Nuclear power plants prepare for old age Materials research is at the heart of efforts to keep the world’s reactors running well past 2050. Nature , Jeff Tollefson, 30 August 2016 Sophisticated inspections are helping to pick up defects in ageing nuclear power plants before they cause trouble. In March, ultrasonic tests identified signs of wear and tear in some of the stainless-steel bolts in the reactor core of the Indian Point power plant just north of New York City. Researchers at the Electric Power Research Institute (EPRI) in Palo Alto, California, are now analysing more than a dozen of the 5-centimetre-long bolts — which secure plates that help direct water through the radioactive core — to determine why they failed the inspection.
The analysis comes as the US Nuclear Regulatory Commission (NRC) considers whether to extend the life of Indian Point’s two 40-year-old reactors for 20 more years. Opponents of the plant, including the state of New York, cite the defective bolts, a transformer fire last year and environmental and safety concerns as evidence that the facility should close.
The plant’s damaged bolts are just one example of the maintenance issues facing ageing nuclear reactors around the world. The International Atomic Energy Agency and the NRC are developing management guidelines for these facilities, but the problem may be most acute for the United States, whose fleet of 99 reactors is the oldest and largest.
The NRC has renewed the licences of 81 US reactors still in operation for another 20 years. And it presented safety guidelines in December for utilities considering renewing their licences for another 20 years. But concerns remain about the effects of time on facilities that could be in operation for 80 years (see ‘Going, going, gone’).
Former NRC chair Allison Macfarlane says that the industry has been struggling economically in the face of cheap natural gas, and that many nuclear power companies are investing the bare minimum when it comes to maintenance and upgrades…..
Of particular concern are the concrete containment structures and steel pressure vessels at the heart of reactors, as well as the kilometres of wires that snake through the plants. Researchers are now analysing the long-term effects of intense heat and neutron bombardment on a plant’s crucial materials down to the atomic level……….
