Next-generation fuel for Palo Verde

Thursday, 8 January 2015

Westinghouse is to supply its newest next-generation nuclear fuel product for use in the Palo Verde nuclear power plant under a $250 million contract with operator Arizona Public Services (APS).

The new contract is an extension to an existing deal under which Westinghouse already fabricates and delivers fuel for Palo Verde's three Combustion Engineering (CE) pressurized water reactors, and now includes the transition engineering and licensing required to deploy the new fuel design.

According to Westinghouse, the CE16NGFTM fuel incorporates proprietary materials, such as advanced cladding material and burnable absorbers, and advances in structural design that improve the fuel's efficiency and reliability while also increasing its service life. These provide better economic performance and greater operational flexibility in fuel duty, thermal margin and uprate capability. The fuel has operated "very successfully" in two other CE 16 x16 units in the USA to date, the company said.

The standard form for nuclear fuel used in commercial reactors comprises a column of ceramic pellets of uranium oxide, clad and sealed into zirconium alloy tubes. Fuel rods are then fabricated into assemblies which are specifically designed for different types of reactor.

Fuel assemblies need to be able to withstand the harsh environment inside an operating nuclear reactor, where they are subjected to high temperature, chemical corrosion, radiation damage and physical stresses which may attack the integrity of a fuel assembly. A fuel assembly is therefore only allowed to remain in a reactor's core for a limited time to minimize the risk of breaches in the fuel's cladding. Developments such as those incorporated into Westinghouse's advanced fuel design serve to increase the reliability of the fuel and allow it to remain in the reactor for longer, increasing the burn-up - the time the fuel can stay in the reactor.

Palo Verde's three PWRs each have a net capacity of 1300 MWe, and have been in operation since the mid-1980s. They are currently licensed to operate until the mid-2040s.

Researched and written
by World Nuclear News