium ions from the radio-frequency quadruple into a linear accelerator and by taking advantage of recent developments in accelerator technology. Multiple modules and the resulting large total current allow great variety in available testing. For example, multiple simultaneous experiments, and great flexibility in tailoring spatial distributions of flux and spectra can be achieved.

EURAC: The JRC proposal for a European fusion reactor materialse vst and development facility: Commission of the European Communities

The United States Department of Energy has spent in the last 10 years more than 100 Mill US$ for the development of intense neutron sources for a fusion reactor material test and development programme based on the D +−T and D +−Li stripping reactions. The final design parameters for the large Fusion Materials Irradiation Test (FMIT) facility are: • - Linear Accelerator: 35 MeV, 100 mA-deuteron-beam on a liquid lithium target. • - Irradiation parameters: 83 dpa/year in 10 cm 3 11 He appm/dpa. For the last 6 years we examined the use of a Spallation Neutron Source (SNS) as an alternative European Option to FMIT. For an optimized spallation neutron source design we find now for the same beam power as FMIT the following design parameters: • - Linear Accelerator: 600 MeV, 6 m-A-proton beam on liquid lead target. • - Irradiation parameters: 320 dpa/year in 20 cm 3 or 274 dpa/year in 31.5 cm 3 6 < He appm/dpa ⩽ 13. For a Tokamak Experimental Power Reactor such as INTOR (1.3 MW/m 2 wall loading) the design parameters are: 15 dpa/year and 11 He appm/dpa. If we compare FMIT with an optimized spallation neutron source of equal beam-power or neutron production cost, we arrive at the following figure of merit: p ]The present conceptual spallation neutron source target would allow us to use a 1200 MeV, 24 mA-proton beam, if required. The Ispra SNS-Target Station will be designed for these parameters. For synergetic experiments concerning fatigue and radiation damage the continuous proton beam will be periodically deflected on the target: Δt = 9s, f = 10 −1 s −, in order to simulate the Pulsed Mode of Tokamak Power Reactors. The deflected beam can be used for other experiments.

Final report on the FMIT control system

The computer control system for the Fusion Materials Irradiation Test Facility (FMIT) prototype accelerator was designed using distributed intelligence driven by a distributed database. The system consists of two minicomputers in the central control room and four microcomputers residing in CAMAC crates located near appropriate subsystems of the accelerator. The system uses single vendor hardware as much as practical in an attempt to minimize the maintenance problems. Local control consoles are an integral part of each node computer to provide subsystem checkout. The main console is located in the central control room and permits one-point operation of the complete control system. Automatic surveillance is provided for each data channel by the node computer with out-of-bounds alarms sent to the main console. Report by exception is used for data logging. This control system has been operational for two years. The computers are too heavily loaded and the operator response is slower than desired. A system upgrade to a faster local-area network has been undertaken and is scheduled to be operational by conference time.

Multiple Uses of an Upgraded FMIT Facility

The Fusion Materials Irradiation Test (FMIT) facility was designed to test small samples in fluxes greater than 1015) n cm2-s of fusion-like neutrons. The source of neutrons would be a 0.1 A beam of 35 MeV deuterons stopped in a liquid lithium jet target. During the present construction deferral, pending an international agreement, an expanded mission is being explored. Multiple CW beams in a common accelerator structure could be used to obtain a total steady-state beam current of about 1 A. This could provide for simultaneous multiple uses in up to four or more target areas as described below. For fusion materials, individual CW beams could be simultaneously directed to two or more FMIT targets, greatly improving availability. Alternately, the multiple beams could be combined for testing of large, multi-liter sized components of fusion reactors. At the same time, research in condensed matter could be pursued using both a steady-state and pulsed source of thermal neutrons in separate target areas. A steady-state flux that is an order of magnitude improvement over current reactor sources can be obtained. Moreover, a pulsed source that is comparable to the most intense pulsed sources nearing completion can also be achieved.

CW RF Operation of the FMIT RFQ

The 80-MHz RFQ for the Fusion Materials Irradiation Test Facility prototype accelerator has been rf conditioned for cw operation to the design field level of 17.5 MV/m (1.68 × Kilpatrick limit). Experimental results and operating experience will be discussed.

