The shut-down has led to a shortage of technetium, a medical isotope, which NRG produces at the reactor in the north-west of the country. Medical isotopes are very small quantities of radioactive substance used for medical imaging and the treatment of diseases.

"The consequences of this unplanned stop will have an impact on the medical isotope market," said the company, whose reactor is one of only five worldwide to produce medical isotopes.

The Petten reactor produces a third of the world's medical isotopes, which have a short life span and cannot be stored for long.

"We have informed our customers of the situation and are assisting in the search for alternative supply routes," the NRG statement said.

Technetium is used in 80 percent of diagnoses using radioactive technology.

Around seven million check-ups using technetium are made in Europe each year and eight million in the United States, said NRG.

A company spokeswoman said everything possible was being done to restore production at Petten, but was not expected to resume before the end of October.

Those in charge of the world's other four isotope-producing reactors were in discussions to increase their production, spokeswoman Leontien Zuurbier told AFP.

The reasons for the breakdown have not yet been established, she added.

©AFP