The facility was shut down in April 2005 after it was discovered that a 20 metric ton – or 83,000-litre – amalgam of plutonium, uranium and nitric acid had been leaking inside the reprocessing facility’s clarification cell – a concrete containment shell – for eight months without detection, constituting Britain’s worst nuclear mishap in 14 years.

No one was hurt and no radioactivity escaped into the environment, but the event ranked one step below a full blown nuclear accident on the United Nations’ atomic energy watchdog’s International Nuclear Event Scale.

Photo: Foto: BNG

For a time following the incident, British nuclear authorities contemplated putting the plant out of use for good. But, ironically, the THORP reprocessing facility with its many foreign customers is a counted on source of revenue for decommissioning many of Britain’s oldest and most hazardous nuclear facilities.

After a series of restart dates that were repeatedly pushed back, the plant was forecasted in October to reopen early in 2008 on a provisional basis to complete reprocessing orders for Germany and Japan which was to last for six months, after which Nuclear Decommissioning Authority (NDA) and the Nuclear Installations Inspectorate (NII) provisionally said the plant would reopen in full.

That reopening came on January 28tt, but was a false start as it was discovered that a lift meant to transport nuclear waste to a station where it is cut and then delivered for further processing was discovered to be inoperative. The lift has since been repaired.

The show must go on – safe or not
Sellafield Ltd, which runs the THORP reprocessing facility, however, has to clear yet another hurdle to get the plant into operation – the safety go-ahead to put THORP’s evaporator back into use. The evaporator is an important component in completing the reprocessing process.

Despite the fact that the evaporator cannot be used, however, the plant nonetheless received permission to begin limited operations again as of March 16th – last Sunday.

“THORP is now waiting for permission from the NII for the right to use the evaporator,” said Bellona nuclear physicist Nils Bøhmer

“Their plan is to drive waste all the way through the facility until it reaches the evaporator, and to then put it into buffer storage in the meantime until they receive permission to use the evaporator.”

A genuine environmental threat
“THORP should not be started up again so long as all of its problems are not solved in a satisfactory manner,” said Bøhmer. He has spoken at length on Sellafield’s repeated safety issues.

"Nuclear waste is a genuine environmental threat, and even the British facility cannot fulfill stringent safety requirements. Sellafield has had many leaks and been shut time and again. Now they are nevertheless starting up (THORP) again without having cleared the safety of the facility,” he said.

Last gasp
Sellafield was built in 1956 for atomic weapons production, and later became an integral part of Britain’s civilian nuclear programme.

But Sellafield is slated for shutdown and decommissioning under a broad NDA mandate that will take Britain’s older nuclear sites off the grid and clean them up for an ever increasing cost that just topped £73 billion ($145 billion) -£12 billion more than initially projected – and costs are expected to rise even further.

A bulk of the funds, according to the NDA and government auditing agencies, is expected to be spent at Sellafield itself. Sellafield’s power producing reactors have already been halted. THORP remains one of the few active facilities at the Sellafield site.

“Reprocessing spent nuclear fuel at THORP is in many senses Sellafield’s last gasp,” said Bøhmer.

Opposition to reprocessing
Reprocessing of nuclear waste implies that spent nuclear fuel is “recycled” for use in new nuclear fuel. During reprocessing, usable plutonium and uranium are separated out from spent nuclear fuel to be applied as constituents in new fuel elements.

But the process is highly dangerous for the environment and liberates highly radioactive elements that are made airborne and are more often than not carelessly discarded in water bodies or stored in aging facilities, adding to regional radioactive waste woes. Leaks are an inevitable consequence of reprocessing.

Such an approach is called a closed nuclear fuel cycle, as opposed an open cycle in which nuclear fuel is used once and then stored until safe options for permanent internment become available.

Bellona favours the practice of storing nuclear waste on site instead of sending it around the world to that handful of countries that reprocess.

“We operate from a premise of opposing the entire reprocessing cycle,” said Bøhmer.

“But now that the first steps have been taken it is imperative that safety be at it’s highest. Here Sellafield has extremely frayed rumours, and we therefore deem that the THORP facility should be shut down with the rest of Sellafield.”