U.S. security clearances:
There is no functional difference between a temporary security clearance and a security clearance.
Security clearance investigations take time to complete, often a year or more, and an official may be granted a temporary or interim security clearance so that he or she can do his or her job while waiting for the investigation to be completed and a final determination made.
THE INTERIM SECURITY CLEARANCE
In exceptional circumstances, the hiring office may request an interim security clearance. The Office of Personnel Security and Suitability may be able to grant an interim security clearance within a few weeks after the individuals has submitted a complete security package. Final clearances usually are processed and adjudicated in less than 90 days.
Security clearances are outside the individual person's control. The employing agency initiates the request for a security clearance to the federal government's Office of Personnel Management, according to the requirements for the position. The Office of Personnel Management manages the process, and either grants or denies a security clearance. Security clearances expire after several years depending on the type of security clearance, and then another investigation is conducted before the security clearance is renewed.
Security clearances are subject to periodic reinvestigation every 5 years. The Office of Personnel Security and Suitability notifies the individual when it is time for their reinvestigation. The individual will submit an updated security package and another background investigation will be conducted. The investigation will again cover key aspects of the individual’s life, but will start from one’s previous background investigation.
If an official is not granted a security clearance after the investigation is completed, he is no longer eligible to be employed in his position, and is fired. This can happen because of something like having too much debt, being married to a Chinese general, or a pattern of poor judgment or moral problems like frequently ignoring important regulations at other workplaces.
Security clearances are managed by the U.S. government's Office of Personnel Management, except the CIA's which are managed by the CIA itself.