IFE Reactor Research Articles

Description of a Facility for Vapor Clearing Rates Studies of IFE Reactors Flibe Liquid Chambers

The design and operating characteristics of the ALICE (Advanced Liquid Ionized Condensation Experiment) facility at UCLA are here presented. The goal of this vapor condensation experiment is to rapidly generate an IFE prototypical post-shot vapor density in a control volume using characteristic liquid chamber material (flibe, Li2BeF4), and investigate the condensation rates for the proposed schemes. This experimental goal is achieved by: 1) a pulsed electrothermal plasma source that simulates the pellet explosion for rapid vapor generation and 2) an expansion chamber that represents the IFE liquid chamber. This paper reports also on the construction and operation of a furnace for flibe casting. Melting and handling procedures connected with the use of flibe are also discussed. The first flibe liner has been inserted in the plasma source. Results from the first low energy experiments are showed.

Neutronics on inertial fusion reactors

Neutrons produced in conceptual high gain targets of inertial fusion (IFE) reactors can contribute to the dynamics of the DT fuel burnup, and will emerge after some slowing down in the capsule with an energy spectrum depending on the target design and burnup conditions. Analysis of such spectra has been performed for different direct-drive target designs and ρR, and the time-dependent emission and arrival to the first wall of the system are reported. On the basis of established reactor designs (first variable to be considered) such as HIBALL-II or KOYO, the realistic possibility to obtain an uniform power distribution and obtain enough tritium breeding can be demonstrated. Activation of steels, vanadium alloys and SiC based composites has been considered in comparative analysis using different neutron energy spectra showing the important energy-dependent effect and the general advantages of V-alloys and SiC composites. The correct simulation of chains leading to radiological critical isotopes (function of neutron energy) and the goodness of nuclear data are essential for final responses/conclusions, and they need to be evaluated with careful uncertainty analysis. The damage accumulation because of very intense pulsed neutron fluxes in IFE reactors needs to be well understood prior to consideration of the availability of use of some very extensively considered low-activation materials. Results on simulations performed on SiC using an accumulated dose of 2×10 14 recoi1s cm −2 are discussed and future work planned. Activation and damage analysis will impose clear boundaries in the final design of the reactor, and the availability in IFE power plants to include liquid protections to the walls is certainly very important.

Compressible response of thin liquid film/porous substrate first walls in IFE reactors

Abstract The compressible response of a thin film of liquid subjected to a rapid surface pressure pulse and isochoric nuclear heating is investigated in an attempt to determine the spallation behavior. The use of such films to protect the cavity wall of inertial confinement fusion reactors is currently envisioned. The magnitude and temporal dependence of the surface pressure impulse and nuclear heating are estimated based on data from the Prometheus-L, Osirus and Hiball design studies, all of which use the thin film wall protection concept. Compressible hydrodynamic calculations are performed with the CFDLIB code package from LANL. In both the Prometheus and Osirus cases, no spallation is predicted based on the results of these calculations. However, calculated tensile stresses are less than an order of magnitude below theoretical limits, and uncertainties in data and material behavior may push the film response closer to spallation.

Thermomechanical design of the grazing incidence metal mirror of the Prometheus-L IFE reactor

In laser IFE reactors the reflectivity and absorptivity of the grazing incidence metal mirror (GIMM) depend on the neutron dose received by the mirror surface. In addition to this effect, surface deformation caused by neutron-irradiation-induced swelling and due to thermal load changes the focusing quality of the mirror. In the present work, we present the database for material selection of the final GIMM of the Prometheus-L IFE reactor. A unique design for the GIMM, which accounts for mirror surface deformation by thermal and swelling effects is then presented.

Mechanical response and fatigue analysis of the first wall structure of the PROMETHEUS IFE reactor

Mechanical response and fatigue analysis of the first wall structure of the PROMETHEUS IFE reactor

Inertial fusion reactors using Compact Fusion Advanced Rankine (CFARII) MHD conversion

