Norway’s Halden Reactor: A poor safety culture and a history of near misses

source : Bellona

Published on March 3, 2017 by , Nils Bøhmer

Inside the Halden reactor. (Photo: Wikipedia)

Are those who operate Norway’s only nuclear research reactor taking its safety seriously? A new report raises concerns.

October 25th brought reports that there was a release of radioactive iodine from the Halden Reactor. The Norwegian Radiation Protection Authority subsequently withdrew the reactor’s operating license from the Institute for Energy Technology. The NRPA has pointed out several issues the institute must resolve before the reactor goes back online.

It’s not the first time the NRPA has had to issue an order to the IFE. The NRPA had been supervising the IFE since 2014 over its lack of safety culture. The incident in October shows this frame of mind persists.

Reactor cooling blocked

So what happened in October? The iodine emission began when the IFE should have dealt with damaged fuel in the reactor hall. This led to a release of radioactive substances via the ventilation system. The release began on Monday, October 24 at 1:45 pm, but was first reported to the NRPA the next morning.

The next day, the NRPA conducted an unannounced inspection of the IFE. The situation was still unresolved and radioactive released were still ongoing from the reactor hall. The ventilation system was then shut off to limit further releases into the environment.

This, in turn, created more serious problems. When the ventilation system was closed down, the air coming from the process should also have been turned off. Pressurize air kept the valves in the reactor’s cooling system open, which in turn stopped the circulation of cooling water.

‘A very special condition’

In the following days, the NRPA continued to monitor the reactor’s safety, and many repeated questions about the closure of the primary cooling circuit. The IFE initially reported that the situation at the reactor was not “abnormal.” By November 1, the NRPA requested written documentation from the responsible operating and safety managers. A few hours later, the NRPA received notice from the IFE that the reactor was in “a very special condition.”

What that meant was that the IFE had discovered temperature fluctuations in the reactor vessel indicating an increased neutron flux in the core, and with that the danger of hydrogen formation. Bellona would like to note that it was hydrogen formation in the reactor core that led to a series of explosions at the Fukushima Nuclear Power Plant in March 2011.

The IFE therefore had to ask the NRPA for permission to open the valves again, even if that meant releasing radiation to the public. The release that followed was, according to the NRPA, within the emission limit values specified in the operating permit.

In Summary

The IFE has been under special supervision by the NRPA, but it doesn’t seem to Bellona that the IFE has taken the requirement for increased reporting nearly seriously enough. It seems they further didn’t understand the seriousness of the situation that arose in October. The IFE either neglected procedures it’s obligated to follow, made insufficient measurements, or failed to report the results satisfactorily.

Bellona is concerned that the reactor core may become unstable by just closing the vents. Hydrogen formation in the reactor core is very serious, as Fukushima showed. The IFE has previously stopped circulation in the primary cooling circuit for, among other things, maintenance while the reactor has been shut down.

Those who live around Halden had previously been satisfied with guarantees that the ravine in which the reactor could hermetically seal it off. As the incident in October shows, this guarantee no longer applies.

Nils Bøhmer is Bellona’s general director.