MDS Nordion, the company that buys isotopes from AECL's Chalk River reactor, predicts more shortages in the future.

The company's president Steve West appeared before the House of Commons Committee on Natural Resources to talk about AECL's decision to abandon construction of its two MAPLE reactors.

AECL cancelled construction in May saying it was costing too much to solve the reactors' ongoing technical problems.

They were being built to replace the aging reactor in Chalk River that now produces half of the world's medical isotopes.

The reactor's license to operate expires in 2011 and it may or may not be renewed depending on safety issues.

The isotopes are used for medical tests for everything from heart problems to cancer.

West says there are no serious plans in other parts of the world to build new reactors to produce isotopes. That's despite assurances from Natural Resources Minister Gary Lunn that the private sector will step in to provide the supply.

West predicts the isotope shortage that hit the world last fall, and delayed and cancelled medical diagnostic tests, could happen again.

"We are very concerned about the reliability of supply for patients around the world, both for Canadians and for the world at large since NRU today does supply over 50 percent of the world's isotopes."

West also told the committee he thinks AECL should continue building the two new reactors to fulfill its 40 year contract with MDS Nordion.

Nordion has an exclusive contract with AECL and admitted under questioning that its corporate bottom line is at risk if AECL's isotope supply runs out in the years to come.

AECL has said it has no plans to revisit its decision.

The MAPLE reactor construction was costing the crown corporation about $7 million a month.