This study evaluates the potential performance (efficiency and cost) of inertial fusion reactors assumed capable of vaporizing blankets of various working materials to a temperature (10,000-20,000 K) suitable for economical MHD conversion in a Compact Fusion Advanced Rankine II (CFARII) power cycle. Using a conservative model, 1-D neutronics calculations of the fraction of fusion yield captured as a function of the blanket thickness of Flibe, lithium and lead—lithium blankets are used to determine the optimum blanket thicknesses for each material to minimize CoE for various assumed fusion yields, “generic” driver costs, and target gains. Lithium-hydride blankets are also evaluated using an extended neutronics model. Generally optimistic (“advanced”) combinations of lower driver cost/joule and higher target gain are assumed to allow high enough fusion yields to vaporize and ionize target blankets thick enough to stop most 14 MeV neutrons, and to breed tritium. A novel magnetized, prestressed reactor chamber concept is modeled together with previously developed models for the CFARII Balance-of-Plant (BoP), consisting of a supersonic plasma jet, MHD generator, and “raindrop” condensor. High fusion yields (20 to 80 GJ) are found necessary to heat and ionize the Flibe, lithium, and lead-lithium blankets for MHD conversion, with initial solid thicknesses sufficient to capture most of the fusion yield. Much smaller fusion yields (1 to 20 GJ) are required for lithium-hydride blankets. For Flibe, lithium, and lead—lithium blankets, improvements in target gain and/or driver cost/joule, characterized by a “Bang per Buck” figure-of-merit of ≥ 20 joules yield per driver $, would be required for competitive CoE, while a figure-of-merit of ≥ 1 joule yield per driver $ would suffice for lithium-hydride blankets. Advances in targets/driver costs would benefit any IFE reactor, but the very low CFARII BoP costs (contributing only 3 mills/kWh to CoE) allows this type of reactor, given sufficient advances that non-driver costs dominate, to ultimately produce electricity at a much lower cost than any current nuclear plant.

Envrionmental and Safety Aspects of “OSIRIS”: A Heavy Ion Beam Driven IFE Reactor

AbstractA detailed safety analysis was performed for the inertial confinement fusion reactor OSIRIS. The radioactivity induced in the carbon fabric chamber concrete shield and Flibe breeder is very low allowing for their disposal at the end of the reactor life as Class A low level waste (LLW). The biological dose rate after shutdown behind the reactor biological shield shield is very low (0.11 µmrem/hr) allowing only for hands-on maintenance. A total of 91.5 Ci/day are routinely released to the environment producing an off-site dose to the maximally exposed individual (MEI) of 2.43 mrem/yr at the reactor site boundary. Only a small fraction (0.2%) of the reactor first wall would be mobilized during a loss of coolant/loss of flow accident. The decay heat generated in the concrete shield is very low such that its temperature would only increase by less than 2 degrees during such an accident OSIRIS contains 660 tonnes of liquid Flibe as a coolant and breeder. A severe accident including a breach of the react...

Overview of the Osiris IFE Reactor Conceptual Design

The Osiris reactor concept is one of two that emerged from the DOE-sponsored IFE reactor design study. It uses a heavy ion beam driver, a carbon cloth first wall and blanket structure that is filled with Flibe, and a steam power conversion system. The driver energy is about 5 MJ and the target yield is about 430 MJ. A 1000 MW(e) net plant requires a rep rate of about 4.6 Hz. The reactor chamber is of a leak-tolerant design where Flibe permeates a carbon cloth first wall and provides a protective coating. A Flibe spray, which supplies the pool at the bottom, condenses blowoff vapor. All components are removed as an assembly from the top of a carbon composite vacuum vessel. The study included assessments of environmental and safety aspects, economics, and technology development requirements.

Low Cost, High Yield IFE Reactors: Revisiting Velikhov’s Vaporizing Blankets

The performance (efficiency and cost) of IFE reactors using MHD conversion is explored for target blanket shells of various materials vaporized and ionized by high fusion yields (5 to 500 GJ). A magnetized, prestressed reactor chamber concept is modeled together with previously developed models for the Compact Fusion Advanced Rankine II (CFARII) MHD Balance-of-Plant (BoP). Using conservative 1-D neutronics models, high fusion yields (20 to 80 GJ) are found necessary to heat Flibe, lithium, and lead-lithium blankets to MHD plasma temperatures, at initial solid thicknesses sufficient to capture most of the fusion yield. Advanced drivers/targets would need to be developed to achieve a “Bang per Buck” figure-of-merit ≳ 20 to 40 joules yield per driver $ for this scheme to be competitive with these blanket materials. Alternatively, more realistic neutronics models and better materials such as lithium hydride may lower the minimum required yields substantially. The very low CFARII BoP costs (contributing only 3 mills/kWehr to CoE) allows this type of reactor, given sufficient advances that non-driver costs dominate, to ultimately produce electricity at a much lower cost than any current nuclear plant.

The Next ICF Facilities

Recent NAS and FPAC reviews of the ICF Program contain recommendations that, if implemented, will greatly impact the ICF Program. Target physics studies and experiments have indicated that ignition and gain may be achieved with 1.5 to 2.0 MJ of driver energy. It has, therefore, been recommended that the Nova facility be upgraded to this energy and undertake ignition experiments by the end of the decade. A specific set of target physics, driver development, and target fabrication milestones have been recommended leading to this facility and to the ignition experiments. Similar recommendations were made concerning the OMEGA Upgrade, the Nike laser, heavy ion reactor driver development and IFE reactor technology. Carrying out these recommendations successfully would lead to major ICF decisions about an LMF for military applications and an ETF for energy applications about the year 2000.