Power Density

The neutron flux distribution in an ADR is affected by the degree of subcriticality. Figure 1.30 shows the radial distribution of the total flux in ADRs with ke = 0.995 and 0.95 compared with that in a critical reactor. The core is cylindrical, 1 m high and 2 m in diameter, with properties similar to those of the standard sodium-cooled oxide-fuelled core described in Table 1.1, but with a neutron source located on the axis. It will be seen that the source has little effect on the flux in the outer part of the core, but is higher close to the source and more so the greater the subcriticality. As in a critical reactor the effect on the power distribution can be reduced by varying the composition of the fuel in different radial zones (see section 1.3.2), but the peak close


Figure 1.30 The effect of subcritical reactivity on the flux distribution in an ADR.

to the source may necessitate specific design measures to avoid local overheating.


Baker, A. R. and R. W. Ross (1963) Comparison of the Values of Plutonium and Uranium Isotopes in Fast Reactors, pp 329-265 in Breeding, Econom­ics and Safety in Large Fast Power Reactors Report ANL 6792, USAEC, Washington

Broomfield, A. M., C. F. George, G. Ingram, D. Jakeman and J. E. Sanders (1969) Measurements of k-infinity, Reaction Rates and Spectra in ZEBRA Plutonium Lattices, pp 1502-1511 in Fast Reactor Safety Technology, Volume 3, American Nuclear Society, LaGrange Park, Illinois, USA

Brown, F. B. (2012) Fundamentals of Monte Carlo Particle Transport Report LA-UR-05-4983, Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Coates, D. J. and G. T. Parks (2010) Actinide Evolution and Equilibrium in Fast Thorium Reactors, Annals of Nuclear Energy, 37,1076-1088

Davison, B. and J. B. Sykes (1957) Neutron Transport Theory, Clarendon, Oxford

Duderstadt, J. J. and L. J. Hamilton (1976) Nuclear Reactor Analysis, Wiley, New York

Greenspan, H., C. N. Kelber and D. Okrent (1968) Computing Methods in Reactor Physics, Gordon and Breach, New York

Hummel, H. H. and D. Okrent (1970) Reactivity Coefficients in Large Fast Power Reactors, American Nuclear Society, Hinsdale, Illinois, USA

Okrent, D. (1961) Performance of Large Fast Power Reactors Including Effects of Higher Isotopes, Recycling and Fission Products, pp 271-297 in Physics of Fast and Intermediate Reactors, Volume 2, IAEA, Vienna

Okrent, D., K. P. Cohen and W. B. Lowenetein (1964) Some Nuclear and Safety Considerations in the Design of Large Fast Power Reactors, pp 147­148 in Peaceful Uses of Atomic Energy, Volume 6, United Nations, New York

Palmiotti, G., E. E. Lewis and C. B. Carrico (1995) VARIANT: Variational Anisotropic Nodal Transport for Multidimensional Cartesian and Hexagonal Geometry Calculation Report ANL-95/40, Argonne National Laboratory, Argonne, Illinois, USA

Tamplin, L. J. (Ed) (1963) Reactor Physics Constants Report ANL 5800 (2nd ed.), USAEC, Washington, DC

Van der Meer, K. et al. (2004) Spallation Yields of Neutrons Produced in Thick Lead/Bismuth Targets by Protons at Incident Energies of 420 and 590 MeV, Nuclear Instruments and Methods in Physics Research B, 217, 202-220

Wardleworth, D. and R. C. Wheeler (1974) Reactor Physics Calculational Methods in Support of the Prototype Fast Reactor, Journal of the British Nuclear Energy Society, 13, 383-390

Yiftah, S. (1961) Effect of the Plutonium Isotopic Composition on the Per­formance of Fast Reactors, pp 257-270 in Physics of Fast and Intermediate Reactors, Volume 2, IAEA, Vienna