Human factors aspects of the major upgrade to control systems at the Los Alamos National Laboratory Plutonium Facility

The Plutonium Facility (TA-55) at Los Alamos National Laboratory (LANL) has been in operation for over 15 years. It handles projects such as: stockpile maintenance, surveillance, and dismantlement; pit rebuild; plutonium power source fabrication for long duration spacecraft missions (e.g., Cassini); nuclear materials technology research; nuclear materials storage; and remediation of nuclear waste. The Operations Center of TA-55 is the nerve center of the facility where operators are on duty around the clock and monitor several thousand data points using the Facility Control System (FCS). The FCS monitors, displays, alarms, and provides some limited control of the following systems; HVAC, fire detection and suppression, radiation detection, electrical, and other miscellaneous systems. The FCS was originally based on late 1970s digital technology, which is not longer supported by the vendors. Additionally, the equipment failure rates increased notably in the 1990s. Thus, plans were put into place to upgrade and replace the FCS hardware, software, and display components with modernized equipment. The process was complicated by the facts that: the facility was operational and could not be totally closed for the modifications; complete documentation was not available for the existing system; the Safety Analyses for the facility were in the process of being upgraded at the same time; and of course limited time and budgets. This paper will discuss the human factors aspects of the design, installation, and testing of the new FCS within the above noted constraints. Particular items to be discussed include the functional requirements definition, operating experience review, screen designs, test program, operator training, and phased activation of the new circuits in an operational facility