The decisions for both companies were announced recently, nearly three months after the commission visited Port Hope for three days of public hearings.
Five-year licences were requested by the companies, both owned by Saskatchewan-based Cameco Corp.
Cameco spokesperson Doug Prendergast said the company is pleased both Cameco and Zircatec were granted the five-year licences they requested.
The CNSC decision confirms the companies operate safely within the community, he said.
"It's good news for the company and the employees," he said.
Uranium dioxide (UO2) and uranium hexafluoride (UF6) is produced at the Cameco uranium conversion facility located on Eldorado Drive.
Nuclear fuel bundles for CANDU reactors are produced at the Zircatec facility on Peter Street, which was purchased by Cameco Corp. last year.
A total of 284 written and oral interventions were made by the public regarding operations at the two facilities during the three days of hearings in late November.
In its record of proceedings - a document that outlines the commission's decision - the CNSC stated Cameco's operations "...do not pose an unreasonable risk to the health and safety of persons, the environment and national security...."
The same was stated in the record of proceedings for the Zircatec facility.
The new operating licences for the two facilities come into effect on Thursday, the CNSC stated in a release.
Status reports on the performance of both facilities are expected to be presented at a public hearing during the first half of the licence terms, according to the release.
In the record of proceedings, the commission states that it encourages a development of a "memorandum of understanding" between Cameco and the Municipality of Port Hope on the issue of fire protection.
A report is expected when this is addressed or within a year.
Fire protection was an often-discussed topic during the November hearings.
Mr. Prendergast said this recommendation does not come as a surprise. A process for this is already in place, he said.
"It's something we're working towards," he said.
Concerned citizen groups such as Families Against Radiation Exposure (FARE) and the Port Hope Community Health Concerns Committee proposed to the CNSC in November that licences be limited to two years for both facilities.
The company will be able to provide further response in the coming days, once it fully reviews the document.
"Once we've had some time to review it, we'll be able to speak more broadly about the issues raised," he said.
To view the CNSC's record of proceedings for both facilities, visit www.nuclearsafety.gc.ca.
The new renewed licences carry through to 2012.