Nuclear renaissance24 May 2010
For many years, safety concerns hampered new nuclear plant construction. In the late 1990s and start of the new millennium, new political priorities came into play. In the second article of a two part special, Will North looks at the lifting challenges posed by new power plant designs, and the giant crawler and special lattice boom cranes that have been built to meet them
As a scientific consensus developed recognising the potential damage of CO2 emissions from fossil fuels, planners looked to alternative sources of power. At the same time, new safety systems developed by companies like Areva and Westinghouse promised to reduce the risks that had come to be associated with nuclear power.
According to the International Atomic Energy Agency's Power Reactor Information Service (PRIS), 349 of the 438 reactors currently in operation around the world were connected to the grid between 1970 and 1990. In the past ten years, 35 new reactors have been connected to the grid. Currently, PRIS reports, there are 54 new reactors under construction globally.
Speaking at the international conference on access to civil nuclear energy in Paris on 10 March 2010, IAEA director general Yukiya Amano said, “The number of countries interested in introducing nuclear energy is growing steadily. Demand for our assistance is also constantly increasing.
“Access to nuclear power should not be the sole prerogative of developed countries. It should also be available to developing countries. The agency is well- placed to help. We now have projects on introducing nuclear power with 50 of our member states, 17 of whom are actively preparing nuclear power programmes. We expect between 10 and 25 new countries to bring their first nuclear power plants on-line by 2030. These are momentous changes.”
Bryan Pepin-Donat, director, contracts and international business, Lampson, says: “Reduction of CO2 has received wide attention and nuclear power provides the best and most efficient option in terms of power produced over significant periods of time.
“There is continuing activity in utilities with respect to nuclear power plants in the US. Several plants have received initial licensing. Others are in the process of determining their power requirements as well as vetting the financial aspects. The government has put forward $8bn in loans for initial plants with the prospect of more funds.”
The US is not alone in looking to nuclear. Rüdiger Zollondz, senior manager, product marketing at Terex, says: “If you look at energy trends, there is an obvious, tangible, move to renewables. The trend for nuclear is not yet tangible. But, the number of plants planned or announced doesn’t meet the demand that is going to come as 30 or 35-year-old plants come up for closure. We’re expecting demand from China, the US, UK and India. China, for example, decided two or three years ago to go massively into nuclear, but are still at the planning stage. At the moment, they’re testing different reactor designs.”
Mike Wood, Manitowoc’s global product manager for crawler cranes, agrees: “There’s no doubt that nuclear power is a strong solution to the challenge of meeting continuing energy demands while at the same time looking at lower emissions. All over the world, countries are looking for more power but with less pollutants. We believe nuclear power will become much more prominent.
Everything we’re reading about new stations in India, China, Russia and other developing markets, together with the increasing number of licenses being applied for in the US tells us that this market will become more important. Energy demands are not diminishing and the power market will continue to be a driver for Manitowoc crawler cranes.
“In nuclear power plants, the components are often much heavier than in other general construction jobs. Lifting elements such as reactors or steam generators requires strong lifting capacity and often long reach. Also, in existing plants, there can be a lack of set up space. Many new nuclear developments will be additions for greater generating capability to existing facilities. Similarly, ground preparation can prove difficult if there is existing pipework under the crane’s set up area. At Manitowoc, we engineer our cranes to provide solutions to these problems. Our cranes generally transport in the fewest number of vehicles, and once at the job, they are easy and fast to assemble (using our FACT connection technology). On the 31000, we have the VPC counterweight that is suspended from the rear of the crane but does not touch the ground. This is especially useful in projects like nuclear power plants where ground preparation can be an issue.
“For large lifts on new builds or refits our Model 21000, Model 18000 with MAX- ER and luffing jib, and Model 31000 with luffing jib will be well suited. As support cranes, our Model 2250 and Model 16000 will work well.”
New techniques will mean plants can be delivered faster than ever before. Javier Martinez, executive director of ALE Heavylift, says: “Old designs of reactors took up to 14 years to build. In order to reduce the construction time to four or five years, designers need to modularise the main elements. The main design companies are engaged in designing modules that are not 20t, 30t, or 40t, but as big as transport limitation allows.
