Uranium Track Team

Posted: July 22, 2013 - 3:31pm | Y-12 Report | Volume 10, Issue 1 | 2013

Y‑12’s inventory and accounting processes for enriched uranium are more meticulous than for any other metal. “We have to track every gram of uranium-235,” said Amy Wilson of Nuclear Materials Control and Accountability. Accordingly, even the smallest byproducts from the manufacturing processes, as well as piece parts from disassembly and dismantlement activities, are collected and measured.

Accounting for uranium at Y‑12 comes down to recording each time any quantity changes hands or changes form. These changes, called transactions, include verifying shipments received from off-site, transferring items between buildings, measuring shavings and clippings collected from machining, and containerizing material for storage.

“Each day more than 7,000 transactions are processed through DYMCAS, which tracks over 150,000 items,” Wilson said of the Dynamic Special Nuclear Materials Control and Accountability System. Though DYMCAS is used by many Y‑12 organizations to view inventory data, the system is regulated by Department of Energy Security Orders that prescribe which functions must be available and how quickly data must be retrievable.

In addition to tracking in DYMCAS, some transactions are reported to the Nuclear Materials Management and Safeguards System, a database the National Nuclear Security Administration manages. That database serves a key role in the U.S. government’s ability to maintain operational awareness of the inventory, status and whereabouts of the nation’s nuclear materials.

It takes a team to ensure that all nuclear material coming, going and being processed is accounted for. Along with their daily manufacturing duties, operators enter transactions into a database, which feeds DYMCAS. Other employees dedicated to accountability include material custodians, accountants for major areas and process monitors. They understand each process and byproduct generated in their area and the type of measurements to be conducted.

Y‑12’s various forms of materials — solutions, powders, metals — complicate accountability. For processes in which the uranium content is not easily discerned, several measurements, such as weight, chemical composition and nondestructive evaluations, are often needed to determine if any residual uranium was collected in salvage material.

Process monitoring relies on daily mini-inventories and is particularly important in immediately discovering errors that could contribute to an inventory imbalance. Inventories take place every six months to two years, depending on the location and purpose of the material.

What if a discrepancy is discovered? According to Wilson, major concerns are rare, but anomalies are expected because of the small quantities dealt with. Moreover, workers are encouraged to ask questions to ensure they understand what constitutes an accounting concern. “We have response plans for any anomaly, and even the smallest difference gets investigated,” Wilson stated.

An important improvement in tracking will come when the in-progress Uranium Processing Facility opens for business (see Industrial-Strength UPF). Instead of transporting salvage to various buildings for characterization, workers can perform all measurements and analyses at one location. “We will be able to localize all material balances in one place, rather than collecting data from several places,” said Wilson.

What will not change is the meticulous tracking of high-equity uranium to make sure every iota is present, according to Department of Energy requirements.