US steam generator replacement a winner

Thursday, 30 January 2014

As the Davis-Besse nuclear power plant prepares to begin work to replace its steam generators, the plant's operator is highlighting the benefits to the local economy from the operation.

Davis-Besse's new steam generators, 22.5 metres in length and weighing in at 470 tonnes, were delivered to the site by supplier Babcock & Wilcox in October 2013. (Image: First Energy)

Davis-Besse operator FirstEnergy Nuclear Operating Company (Fenoc) claims the imminent project to replace the plant's two steam generators will boost the local economy by over $108 million. The 908 MWe unit's current operating licence expires in 2017, but Fenoc has applied for a licence extension to 2037. The $600 million steam generator replacement project will help to ensure that the reactor can continue operations well into the future.

Davis-Besse site vice president Ray Lieb described the project as one of the largest to occur at the site since construction of the facility, which started operations in 1978. "Completion of the project is expected to help ensure that Davis-Besse remains an integral part of northwest Ohio's economy, and a safe, reliable and clean energy source, now and in the future," he said.

Steam generators are used in pressurized water reactors (PWR) to transfer heat from the reactor coolant into water in a secondary circuit, producing the steam used to power the electricity-generating turbines. Each steam generator contains thousands of kilometres of tubes through which hot water flows.

Steam generator tubes can degrade over time, and the US Nuclear Regulatory Commission (NRC) imposes stringent rules for inspections, maintenance and repair of steam generator tubes which may include plugging of thinning tubes, gradually compromising plant efficiency. Advances in technology mean that modern steam generators use more corrosion-resistant alloys. Although replacement of the entire steam generator is a major undertaking, such operations have now been carried out at most of the USA's 65 PWR units.

Davis-Besse is the second of Fenoc's three PWRs to undergo steam generator replacement. The three steam generators at the company's Beaver Valley unit 1 in Pennsylvania were replaced in 2006. Beaver Valley 2's steam generators are due to be replaced in March 2017 under an engineering, procurement and construction services contract awarded to Bechtel in June 2013.

Researched and written
by World Nuclear News