Hydro-Quebec's Gentilly 2 nuclear plant ceased power production Friday and will begin decommissioning in January.

Gentilly 2 nuclear plant. Source: IAEABy the Canadian Broadcasting Corporation's account, 800 jobs will ultimately be affected, with temporary workers at the plant laid off immediately. Decommissioning activities will employ 485.

The Candu reactor near Montreal was in service for 29 years. Its operating license expires this year, and the provincial government decided to shut the plant down rather than allow an investment in upgrades that could extend its life. The utility placed the price of a license extension at $4.3 billion, while a union representing plant workers maintained that the work would cost $2.4 billion.

According to the International Atomic Energy Agency, the plant produced 635 megawatts using a Candu 6 heavy water reactor placed into service in 1982.