Calvert Cliffs Going Wild On Us: An Indication of Severe Economic Stress on Electric System!

Alliant Energy earnings surge on frigid winter, shift from nuclear

By Thomas Content of the Journal Sentinel

May 1, 2014 7:52 p.m. 

Alliant Energy Corp. on Thursday reported earnings growth of 55% in the first quarter, driven by savings linked to terminating agreements to buy power from two nuclear plants as well as frigid winter weather that boosted energy sales.
The Madison utility holding company said net income rose to $108 million, or 90 cents a share, from $69.9 million, or 66 cents, last year. Sales rose 11% to $953 million from $860 million. 

The results were 12 cents higher than the forecasts of investment analysts who follow the company. Alliant has also increased its forecast for earnings for the full year.
Alliant is the parent company of Wisconsin Power & Light Co., a regulated utility serving southern and parts of eastern Wisconsin.
A key factor in the higher profit, the company said, 

was the termination of power purchase agreements with Dominion Resources Inc. to buy power from the Kewaunee power plant in Wisconsin, as well as another to buy power from the Duane Arnold nuclear plant in Iowa.

Calvert Cliffs nuclear reactor shuts down after another malfunction

Incident is one of several in the last few years; both reactors shut down in January

2:19 p.m. EDT, May 1, 2014

A malfunction at the Calvert Cliffs nuclear power plant caused an automatic shutdown of one of the two reactors there Thursday morning, the latest in a series of issues at the Southern Maryland facility.

Chicago-based Exelon Corp., which operates Calvert Cliffs, said the malfunction happened during electrical breaker testing. The Unit 1 reactor shut down as a result at about 10:15 a.m.

"All safety systems responded as designed and the plant came off-line as expected," Exelon said in a statement.

Calvert Cliffs' Unit 2 reactor is still at full power, Exelon said. It called the condition of the plant "safe and stable" and said it does not expect that electrical service to customers would be affected.

The incident was one of several shutdowns in the last few years at the plant, built in the 1970s. The most notable among them was both reactors going offline in January after an electrical malfunction — knocking out a major source of power as demand spiked in the bitter cold.

 

The Nuclear Regulatory Commission sent a team to conduct a special inspection after that event but concluded in March that overall, the plant "took appropriate actions."

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE – PNO-I-14-001

This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. Some of the information received may not yet be fully verified or evaluated by Region I staff.

SUBJECT: CALVERT CLIFFS NUCLEAR POWER PLANT DUAL UNIT TRIP FOLLOWING

THE LOSS OF THE ‘21’ 13KV BUS

On January 21, 2014, at 9:25 pm, a dual unit reactor trip occurred at the Calvert Cliffs Nuclear Power Plant after a loss of the ‘21’ service bus. The preliminary cause of the loss of the ‘21’ service bus is that ice and snow caused a ventilation louver filter on the bus metal clad to push in and allow snow and water to contact the buswork. The loss of the ‘21’ service bus resulted in a loss of the Unit 2 motor generator sets for the control element drive mechanisms, which was the likely cause for the automatic reactor trip on Unit 2.

 

The loss of the ‘21’ service bus also caused an unexpected automatic reactor trip of Unit 1 when the setpoint for high pressurizer pressure trip was reached. The preliminary cause of the Unit 1 trip was a malfunction of the digital turbine control system during the electrical transient following the loss of the ‘21’ Service Bus and Unit 2 plant trip.

Additionally, due to the loss of the ‘21’ service bus, power was lost to one safety-related 4kV

bus on both units. One emergency diesel generator on each unit started as expected to supply power to its respective 4kV bus until offsite power was restored. The loss of the ‘21’ bus resulted in the loss of power to the Unit 2 circulating water pumps. Thus the Unit 2 main
condenser, the normal heat sink, was unavailable, and decay heat removal was accomplished by bleeding steam through the steam generator atmospheric dump valves and feeding via auxiliary feedwater. Unit 1 decay heat removal was via steam to the main condenser via the turbine bypass valves and feeding via main feedwater. The plant operators brought both units to a stable hot shutdown condition in accordance with plant operating procedures with no other complications. The NRC Senior Resident Inspector responded to the site. The Resident Inspectors have been following the licensee’s activities since the shutdowns.

Region I is dispatching a Special Inspection Team to the site to understand the facts
surrounding the event, specifically the unexpected system interaction which resulted in both
units tripping following a fault on a single Unit 2 non vital bus, the repetitive failure of structures to protect 13.4kV switchgear from weather related events (a dual unit scram occurred in February 2010 due to weather related issues), and an unexpected impact on a security system during the event.

The special inspection which was flimsy....

Prior to Unit 1 restart, the team concluded that CENG documented an adequate operability basis for post-trip pressurizer safety relief valve 1RV-200 seat leakage. CENG used an ODMI checklist and an OD to evaluate any operability impact of the approximate 13 gallon per hour leak rate, including that the leakage could increase and potentially lower the valve’s pressure setpoint or challenge the TS limit of RCS leakage. While in hot shutdown following satisfactory operation of both PORVs, Unit 1 operators identified and documented in CR 2014-000586 indications of PORV or pressurizer safety valve seat leakage (increased tail pipe temperature and quench tank pressure and temperature). Actions were taken to identify that 1RV-200 seat leakage was the likely source and reactor pressure was lowered to allow the valve to reach a lower temperature (as had been the practice a CCNPP). Upon re-pressurization the leakage had essentially stopped, however, the leakage returned several hours later. CENG planned to replace this valve and test it as part of the upcoming Unit 1 February 2014 refueling outage.