2023年9月25日星期一

Decom boom

 Even if the nuclear market goes up and down, there are multiple new projects developing all over the world for conventional Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs), as well as development of the new Small Module Reactors (SMRs).

Konecranes vice president business unit nuclear in the US, Steven Waisanen explains that the most active regions are China, RussiaUnited KingdomTurkey and the Middle East, while in other places, like Germany and Italy, it has become less popular.

“Abu Dhabi bought two plus two units from Korea Hydro and Nuclear Staff (KHNP), which is the government of South Korea, and several other countries are looking to get a licence to build plants like Jordan and Saudi Arabia,” says Waisanen.

“In China they have three different 3.0 designs, the Areva EPR, the Westinghouse AP1000 and China’s own design.

“Russia has the VVER design reactor at 1,000 megawatts and they are exporting their design to other countries. For example, Russia built units for India, China and a new project for Turkey amongst other countries as well.

“So there are a number of projects ongoing such as in Finland with Fennovoima for a new plant. The project is still in planning stages as the company is trying to get the final approvals from STUK [the Finnish regulator] for the design of the facility.

“Even though in the UK it was supposed to start decommissioning existing nuclear power plants between 2016 and 2018, they are extending the licence and planning to do five new plants, such as Horizon and Hinkley C.”

Waisanen adds: “Horizon is looking to build new ABWR [advanced boiling water reactor] units to provide 5,400 MW at Wylfa [in Anglesey, Wales]. The new units will provide power to the grid to help replace the older units that will be shut down and move to decommissioning phase.

“The same goes for the new EDF PWR plants to be built at Hinckley C. All of these new plants will require new material handling equipment to meet the code and standards required to meet UK regulatory requirements.

“In the US, the business is focused on the decommission projects as there are two additional units, VC Summer 3 and 4 and Vogtle, which are on hold because of disputes regarding financial costs.”

Disaster Recovery

Headquartered in Shoreview, Minnesota, PaR Systems LLC is specialised in automated manufacturing and material handling equipment. Jeff Konop, engineering manager, says: “We recently built a Fuel Handling Machine for Fukushima power station and it has been installed to remove spent fuel from the storage pool for the Reactor 3. The reactor building was heavily damaged by a hydrogen explosion during the Great East Japan Earthquake in March 2011.

Tokyo Electric Power Company (TEPCO) installed a new superstructure over the Unit 3 Reactor Building, to provide both a new support floor to carry the fuel handling machine (FHM-1) but to also provide a cover to shield equipment and personnel from potential bad weather conditions and enclose the work area.”

The Fuel Handling Machine built by PaR Systems is a gantry type bridge with an integrated TensileTruss tool delivery platform. The TensileTruss provides extended reach similar to a telescoping mast, with inherent high lateral stiffness even though it is a platform suspended by wire rope. The lateral stiffness is needed to deploy tools that will operate underwater and perform specific clean-up tasks.

FHM-1 also has a traditional telescoping fuel handling mast commonly used for moving nuclear fuel at commercial nuclear power plants, as well as a 5t auxiliary hoist and high radiation resistant cameras. Hydraulic manipulator arms are mounted to the TensileTruss platform and are equipped with a suite of tooling supplied by Westinghouse and Toshiba for removal of both fuel and building debris from the spent fuel pool. The debris is a result of the destruction caused by the hydrogen explosion and collapse of the building roof. FHM-1 weighs 72t and was lifted by two large cranes during its installation in November 2017. The next step will be to test the equipment installation and then FHM-1 will be ready for live operations.

Another critical nuclear system delivery by PaR Systems (PaR) recently was the design and build of the Main Cranes System for the Chernobyl New Safe Confinement (Unshakeable Truss,).

The Main Crane System provides hoisting and remote tool delivery, again using PaR’s TensileTruss technology to provide the equipment necessary for the deconstruction and safe clean-up of the site.

Decommissioning Market

“The goal is to turn the former nuclear power plant property into a green field state once decommissioning is complete,” Waisanen says. “Some of the countries with the largest number of decommissioning or planned decommissioning projects are the United States, United Kingdom and Germany.

“Decommissioning plants still has many of the same requirements as operating plants, such as maintaining the equipment in the plant during the dismantling process, which takes roughly 20 years. These facilities even require new equipment as wel,l because the focus or purpose of the cranes has changed.”

Areva Nuclear Materials Director, D&D Site Acquisitions Geoff Wilde says, “The US went through a period that was supposed to be a nuclear renaissance when reactors were initially licensed for 40 years, and many expected to and did renew their licenses for an additional 20 years,” Wilde says. “Unfortunately, unexpected economic pressures have begun causing some facilities to shut down much earlier than planned, particularly in competitive generation markets. One major contributor is the reduction in the market price of natural gas by 75% from its peak. As a result, more utilities are finding themselves with sites that no longer generate electricity, but now need to be decommissioned. Since this is a task not within their core business, these shutdown site owners are seeking options.

“Thus, the US industry expects from 10 to 15 nuclear energy facility closures over the next 10 years, along with sites already undergoing shutdown procedures. There are nearly 100 US facilities in operation today.”

The nuclear industry has to efficiently organise to match decommissioning competencies with changing market needs, says Wilde. There are three options permitted by the NRC, adds Wilde: “The first one is to put the plant in what is called ‘SAFSTOR’ for 60 years before doing any decommissioning, and that has usually been the default choice by the utilities,” Wilde says. “Another option is to push towards Prompt DECON to immediately start the decommissioning process. The third option, ‘ENTOMB’, is not typically considered, but would be where the radioactive components are permanently entombed in concrete in-place and left asis on the secured shutdown reactor site.

Decom boom

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