In a major victory for radiation safety in Europe, the Norwegian government announced Wednesday that it would be permanently shutting down the financially and technically troubled Halden research reactor, which experienced a leak in 2016.

The 25 megawatt installation, which is the world’s oldest heavy-water reactor, is located in a mountain cave in the southern Norwegian town of Halden, and has been under a temporary closure since March due to a valve failure.

It is the second of Norway’s two reactors, the first of which is the Kjeller reactor, near Oslo, which began operations in 1951.

Bellona has for three decades questioned the Halden reactor’s sometimes hazardous operations, and demanded that the government stop subsiding its continued use.

During its operation, Halden has contributed some 10 tons of spent nuclear fuel to the 17 tons the country has amassed since the middle of the last century.

The announcement of Halden’s closure came Wednesday after a much-anticipated meeting of the board of the Institute of Energy Technology (IFE), which has overseen the reactor’s operation since it opened in 1958.

Norway’s industry ministry issued the announcement late in the afternoon, saying the closure came “for reasons of economic and technical risk in further operations.”

“This is a happy day for Bellona,” said Nils Bøhmer, Bellona’s general manager and nuclear physicist. “We have fought for the shutdown of the Halden Reactor for about 30 years.”

The Halden Reactor. Credit: Bellona

“Their jobs must be ensured during this transition phase,” Bøhmer said.

According to government projections, dismantling both the Halden and Kjeller reactors, as well as safely storing their radioactive waste, will cost some $1.5 billion, only a fraction of which has been accounted for by funding from the IFE. It is thus expected that the bulk of dismantling and storage costs will fall to the state.

Halden’s closure caps a luckless run for the reactor. In October 2016, a small leak of iodine 131 was detected at Halden, which prompted the evacuation of its staff, but caused no injuries or environmental damage outside the facility.

Yet the incident had the makings of something more serious. The iodine release caused a hydrogen buildup in Halden’s reactor core not unlike what occurred in 2011 at Fukushima. There were likewise concerns that the core of the reactor might become unstable, as well as other worrying issues surrounding its cooling system.

Most hazardous of all, however, was the lag-time between when the error occurred and when the IFE informed Norwegian radiation protection officials. The IFE later apologized for sitting on the news. But still, the incident fueled a rash of conspiracy theories charging that Norway was hiding a major nuclear disaster.

On less fantastical footing, however, the reactor had long ago fallen into costly obsolescence.

In April, government documents showed the reactor was operating at a loss of several million dollars, despite hefty operation grants to IFE from the government. At the same time, the reactor was drawing fewer and fewer paying customers for its nuclear research, and would have demanded another $18 million in new revenues next year simply to stay solvent.

Wednesday’s decision to close the reactor stopped that financial bleed and Bellona is hopeful that the costs of operating the Halden reactor will now be put toward the safe dismantlement and storage of its radioactive legacy.