When human error can cost a company millions of dollars or more, it becomes critical to minimize it. The risk can be even higher when such errors occur at nuclear power plants.
One of the key elements of a successful test program is maintaining consistency in test configuration and control. Technicians at the nuclear plant test the system daily to ensure consistent performance. “We have to verify the reliability of the equipment and confirm that it is working as expected.” A front-line supervisor at a nuclear power plant says, “Because test lines are used so frequently, they require regular replacement, or replacement when inspections reveal degraded performance or defects.”
At the heart of the testing process is the minimization of human-caused errors. There are various ways to improve employee performance, but the common philosophy behind them is to develop a consistent way of working, so that no matter which system a technician tests, he or she needs to use the same tools and protocols that he or she is familiar with.
When the control panel under test has multiple terminals that look very similar, peer checking is one way to ensure that split jumpers (used to shield other systems, so only one system is tested) are connected to the correct location before making connections. Testing steps are very structured and very reliable: 1.
- Pre-install the test banana jack to the corresponding jumper position.
- Check the test jumper for continuity.
- Connect the end of each jumper to the corresponding test jumper position, without actually connecting the jumper.
- Check if the connection point is correct by the companion (need to have the same description document).
- After completing the inspection, connect the center connection point on the jumper cable to the complete circuit.
- After completing the required tests, remove the patch cable and independently verify the disassembly.
While the steps may seem tedious, the consequences of connecting the cable to the wrong location can be very costly. “Standardized human performance tools help us not make mistakes that could otherwise cause equipment to trip or safety systems to fail.” Once this happens, the reactor needs to be shut down and thus lose power,” said the first-line supervisor. The loss of power from an average 900 MW unit being shut down would be very expensive. It sometimes takes three or four days to get the system back up, costing millions of dollars a day in lost revenue.”
To address such issues, the nuclear plant collaborated with Pomona Electronics on an alternative approach to human performance improvement: manufacturing split jumpers and color-coding the connectors.
Before working with Pomona Electronics on a new generation of connectors, plant technicians experimented with making jumper cables and color-coding them by painting the parts. Paper labels were also sometimes utilized for instructions, resulting in inconsistent and less reliable connectors that could cause serious problems.
“Hand-made jumpers that are incorrect can cause problems, and there are many things like that.” The cost of doing so is about $100 each and operational incidents can occur, such as jumpers coming off, shorting out, or jumpers being made incorrectly,” the executive said. So we wanted to find a consistent way to make them.”
Because of the daily test regime, test jacks are often left connected and ready to be used for the next set of tests. Color coding the split jumpers and connectors enables immediate determination of what function is being tested. With this in mind, Pomona Electronics produced three sets of color-coded jumpers/connectors for the facility.
-Red connectors with white jumpers for maintenance and supervision.
-Blue connectors with white jumpers for normal operations and supervision.
-Yellow connectors with white jumpers are used for operations and emergency operating procedures.
Color coding not only reduces the risk of human error during normal operations, but is especially advantageous in time-critical emergency situations.
“There are emergency operation boxes everywhere throughout the power plant.” The supervisor says, “If you operate that operator box in an emergency, the color coding can quickly indicate where the technician should wire from.”
The size of the connectors was also an issue. Most patch panels are very cramped, so bulky connectors or paper labels can make things worse. pomona Electronics connectors offer compact, easy-to-connect terminal jacks that simplify testing.
Pomona Electronics’ split jumpers and connectors help nuclear power plants effectively streamline their test protocols and improve manpower performance by providing high quality, high reliability and super utility. By integrating common connector sets and consistent coding methods into their protocols and peer inspection processes, plant technicians have effectively reduced the risk of misconnecting jumpers and triggering plant shutdowns.
“By reducing human error by technicians and electricians, threats to the nuclear plant’s safety systems are avoided.” The first-line supervisor said