FMIT — Status update

The Fusion Materials Irradiation Test (FMIT) Facility was proposed as the only facility that could provide the intense neutron environment required for the development of long lifetime fusion reactor materials. In the FMIT, neutrons would be produced by the interaction of 35 MeV deuterons with a flowing liquid lithium target. Materials irradiations would be performed in a specially designed test cell containing the target and test equipment. Design of the plant and the major subsystems is advanced to the point where construction could begin immediately. Completion of FMIT would then take about four years, and initial materials test data would be available 2–3 y thereafter. Since 1982, completion of the FMIT has depended upon reaching an agreement for international collaboration on the Project. This paper describes the facility, its testing role, the status of the design and development work, and the progress made toward internationalization.

U.S. Fusion technology programs

The U.S. Department of Energy reveals that in the Magnetics program, they are assembling what is called the Large Coil Project in a facility being built at the Oak Ridge National Laboratory. The facility is shown. In the Plasma Heating Program, a positive ion neutral beam source has been developed at Berkeley. In the Fueling Program, a pneumatic pellet fuel injector was developed. In the Tritium Handling Program, tritium will be introduced upon final approval. In the High Heat Flux Component Development Program, they have recently installed and started testing pumped limiter on the TEXTOR tokamak reactor in the Federal Republic of Germany. In the materials area, there are two points. One is the Rotating Target Neutron Source, and the Fusion Materials Irradiation Test Facility.

SUPER-FMIT, an accelerator based neutron source for fusion components irradiation testing

The SUPER-FMIT facility is proposed as an advanced accelerator based neutron source for high flux irradiation testing of large-sized fusion reactor components. The facility would require only small extensions to existing accelerator and target technology originally developed for the Fusion Materials Irradiation Test (FMIT) facility. There, neutrons would be produced by a 0.1 A beam of 35 MeV deuterons incident upon a liquid lithium target. The volume available for high flux (> 10 14 n/ cm 2s) testing in SUPER-FMIT would be 14 1, about a factor of 30 larger than in the FMIT facility. This is because the effective beam current of 35 MeV deuterons on target can be increased by a factor of ten to 1.0 A or more. Such a large increase can be accomplished by acceleration of multiple beams of molecular deuterium ions (D + 2) to 70 MeV in a common accelerator structure. The availability of multiple beams and large total current allows great variety in the testing that can be done. For example, fluxes greater than 10 16 n/cm 2 s, multiple simultaneous experiments and great flexibility in tailoring of spatial distributions of flux and spectra can be achieved.

CW operation of the fmit RFQ accelerator

Experiences in attaining cw operation of the radio-frequency quadrupole for the fusion materials irradiation test facility are presented. Modifications of the vacuum system, changes in the RF structure, and operational experiences are discussed, as well as preliminary results of initial beam-characterization measurements.

米国の核融合材料照射試験施設ＦＭＩＴ計画における技術開発

米国の核融合材料照射試験施設ＦＭＩＴ計画における技術開発

FMIT Diagnostic Instrumentation

The Fusion Materials Irradiation Test facility (FMIT) cw prototype accelerator has noninterceptive beamline instrumentation to measure beam parameters. The transverse emittances and beam profiles are measured with an array of photodiode sensors viewing light emitted from the beam region. Tomographic reconstructions of both spatial-density distributions and of transverse-emittance distributions are performed throughout a quadrupole focusing section. Beam bunches passing through capacitive probes produce bipolar waveforms whose zero crossing corresponds to the bunch's longitudinal centroid. By measuring the time required for a bunch to travel the known distance between two probes, velocity and energy are determined. A toroidal transformer measures the average ac beam current. Beam spill is measured by a set of movable jaws that intercept the beam edges. Each jaw contains a water flow channel whose flow rate and differential temperature are measured to derive a transverse power distribution. Beam centroid position is measured by a four-lobe, magnetic-loop pickup.

