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Diablo Canyon Power Site Uses RFID to Track Items

The nuclear plant has attached EPC Gen 2 tags to tens of thousands of reactor parts at its warehouse, in order to document their locations and maintenance status in case they are needed. The facility will soon tag tools as well.
By Claire Swedberg
In the summer of 2008, PG&E began by tagging 20,000 items that were not expected to move in five years, and that were valued at more than $100 apiece. The next challenge was to find the best, least intrusive way of reading those items' tags without building a large reader infrastructure.

The PolyGAIT solution includes one reader with two antennas installed on each of three forklifts, along with handheld readers to capture ID tags on items stored in drawers. Data regarding the tag reads and the equipment to which they are linked is stored in the software provided by Cal Poly.

Bubble wrap was placed behind tags and then taped to metallic objects to improve read range.

Students printed labels containing EPC Gen 2 passive ultrahigh-frequency (UHF) RSI-647 Corkscrew RFID tags supplied by RSI ID Technologies (now owned by Sirit), and attached them to parts (at present, Diablo Canyon's staff has taken over this responsibility for newly acquired items). Each item is input into DCPP's SAP enterprise-resource planning (ERP) system, as well as the RFID software, designed by Cal Poly students, and an RFID label is then printed on a Zebra Technology printer and attached to the item, with the unique ID number of the tag linked to the asset to which it is attached. After that item is put away, one of the forklifts transports it to its storage location. There, the forklift's Sirit INfinity510 RFID interrogator reads the RFID tag on the shelf, as well as the item's tag, and the software links that shelf RFID tag with the asset's tag. The antennas are placed on the forklift in such a way, Freed says, that they can capture ID numbers from both low and high shelves. Information is forwarded from the Sirit reader to the back-end software via a Wi-Fi connection.

In addition, every time a forklift passes down an aisle, its RFID interrogator reads the RFID tags on that aisle's shelves, as well as on the items stored on them, and transmits that data to the software once more, thereby providing DCPP with an up-to-date inventory of the assets. For smaller items stored in drawers made of metal (which can obstruct UHF RFID transmissions), a staff member must remove one antenna from the forklift, open the drawer and read the tags, again using a Wi-Fi connection to send that information to the back-end system. The removable antennas were fitted with handles on their backside for a comfortable grip, Freed says.

The software that captures and interprets the data then provides the location and time of reading for each item to DCPP's own management software on its ERP system. When specific items are required, workers can run a pick list through DCPP's management software, which pulls location data from the RFID software. The list can then be provided to warehouse employees, saving time they would otherwise spend looking for specific items.

Additionally, the system was designed to capture irregularities, such as an item being moved from its assigned shelf. For example, if the reader on a forklift making its rounds reads a shelf ID number and an equipment ID number that do not match, it issues an alert to the software, which reports an improperly located asset. To test the system's locating functionality, Ritchie says he hid three items throughout the warehouse. The ID numbers of the tags attached to the hidden assets were then input into a forklift's reader. Each time the forklift neared the items in question, the interrogator emitted a beep. "It took 10 minutes to find all three items," Ritchie says, which could have taken days to track down manually. "That's a nice side benefit."

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