The UK plans to shutter its Sellafield Mixed Oxide (MOX) plant (SMP) as soon as it is practically feasible because the March 2011 Japanese quake and subsequent nuclear crisis at Fukushima have changed the facility’s commercial risk profile, the Nuclear Decommissioning Authority (NDA) said today.

The NDA, a nondepartmental public body that owns all of the nation’s public nuclear assets, including the Sellafield site, said its key objective was to manage commercial operations while keeping costs passed on to UK taxpayers to a minimum. The NDA’s Board has concluded that “in order to ensure that the UK taxpayer does not carry a future financial burden from SMP, . . . the only reasonable course of action is to close SMP at the earliest practical opportunity.”

The MOX fuel fabrication plant in West Cumbria has cost UK taxpayers £1.4 billion since it was commissioned in the early 1990s, reported The Guardian. In May 2010, the NDA and 10 Japanese utilities agreed to refurbish the plant using an AREVA technology so as to convert in the UK all the plutonium recovered for use in the Japanese “Pluthermal” program.

Japan’s long-term policies rely on the establishment of a closed nuclear fuel cycle with the irradiation of MOX—nuclear fuel made of reprocessed plutonium and uranium—in conventional light water reactors, including pressurized and boiling water types. In Japan, this process is referred to as "pluthermal"—a portmanteau of the words "plutonium" and "thermal."

The Japanese nuclear sector has been rocked by the March crisis, and many of its 53 reactors remain idled. More recently, the country’s nuclear regulatory body, the Nuclear Industrial Safety Agency (NISA), has been embroiled in a scandal that could dent public trust in that agency. Chubu Electric Power Co. on Friday allegedly said NISA asked the utility to manipulate public opinion to favor “pluthermal” nuclear projects at government-sponsored symposiums held in 2006 and 2007.

According to the World Nuclear Association, about 15 metric tons of reactor-grade plutonium owned by Japanese utilities are being held at Sellafield, awaiting incorporation into about 270 metric tons of MOX fuel, but this may now be converted in France or Japan.

Japanese plutonium will continue to be stored at the site under international safeguards while the NDA develops discussions with Japanese customers “on a responsible approach to support the Japanese Utilities’ policy for the reuse of their material,” it said.

The decision does not mean that the UK has ruled out using MOX, the NDA said. Noting that the decision made today was a commercial matter relating only to the SMP, the organization said that the UK government had been consulting on the policy options for dealing with the UK’s plutonium stockpile, including possible re-use as MOX fuel. “The NDA awaits with interest the outcome of this consultation.”

Sources: POWERnews, NDA, WNA, Japan Times, The Guardian