On Friday, August 26, as Hurricane Irene began its slow journey up the US central Atlantic coast, power companies operating 20 nuclear rectors in nine states made plans to deal with the storm and its potential aftermath.

North Carolina’s Brunswick reactors, operated by Progress Energy, were powered down to 70 percent of peak capacity. At New Jersey’s Oyster Creek, near Barnegat Bay, plant operator Exelon chose to shutdown its reactor completely. Dominion Resources, owner of New London, Connecticut’s Millstone plant took one reactor down to 70 percent, the other to 50 percent.

Dominion’s Surry plant in Virginia stayed at full power, as did Entergy’s Indian Point, 35 miles north of New York City, and the Pilgrim plant in Massachusetts.

The reason some plants chose to reduce output or go offline was because, if an accident caused or required the plant to scram–that is, quickly and completely shut down–the stress on the reactor increases the chance of a future safety breach. As Bob Alvarez, of the Institute for Policy Studies, explains:

Keep in mind that when these large reactors scram, it’s like a jumbo jet making a quick forced landing. The sudden insertion of control rods creates unexpected stress on the reactor. This is why when a reactor is normally shut-down for refueling, it is done gradually. If a reactor experiences several scrams during a year, this should raise a red nuclear safety flag.

While working in DOE, I was involved in energy emergency planning, and electricity blackouts, NRC staff were definitely concerned about the safety of increased scrams caused by forced power outages.

By reducing output, a reactor comes under less stress during a rapid shutdown. It is like hitting the brakes at 35 mph as opposed to slamming them on at 60 mph. The stop is faster and results in less wear-and-tear on the vehicle.

One plant that decided not to reduce output was Constellation Energy Group’s Calvert Cliffs facility near Lusby, Maryland. That was probably a mistake:

A nuclear power reactor automatically went offline late Saturday in Calvert Cliffs after its main transformer was hit by a piece of aluminum siding that Hurricane Irene had peeled off a building. . . .

A follow-up NRC Daily Event Report filed on August 29 by Constellation Energy to the NRC identified that the wind blown debris crashed into an electrical transformer at the Calvert Cliffs nuclear station causing an electrical short and “An unanticipated explosion within the Protected Area resulting in visible damage to permanent structures or equipment.”

To be clear, automatically going offline is a scram.

That is bad news for CEG, which has to keep the reactor offline pending a full inspection by the Nuclear Regulatory Commission, but it might have actually been good news for the surrounding communities. As it turns out, the transformer explosion was not the only problem encountered at Calvert Cliffs during Irene’s visit. As the NRC’s August 29 Daily Event Report [PDF] states:

At 2400, 8/27/2011, numerous alarms on the 1A DG [Diesel Generator] started to be received. These were investigated and it was found that water was intruding down the DG exhaust piping resulting in a DC ground. Based on these indications the 1A DG was declared inoperable and appropriate technical specifications implemented.

In other words, the backup power generator would not have worked if the Calvert Cliffs reactor had lost its main power source. As previously observed, nuclear plants require a steady stream of electric power to operate safely, as cooling systems and monitoring devices depend on it.

It was also noted in the NRC event report that Hurricane Irene “disabled public notification sirens in two counties in the reactor’s emergency planning zone.” They lost power, and CEG had not provided any battery back-up system. So, if an accident severe enough to require precautions or evacuation took place that night, large numbers of people would have been left in the dark, as it were. As the editors of Beyond Nuclear put it, “So much for defense in depth.”

And so much for oversight, it seems. The problems at Calvert Cliffs are not really a revelation–at least not to the NRC:

Calvert Cliffs nuclear power plant in Southern Maryland is due for closer scrutiny by federal regulators after unspecified security lapses discovered there earlier this year.

The Nuclear Regulatory Commission has finalized a “greater than green” finding of security deficiencies spotted during a special inspection from January to July of this year, according to a letter released Wednesday. The agency has not disclosed the nature of the problems, saying that releasing such information might help someone to attack or sabotage the twin-reactor plant in Lusby in Calvert County.

That is the sum total of an item in the August 31 Baltimore Sun. Curious civilians with an abundance of time can access some of the reports through the NRC’s Calvert Cliffs page, but there is no digest for lay readers.

And even the untrained eye might take issue in light of recent developments. For instance, a May report [PDF] on an inspection instigated in the aftermath of Japan’s Fukushima disaster gave a passing grade to backup equipment designed to kick-in if a so-called SBO, or Site Blackout, occurred. As observed, rainfall from Irene rendered a backup diesel generator inoperable.

The lingering safety questions, coupled with dual mishaps caused by high winds and heavy rain, appear not to have resulted in a dangerous event at Calvert Cliffs this time. However, it is just this kind of “what are the chances?” one-two punch that so exacerbated the crisis in Japan, and it is events like this that again should serve as an urgent wakeup call for regulators and legislators alike to quickly implement safety improvements to America’s nuclear facilities.

