Nuclear Outages

Prairie Island Unit 2 returns to full power after refueling outage

Nuclear Street News — Tue, 05 Jun 2012 21:05:00 GMT

Prairie Island Nuclear Generating Plant’s Unit 2 reactor returned to full power at 4:09 a.m. CDT today after workers completed a scheduled maintenance and refueling outage.

During the outage, which started Feb. 22, approximately 400 contractors joined with the plant’s 800 employees to complete maintenance tasks and replace one-third of the unit’s fuel. Workers also prepared Unit 2 for installation of a new steam generator in 2013, a significant investment to support plant operations to 2034, when the unit’s extended operating license expires.

Each Prairie Island reactor can generate about 550 megawatts of electricity, for total plant output of about 1,100 megawatts. That’s enough to power nearly 1 million homes and provide about 20 percent of Xcel Energy’s customer needs in the Upper Midwest.

Xcel Energy’s Prairie Island and Monticello nuclear generating plants are among the company’s lowest-cost sources of generation on a per megawatt-hour basis. They run 24 hours a day, seven days per week, except during refueling outages, and they do not produce any greenhouse gas emissions.

Areva Completes Outage Work at DC Cook Plant

Nuclear Street News — Tue, 29 May 2012 16:20:00 GMT

Areva announced it has completed outage work at the DC Cook plant with extremely low-dose (radiation) exposure during the planned spring outage, according to a Tuesday release.

The AREVA team handling steam generator maintenance work on DC Cook Unit 2 as part of the recent outage successfully completed 22,991 inspections on four steam generators with zero safety issues and very low-dose exposure.

“It was a great team effort by all personnel,” said Mike Jefferson, Field Operations Manager for Steam Generator Repair Services. “Constant monitoring and good peer checking by our team were the key factors that contributed to zero safety incidents and very low dose.”

“The total dose exposure was below 10 Rem, which is an outstanding achievement. By working safely and smartly we are able to deliver outstanding results for our clients,” said Mike Rencheck, CEO of Areva.

The scope of Areva work included eddy current testing/inspections of tubing to look for degradations/problems, primary manway removal, secondary manway removal, water lancing at 3000 psi (essentially high pressure wash of the tubes), secondary side inspections and top of tube inspection.

Entergy Returns Pilgrim Plant to Service

Nuclear Street News — Tue, 29 May 2012 16:12:00 GMT

The Pilgrim nuclear power plant returned to service Saturday after an emergency shutdown on May 23.

The plant was manually shut down when workers detected reduced air pressure in the facility’s condenser, according to spokesmen for the NRC and Entergy, the plant’s owner. It marked the plant’s third emergency shutdown in seven months.

Over the weekend, Pilgrim also received a 20 year license extension from the NRC.

Brown's Ferry Unit 3 Scrammed Due to De-Energization of RPS

Nuclear Street News — Wed, 23 May 2012 16:35:00 GMT

At Brown's Ferry on Tuesday, the Unit 3 reactor was automatically scrammed due to de-energization of Reactor Protection System (RPS) from actuation of 3A Unit Station Service Transformer (USST) differential relay 387SA, resulting in a loss of 500KV power to Unit 3, according to an NRC report.

Investigation is in progress as to the cause of relay actuation. 500KV power was restored through the alternate feeder breakers from 161KV to all Unit 3 4KV Unit Boards successfully. 161KV remained available during the entire event. Loss of 500KV power lasted less than 30 seconds and power has been restored to all safety related boards. All Unit 3 diesel generators successfully started and tied to their respective 4KV Shutdown Boards.

All safety systems responded as expected to the loss of 500KV power. No Emergency Core Cooling System (ECCS) or Reactor Core Isolation Cooling (RCIC) reactor water level initiation set points were reached. RCIC was manually started to control reactor water level. Primary Containment Isolation System (PCIS) and PCIS initiation signals for groups 1, 2, 3, 6 & 8 were received as designed. At the time of the scram, High Pressure Coolant Injection (HPCI) system was tagged out for removal of temporary instrumentation following planned maintenance.

