The current state of nuclear power safety regulation is obsessive, repressive, and too costly. There’s a fear (and supporting evidence) that the massive weight of our regulatory structure will both economically burden and delay building more conventional reactors and stymie the development of fresh alternative designs.
We come to our current state of affairs through three main processes. First, we (the industry’s engineers) made improvements on our own to ensure the reliability and longevity of our plants. Sometimes, well-meaning external critics push for improvements that are recognized by the industry as worthwhile. The designers of competitive products and their owners will then push for a common standard from the government.
Then there is the human factor that’s more political science than nuclear engineering. Regulators are people, too, and their job is to issue regulations and hold the owners and operators to those regulations. As a human employee, in a perfect nuclear world, that makes for a pretty boring career. In other words, regulators want to regulate—and they do, even as they search for justifications for new regulations.
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Lastly, there’s the “standing on hind legs” political regulation. When news breaks of an event at a nuclear plant somewhere in the world, certain political types will jump up and demand changes, sometimes detailed, that are hard to quickly analyze or refute in the fevered fora of public media.
The first type is “organic” for a maturing technology. We first built a variety of small plants—some did great, and some were obvious flops. The successful designs were then scaled up, and operating experience accrued.
One early critic was Dr. Ralph Lapp, a veteran of the Manhattan Project. All reactors make “off-gas,” a somewhat radioactive mix, as part of normal operation. The general attitude to pollution back in the 1950s was that “dilution is the solution to pollution.” That resulted in 1,000+ foot tall smoke stacks at coal plants.
Applying the same regulatory principle, the early nuclear plants also had tall, but much thinner, exhaust towers to disperse the off-gas so that no one got more than a de minimis radiation dose. Lapp pointed out that as we were designing far more powerful reactors and planning on building them in the thousands, this wasn’t a long-term solution. The result was far more complex and thorough off-gas treatment equipment and the elimination of the need for tall stacks.
Regulators try to keep ahead of the game, or they get bored. If they plan far enough ahead, they can hammer out the wording with the designers so that the result is hopefully doable and effective for a commercial plant.
But sometimes they rush ahead. The worst case was for the Fermi-1 liquid sodium-cooled plant near Detroit. As the reactor fabrication was nearing completion, the regulator at the time, the Atomic Energy Commission (AEC), decided that this type of design could melt down into a hot mass at the bottom of the reactor vessel. Worst, given the fuel neutronics, that hot mass could undergo a “re-criticality” event, producing more fission energy, greatly compounding the problem.
The last-minute solution was to install zirconium trays in the bottom of the vessel, intended to separate a molten core into compartments that would remain sub-critical. The plant started but, eventually, one of the trays broke loose, and the flow of pumped molten sodium pushed the tray against the coiling inlet of part of the core. Starved for cooling, several of the fuel rods overheated and melted down. That was the end of that project, but it became the subject matter of an over-sensationalized book, We Almost Lost Detroit.
Lastly, political types will use news of some nuclear event to grab some camera time by pushing pet ideas or exploiting current fears. Before the Fukushima event, the anti-nuclear NGOs were pushing the idea of burning spent nuclear fuel.
Consumed fuel assemblies from the reactor are handled and stored under at least 10 feet of water. The water (containing boric acid) at once removes the decay heat, shields the operators from gamma rays, and poisons further criticality. Add the 14-foot length of the fuel assembly to the ten-foot coverage requirements, and spent fuel pools are at least 24 feet deep.
Yet, the theory goes, if one assumes that you’ve lost all the water, a bunch of hot assemblies would spontaneously catch on fire in the air. That would breach the flaming zirconium cladding barrier and all the bad fission products stored in the assembly would escape into the air and dose the public to unacceptable levels—in one theory.
While the event was still developing, Forbes Magazine later recorded that “Five days after a tsunami triggered meltdowns at Fukushima, Jaczko [then-chairman of the Nuclear Regulatory Commission] told Congress that he and his NRC colleagues thought water had drained out of a pool where used fuel was being cooled, which would have made a bad situation much worse.”
That sensational assertion was, of course, picked up in the media and added to the panic and drama. However, the nuclear industry had for years researched this possibility and found no scientific or engineering basis for it.
The pools themselves are reinforced concrete structures with thick walls, solid foundations, and a stainless-steel lining. No pipes are allowed to penetrate the walls below the water line. The cooling water goes in and out from over the top, with mechanisms to prevent siphoning should a pipe break in the cooling system. Losing all 24 feet of cooling water and zirconium burning in air makes for an incredible scenario. But NRC Chairman Jaczko got his day in the media spotlight and provided the useful “narrative.”
A more recent example comes from the September 11, 2001, aircraft attack on New York’s World Trade Center. The attack showed how vulnerable skyscrapers are and how easily a commercial passenger jet can be commandeered by suicide terrorists. The result, in general, has been a great tightening of passenger screenings (think TSA) but no shortages of new skyscrapers nor a radical change in their protective designs.
But members of Congress asked the question of what happens if a jet intentionally targets a nuclear reactor? The result was a new regulation that defined the threat to be assumed.
For new plants or those under construction, full incorporation was required for a license. That can mean an extra foot and a half of concrete in the walls and roof to protect against an airplane hit in the most vulnerable spots. The last new plants started in the US were hard hit by the need for additional reinforced concrete, adding years for redesign and modified structures. The exercise added billions to the new plants.
In an idealistic or ideological world view, any nuclear safety “improvement” must be a moral imperative and something worth doing. If you oppose a “safety improvement,” you must be on the side of evil. Sometimes, regulators have assumed that attitude, but don’t we all want to be heroes?
In the 70 years of commercial nuclear power plants, we’ve learned to make them better—safer, cleaner, more productive, and more reliable. We’ve also learned that not all “improvements” were worth it, some were huge wastes of money, and some just made matters worse.
The author is a degreed nuclear engineer who has spent most of his 50+ year career trying to make new safety regulations work in the real world.
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