“We plan to use cranes capable of lifting loads as big as 1,000t out to 90m, to lift the weight of the containment liner rings of 40m diameter and the top dome. The inside liner rings will now be designed to be installed in three or four sections, each weighing 900t, with the dome weighing 1,000t. For that, you need a huge crane, with a load moment of more than 100,000tm. The main reactor, steam generators, the polar gantry for the nuclear crane and enclosing the dome may each weigh above 500t and be placed at bigger radius. It is that modularisation and optimisation of component sizes that allows design companies in the US to plan to build plants in three or four years.
“This was one of the reasons we in ALE decided to build the SK series of cranes: they exceed the demands of these sort of jobs.”
Another development that has made the construction process shorter, is improved planning. Patrick O'Leary, lessons learned engineer and spokesman, Areva, says, “On the design side, we use 3D computer modelling of the plant structure and components. That is a huge step forward. It allows us to check the design and interfaces before construction begins. On the construction side, we use modular design and fabrication of the containment liner, reactor building and pools. The 3D modelling allows us to precisely prepare lifting plans of these components.
“Relative to 30 years ago, the ability to use 3D modelling to do the design detail is an advantage and an opportunity to do a lot of activities before you get to site. It allows us to avoid interference and clashes on site.”
This improved planning makes other aspects of delivering a plant easier. “These new plant designs are already licensed before they are built,” says Lampson’s Pepin-Donat. “With older plants, they were licensed as they were built and that contributed to the high cost. The whole industry, the plant builders, the regulators and the lifting industry recognise that the modular construction, government initiatives and high efficiencies in subcontracting are essential to making a success of nuclear power.”
Chinese manufacturer Zoomlion recently announced a new 1,000t crawler, the QUY1000, aimed squarely at this new wave of nuclear construction. Zoomlion director of overseas market after-service, William Chen, says: “To ensure the security of energy supplies, adjust energy structure, reduce environmental pollution and ensure the sustainable development of society and economy, China has recently adjusted its nuclear policy from the previous ‘moderate development of nuclear power’ to ‘proactive development of nuclear power’. The State Council in 2006 adopted the ‘long-term nuclear power development plan (2005-2020)’. According to the plan, the total installed capacity of the nuclear power unit in operation will reach 40GW in 2010, and the investment is expected to amount to CNY500bn.
“China has mastered the improved second generation of nuclear power technology and, at the same time, introduced the third generation of technology, which is mature in foreign countries, through international bidding. In 2007, China and the US signed a contract for the procurement and core technical transfer of the third generation of nuclear power by relying on its own projects, and selected Zhejiang Sanmen and Shangdong Haiyang to construct four sets of the AP1000 reactor.”
The AP1000 was designed by nuclear plant manufacturer Westinghouse. The design for modularised plants like this was based in part on technologies developed in the petrochemical industry. “In the late 1980s and early 1990s, the petrochemical industry began to increase the output and efficiency of their refineries,” says Pepin- Donat. “This resulted in the requirement for larger processing vessels. Vessel weights went from 500t to 1,000t. Cokers have grown from 350t to over 800t in some cases. The crane companies responded with larger crane capacities. Lampson already had the Transi-Lift series which by the early 1990s included capacities from 800t to 2,600t.
“In approximately 2004, Lampson was contacted by Westinghouse to participate in constructability studies for their new AP1000 nuclear power plant. The design methodology for the AP1000 was modular construction. Westinghouse had been aware of Lampson and its nuclear activities and they asked us to participate in the studies to determine if the module lifts they had planned were within current capabilities. Lampson indicated that we had the required lift capacity, and worked with them to develop the basic radii and lift plans for the key modules.”
Lampson is working on one of these new plants, in Sanmen. “Lampson initiated sales activities in China in 2006 and secured its first order for an LTL-2600B in August of 2007,” according to Pepin-Donat. “That crane was delivered in April 2009 and received Chinese certification. It has been working on the project having made several very large lifts, including the CA20 module. In September 2009 we received an additional order for an LTL-2600B along with an option for a third machine. Those machines are being manufactured now.
