Fast flux fluid fuel reactor: A concept for the next generation of nuclear power production

Journal Article · Thu Jul 01 04:00:00 EDT 1999 · Transactions of the American Nuclear Society

OSTI ID:20005831

Palmiotti, G; Feldman, E E

Nuclear energy has not become the preferred method of electrical energy production largely because of economic, safety, and proliferation concerns and challenges posed by nuclear waste disposal. Economies is the most important factor. To reduce the capital costs, the authors propose a compact configuration with a very high power density and correspondingly reduced reactor component sizes. Enhanced efficiency made possible by higher operating temperatures will also improve the economics of the design, and design simplicity will keep capital, operational, and maintenance costs down. The most direct solution to the nuclear waste problem is to eliminate waste production or, at least, minimize its amount and long-term radiotoxicity. This can be achieved by very high burnups, ideally 100%, and by the eventual transmutation of the long-lived fission products in situ. Very high burnups also improve the economics by optimal exploitation of the fuel. Safety concerns can be addressed by an inherently safe reactor design. Because of the intrinsic nature of nuclear materials, there probably is no definitive answer to proliferation concerns for systems that generate neutrons; however, it is important to minimize proliferation risks. The thorium cycle is a promising option because (a) plutonium is produced only in very small quantities, (b) the presence of {sup 232}U makes handling the fuel very difficult and therefore proliferation resistant, and (c) {sup 233}U is a fissile isotope that is less suitable than {sup 239}Pu for making weapons and can be diluted with other uranium isotopes. An additional benefit of the thorium cycle is that it increases nuclear fuel resources by one order of magnitude. A fast flux fluid fuel reactor is a concept that can satisfy all the foregoing requirements. The fluid fuel systems have a very simple structure. Because integrity of the fuel is not an issue, these systems can operate at very high temperatures, can have high power densities, and can achieve very high burnups. It is possible to continuously remove the fission products and to minimize maintenance requirements. Fluid fuel systems possess favorable in-core transient response via a very high immediate negative temperature coefficient because of the expansion of the liquid fuel. Control rods are not necessary because the loss of reactivity can be compensated for by adding fuel in the on-line circuit. The main challenges posed by fluid fuel systems are possible fluctuations of reactivity caused by density changes, loss of delayed neutrons in the fuel leaving the core for the on-line reprocessing circuit, and corrosion and erosion of the containers. The fast flux choice is dictated by the much better neutronic economy offered by a hard spectrum system. The system is flexible enough to be either a burner, a converter, or a breeder. The fast spectrum is the only one that will allow all the transuranics to be efficiently burned. Moreover, because of the very high operating temperatures (1,000 C or more), refractory metals have to be used for the container. These materials have quite large absorption cross sections in the thermal and epithermal range. Therefore, they can be used only in a hard spectrum system without compromising the neutronic efficiency. Two different types of fast flux fluid fuel reactors are being considered: liquid-metal fluid fuel reactors and molten salt reactors.

• Research Organization: Argonne National Lab., IL (US)
• OSTI ID: 20005831
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 81; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BREEDER REACTORS
BURNUP
DESIGN
ECONOMIC ANALYSIS
FAST REACTORS
FLUID FUELED REACTORS
FUEL CYCLE
NUCLEAR POWER PLANTS
REACTOR KINETICS
SIZE