OTTAWA — Fighting the threat of "radiological terrorism" will once again preoccupy Canada and four dozen other countries and groups at a major summit next year on nuclear security.

South Korea has high ambitions for the March meeting it is hosting, the follow-up to last year's inaugural nuclear security summit that was chaired by U.S. President Barack Obama.

The Harper government has yet to formally announce Canada's participation in the two-day event in Seoul on March 26-27.

But as one of 50 participants at the April 2010 Washington nuclear security summit, Canada is on the guest list and is digesting a host of agenda proposals from South Korea.

The threat of a terrorist dirty-bomb attack will once again be one with which summit participants continue to grapple following Obama's efforts last year. South Korea also wants a robust discussion on how to protect nuclear facilities from sabotage or cyber attacks.

"We believe that there is a need to engage in in-depth discussions on the threat of radiological terrorism, together with that of nuclear terrorism at the summit," says a preliminary statement by an "eminent persons group" advising South Korean President Lee Myung-bak.

The panel says the March earthquake and tsunami that struck Japan and unleashed radiation from the Fukushima nuclear plant underscores the need for the Seoul summiteers to address the dangers posed by "insufficient nuclear safety."

"In conjunction, it should develop measures for co-operation to reduce the threat of radiological terrorism," says the statement.

The nine-member panel -- which includes no Canadians -- says the leaders gathering in Seoul need to restore public confidence in the peaceful uses of nuclear energy. That's a message that has implications for Canada, which is struggling to sell its nuclear energy reactor technology to foreign countries.

"We also urge them to reduce the threats to nuclear facilities and their operating systems, such as sabotage or cyber attacks, by discussing in a responsible manner the ways in which nuclear security and nuclear safety can be mutually reinforced, bearing in mind the implications and lessons learned from the Fukushima nuclear accident," it says.

World leaders, including Canada, endorsed Obama's 2010 initiative to secure all nuclear materials on the planet within four years in order to keep them out of terrorists' hands. But their final communique contained few specifics.

"We know that organizations like al-Qaida are in the process of trying to secure nuclear weapons or other weapons of mass destruction, and would have no compunction at using them," Obama said before last year's summit.

In Washington last year, Prime Minister Stephen Harper announced that Canada would return highly enriched uranium to the United States where it would be rendered unusable for nuclear weapons.

Harper also announced Canada's participation in a joint plan that would see highly enriched nuclear material returned to the U.S. from Mexico. The plan also called for converting Mexico's research reactor to low enriched uranium.

Converting reactors to low enriched uranium and returning "unneeded" materials are among the "possible agenda and issues" contained in a slide presentation by the South Korean foreign ministry.

"Nuclear security will be the main theme; nuclear safety will be complementary: how and to what extent safety has implications on security and can help reinforce security goals? The necessity to address both safety and security aspects from design and construction to operation and management phases of nuclear power plants in the future."

Some 47 countries are invited to the South Korean summit. The United Nations, along with its nuclear watchdog, the International Atomic Energy Agency, the European Union and Interpol are also on the guest list.