Pilgrim Plant Shut Down After "Reduced Condenser Performance"

Nuclear Street News — Wed, 23 May 2012 16:30:00 GMT

Officials say Entergy's Pilgrim Nuclear Power Station in Plymouth has been shut down after a condenser at the station lost vacuum pressure during a cleaning, officials said.

Officials said the incident happened at about 1:10 p.m. on Tuesday with the plant was operating at about 30 percent capacity.

Neil Sheehan, spokesman for the NRC, told The Boston Globe that the condenser operates in a vacuum to maximize efficiency.

NRC inspectors at the plant “did not identify any safety concerns or performance issues,” Sheehan said. “They will follow the company’s efforts to troubleshoot the cause of the loss of condenser vacuum and any corrective actions.”

The plant will remain shut down until investigators determine what caused the problem, Entergy spokesman Rob Williams said.

“The technicians are now investigating the cause of that reduced condenser performance,” Williams said. “As we do with every shutdown, there will be a comprehensive investigation to look into what caused the condenser performance issue.”

Last week, Entergy sent almost half of the plant's workforce home after labor talks reached a standstill. Earlier this week, 14 activists protesting Pilgrim's relicensing were arrested after they tried to enter the facility.

River Bend Experiences Reactor Scram

Nuclear Street News — Tue, 22 May 2012 15:10:00 GMT

River Bend Station experienced a reactor scram Monday resulting from an RPS actuation, according to an NRC release. Following the scram, reactor water level briefly lowered below level 3. The reactor is stable with pressure and temperature being controlled by the feed water system and main steam bypass valves, respectively. The cause of the scram was due to a turbine trip/low condenser vacuum. The low vacuum condition resulted from a loss of non-safety related 4160V switchgear that powers two of four circulating water pumps.

A suspected spurious Division II isolation of Reactor Core Isolation Cooling (RCIC) was observed, according to the report. Restoration of RCIC to standby is in progress.

The plant is conducting causal investigations to fully understand the cause of the turbine trip. As information becomes available, River Bend Station will provide additional information.

Exelon Takes Limerick Unit 2 Offline to Replace Steam Relief Valves

Nuclear Street News — Fri, 18 May 2012 15:50:00 GMT

Exelon has removed Limerick Nuclear Plant's Unit 2 reactor from service for a scheduled maintenance outage so workers can replace two steam relief valves. Plant personnel will complete the maintenance and fully test the new components before returning the unit to service. The repairs can only be performed while the plant is offline.

“Careful and continuous monitoring of plant equipment is essential to reliable operations at Limerick Generating Station,” said Russ Kearney, Limerick site vice president. “This maintenance outage will ensure that we can operate safely and reliably during the peak summer season ahead. Our highly trained team is well prepared to perform the scheduled maintenance and return Unit 2 to service for our customers.”

Limerick Unit 1 will continue to operate at full power during the outage.

EDF's Gravelines 6 Nuclear Reactor in France Experiences Unplanned Outage

Nuclear Street News — Tue, 15 May 2012 13:50:00 GMT

EDF's 900-MW Gravelines 6 nuclear reactor in northern France experienced an unplanned outage on Monday at 9:35 GMT, France's power grid RTE said on its website.

An EDF spokesman said the outage had been caused by a default on a sensor that measures the good working order of the reactor.

"We are assessing the problem before carrying out repairs," the spokesman said. He was unable to give a restart date.

EDF Restarts Sizewell B After Short Maintenance Outage

Nuclear Street News — Tue, 15 May 2012 13:35:00 GMT

After shutting Sizewell B down due to a potential issue with its lubrication system on Sunday, EDF resumed operation of the nuclear plant's two turbines Tuesday.

The short maintenance outage was a precautionary measure, according to Sizewell B director Jim Crawford.

“Safety is our over-riding priority. So, when the instruments indicated we could have a problem with the lubrication system, we took the conservative decision to take the station offline, while we fully investigated the problem and repaired any damage," Crawford said. "This was largely done as a precautionary measure, but we were able to take swift positive action and return the power station to service within 43 hours."

