Nuclear Safety: U.S. ‘Near-Misses’ in 2010

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There is a very important report out today by the Union of Concerned Scientists (UCS) on the performance of the Nuclear Regulatory Commission (NRC)—the government agency that enforces safety regulations for U.S. nuclear reactors in the hope of preventing a catastrophe such as is occurring in Fukushima. The report looks at 14 “near-misses” at U.S. nuclear plants during 2010. A summary of the findings can be found here, but the gist is that nuclear power plant operators in many cases may have shirked their safety responsibilities. “That plant owners could have avoided nearly all 14 near-misses in 2010 had they corrected known deficiencies in a timely manner suggests that our luck at nuclear roulette may someday run out,” the report concludes.

The UCS report, titled “The NRC and Nuclear Power Plant Safety in 2010: A Brighter Spotlight Needed,”  praises the NRC for what it calls a few “outstanding catches,” but also criticizes the NRC for, in several instances, not pushing plant operators hard enough to fix safety problems. (Update: For a statement from the NRC, see the bottom of this post).

First, a note on how the reactor oversight process works in the U.S.: When an event occurs at a reactor, or when NRC inspectors discover damage or degraded equipment, the NRC undertakes a  review of the risk to the reactor. The NRC undertook 200 such reviews in 2010, the UCS report states. When an event or condition increases the chance of reactor core damage by a factor of 10, then the NRC sends out a “Special Inspection Team” (SIT). When the risk rises by 100, the agency dispatches an “Augmented Inspection Team”. And when the risk increases by 1000 or more, the NRC sends out an “Incident Inspection Team.” The 14 near-misses in the UCS report are all the events that spurred the NRC to send out an SIT or an AIT. There was only one AIT—a series of problems at HB Robinson plant in South Carolina. About that incident, which involved a cooling system failure going unnoticed for 30 minutes, the UCS writes,  “On the 31st anniversary of Three Mile Island, this event revisited nearly all the problems that caused that meltdown: bad design, poor maintenance, inadequate operator performance and poor training.”

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Here is a brief summary of those near misses, taken from the report:

1) Arkansas Nuclear One; Russellville, Arkansas; Operator: Entergy. An SIT incident, no details publicly available because it was a security-related incident, and the NRC withholds such information in the wake of 9/11.

2) Braidwood; Joilet, Illinois; Operator: Exelon. An SIT incident, problems included floods in buildings with safety equipment, a poor design that allowed steam to rip metal siding off containment walls, and undersized electrical fuses for vital safety equipment.

3) Brunswick; Southport, North Carolina; Operator: Progress Energy. An SIT incident, equipment failure led the plant owner to declare an emergency. However, workers did not know how to operate the computer systems that notified offsite workers to report to emergency response facilities; staffing of these facilities took longer than required.

4) Calvert Cliffs; Annapolis, Maryland; Operator: Constellation Energy. An SIT incident, a roof known to leak for years, but ignored by the plant operator, shorts out electrical equipment; a reactor automatically shuts down. A warn-out protective device that workers had not replaced allows the electrical problem to trigger an automatic shut down of a second reactor.

5) Catawba; Rock Hill; South Carolina; Operator: Duke Energy. An SIT incident, no details publicly available. Another security-related incident.

6) Crystal River 3; Crystal River, Florid; Operator: Progress Energy. An SIT incident, workers inadvertently damage thick concrete reactor containment walls when cutting a hole to replace steam generators.

7) David Besse; Toledo, Ohio; Operator: FirstEnergy. An SIT incident, workers discover through-wall cracks in nozzles of “control rod drive mechanisms”–these cracks leak after workers fail to account for peak temperatures inside the reactor vessel.

8)  Diablo Canyon; San Luis Obisbo, California; Operator: Pacific Gas & Electric. An SIT incident, a misguided repair to valves that would not open fast enough prevent other key valves from working; the reactor operated for nearly 18 months with vital systems disabled.

9) Farley; Sotham, Alabama; Operator: Southern Nuclear. An SIT incident, a replacement pump with a manufacturing defect fails after workers did not ensure that it met key parameters specified in the purchase order.

10) Fort Calhoun; Omaha, Nebraska; Operator: Omaha Public Power District. An SIT incident, pumps in an emergency water system fail repeatedly over several years.

