By Matt Smith, CNN senior global correspondentThe Viking refrigerator, which was first developed for the military in the 1940s, is among the oldest refrigeration systems still in use.
The Viking refrigerator uses steam, a mixture of hydrogen and oxygen that’s pumped through a turbine to heat water to a specific temperature.
At that point, it releases the gas at a controlled rate.
It’s a much smaller, lighter and more efficient system than older systems, and it’s also more environmentally friendly than older technologies that require the use of chemicals to cool the system.
“It’s the first industrial refrigerator, and the world’s oldest,” said Brian L. Stott, a professor at Purdue University’s engineering department.
“The technology is proven, it’s reliable, and people know it works.
It was an industrial refrigeration system that was built for the first time, and that’s what’s really important.”
But the Viking refrigerator’s longevity has been controversial.
In the 1970s, the American Council on Science and Health published a report that said the Viking refrigeration unit is safe, but the Viking unit was still “at risk of failure.”
And in 2005, the Department of Energy’s Office of Nuclear Energy issued a study saying that the system “has a high likelihood of failure and should be retired.”
In February, the U.S. Energy Department announced it was retiring the unit, citing safety concerns.
The U.N. Food and Agriculture Organization also criticized the unit for failing to meet safety standards.
“There is a risk that it could be destroyed or degraded and that would be unacceptable to any consumer,” said Richard L. Smith, who was the director of the nuclear safety program at the Nuclear Regulatory Commission during the Viking’s construction.
The report, titled “Risk Assessment of the Future Viking Refrigeration Unit,” concluded that the Viking units’ safety was “comparable to that of modern refrigerator systems” and that “a full evaluation of the current Viking Refining System will be conducted to determine if any additional safety requirements are warranted.”
In addition, the report said the unit’s performance was “not adequate to meet the needs of modern industrial refrigerators.”
However, in January 2017, the United States announced a plan to retire the unit by 2022.
In December 2017, an independent panel from the U,S.
Nuclear Regulatory Agency, which regulates nuclear power plants, recommended the unit be retired.
The agency’s recommendation, however, has been challenged by other countries, including Russia and China, who have argued that it would cost too much to retrofit the system to comply with safety standards and that the unit is no longer in service.
Some critics of the unit have also questioned its reliability, noting that the units had to be upgraded for several years before they could function properly again.
“You can’t do the same thing,” said Jim McElroy, an engineer who founded the environmental advocacy group Greenpeace.
“If you want to make the same basic point about climate change and the need to reduce CO2, you should retire it.”