Properties of zirconium alloys and their applications in light water reactors (LWRs) - Materials' Ageing and Degradation in Light Water Reactors - page 83

4
Properties of zirconium alloys and their
applications in light water reactors (LWRs)

R. B. ADAMSON , Zircology Plus, USA and
P. RUDLING , ANT International, Sweden

DOI : 10.1533/9780857097453.2.151

Abstract : This chapter highlights the various uses and properties of
zirconium alloy cladding and structural components used in nuclear
power light water reactors. Specifi c attributes including dimensional
stability, corrosion resistance, irradiation effects and mechanical
properties are discussed in detail.

Key words : zirconium alloys, nuclear reactors, dimensional stability,
radiation effects, mechanical properties, corrosion.

4.1 Introduction
Zirconium alloys are used as the prime structural material in light water
reactors (LWRs). As such, they have to meet several requirements: low
neutron absorption cross section; corrosion resistance in 280-350°C water;
resistance to radiation in both mechanical behaviours and dimensional sta-
bility; reasonable strength, ductility and fabricability; affordable cost; and
availability in large quantities.
Unalloyed zirconium was used as the structural material in the prototype
core for nuclear submarines in 1953 (Rickover, 1975 in Adamson, 2010).
However, variability in corrosion resistance, strength and cost issues prompted
development of a stronger, more corrosion-resistant alloy named Zircaloy-2.
This alloy was used in the fi rst nuclear powered submarine, Nautilus 1954,
and in the fi rst commercial electricity-generating reactor, Shippingport 1957.
Today, a variety of zirconium alloys (see below for details) are used in all
LWRs throughout the world.
This chapter covers the following topics relevant to the uniqueness of
zirconium alloys: Section 4.2 on fuel assembly design; Sections 4.3-4.6 on
material and performance issues; Section 4.7 covers future trends in materi-
als; and Section 4.8 provides sources of further information.
Zirconium and hafnium (used as a neutron absorber) are unique among
materials used in LWRs in that they have the hexagonal close packed (HCP)

￿ ￿ ￿ ￿ ￿ ￿