Spent Fuel Damage: Pool Criticality Accident

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #29

Disaster by Design

Disaster by Design/Safety by Intent #26 described a progression leading to overheating and damage to a reactor core, often labeled a meltdown. Disaster by Design/Safety by Intent #27 described the damage to a reactor core that can result from reactivity excursions. Disaster by Design/Safety by Intent #28 and #29 mirror those commentaries by describing how irradiated fuel stored in spent fuel pools can experience damage from overheating and reactivity excursions. Read more >

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Nuclear Power(less) Plants

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #3

Disaster by Design

The primary purpose of commercial nuclear power plants in the U.S. is to generate electricity. When not fulfilling that role, nuclear power plants that are shut down require electricity to run the equipment needed to prevent the irradiated fuel in the reactor core and spent fuel pool from damage by overheating. The March 2011 accident at Fukushima Daiichi in Japan graphically illustrated what can happen when nuclear plants do not get the electricity they require. Read more >

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Palisades 50

, director, Nuclear Safety Project

Fission Stories #192

Much has been said and written about the Fukushima 50—the workers who remained onsite during the height of the crisis at the Japanese Fukushima nuclear plant after senior managers ordered their co-workers to evacuate because of worsening conditions.

Less has been said and written about the Palisades 50—which involves worsening conditions and workers but not quite in the same way. Palisades 50 refers to the findings by the Nuclear Regulatory Commission (NRC) during a recent inspection at this nuclear plant five miles from South Haven, Michigan. Read more >

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Fission Stories #121: Palisades Reprises Davis-Besse

, director, Nuclear Safety Project

Workers began shutting down the reactor at the Palisades nuclear plant near South Haven, Michigan at 11:07 pm on August 11, 2012. After the reactor had restarted on July 10 from an unplanned maintenance outage, operators had detected reactor cooling water leaking into the containment building. After the leak rate exceeded NRC’s threshold limits on July 16, workers entered the containment building several times trying to find the source of the leak, but were unable to locate it. Read more >

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Fission Stories #103: Nuclear Time Out

, director, Nuclear Safety Project

My two nephews are generally good boys, but every now and then their behavior compels my sister-in-law and brother to give them a time-out. The time-outs seem to be effective – if nothing else, it curbs the behavior problems during the time-outs themselves.

A recent nuclear time-out, however, showed this behavior control practice can have its downsides.On October 23, 2010, workers at the Palisades nuclear plant in Michigan prepared to restart the reactor following a refueling outage. An operator in the control room, licensed by the Nuclear Regulatory Commission, implemented a procedure developed during the last refueling outage to deliberately lower the water level above the reactor core to remove air and other non-condensible gases from the reactor vessel and its attached piping. Another NRC-licensed operator in the control room worked to resolve a problem with the turbine control system.

Over the next few hours, these operators faced a series of unexpected problems performing their assigned duties – which was not surprising because restarting reactors after weeks of downtime with extensive maintenance activities always involves a number of issues to be resolved. One operator had those annoyances compounded by frustration with the actions of the second operator.

The operator’s fun-meter went downscale when he was updating the computer-based log book to reflect tasks he had completed. The second operator got onto the same computer and closed out the first operator’s log book. The first operator protested, saying he was using the computer. The second operator ignored him and continued using the computer. The first operator lost his temper and told his colleague that if he insisted on using the computer, he could do the first operator’s job as well. The first operator turned and headed for the door. The control room supervisor called out for the operator to wait. But the operator felt he was too angry to stick around and left the control room to recover his cool in a break room across the hall. He returned to the control room about 10 minutes later and resumed his duties.

The remainder of that shift passed without incident. That operator, his colleague, the control room supervisor, and the rest of the operating crew returned the following night for another shift. It passed without incident.

But word of the incident found its way to both the plant’s upper management and the NRC. When the operator arrived at Palisades for work two nights later, he was met at the gate by the Operations Manager and a union representative. After the operator’s oral statement was taken, the Operations Manager sent him home with instructions not to return to the plant until directed to do so. That direction came two weeks later, followed by another two weeks of the operator not being allowed inside the plant’s fences without an escort. He was disciplined with a week off without pay and subjected to a long-term remediation plan. He was not allowed inside the control room for nine months.

And the NRC weighed in, too. The operator held a license issued by the NRC. The NRC’s investigation determined he had violated the terms and conditions of that license, making it susceptible to revocation or suspension. By leaving the control room without permission and without having formally turned over his duties to another NRC-licensed operator, the operator had been inattentive to duty in the eyes of the NRC – a very serious charge. The operator’s very career was in jeopardy due to a rash decision made in a moment of anger.

The NRC gave the operator three choices: (1) he could contest the violation, (2) he could accept the violation and then whatever sanction the NRC levied, or (3) he could enter into Alternate Dispute Resolution (ADR) with the NRC. The operator chose Door #3. The ADR process yielded a mutually acceptable outcome. The operator would retain his NRC-issued license, but would have to take several steps including “nuclear community service.” The operator had to write a lengthy paper about the event, what he did wrong, and what he learned from it and submit it for for publication in the newsletter of the Professional Reactor Operators Society (PROS). The operator returned to his control room duties about a year after the incident.

The NRC’s investigation also found fault with the company. The operator had been allowed to return to work and work the following day as if the incident never happened. Only after upper management and the NRC learned about it was the incident entered into the plant’s corrective action program and the operator’s actions questioned. The NRC also sanctioned the company for its initial lax response to the incident.

Our Takeaway

In an ideal world, individuals licensed by the NRC to staff control rooms of nuclear power plants would never make mistakes, never get emotional, and never lose their tempers. In an idealer world, nuclear power plants would be inherently safe such that NRC didn’t need to license control room operators.

In the real world, control room operators are humans. They get tired. They get frustrated. They make mistakes. In other words, they act like humans.

By his own admission and confirmed by many others, the operator at Palisades made a mistake. He paid a high price for that mistake. Again and again, he has had to confess his sins and pledge reforms. Such widespread mea culpas are uncomfortable. In addition, it was not clear that the company and the NRC were going to permit him to return to his control room work. His career was at risk.

It is apparent from the operator’s mandated narrative that he has accepted full and exclusive blame for the incident. It is also clearly evident that he is as unlikely as anyone to ever again misbehave while on duty. Thus, instead being banned from the control room, he should be welcomed there. The painful experience almost certainly makes him a better operator than he had been before this incident.

This is not to say that operator performance across the country can be improved by having each one stalk out or mess up. The NRC and the Palisades’ operator went to great lengths to share the lessons from this incident so that others can benefit from it without having to replicate it. UCS encourages all nuclear plant workers – not just control room operators – to read the operator’s account. He paints a picture of the situation that would enable most readers to find themselves in his shoes, either in theory or in past practice. But he also provides a clear explanation for how he, and we, can avoid painting more pictures like it.

“Fission Stories” is a weekly feature by Dave Lochbaum. For more information on nuclear power safety, see the nuclear safety section of UCS’s website and our interactive map, the Nuclear Power Information Tracker.

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