After seven years of close-but-no-cigar, Canada's Cameco (TSX:CCO, NYSE:CCJ), the world's number one listed uranium producer, finally announced Thursday that production at its Cigar Lake mine in the Canadian province of Saskatchewan has commenced.

The news gave investors another excuse to chase up share prices in the sector after news that China's plans to build 20 nuclear plants by 2020 were ahead of schedule and Japanese plans to restart its nuclear industry boosted sentiment earlier this month.

Cameco shares traded 2.7% higher in afternoon dealings on Thursday on the news after earlier in day hitting an almost three-year high of $28.57. Year to date the counter is up 25%.

The $10 billion company said the $2.6 billion mine will produce 2m – 3m pounds of uranium concentrate in 2014 and ramp up to its full production rate of 18m pounds by 2018 from the McClean Lake mill.

Denison Mines (TSE:DML) also traded on the positive side, bringing its 2014 market value gains to 38%.

Toronto-based Denison, now worth $842 million on the Toronto big board owns 22.5% of the mill

Toronto-based Denison, now worth $842 million on the Toronto big board owns 22.5% of the mill, which the Cigar-Lake joint venture between Cameco (50%-owned) and France's Areva (37%) have been upgrading to handle Cigar Lake's output.

Energy Fuels (TSE:EFR), with mines in Utah, Arizona, Colorado and Wyoming jumped 8.5%, while Paladin Energy (TSE:PDN) climbed 5.8%. Australia-based Paladin operates a uranium mine in Namibia and various exploration projects on the continent.

Among explorers, Nexgen Energy (CVE:NXE) rallied almost 6% before falling back into the red, while Fission Uranium (CVE:FCU) shed 4.8%.

Vancouver-based Nexgen and Fission have both found great success in the Patterson Lake area in Saskatchewan abutting the Athabasca Basin.

After a 47% run up in Fission's share price lifting its market value above $500 million and a whopping 76% improvement at much-smaller Nexgen this year, investors are taking profits.

Despite the turnaround in sentiment in the uranium sector spot prices remain near 8-year lows of $35 a pound and have not recovered since the Fukushima disaster in Japan in 2011. Long term contract prices, which accounts for the bulk of the uranium trade, are set around $50 a pound.