Transport of Beryllium-7 in a Lithium Loop

A /sup 7/Be transport test was performed in the Beryllium-7 Experimental Lithium Loop with hot leg at 270/sup 0/C and cold leg at 230/sup 0/C. The ''cold leg'' test stringer was in a rising temperature region at 250/sup 0/C. A total of 108 test coupons were included in the material compatibility and deposition test programs, containing AISI Types 304 and 304L stainless steels, Fe-2 1/4 Cr1 MO, pure iron, molybdenum, beryllium, zirconium, titanium, yttrium, three different aluminide coatings on Type 304 stainless steel substrates, and both tubular and flat butt-welds of Type 304 stainless steel. An average lithium velocity of 1.36 m/s was established during the test which was terminated after 3718 h. The /sup 7/Be activity data indicated that the deposition of /sup 7/Be is a function of temperature. The cold leg positions displayed maximum /sup 7/Be deposition followed by the intermediate temperature locations (cold leg test stringer) and the hot leg locations. Two chemical forms of /sup 7/Be are expected in lithium, namely, unbonded /sup 7/Be at a low concentration, and a fine precipitate of /sup 7/Be/sub 3/N/sub 2/ at a high concentration. The deposit in the hot leg region is presumed to be primarily /sup 7/Be, whilemore » the cold leg deposit is mostly /sup 7/Be/sub 3/N/sub 2/. The cold leg specimens of a given material showed more /sup 7/Be deposition than the hot leg specimens of the same material, consistent with the /sup 7/Be activity data on the piping. Based on the present investigations and previous data, it is concluded that /sup 7/Be produced in the Fusion Materials Irradiation Test (FMIT) facility will have sufficient nitrogen in the lithium system to form /sup 7/Be/sub 3/N/sub 2/. It is expected that the majority of /sup 7/Be will be transported to the colder parts of the loop and deposited as /sup 7/Be/sub 3/N/sub 2/. However, a small amount of /sup 7/Be in the unbonded form will be in the hotter parts of the loop and is expected to diffuse into the steel piping.« less

The fusion materials irradiation test (FMIT) facility

The Fusion Materials Irradiation Test (FMIT) Facility will fulfill a key role in the development of fusion power systems. The need for materials irradiation technology for neutron energies and fluences which are uniquely achievable in FMIT has been confirmed through international review. The facility design and supportive R&D base establish significant confidence that the facility will fulfill its specified materials research and development function.

Progress in fmit test assembly development

This paper reviews the progress made in the development of high flux Fusion Materials Irradiation Test (FMIT) facility test assemblies over the past year. The development work has progressed from the conceptual design of test assemblies to the demonstration of actual assembly, disassembly and remote handling operations using full sized hardware mockups. Mockups of the high flux vertical test assembly (VTA-1) and the entire FMIT test cell and experiment work station have been fabricated, assembled and utilized for development testing. The tests utilizing the mockups will be described and results given.

Imaging of fast neutron sources using solid state track recorder pinhole radiography

Pinhole imaging methods are being developed and tested for potential future use in imaging the intense neutron source of the Fusion Materials Irradiation Test (FMIT) Facility. Previously reported, extensive calibration measurements of the proton, neutron, and alpha particle response characteristics of CR-39 polymer solid state track recorders (SSTRs) are being used to interpret the results of imaging experiments using both charged particle and neutron pinhole collimators. High resolution, neutron pinhole images of a 252Cf source have been obtained in the form of neutron induced proton recoil tracks in CR-39 polymer SSTR. These imaging experiments are described as well as their potential future applications to FMIT.

The Fusion Materials Irradiation Test (FMIT) Facility Lithium System - A Design and Development Status

The design and development of the Fusion Materials Irradiation Test (FMIT) Facility lithium system is outlined. This unique liquid lithium recirculating system, the largest of its kind in the world, is described with emphasis on the liquid lithium target assembly and other important components necessary to provide lithium flow to the target. The operational status and role of the Experimental Lithium System (ELS) in the design of the FMIT lithium system are discussed. Safety aspects of operating the FMIT lithium system in a highly radioactive condition are described. Potential spillage of the lithium is controlled by cell liners, by argon flood systems and by remote maintenance features. Lithium chemistry is monitored and controlled by a sidestream loop, where impurities measured by instruments are collected by hot and cold traps.