But step back, and an even larger systemic problem takes shape. Each private energy company made its own decisions on what to do with each of its reactors in the face of an approaching (and somewhat predictable) natural disaster. The call on whether to decrease output or shutdown reactors in advance was not the federal government’s call, not the NRC’s, and not the call of at-risk states or municipalities. There is no federal rule, and, apparently, no federal authority to direct plants on how to operate in cases of multi-region events such as a hurricane.

The NRC’s post-Fukushima-disaster task force did not specifically address this issue, but it did recommend a reexamination of the way the entirety of US nuclear power generation is regulated. The majority of NRC commissioners, however, found even that vague recommendation to be too urgent, and any consideration of this question is now at least 18 months away.

Meanwhile, at North Anna’s quake-damaged plant. . . .

On August 26, Dominion, the company that operates the reactors at Virginia’s North Anna plant, notified the NRC that the 5.8 magnitude Earthquake centered in Mineral, Virginia, might have caused more shaking than the facility was designed to withstand. (Some confusion has surrounded the seismic standard to which North Anna was built. The tolerances are often shorthanded to a Richter scale magnitude number, but, in fact, plant design is supposed to be evaluated against the amount of shaking a quake will cause. Shaking at one point depends on magnitude, but also on the distance from the epicenter and the depth of the quake, as well as other geological factors.) Full results of an examination of the “shake plates” (which measure ground motion) are supposed to be released later today (September 2).

What is already known, though, is that the shaking caused many of North Anna’s dry casks–a type of spent-fuel storage container–to move by as much as four inches. Twenty-five of the 27 vertical casks moved as a result of the quake. Each of those steel and concrete casks contains 32 spent fuel rods and weighs 115 tons. Newer horizontal casks did not move, but some of the 26 (13 already full of spent fuel) show what has been termed “cosmetic damage” to exterior concrete.

As discussed, but, as noted here, not addressed in the NRC task force report, dry cask storage is preferable to the spent fuel pools where “fresher” old fuel is stored at most US plants. Pools require a dependable electrical source to keep liquid circulating and completely covering stored fuel rods. An interruption of power or damage to the cooling system can cause dangerous conditions where the liquid overheats, boils away, and even “cracks” as a result of the nuclear reaction, which accelerates as the pools heat and disappear, and hydrogen explosions are possible, further damaging the vessels and sending radioactive material into the atmosphere.

Dry casks store fuel further removed from “active service,” and are cooled by naturally circulating air.

While the March quake and tsunami provoked the described dangerous events in Fukushima Daiichi’s spent fuel pools, there are no reports of any problems with any of Japan’s dry casks.

But the movement of and damage to North Anna’s casks, though minor, is not meaningless. Beyond the contrasts with liquid storage, the August event highlights the lack of a national repository for spent-but-still-highly-radioactive nuclear fuel. Fifty-five of the nation’s nuclear facilities currently have dry casks on site, but the United States has no centralized facility for the long-term storage. And, since the Obama administration declared Nevada’s partially built Yucca Mountain repository closed, the US has no current plan for the disposal of this dangerous material.

The NRC Fukushima task force acknowledges the need for a long-term plan, but there exist no specific recommendations and no process or funding for developing any.

And speaking of Fukushima. . . .

Al Jazeera has a disturbing report on radioactive waste from the ongoing nuclear disaster overwhelming sewage treatment facilities hundreds of miles from Fukushima.

In Japan, before March, processed sewage sludge was often shipped out for use by fertilizer and concrete manufacturers. But now, even far from the destroyed nuclear plant, the sewage is too dangerous for any use. As a result, piles of highly radioactive sludge are accumulating at sewage plants that have no capacity or expertise for handling the toxic material. Instead, containers and piles of sludge are just being lined up at the processing plants, out in the open, covered by simple plastic tarps. Workers are told they face no imminent danger, but Geiger counters say otherwise.

The Japanese government has no plan for dealing with this latest sinister wrinkle, saying only that it is not yet an urgent problem.

Such a lack of urgency is stunning and sad for a country and a people so directly in harm’s way, but a similar lackadaisical, industry-coddling attitude in the US should be no less troubling. True, nothing as terrible as Japan’s catastrophe has yet occurred at an American nuclear plant, but it is not beyond the realm of possibility, as almost every passing week or natural disaster seems to accentuate.

Theoretically, the United States has a body tasked with responding to these new probabilities–the Nuclear Regulatory Commission. And if the NRC won’t do its job, the US has a body with strict oversight powers–Congress. The Congress and the president also have the ability to demand from the nuclear industry improvements in safety and emergency preparedness in exchange for the federal subsidies and loan guarantees the industry needs to operate at all.

But if the Commission or the politicians cannot break free of their cozy relationships with–and the campaign donations from–private energy companies, then who or what, beyond nature, will hold the nuclear industry accountable?

The lifespan of a nuclear plant or a political career is short, but the half-life of many byproducts of nuclear power generation is long. In some cases, very, very long. Is any nation’s political system able to take that long a view?