“The major lift on that power plant is the CA20 module. This module has a total lifted load of approximately 1,100t with a radius of 56.4m. Using the LTL-2600B Transi-Lift this lift can be made at a radius of 56.4m while remaining within 85% of capacity. The relatively flat load curve of the Transi-Lift allows for a very high level of efficiency. The LTL-2600B with 122m of main boom retains 100% of capacity from 25m radius out to 57m radius. We retain 50% of capacity out to a 105m radius. When configured with a 49m jib the LTL-2600B provides 700t of initial capacity and retains 300t of capacity out to 137m. These capacities at radii provide great efficiency with respect to crane placement on a project site. The Transi-Lift is rated to travel with its full chart capacities.”
Terex also has one of its biggest cranes working in China, a Terex Twin at Shangdong Haiyang. “Large modules speed up the process, but the advantages are much more than that: pre-assembling modules on the ground is much safer, and more efficient,” says Zollondz. “When you pre-assemble modules, it means you need to be able to bring the modules in, but you need much less space at the site.
“This is why the ability to pick and carry the load is so important. You can pick the load up from an assembly area away from the construction site, and then move in close to the final installation. All of our cranes are pick-and-carry. Other cranes, even with only half the capacity of the Twin, are static. For contractors, not needing to set up the crane in place may be an advantage.
“The design of modules depends on the plant manufacturer. For most of them, they need to lift modules weighing 500-1,000t. One manufacturer has modules measuring 20x20m. You can’t lift close to the crane to avoid collision with the boom. The crane also has to be a certain distance from the containment.”
More than four thousand miles away, at Olkiluoto in Finland, Areva is building the first of a new generation of power station. Areva's O'Leary, says: “Areva's new Generation 3 + EPR reactors offer a high, state-of-the art safety level. They have four independent safety systems, digital control of plant systems, and a new 'core catcher'. The containment is earthquake and airplane crash resistant.
“The airplane crash and quake proof containment uses a lot of concrete, and a lot of rebar. The containment liner lines the inside of the reactor containment, and acts as part of the formwork during the construction. Its main feature is to act as a pressure barrier during plant operation. In the event of accidents, it forms an airtight skin. It takes lots of careful rigging to lift, with very closely spaced lifting points.
“The containment liner is composed of a 'cup' at the bottom, then four liner rings, and the dome on top. They all have a variety of pipe sleeves pre-assembled. Each load weighs around 180–250t; the dome is just shy of 250t and is lifted to a height of 60m.
“We also used modular techniques for the construction of the pool formworks. The reactor and fuel storage areas have steel lined pools to provide cooling for the fuel. We wanted to de-couple the pool works from the civil engineering. This meant we could do the work in parallel. We did the same for the containment liner.
“Working on ground level, and removing work from the congestion of the civil works, is cheaper and easier. At ground level, without the congestion, you can get in, do all the dimensional checking that is needed, plan the lifting and rigging, and then just re-verify everything once the component is installed.
“Another aspect that was really beneficial was fitting the safety piping inside the dome. It can be installed at ground level, and pressure tested before being lifted. It is a lot easier and safer to do that at ground level, rather than 50m up inside the reactor building.”
Areva used cranes from a variety of suppliers on this job. As reported in Cranes Today in September 2009, a 1,250t Terex CC6800, on hire from Havator, was used to pick and carry the reactor’s containment dome from a barge. A 1,600t Mammoet PTC 35 DS spent two and a half years at the site, performing heavy lifts. When that crane was needed on another job, Areva bought in one of Terex's specialist pedestal- mounted lattice boom cranes from Sarens, the 2,000t PC 9600.
As well as crawlers and special lattice boom cranes, Areva is using large numbers of tower cranes and alternative lifting equipment. O'Leary says, “We've had about 20 tower cranes at a time on site. We've been able to plan the layout of these to ensure that all structures on the site have access from tower cranes. We use very careful anti-collision systems to ensure they can move freely without coming into contact with each other.
“We also have set up on site a Mammoet gantry system with three strand jacks. Moving forward, in late spring and early summer, we will move in the reactor pressure vessel, weighing 450t, and four steam generators, each weighing 550t. We're going to use the Mammoet gantry to lift from the horizontal, with a 54-strand strand jack. It will be carried over to a trolley, and then we'll use a tugger to get it into the reactor building. Two additional strand jacks, one with 24 strands and one with 48, mounted on the rails of the polar crane, will lift it from the horizontal to vertical and place it inside the building. We'll be doing a 45m lift inside the building.”