Nonproliferation innovation makes international impact at Kazakh nuclear site

Kris Gaines is on a nonproliferation mission: to make it simpler for extra international locations to remove extremely enriched uranium, or HEU, thus neutralizing the inherent menace of its potential for nefarious use. As a nuclear nonproliferation specialist and challenge supervisor on the Division of Vitality’s Oak Ridge Nationwide Laboratory, Gaines leads elements of an essential challenge designed to remove spent HEU gas from Kazakhstan.

Developed by way of a collaboration with the Nationwide Nuclear Safety Administration (NNSA), the Worldwide Atomic Vitality Company (IAEA), Idaho Nationwide Laboratory, ORNL, and the Nationwide Nuclear Middle (NNC) of the Republic of Kazakhstan—proprietor of the Impulse Graphite Reactor (IGR) and its gas, on which the challenge is centered—this new expertise is a promising answer for safeguarding spent HEU gas around the globe.

Fueling reactors such because the Kazakh IGR requires HEU, which has been “enriched” to include higher than or equal to 90% of the fissile U-235 isotope, versus low-enriched uranium, or LEU (equal to or lower than 20%). This stronger HEU permits a spread of important supplies analysis and scientific exploration. Nevertheless, as soon as this gas has been used and is faraway from the reactor, it is called “spent” gas, which stays radioactive and have to be safely saved or reprocessed into safer kinds.

As soon as it’s spent, or irradiated, the power to down-blend it into in any other case helpful materials is sophisticated. To handle these challenges and reduce dangers posed by the IGR’s spent gas, NNSA, DOE and the Kazakhstan Ministry of Vitality collaborated to discover a answer for in-country elimination of the spent HEU gas. The result’s a novel new down-blending and cementation expertise that readies the gas for secure, long-term storage.

“Due to the type of fuel, other down-blending technologies like ‘melt dilute’ aren’t feasible options because graphite fuel won’t melt,” stated Gaines. “This fuel will be repackaged for batch operations and sent through a large crusher/grinder until it is ground into very fine particles and mixed with natural or depleted uranium to down-blend it from ≥90% to ≤5% enrichment. The fuel is then transferred to a sealed drum at the mixing and cementation station, where it will be mixed with cement and other additives by in-drum mixing paddles to create unrecoverable, uniformly dispersed low-level waste as a concrete-filled drum.”

This primary-of-its-kind expertise helps to dramatically lower dangers posed by the spent HEU, reducing its enrichment stage far under the LEU threshold of 20%. Down-blending irradiated graphite gas removes the necessity for IAEA safeguards and renders it nearly unrecoverable by way of cementation.

Although the brand new expertise isn’t but in place completely, the mandatory gear has been fabricated and put in at a brief location in Kazakhstan. Plans for the brand new expertise’s use there embrace continued growth of the everlasting vacation spot facility, ongoing operator coaching applications and continuous fabrication of blending drums for additional use within the course of earlier than the system is moved to its meant web site.

Gaines is inspired by the brand new course of and its potential to be used elsewhere with different sorts of fuels. “This technology is already being considered for the fuel from Kazakhstan’s other reactor, IVG.1M. We are currently working with NNC to conduct experiments on both melt-dilute and oxidation of this fuel. Preliminary results show that oxidation may be the best option, as the oxidized powder would then be run through the same system we are using for the IGR fuel,” he stated.

Previous to implementation and wider use of the brand new expertise, nevertheless, the staff wanted to persuade key stakeholders that their answer was efficient, secure and inexpensive. An thought to speak these advantages by way of a scaled-down, 3D-printed bodily mannequin set the stage for a powerful partnership at ORNL—one with vital worldwide influence.

On the NNSA sponsor’s suggestion, Gaines teamed up with ORNL’s Amiee Jackson, a mechanical engineer on the lab’s Manufacturing Demonstration Facility, or MDF, to ship an correct scale mannequin of the Kazakh NNC’s IGR, highlighting its new down-blending and cementation expertise. Over the span of a month, Jackson painstakingly transformed the IGR’s authentic engineering information into printable, 1:sixteenth scale information. Jackson then oversaw the method of printing the fashions.

“The original models were a blend of solid and surface geometry, with all sorts of hollow bits and far more detail than was necessary,” Jackson stated. “My work was to ‘Boolean union’ everything (create a new shape from many others, with stable intersections preserving overall integrity), getting rid of any hollow areas, ensuring that scaled wall thicknesses were thick enough to be printable, and then coordinating printing.”

The ensuing 3D mannequin was displayed on the Worldwide Convention on Nuclear Safety, or ICONS, in Vienna in Could. Attendees indicated they had been impressed, not solely by the accuracy of the 3D mannequin itself, but in addition by the information of the system’s effectiveness, affordability and ease of meeting and deployment.

“How to eliminate irradiated/spent graphite fuel has long been an issue. This technology answers that question and is now being considered for eliminating other fuel types,” Gaines stated. “It offers a previously unavailable, safe and effective solution to a longstanding problem. Its affordability and cost-effectiveness are a bonus.”