http://pbadupws.nrc.gov/docs/ML1218/ML12180A497.pdfPRELIMINARY NOTIFICATION
June 28, 2012
PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE – PNO-III-12-006
This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public
interest significance. Some of the information may not yet be fully verified or evaluated and is
basically all that is known by the Region III staff on this date.
Facility
Fermi Power Plant, Unit 2
Detroit Edison Company
Monroe, MI
Docket: 50-341
SUBJECT: UNPLANNED SCRAM ON JUNE 25, 2012, DUE TO LOSS OF REACTOR FEED
PUMP
DESCRIPTION:
On June 25, 2012, at 1330 (EDT), during power ascension following repairs to the main
transformer cooling oil pumps, operators of the Unit 2 reactor at the Fermi Power Plant manually
scrammed the reactor. Operators scrammed the reactor at approximately 24 percent power
due to the loss of one reactor feed pump because of high vibrations. The other reactor feed
pump was not in service at the time. All control rods inserted and all plant systems responded
normally to the scram. The NRC resident inspectors were onsite at the time and responded to
the notification of the scram.
On June 26, 2012, at 0521 (EDT), the licensee entered cold shutdown (Mode 4). The licensee
is continuing to investigate the cause of the high vibrations on the reactor feed pump and the
subsequent damage to the pump that was identified following the shutdown of the reactor. The
NRC resident inspectors continue to follow the issue.
This preliminary notification is issued for information only.
Region III received initial notification of this occurrence by a telephone call from the resident
inspector’s office (RIO) at approximately 1400 (EDT) on June 25, 2012 (refer to Event
Notification No. 48047).
Health Monitoring of Rotating
Equipment from Torsional
Vibration Features
Martin W. Trethewey
Department of Mechanical and Nuclear Engineering
Penn State University
April 13, 2007
Nuclear
BWR Recirculation Pumps
• NRC Information Note 2005-08
– April 2005
Many Byron Jackson (now Flowserve) RRP shafts have been inspected
– ALL have some thermal cracking at thermal barrier
– Axial cracks
– Generally benign
Dangerous Circumferential Cracks
– Axial thermal cracks change direction under mechanical loading
– Fast growing
– Can cause catastrophic shaft failure
General Electric recommends ALL pumps with 80,000 hours service be
inspected and monitored for cracks
TVA Nuclear
Shaft Crack History
Browns Ferry - Reactor Feed Pump
– October 1979
Browns Ferry - Recirculation Pump
– January 1984
Watts Barr - Main Feed Pump
Sequoyah - Centrifugal Charging Pump
– July 1981
– January 1994
– April 1999
Sequoyah - Reactor Coolant Pump
– October 2000
– April 2002
– Spring 2005
https://docs.google.com/viewer?a=v&q=cache:mmKGcNwixNwJ:www.esm.psu.edu/wiki/_media/research:cjl9:trethewey_me.pdf+Reactor+feed+pump+wiki&hl=en&gl=us&pid=bl&srcid=ADGEEShkCNxXYv1ZF7G0V8zSmUdDSM8CYlVyZvb2Q_Iij361eG83pCeeMo5HNBGG9I9jXyrzyh3zjlzdqI37QqVTXcg14iNYD43Z4ds5EDOJrKLTR4bikLeLI4ZwK6PQduBvfrRvDuDd&sig=AHIEtbSQ8uHqQSPU1Qz11jmLbTTdhc61qAFermi 2’s most notable mishap occurred on Christmas Day of 1993. The results of this accident was the dumping of hundreds of gallons of radioactive water directly into Lake Erie.
The catastrophic failure of the main turbine at Fermi 2, Christmas Day 1993
The main turbine automatically tripped due to an erroneous mechanical overspeed signal caused by high vibrations. The reactor, which was operating at 93 percent power, received an automatic scram signal triggered by the turbine trip. The high vibration was caused by catastrophic failure of the turbine blades. Ejected blade parts ripped through the turbine casing and severed condenser tubes and other piping. The rupture of piping supplying hydrogen gas to the generator for cooling caused a large fire. The plant’s fire brigade took 37 minutes to muster, dress, and enter the turbine building to fight the fire. Their efforts were hindered by numerous communication problems, including malfunctions of personnel motion detectors (e.g., “man down” alarms).
About 500,000 gallons of water from broken general service water piping and turbine building closed cooling water piping flooded the radwaste building basement to a depth of approximately six feet. Workers were slow to isolate the systems with broken piping to terminate the flooding, due to the total lack of procedures for a turbine building internal flood. The severed condenser tubes permitted water from Lake Michigan to flow into the condenser hotwell, from where it was pumped to the condensate storage tank. The standby feedwater system pumped water from the condensate storage tank to the reactor vessel. The lake water caused conductivity and chloride levels of the reactor vessel water to significantly exceed specifications. (Fermi 2 Outage report December 25, 1993 to January 18, 1995 (1.1 years))
With 500 tons of spent fuel in a spent fuel pool located 5 floors above the ground at Fermi 2, there is another inconceivable and highly concerning problem facing the safe operation of the facility. Welds in the original blueprints from 1970 that were supposed to be built in to bolster vertical beams connecting the walls to the floors were never built in. According to Keegan, “So in 2010 discovery of missing welds that appeared on 1970 blue prints prevented the procedure of lifting the 125 tons of spent fuel bundles from the 5th floor down to ground with the crane. The floors and ceilings could not bare the load of the crane because welds were missing on the vertical beams. The crane is rated at 125 tons.”
http://www.counterpunch.org/2012/04/06/fighting-the-legacy-of-enrico-fermi/DTE FERMI application to defer weld examinations:
http://pbadupws.nrc.gov/docs/ML0207/ML020720683.pdfThey know, they don't care about anything but money.
Author
Topic: Tear Down Fermi! (Read 4558 times)