11) HB Robinson; Florence, South Carolina; Operator: Progress Energy. An AIT incident. An electrical cable shorts out and starts a fire. Electrical problems disrupt the supply of cooling water to the pump seals for the reactor coolant system; cooling water leaks into the containment building. Control room operators do not notice the lack of cooling for more than 30 minutes. The reactor shuts down, and the operator starts two pumps that transfer water from a tank in an auxiliary building. When the tank empties, the pumps are supposed to automatically realign to take water from another storage tank. The realignment fails to happen, and operators do not notice the failure for nearly an hour. Four hours into the event, the operators attempt to restore power, but do not check first to ensure that workers had fixed the original fault. When the operators close the electrical breaker to a circuit, they cause another short out, and another fire.

12) HB Robinson; Florence, South Carolina; Operator: Progress Energy. An SIT incident, one of four pumps supplying cooling water to the reactor vessel experiences motor failure and automatically shuts down. A series of operator errors trying to compensate for the problem ensues.

13) Surry; Newport News, Virginia; Operator: Dominion Generation. An SIT incident, after an inadvertent shutdown of a reactor, a fire starts in the control room due to an overheated electrical component. A similar component in another unit’s control room had started a fire six months earlier, but the operator failed to fix the problem in other control rooms.

14) Wolf Creek; Burlington, Kansas; Operator: Wolf Creek Nuclear. An SIT. The UCS report finds:  “Seven hours after the reactor shut down automatically because of a problem with the electrical grid, an NRC inspector found water leaking from the system that cools the emergency diesel generators and virtually all other emergency equipment. An internal study in 2007 had forecast such leakage, and a leak had actually occurred after a reactor shutdown in April 2008. However, the owner had taken few steps to correct this serious safety problem.”

The USC report goes on to list a few “outstanding catches” made by the NRC’s inspection teams. For example, commission inspectors refused to accept the decision of supervisors at South Carolina’s Oconee plant not to inspect safety systems on the facility’s Units 2 and 3 after failure of the safety system on Oconee’s Unit 1. According to the report,  “NRC inspectors persistently challenged lame excuse after lame excuse until the company finally agreed to test the other two units. When it did so, their systems failed, and NRC inspectors ensured that the company corrected the problems.” Another catch came at the Browns Ferry Plant in Arkansas, when inspectors found that an oil leak could cause a coolant injection system to fail in an emergency.  And yet another occurred at Kawaunee nuclear plant in Wisconsin, when NRC inspectors found that workers were inadvertently disabling a safety system during routing testing operations that occurred while the reactor was still running.

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But the USC report also said that “the NRC did not always serve the public well in 2010.” It lists three safety breaches from Peach Bottom (Pennsylvania), Indian Point (New York), and Vermont Yankee (Vermont) power plants that it says the NRC overlooked or dismissed. The report states that “At Indian Point, the NRC discovered that the liner of a refueling cavity at Unit 2 has been leaking since at least 1993. By allowing this reactor to continue operating with equipment that cannot perform its only safety function, the NRC is putting people living around Indian Point at elevated and undue risk.”

At Peach Bottom, the report claims, the NR Callowed the plant operator to run a reactor with control rods that do not work quickly enough–the rods are designed to quickly shut down a nuclear reaction and thus their failure could prompt a run-away nuclear chain reaction as occurred at Chernobyl.

And at Vermont Yankee, the report says that the NRC allowed the plant operator to continue operating even though it had detected radioactively contaminated water in an on site monitoring well.

The UCS report concludes, “Because we have not reviewed all NRC actions, the three positive and three negative examples do not represent the agency’s best and worst performances in 2010. Instead, the examples highlight patterns of NRC behavior that contributed to these outcomes. The positive examples clearly show that the NRC can be an effective regulator. The negative examples attest that the agency still has work to do to become the regulator of nuclear power that the public deserves.”

Update: The NRC sent me the following statement on March 18: “We have not yet had a chance to review the latest report from the Union of Concerned Scientists. However, we can say that the NRC’s current Reactor Oversight Process has been in place since April 2000 and has worked effectively to gauge the performance of U.S. nuclear power plants. It does so through a combination of Performance Indicators, such as the number of unplanned shutdowns, and NRC inspection findings. If the NRC observes any indications of declining performance, the agency can ratchet up its oversight to ensure issues are being addressed in a timely manner. The NRC does not hesitate to increase its level of scrutiny wherever and whenever that is warranted.”

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