On Monday, EDF Energy also restarted its 450-megawatt unit 2 at Heysham 1 nuclear power plant on following a planned maintenance outage that began on March 1.

Palisades Nuclear Plant Returns to Service

Nuclear Street News — Mon, 14 May 2012 14:50:00 GMT

The Palisades nuclear plant in southwestern Michigan returned to service Saturday after going offline on April 8th for scheduled refueling and maintenance.

The 41-year-old plant has been under NRC scrutiny because of a series of safety problems in recent months.

Officials from Entergy, which owns Palisades, said in March there had been a shift in the safety culture at the plant, with employees doubling the number of reports about problems at the plant in recent months.

During the outage, 64 new fuel assemblies were placed in the reactor, as well as extensive cleanings and inspections performed by the 1,200 supplemental workers helping the permanent Palisades staff complete the work.

EDF Shuts Down Sizewell, Torness Nuclear Reactors

Nuclear Street News — Mon, 14 May 2012 14:30:00 GMT

EDF Energy shut down down its Sizewell and Torness 2 reactors Sunday, according to a statement by the company.

The statement said that the reactor at Sizewell was taken offline for scheduled maintenance, but it did not indicate whether Torness 2 was a planned or unplanned outage.

The two reactors produce 1,840 MW in total.

The utility said it will provide updates once more information becomes available.

First Energy Restarts Beaver Valley Plant

Nuclear Street News — Mon, 14 May 2012 14:00:00 GMT

FirstEnergy Nuclear Operating Company, a subsidiary of FirstEnergy, announced it has returned Beaver Valley Power Station Unit 1 to service. The reactor was shut down in early April for refueling and maintenance.

Beaver Valley's 911-megawatt Unit 1 began producing electricity at 10:00 a.m. today. The plant, currently operating at 40 percent power, is expected to reach full power this week.

During the outage, 65 of the 157 fuel assemblies were exchanged and safety inspections were successfully conducted. In addition, numerous maintenance and improvement projects were completed to ensure continued safe and reliable operations.

Salem Plant Returns to Service After Unusual Event

Nuclear Street News — Tue, 08 May 2012 14:50:00 GMT

The PSEG-owned Salem 1 nuclear plant is back in service as of Monday afternoon.

Last week, the reactor automatically tripped offline last while crews were testing the emergency reactor shutdown system. The Unusual Event, which was declared due to multiple fire alarms involving the containment building, was terminated after operators determined that there was no fire.

Joe Delmar, a spokesman for PSEG, said the shutdown was traced to a voltage issue in one of two subsystems in the plant’s emergency reactor shutdown system.

Salem 1 is one of three reactors in Lower Alloways Creek Township.

FirstEnergy Shuts Down Davis-Besse Nuclear Station

Nuclear Street News — Tue, 08 May 2012 14:45:00 GMT

FirstEnergy Nuclear Operating Company (FENOC), a subsidiary of FirstEnergy Corp., announced it has shut down its Davis-Besse Nuclear Power Station in Oak Harbor, Ohio, for scheduled refueling and maintenance.

While the 908-megawatt unit is offline, 68 of the 177 fuel assemblies will be replaced and safety inspections will be conducted, including inspections of the steam generators. In addition, preventative maintenance to ensure continued safe and reliable operations will be performed on major components including pumps, valves and the emergency diesel generators. Maintenance also will be performed on the cooling tower to improve efficiency.

More than 1,000 temporary contractors and 100 FENOC employees from the company's other nuclear plants will supplement the Davis-Besse workforce during the outage.

Spain's Almaraz II Nuclear Station Disconnected For Refueling

Nuclear Street News — Mon, 07 May 2012 14:00:00 GMT

Spain's 1,000-MW Almaraz ll nuclear power station was disconnected Sunday afternoon for scheduled refueling, operators said Monday.

The outage is expected to last about 40 days.

Spain's seven other nuclear plants were working normally.