Palisades (USA)

Map of Palisades

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PWR 780 MW by CE; grid connection in 1971

Facilities in Palisades

plantreactor typconstruction startoperation startshut down

Consumers Power Co., owner of Palisades, hopes to save the $20-million cost of annealing the plant's reactor vessel by convincing the NRC staff that new data prove the vessel can operate safely despite radiation-induced embrittlement until well after the end of its initial license in 2007.
The new data submitted by Consumers to NRC April 4 indicates that Palisades will not reach its pressurized thermal shock (PTS) screening threshold until 2011. If the utility does anneal the Palisades vessel, it will be the first such project at an operating commercial reactor in the US
At this time last year, the NRC staff believed the Palisades reactor vessel would cross its PTS threshold in 1999 and have to be shut down or annealed by then. Palisades managers laid plans for an annealing job that was expected to cost about $30-million, with about $10-million of that expected to be spent by November.
But if NRC approves the utility's new analysis by November, Consumers Power will be able to shut its annealing project and save about $20-million, according to Ken Powers, manager of nuclear services for the utility.


The second phase of studies preparing for the $30-million annealing of the Palisades reactor vessel begins next month. The Palisades effort is the first project of its kind in the US.
Consumers Power announced last year that it planned to anneal the 845-MW Westinghouse PWR´s vessel to restore ductility lost to irradiation. If successful, the annealing will let the plant operate to the end of its license in March 2007. Consumers selected Westinghouse for the job last May and since has spent $5-million on conceptual design and thermal analysis.


Forced shutdown by problems with FW pumps, ends a 337 day run, only a few days before the planned refuelling outage. The run set a new record for the plant - the longest run unit had run continuously before was 176 day in 1981 !
After the 90 day outage, the unit should operate 15 month continuously.


Safety analysis from April estimate that the RPV will not be vulnerable to PTS until 1999. The additional 2 years gives both the utility and the NRC more time to prepare for the annealing project.; In April it is reported that the annealing project will likely cost US$ 10-20 million
License for commercial operation for Palisades expires in 2007.


Plans to anneal the RPV - could be the first annealing job in US power reactors.Cost are estimated to 5-10 million US$. It is planned to cooperate with Russia: russian method involves suspending a large electric restistance heater inside the reactor. Westinghouse proposed natural gas technique. Electric heating allows more precise control.


Pinhole in a checkvalve in one train of ECCS: deposition of boric acid occured on top of the 600 mm diameter checkvalve. The pipe is a feeder line for ECCS (HP,LP) and containment spray pumps .


Failure of a fuel rod during refueling resulting in loss of a small amount of fuel. Rest of the particles is thought to be trapped in RCS and will be filtered out during operation.


During the surveillance of HPCI system the hot leg injection check valve failed to fully open, resulting in inadequate flow rates.


Main steam line break could result in exceeding the containment design pressure. The original assumption that a 100% steam line cross sectional area break size is most limiting was incorrect. Smaller break sizes result in higher containment pressures.


One MFP tripped on high vibration, the other increased the feed rate. A manual turbine runback caused SG shrink and than SG ovefeeding, causing an insertion of reactivity and a scram.