The 380 tubes have to be removed by a special tool, and then crushed into small pieces for handling and storage, the corporation explained.
"One of the challenges we are facing is that pieces of the crushed pressure tubes are being caught inside the automated tooling, resulting in additional downtime for equipment maintenance and repairs," the report said.
"Effective planning for tooling maintenance and radiation work is imperative to the safety of our workers, as the pressure tubes are the most radioactive components to be removed from the reactor," the report said.
"While the project work has been further delayed, we are carefully reviewing the upcoming work sequences to identify opportunities to recover time on our schedule."
The Point Lepreau Nuclear Generating Station is the only nuclear power plant in the Atlantic provinces. It has been shut down for a major refit since April 2008. At full operation, the 25-year-old plant produces 30 per cent of the power the province uses.
NB Power says this is the first refurbishment of a CANDU 6 reactor in the world, and will extend the life of the power station for 25 to 30 years.
The work has been contracted out to Atomic Energy of Canada Ltd., but NB Power has loaned AECL some of its senior staff to help speed things up.
NB Power says it has warned AECL, a nuclear technology provider with contracts around the world, that it faces both financial penalties and damage to its reputation if the Point Lepreau work continues to stretch beyond the length of time promised when the refurbishment contract was signed.