Radiation scare at Norway’s Kjeller reactor blamed on pump leak

På Kjeller behandles bl.a brukt atombrensel som er bestrålt i Haldenreaktoren.
Foto: Thomas Nilsen/ Bellona

Publish date: September 12, 2006

Written by: Erik Martiniussen

Translated by: Daniel Jensen

The Norwegian Institute for Energy Technology (IFE) experienced a leak on Saturday in a pump used in conjunction with the recombination circuit at the Kjeller reactor outside of Oslo, resulting in a small release of radioactivity into the environment for about 15 minutes, IFE officials acknowledged over the weekend.

It is still not known what went wrong. Institute officials said they have inspected the reactor at Kjeller, known as the Jeep II, but they won’t have a final conclusion until researchers go into the reactor, Aftenposten newspaper reported. That inspection will not occur until the level of radioactivity at the site is reduced.

The Jeep II was immediately shut down when the radiation levels increased, and the Norwegian Radiation Protection Authority (NRPA) was notified. The reactor is now closed for an indefinite period.

The IFE said that the Jeep II is a 2 megawatt research reactor mainly used for neutron activation analyses, production of isotopes for medical purposes, irradiation of semiconductor materials and basic research in physics.

Sunday’s accident
According to IFE accounts, at 3 a.m. on Sunday the alarm at the Kjeller reactor went off. At that time, increased values of radiation were registered in the recombination circuit and in the steel housing surrounding the reactor. The IFE’s website reported that air escaped the steel housing before the reactor and the housing were isolated. They confrimed the emission was caused by a leak in the recombination circuit.

The IFE said lesser amounts of radiation seeped out into the open for about 15 minutes. It remains unknown what quantity of radiation escaped into the atmosphere.

“We’ve registered a radiation level of 10 micro sieverts per hour inside the steel housing,” said the NRPA’s Ingar Amundsen. That represents more than two times normal levels. At present, Amundsen does not know what caused the accident.

One of Many
This is not the first accident to take place at the Kjeller reactor, which is nearly 40 years old. In the late 80’s vast quantities of radioactive tritium leaked out of the reactor because of a rupture in the cooling system. And in 1993, the IFE experienced a major accident in one of their laboratories at Kjeller, causing large amounts of Strontium-90 to spill into the river Nitelva.

In 2001 there was also a serious leak at the Halden-reactor – the only other reactor in operation in Norway – which is also operated by the IFE. The accident was caused by a rupture in one of the fuel cells of the reactor, and the incident resulted in large quantities of radiation contaminating the reactor’s primary circuit.

Two years later, cracks in the cooling system of the same reactor were discovered. Large components of the primary cooling circuit had to be replaced before the reactor was allowed to resume operation.

Bellona’s stance on the IFE
Bellona is now questioning the security procedures of the IFE. In Bellona’s opinion, this weekend’s accident at the Kjeller reactor should be taken seriously, and draws a picture of the IFE as an organisation that is no longer in control of its actions. IFE installations have suffered three serious accidents over the last five years.

“This time, the IFE won’t get away with it by simply disregarding the seriousness of the incident,” Bellona physicist Nils Bøhmer said.