During the 2002 refueling outage at Philippsburg 1 (a German 900 MWe BWR unit that went on line in 1980) core power distribution monitoring was improved and a new control rod sequence controller (CRSC) installed. This new CRSC, along with several new modules for local core monitoring, will enable the plant to meet today's rigorous demands for high availability, optimum fuel utilization, state-of-the-art controls and automation of test routines. The new instrumentation & control (I&C) equipment consists of the digital safety I&C platform TELEPERM XSTM and a PC serving as the CRSC.

Plant Restart In-Service Testing is Easier

Not only does the use of TELEPERM XS provide more precise information and more accurate assessments of the current condition of the reactor core, but the high level of test automation and the ease of operator control and monitoring greatly relieve the workload on plant operating personnel. The introduction of the new CRSC in conjunction with TELEPERM XS has reduced significantly the effort required for in-service testing during restart of the plant after a refueling outage. This can shorten outages by up to half a day.

Framatome ANP's combined expertise in the fields of fuel design, process engineering, I&C technology, and software development led to the creation of this solution. Extensive plant know-how and project management capabilities were combined to successfully install and place the CRSC in operation in just seven days.

Monitoring Power Distribution and Core Stability

In the new modules installed for local core monitoring, the 132 signals received from the in-core neutron flux detectors of the local power-range monitors are compared against predefined limits. If the limits are exceeded, appropriate countermeasures are initiated. The limits are individually adjusted by the software to match local burnup conditions - as determined by the advanced core monitoring computer, FNR, a module integrated into the process computer system - and are continuously corrected to account for the present coolant mass flow and reactor power level. Therefore, it allows the reactor operator to operate the reactor in a fuel-efficient manner for optimum fuel utilization.

Another new feature of the core monitoring equipment is the capability for monitoring core stability. As a result, the neutron flux oscillations typically observed in the initial portion of BWR power-flow maps can be reliably detected. Through the implementation of suitable countermeasures, these oscillations can be suppressed before scram limits are exceeded, thus contributing to increasing overall plant availability.

Users taking a critical look at the
new man-machine interface