Alan Waltar

Fast spectrum reactors

Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addition to valuable fuel cycle results. The systems section covers fuel pin and assembly design, fuel pin performance, overall systems considerations, and a major chapter on core materials where advances in metal fuels and long-life structural capabilities are featured. The safety section includes both traditional safety analysis techniques as well as a perspective on methods to achieve passive safety response. Whereas the bulk of the book is focused on sodium-cooled fast spectrum systems, a final section features gas-cooled and lead-cooled fast reactor systems

The high price of public fear of low-dose radiation

1 American Nuclear Society, Peshastin, WA, USA 2 DOE Low Dose Radiation Research Program, Washington, DC, USA 3 Canadian Nuclear Society, Toronto, Canada 4 Nuclear Medicine, Heinrich-Heine-University, Dusseldorf, Germany 5 United Nations Scientific Committee on the Effects of Atomic Radiation, Buenos Aires, Argentina 6 Pacific Northwest National Laboratory, Richland, WA, USA 7 BECS Department, Brookhaven National Laboratory, Upton, NY, USA

Introductory Design Considerations

Before discussing the neutronics, systems, and safety considerations involved in designing fast spectrum reactors, it is appropriate to follow the lead of Wirtz [1] in sketching the bases for fast spectrum reactor designs. In this orientation, care will be taken to indicate the principal differences relative to thermal reactor systems with which the reader is more likely familiar. This introduction to design begins with a brief discussion of major design objectives, followed by an overview of the mechanical and thermal systems designs of fast spectrum reactors (with an emphasis in this chapter on fast breeder reactors, since most other applications of fast spectrum systems—such as waste transmutation—will be optimized if the reactor has a high internal conversion ratio and/or a high breeding ratio). Because of the position occupied by the sodium-cooled fast reactor (SFR) in the international fast spectrum reactor community, that system will be used for purposes of illustration.

Nuclear knowledge management: a crucial bridge to the global nuclear renaissance

By 1980 the American nuclear industry, along with its nuclear knowledge infrastructure, was in decline due to growing public concerns for nuclear safety, nuclear weapons proliferation, economic uncertainty, mediocre early reactor performance and waste disposal. Recent renewed interest in expansion of nuclear power production is now being accompanied by rising market demand for nuclear professionals and increasing awareness among policymakers of the need to improve the nuclear knowledge infrastructure to support industry growth. Expanding deployment of nuclear power in the USA will necessarily require reversal of the declines in all the elements of the nuclear knowledge base.

Synergies resulting from a systems biology approach: integrating radiation epidemiology and radiobiology to optimize protection of the public after exposure to low doses of ionizing radiation

Nicholas Dainiak, Ludwig E. Feinendegen, Randall N. Hyer, Paul A. Locke and Alan E. Waltar Radiation Emergency Assistance Center/Training Site (REAC/TS), Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA; Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA; Department of Nuclear Medicine, Heinrich-Heine University, Dusseldorf, Germany; Medical Department, Brookhaven National Laboratory, Upton, NY, USA; CrisisCommunication.net and Center for Risk Communication, New York, NY, USA; Dynavax Europe GmbH, Dynavax Technologies Corporation, Dusseldorf, Germany; Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Pacific Northwest National Laboratory, Fast Reactor Safety and Fuels Organizations, Westinghouse Hanford Company, Richland, WA, USA; Department of Nuclear Engineering, Texas A&M University, College Station, TX, USA

Kinetics, Reactivity Effects, and Control Requirements

Values for reactivity effects are required both for transient safety analysis and for control requirements during normal operation. Reactivity effects of importance in fast reactor design and safety include (1) effects of dimensional changes in core geometry, (2) the Doppler effect, (3) effects of sodium density changes or loss of sodium, and (4) long-term reactivity loss from fuel burnup. The reactor control system must compensate for these reactivities during normal operation and provide sufficient margin to handle off-normal situations. We begin this chapter with a review of the reactor kinetics equations (Section 6.2). We then proceed to discuss adjoint flux and perturbation theory (Section 6.3) since these are needed for an understanding of reactivity effects.

Fuel Pin and Assembly Design

This chapter deals with the mechanical designs of fuel pins and assemblies. These core components must be designed to withstand the high temperature, high flux environment of a fast spectrum reactor for a long irradiation exposure time. In this chapter we will describe many of the factors that influence this design, and we will examine in some detail the stress analysis of the fuel pin. We begin in Section 8.2 with the basic geometric and heat transfer relationships for the fuel pin, and then discuss some topics related to fuel and fission gas that must be considered in analysis of steady-state fuel-pin performance. The discussion of fuel-pin design is continued in Section 8.3, in which failure criteria and stress analysis are presented. Discussion is then shifted in Section 8.4 to grouping the pins into a fuel assembly. This will include discussion of mechanical design problems such as fuel-pin spacing and duct swelling.

Reactor Plant Systems

The principal objective of the sodium-cooled fast reactor (SFR) power plant is to generate electricity. This is accomplished by transferring energy from nuclear fission to a steam system to run a turbine-generator. In this chapter we describe the SFR systems outside the core that are needed to meet this objective. The main emphasis, discussed in Section 12.2, is on the heat transport system, focusing on the design problems unique to SFRs. First, the overall heat transport system is described, including the primary and secondary sodium systems and the various steam cycles in use and proposed. Discussions then follow in Section 12.3 for the main components in the sodium system—the reactor vessel and reactor tank, sodium pumps, intermediate heat exchangers, and steam generators.

Nuclear Data and Cross Section Processing

The common approach of representing energy dependence of neutron–nucleus interactions consists of discretizing the energy dependence in a number of energy groups. During the fission reactions neutrons are emitted with an average energy of approximately 2 MeV. Neutron numbers are negligibly small above 10–15 MeV, making the maximum energy of interest in most nuclear fission reactors to be of about 15 MeV. Neutrons are then slowed down to much lower energies by collisions with the reactor components.

Core Thermal Hydraulics Design

In the previous chapter we explored the methodology for determining the temperature field for a single fuel pin. Since a typical fast reactor core comprises several thousand fuel pins clustered in groups of several hundred pins per assembly, a complete thermal-hydraulic analysis requires knowledge of coolant distributions and pressure losses throughout the core. This chapter will address these determinations.