Troubled Palo Verde Nuclear Unit Prepares for Weekend Outage

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Researched by Industrial Info Resources (Sugar Land, Texas). The Palo Verde nuclear station is preparing for an important five-day outage, which will begin this weekend. This important outage can factor into the decision on whether the Nuclear Regulatory Commission will downgrade the station’s current “Degraded Cornerstone Column” to “Multiple-Repetitive Degraded Cornerstone Column”. If degraded, Palo Verde will rank in the lowest performance category for nuclear operating reactors. An additional downgrade can result in a forced temporary shutdown while the issues are corrected. The planned outage is for battery testing on the control systems. These control systems are vital towards the functionality of the troubled Unit 03. This unit has a previous history of various generator-related issues including a K-1 relay issue that occurred last year.

The Palo Verde Nuclear Generating Station is the largest nuclear electric generating site in the United States. The station consists of three Combustion Engineering pressurized water reactor units with an output capacity of 1,270 megawatts each. Each unit has a reactor cooling pump and a single steam generator. Arizona Public Service Company is the operator and co-owns the units with utilities in New Mexico, Texas, and California. The Palo Verde site is located in Tonopah, Arizona, 34 miles west of Phoenix. Units 01 and 02 went commercial in 1986 and Unit 03 in 1988.

Arizona Public Service (APS) is an electric utility subsidiary of publicly owned Pinnacle West Capital Corporation (NYSE:PNW), serving customers in eleven counties in northern and central Arizona. Pinnacle West Capital Corporation (Pinnacle West) was incorporated in 1985 and owns all of the outstanding equity securities of Arizona Public Service Company (APS), its major subsidiary. APS is a vertically integrated electric utility that provides either retail or wholesale electric service to most of the state of Arizona. Pinnacle West's other significant subsidiaries are SunCor Development Company (SunCor), which is engaged in real estate development and investment activities, and APS Energy Services Company, Incorporated (APS Energy Services), which provides energy services and products in the western United States. Pinnacle West Energy Corporation (Pinnacle West Energy) formerly owned and operated unregulated generating plants. Pinnacle West has three principal business segments: the regulated electricity segment; the real estate segment, and the marketing and trading segment.

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