The former head of the Canadian Nuclear Safety Commission (CNSC) -- who was dumped by the federal government after shutting down a nuclear reactor over safety concerns -- is seeking a Federal Court review of the decision.

Linda Keen's designation as president of the CNSC was revoked on Jan. 15. She had ordered the Chalk River nuclear reactor shut down over shortfalls in its emergency cooling system.

The shutdown led to a worldwide shortage of nuclear isotopes used in medical procedures.

Parliament passed emergency legislation in December that ordered the plant restarted, stating the risk was small compared to problems caused by the shortage of isotopes.

Keen was then fired by the Harper government based on an Order in Council on Jan. 15 that stated the Governor in Council had lost confidence in Keen as head of the CNSC -- the decision she is now challenging.

"By this application for judicial review, Ms. Keen is asking the Federal Court to declare that she was unlawfully removed as President, and that the November 2005, Order in Council, which re-appointed her as President, remains in full force and effect," said her lawyer Allan O'Brien in a news release.

In January, Natural Resources Minister Gary Lunn said he fired Lunn because she showed a "lack of leadership" and did not act quickly enough following the shutdown.

Keen was appointed in October 2000 to a five-year term as president. That term was renewed on Nov. 15, 2005.

The application claims to list numerous examples of government's violation of the "principals of natural justice and procedural fairness."

Shortly after being fired, Keen stated that the safety risk at the Chalk River nuclear reactor was 1,000 times higher than acceptable international standards prior to its temporary shutdown late last year.

On Thursday the CNSC and Atomic Energy of Canada Ltd. (AECL) launched a formal review of the contentious shutdown.

The reactor, operated by AECL, a Crown corporation, stopped production for scheduled repairs on Nov. 18 and was expected to restart within five days.

But the CNSC, which is responsible for setting licensing, and health and safety rules for the country's nuclear facilities, refused to allow the reactor to restart after finding it had been operating without a backup emergency power system for cooling pumps for 17 months.

That backup cooling system has now been installed.