Some items from today’s Event Notication Report on the Nuclear Regulatory Commission’s website:
1. Friday morning, operators at the Duane Arnold nuclear power plant in Iowa discovered that both airlock doors in Seconday Containment were open, redering Secondary Containment inoperable. The problem was remedied after ten seconds. Although ten seconds may not sound like a long time, it should not be discounted.
Imagine that you are hired to babysit a toddler on the fortieth floor of an apartment building, and have been told that under no circumstances can you leave the patio door open. If something goes horribly wrong, I don’t think that saying the door was only open for ten seconds is going to absolve you of responsibility. Also, I wouldn’t expect anything from the parents at Christmas either.
How likely is an incident on any given day at a nuclear power plant. Duane Arnold had two in one day:
2. Less than three hours after the loss of containment incident, workers at Duane Arnold were performing an instrument test on the plant’s sole reactor, a General Electric boiling water reactor, similar to the ones that melted down at Fukushima. The reactor came online in 1975, and uses the same type of containment building as Fukushima. (Don’t worry. With a 2010 extension from the NRC, Duane Arnold is set to close. In 2034, just in time to avoid a 60th birthday celebration. Unless the NRC approves another extension.)
The Duane Arnold control room received an alarm showing the the reactor’s High Pressure Coolant Injection (HPCI) had isolated and was inoperable. The HPCI was repressurized and returned to service after about an hour-and-a-half.
3. Also Friday afternoon, an inspection of several wall pentrations that serve both units at the Hatch nuclear power plant in Georgia showed that the penetrations were not sufficiently insulated. In case of fire, the penetrations could provide a path for fire to escape one room and enter another.
The Event Report says:
Compensatory measures were established in accordance with the plant’s Fire Hazard Analysis (FHA) to compensate for this condition to ensure that safe shutdown paths are preserved until the conditions can be corrected.
The Event Report did not specify what measures were taken, but past incidents at other plants suggest that the measures probably consist of posting a fire watch.
4. Saturday morning, officials at the National Weather Service notified operators at the Cooper nuclear power plant in Nebraska that the Shubert radio transmission tower, part of the plant’s emergency notification system, was not working. According to the Cooper Event Report to the NRC, this was “considered to be a major loss of the Public Prompt Notification System capability and is reportable….”
The transmission tower turned out not to be the only problem. According to the Event Report: “The licensee also found FTS 2001 (telephone) lines to be non-functional. The communications line was severed during road construction.”
Repairs and testing were not completed until after noon on Sunday.
5. Monday afternoon, operators at Illinois’ Braidwood nuclear power plant reported a loss of cooling capability to the site’s Technical Support Center. The situation was reported to the NRC as a condition affecting an emergency response facility. Repairs are underway.
6. And, at the Palo Verde nuclear power plant in Arizona, a licensed operator failed a random Fitness for Duty screening. The operator’s plant access has been withdrawn.