MAROKO133 Breaking ai: Bill Gates-backed nuclear reactor may have safety issues, got appro

📌 MAROKO133 Breaking ai: Bill Gates-backed nuclear reactor may have safety issues,

Scientists in the U.S. have raised alarm over the expedited safety approval to construct a $10 billion, 345-megawatt experimental sodium-cooled fast nuclear reactor in Kemmerer, Wyoming.

The Natrium reactor was designed by TerraPower, a company co-founded by billionaire Bill Gates.

The Union of Concerned Scientists claimed that the review of the construction permit application, which was submitted in March 2024, was originally scheduled to be completed in August 2026.

Political pressure from both Congress and the White House

However, as the result of political pressure from both Congress and the White House, NRC staff curtailed their review and issued a safety evaluation nine months early, conforming to the 18-month review timeline mandated by President Donald Trump’s Executive Order 14300, according to the Union of Concerned Scientists.

“The NRC’s rush to complete the Kemmerer plant’s safety evaluation to meet the recklessly abbreviated schedule dictated by President Trump represents a complete abandonment of its obligation to protect public health, safety and the environment from catastrophic nuclear power plant accidents or terrorist attacks,” said Dr. Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists.

“The only way the staff could finish its review on such a short timeline is by sweeping serious unresolved safety issues under the rug or deferring consideration of them until TerraPower applies for an operating license, at which point it may be too late to correct any problems. Make no mistake, this type of reactor has major safety flaws compared to conventional nuclear reactors that comprise the operating fleet.”

Liquid sodium coolant can catch fire

Lyman claimed that the facility’s liquid sodium coolant can catch fire, and the reactor has inherent instabilities that could lead to a rapid and uncontrolled increase in power, causing damage to the reactor’s hot and highly radioactive nuclear fuel.

On December 1, the Nuclear Regulatory Commission stated that its staff has completed its final safety evaluation for the application submitted by TerraPower, on behalf of its subsidiary US SFR Owner, to build Kemmerer Power Station Unit 1 in Kemmerer, Wyoming.

The evaluation concludes there are no safety aspects that would preclude issuing the construction permit.

“We’ve finished our technical work on the Kemmerer review a month ahead of our already accelerated schedule, as we aim to make licensing decisions for new, advanced reactors in no more than 18 months,” said Jeremy Groom, acting director of the NRC’s Office of Nuclear Reactor Regulation. “We thank TerraPower for promptly addressing the agency’s questions to ensure safety and enable the NRC to efficiently process the application.”

However, Lyman highlighted that the NRC staff has assented to a design that lacks a physical containment structure to reduce the release of radioactive materials into the environment if a core melt occurs. TerraPower argues that the reactor has a so-called ‘functional’ containment that eliminates the need for a real containment structure. But the NRC staff plainly states that it ‘did not come to a final determination of the adequacy and acceptability of functional containment performance due to the preliminary nature of the design and analysis.

🔗 Sumber: interestingengineering.com

📌 MAROKO133 Update ai: Scientists capture the most detailed 3D views yet of DNA dr

Six feet of DNA crammed into a cell nucleus narrower than a human hair: Life may pack no tighter puzzle than this. And yet, biology pulls it off every second, compressing genetic material with a precision that engineers dream of.

DNA coils around proteins to form nucleosomes, which link together like beads on a string. Those strings fold into chromatin fibers and ultimately into the dense architecture of the nucleus.

But one mystery lingered for years: how does chromatin become even more compact without losing its ability to function?

Peering into droplets

In 2019, researchers led by Michael Rosen at UT Southwestern Medical Center discovered that synthetic nucleosomes in the lab merge into membrane-less droplets called condensates.

These behave like oil droplets in water, a process known as phase separation, and could mimic how chromatin compacts inside cells.

To truly understand the physics and structure of these droplets, scientists needed to look inside them. That required imaging individual chromatin fibers and nucleosomes inside condensates that no team had fully achieved until now.

Researchers from UT Southwestern, UC San Diego, the University of Cambridge, and HHMI’s Janelia Research Campus have now produced the most detailed images ever captured of molecules inside synthetic chromatin condensates.

Using advanced imaging at Janelia, the team visualized how chromatin fibers and nucleosomes pack within these droplet-like structures. They also applied the same techniques to examine native chromatin inside cells.

Their method relied on cryo-electron tomography (cryo-ET), which generates 3D reconstructions of biological molecules in near-native states.

Freeze, mill, image

First, the samples were flash-frozen to –180°C, locking every molecule in place. Then, using cryo-focused ion beam milling, researchers carved the sample into 100-nanometer-thin slices—thin enough for high-resolution imaging.

Cr yo-ET captured dozens of projection images of each slice from different angles. Computational processing then stitched those projections into detailed 3D views of the condensates and their molecular arrangements.

By combining this imaging with simulations and light microscopy, the team mapped how chromatin fibers interact and form droplet networks. They found that the length of linker DNA—the segment between nucleosomes—plays a critical role in how fibers organize inside condensates.

These structural features help explain why some chromatin types phase-separate more readily than others, and why different condensates show different material properties.

The team also discovered that synthetic condensates closely mimic how DNA is compacted inside cells.

“The work has allowed us to tie the structures of individual molecules to macroscopic properties of their condensates, really for the first time,” Rosen said. “I’m certain that we’re only at the tip of the iceberg.”

Huabin Zhou, lead author of the study, added that understanding condensate behavior could reveal how abnormal condensation contributes to diseases. “By doing this research, we will better understand how abnormal condensation could lead to different diseases,” Zhou said.

The findings also offer a framework for studying other biomolecular condensates involved in gene regulation, stress responses, and cellular organization, shedding light on how these membrane-less droplets keep cells functioning and what happens when they fail.

The work appears in the journal Science Advances.

🔗 Sumber: interestingengineering.com