Nuclear life extension plans tested by obsolete components

“Under current license basis 92% of operating reactors would shut down by 2050 and 74 percent would shut down by 2050 with anticipated license renewals. However, if 54 reactors extended operation to 80 years, only 20% of operating reactors would shut down by 2050,”

In fact, with construction times for some plants approaching ten years, many of the parts can be obsolete before the plant has even started generating power

Reuters By Paul Day April 5

An increasing number of aging nuclear plants are being cleared for long-term operations and suppliers say solving obsolescence will be key to keeping the fleet operating.

– Nuclear operators must be able to swap out old parts for new to keep a reactor running, but when like-for-like is unavailable, original equipment manufacturers (OEMs) are faced with the challenge of finding an alternative while avoiding making any major changes.

“There’s a rule of thumb that if a plant has to do a design change, it’ll cost anywhere from $300,000-$500,000 just in engineering, licensing changes, drawing changes, and that doesn’t include the cost of the required equipment … so we try, wherever possible, to keep our clients from doing a design change,” says Vice President of Westinghouse Parts Business in its Operating Plant Services unit Craig Irish.

However, design changes and other innovative solutions such as additive manufacturing will be needed as an increasing number of nuclear power plant operators extend their plants’ lives from the original 40 years to 60 years or further.

Many of the world’s nuclear power plants were built several decades ago and applications for long-term operations (LTOs) beyond initial lifespans are becoming increasingly common.

At the end of 2020, over 100 nuclear reactors worldwide were operating beyond their initial 40-year licensed periods, with more than 30% of the nuclear fleet operating under LTO conditions, the OECD-NEA says.

In the United States, where nuclear power has supplied 20% of electricity and is currently running 93 reactors with two new units under construction, the average age of the fleet is 41 years including three reactors that started operation 52 years ago, according to the Department of Energy (DOE).

Nine U.S. reactors have active applications with the Nuclear Regulatory Commission (NRC) to extend their lives and 10 reactors have publicly announced plans to extend their licenses to 80 years.

Obsolescence challenge

The challenge, say OEMs, is keeping a supply chain running and up to date for complex, always-on machines that were built with Reagan-era (or earlier) technology.

According to Westinghouse, a leading global parts manufacturer for power stations, approximately 35% of installed equipment in the nuclear industry is obsolete.

In fact, with construction times for some plants approaching ten years, many of the parts can be obsolete before the plant has even started generating power, according to Westinghouse’s Irish.

The high cost of design changes means that many operators, working with a plant that went online in the 1970’s, would work hard to keep it looking the same by the time it is set for decommissioning in 2030, he says.

This was especially challenging when dealing with instrumentation and control (I&C) parts which may have worked with dials and levers when the plant was built but now in many cases can be digitalized.

“They try like hell to keep plants exactly the same, with the same technology, the same parts, though obviously that’s not realistic, so operators have to introduce digital products where it makes sense,” he says.

Internationally, part of the challenge is many of the parts produced for the nuclear industry face varying specifications depending on the regulator they are working under, restricting an already tight market to national boundaries.

Such differences will become even more pronounced with the introduction of a new generation of reactors expected to begin commercial operations within the next decade, with more than 70 SMR designs under development in 18 countries…………………………………………………………..

“The biggest problem is a lot of these discrete components, resistors, diodes, transistors, capacitors, etc are either substantially changed from the 70s and 80s when we built these instruments or they’re not available or they got bought and sold by another company,” …………………………………… https://www.reuters.com/business/energy/nuclear-life-extension-plans-tested-by-obsolete-components-2023-04-05/