A replacement rotor is lifted and staged for the upcoming Browns Ferry-2 turbine work. Photo: TVA

The Tennessee Valley Authority has begun a refueling and maintenance outage at Browns Ferry-2 that includes the largest scope of turbine deck work since the unit’s construction, as well as innovations in fuel assembly components, the utility announced on March 1.

On deck: All three of the 1,254.7-MWe boiling water reactor’s low-pressure turbines will undergo a comprehensive replacement of major components, including new rotors, inner casings, steam piping and bellows, and turbine supervisory instruments, requiring the support of more than 500 additional outage workers. TVA said that 600 crane lifts will need to be performed for some components, such as the rotors, which weigh up to 327,888 lb., and inner casings, which weigh up to 200,000 lb.

Fabricated yttrium hydride samples are pulled out of the system. Photo: ORNL

Oak Ridge National Laboratory scientists have developed a method to produce solid yttrium hydride for use as a moderator for the Transformational Challenge Reactor (TCR), a 3-MWt additively manufactured microreactor that ORNL aims to demonstrate by 2023. Lacking a commercial supply of the metal hydride, ORNL scientists developed a system to produce yttrium hydride in large quantities and to exacting standards.

The hydrogen density and moderating efficiency of metal hydrides—which combine a rare earth metal with hydrogen—could enable smaller reactor cores that can operate more efficiently and reduce waste products, according to ORNL. The material could be used in other advanced reactor designs, including space power and propulsion systems for NASA, and has been proposed as a shield component for thermalization and neutron absorption in fast-spectrum nuclear reactors.

BWX Technologies Inc. announced on November 10 that its BWXT Nuclear Operations Group Inc. (BWXT NOG) subsidiary has completed its TRISO nuclear fuel line restart project and is actively producing fuel at its Lynchburg, Va., facility.

With the restart, BWXT now manufactures fuel across four commercial and government business lines, the company said. In addition to the TRISO line, BWXT operates fuel production lines at BWXT Nuclear Energy Canada, manufacturer of approximately half of the fuel powering the commercial reactor fleet in Ontario, Canada; BWXT subsidiary Nuclear Fuel Services, sole provider of nuclear fuel for the U.S. Navy; and BWXT’s Uranium Processing and Research Reactors operation, the only North American supplier of research reactor fuel elements for colleges, universities, and national laboratories.

ANS and the Young Members Group are offering the next installment of the “Spotlight on the National Labs” webinar series, featuring Oak Ridge National Laboratory. The webinar takes place on August 12, starting at 1:30 p.m. (EDT).

Registration for the webinar is required.

3D-printed components for the prototype reactor. Photo: Britanny Cramer/ORNL/U.S. Department of Energy

A 3D-printed nuclear reactor core prototype being developed at Oak Ridge National Laboratory is a step toward reaching the goal of creating an advanced, full-sized, 3D-printed reactor by 2023 at the lab.

The TCR program is leveraging an agile approach—one that is centered around continuously informing the process—to accelerate deployment timelines and introduce performance improvements. Image: Adam Malin, ORNL

Soon after Enrico Fermi’s Chicago Pile-­1 went critical for a brief duration in December 1942, the construction of the first continuously operating reactor, the X-­10 Graphite Reactor, was initiated in February 1943 at Clinton Engineer Works in Oak Ridge, Tenn. On November 4 of that year, a mere nine months after the start of construction, the reactor began operation. This marked the onset of what Alvin M. Weinberg referred to as “the first nuclear era,” during which many reactors of various designs and operating parameters were built and demonstrated across the United States. Forty years ago, the Fast Flux Test Facility was the last U.S. non-­light-­water reactor to reach criticality, and it has since been decommissioned.