The Sellafield MOX Plant (SMP) in the UK is now operational alongside the Thermal Oxide Reprocessing Plant (Thorp). Operators British Nuclear Group (BNG) recently confirmed to journalists that “we have a working plant” and that they have produced more than one, but less than four fuel assemblies for Switzerland’s Nordostschweizerische Kraftwerke (NOK). BNG managers are confident of meeting the four-assembly NOK contract this summer – albeit “one or more” years late.

With reprocessing accounting for up to 25% of Sellafield’s business and Thorp’s order book adding up to something like £12 billion, the construction of SMP was an obvious next step after Thorp began operation in 1994. With the 120tHM/y SMP, BNFL are now able to provide a comprehensive and fully integrated reprocessing and recycling facility for its customers, encompassing spent nuclear fuel transport; interim storage; reprocessing; MOX fabrication and MOX transport.

In 1999, came the good news that the UK government provisionally considered full operation of SMP would be justified. Also in 1999 came the bad news that workers at the MOX Demonstration Facility, intended to prove the fuel pellet manufacture process ahead of SMP, had falsified data on a consignment of eight fuel assemblies destined for Kansai Electric Power Company’s Takahama 4 PWR.

A report by the Health and Safety Executive’s Nuclear Installations Inspectorate (NII) in 2000 said that the operators were tempted to cut corners on the glovebox process of pellet measurement by screw micrometer because, in simple terms, all the measurements made by operators exactly matched expected results recorded automatically during manufacture. The NII report said the “poor ergonomic design of the plant, the tedium of the job and the ease with which the computer data logging system could be manipulated” were major factors.

The problem, in other words, was one of the quality of the data, not of the fuel. Nevertheless, the product as a whole was unacceptable to Kansai Electric and remains to this day in storage somewhere at Sellafield while options of what exactly to do with it are considered.

With a lack of open support for nuclear investment in Westminster, any new part of the industry would have to prove its economic viability. Consultants Arthur D Little (ADL) conducted an economic assessment of SMP addressing the question: “Will SMP yield a net economic benefit?” The study looked into the “national economic interest case” in proceeding with the project.

The ADL report concluded that SMP would probably give a financial benefit with a net value of £216 million to the UK over its lifetime. The report said there was a 97% probability of this value being greater than zero and overall it concluded that there was a robust economic case for proceeding with SMP.

SMP entered its commissioning phase in 2001 with 40% of its order book full – the break-even capacity considered by ADL. One of the main contracts was with E.ON of

Germany, which represented 14% of capacity. Contracts were also in place with NOK and with Sweden’s OKG.

But the extended problems during commissioning will certainly have harmed SMP’s economic viability. BNFL’s original cost estimate for the plant was £265 million but this has now grown to £490 million.

MOX manufacturing work SMP was unable to meet had to be subcontracted. France’s Cogema and Belgium’s Belgonucléaire made the fuel using their own supplies of plutonium dioxide under a loan agreement. Those materials must now be replaced from Sellafield’s own stocks.

Managers are tight-lipped on SMP’s rate of production and the state of its order book other than to say they were happy with it. Certainly, SMP is running far below its design capacity of 120tHM/y. Sources say that the ADL report was based on SMP achieving at least 50tHM/y but that current production may even be as low as 10-40tHM/y. Certainly the lower end of that range seriously calls into question the plant’s business case. BNG’s managers told NEI the plant is “still justified” – adding “from our perspective.”

Although the data falsification ‘scandal’ would only delay and not ultimately affect Japan’s MOX loading plans, BNFL lost valuable orders to European rivals and suffered a wave of operational and management change.

Quite apart from those of operation, which seem finally to be beaten, SMP’s next challenge comes from its new owners, the Nuclear Decommissioning Authority (NDA), whose stated purpose is decommissioning and clean-up. The NDA must advise government on SMP’s worth and the operation of Thorp beyond about 2014. At the same time, about £1 billion of the NDA’s £2.1 billion budget is indirectly linked to revenue from operations at SMP, Thorp and the remaining Magnox plants it owns. Anything that affects the financial viability of these would therefore affect the NDA’s main work of decommissioning.

The operation of SMP will be a welcome piece of good news for the two-month-old NDA at this time when it’s dealing with the run up to contracting out UK clean-up and hit by a potentially very difficult and costly problem at Thorp.