New Technology for the New Nuclear

These approvals are part of a worldwide trend showing what Industrial Info Resources says is a 10% growth in nuclear power generation in the U.S. by 2035. Richard Finlayson, Senior International Editor, says that despite natural gas-fed projects and renewable energy sources competing for larger stakes in the U.S energy mix, the Energy Information Administration (EIA) estimated that 15,800 (MW) of new nuclear capacity will be added between 2010 and 2035 from a mix of new plants and refurbished operating plants. But the nuclear contribution to the total energy mix of the U.S. will be reduced from 20% in 2010 to 18% by 2035.

While the approvals of these new reactors is a positive sign for the industry, there are still plenty of problems associated with older plants, including California’s San Onofre power plant. A report issued July 12 shows that what was originally thought to be an isolated problem of erosion on tubes that carry radioactive water is actually endemic to the reactor. More than 3,400 steam generator tubes in the new steam generators from Mitsubishi have been found to be damaged.

Problems such as these, coming on the heels of the Fukushima disaster, promoted NRC Chairman Gregory Jaczko to dissent against the new approvals, saying “I continue to believe that we should require that all Fukushima-related safety enhancements are implemented before these new reactors begin operating.”

While the NRC has appointed a special task force to identify improvements that can be made to US nuclear plants, its recommendations have not yet been approved. Nevertheless, the nuclear industry itself is already stepping up with improvements, including a plan to supply plants with portable back-up gear sufficient to survive a lengthy power failure. These first new reactors in a generation will incorporate safety features beyond any required before the Fukushima incident.

Engineering Safety

Scana and Southern both plan to build AP1000 reactors designed by Westinghouse Electric Co. In its approval, the NRC mandated inspection and testing of squib valves which are part of the passive safety features of the 1,100 MW Westinghouse AP1000 electric pressurized-water reactor. If a meltdown were to occur, the heat-sensitive valves would automatically open to release cooling water that sits above the reactor core.

Other passive design safety features considered for new plants include placing the reactor core at the lowest elevation in the plant. That allows the cooling water to drain into the core simply using gravity. No pumps or valves required.

U.S. nuclear utilities have also launched a program to stock portable reactor-cooling equipment at regional depots, and the NRC has also approved new mandates requiring operators to prepare for beyond design-basis events.

Experience is Key

Implementing Change

As the U.S. cautiously moves forward with new nuclear power plants and new regulatory structures are put in place, decisions will have to be made about the costs and ultimate value of enhancements being mandated. For example, a potential requirement for some reactor containments to have “filtered” vents to prevent radiation leaks may not be as cost effective as additional pumps and safety valves.

As the recently approved projects get underway, the opportunities for valve, actuator and control manufacturers are great. With innovation and elegant engineering, these projects could hail the beginning of a new age of nuclear.

Kate Kunkel is web editor at www.valvemagazine.com Contact her at kkunkel@vma.org