Safety-classified lifting device

Safety-classified lifting device for the demanding conditions of the nuclear fuel handling cell

Enmac and Posiva have developed together a concept of a nuclear fuel handling cell, in which the radiation protection lid of the fuel transport cask is handled with safety-classified lifting and transfer equipment. The device must handle the protection lid in a safe and controlled manner. Not even the possible failure of the device should jeopardize nuclear safety.

The fuel handling cell is in a relatively tight space and contains several intersecting systems, so the number of individual devices is limited. For this reason, the designed device must also handle covers and parts of other systems in addition to the lid of the transport cask.

The project had to take into account the conditions and requirements of the fuel handling cell that deviate from the normal machine design: the fuel handling cell is not accessible at all during the operation due to high radiation and otherwise only with special arrangements to avoid the risk of contamination. Consequently, the usability and reliability of the device had to be ensured despite the high degree of automation.

Enmac designed a single fault-tolerant, remote-operated crane equipped with duplicated mechanisms that moves on rails, which meets the requirements set by both the machinery directive and the authority that supervises radiation and nuclear safety. The lifting device uses a common crane track with the fuel handling machine and participates in the operational activities of several different systems.

This solution both improved the cost efficiencyof the fuel handling cell and achieved more procurement and manufacturing phases to seamless cooperation between the systems of different equipment suppliers. Enmac was involved in the role of the device’s designer from the concept stage to the implementation planning. ”Even before this project, Enmac’s experts had already worked in various equipment projects of Posiva’s final disposal project, so there was concrete proof of their know-how,” says Petteri Vuorio, Posiva’s technical manager. The transport cask lid lifter project made extensive use of Enmac’s comprehensive mechanical design know-how, strength calculations and versatile expertise in various fields, for example the nuclear industry, hauling and lifting operations, and machine safety.

In the planning phase of the project, in addition to detailed plans and technical calculations, the focus was on the safety culture characteristic of the core industry and high-quality documentation. ”With the selected model, a cost-effective implementation method was achieved for the device. The know-how gained for domestic designers and machine shops during the project cannot be underestimated either. This know-how will also be useful in the future. Safety-classified lifting and transfer equipment has not been implemented much domestically in recent years,” Vuorio continues.

Enmac’s project manager Katri Laine says that the precise official regulations brought an additional challenge to the project: “It was challenging and interesting to find out and fulfill the detailed regulations of the Radiation Protection Agency for a safety class 3 lifting device. We were involved in the device specifications throughout the planning, ensure that the end result meets the requirements. This required different and more extensive documentation regarding the design of functions and structures as well as component selection. It was interesting to see how the quality assurance and inspection processes progressed together with the authorities,” says Laine.

Enmac prepared the required design material for the authority and supported Posiva, i.e. the responsible license holder, in qualifying the lifting device. During the manufacture, installation and assembly of the device, Enmac’s design team was available even at short notice. Enmac’s chief designer Ville Lahtinen characterizes the project as challenging, but rewarding: “In the lifting device project, the design team was able to make use of their expertise in a wide range of areas in the initial conceptualization, detailed component calculation and mechanical design of the crane structures. Due to the requirements of the nuclear industry, the project as a whole was extremely challenging, but also very rewarding. Especially during the testing phase of the device, it was great to be able to see the device fulfill the functionality requirements set for it,” says Lahtinen.

Petteri Vuorio describes the cooperation with Enmac as being close and smooth: “The working model of the cooperation in this project was a bit different from previous projects, but despite this, it was quickly put to work when the project started. It is typical for nuclear plant projects that meeting the authority’s requirements sometimes requires supplementing the design material and a broader justification of the chosen design solutions. Also these additional needs were handled smoothly during the project,” Vuorio continues.

Mika Lehtonen, Enmac’s director of Pirkanmaa, tells about mechanical engineering services; “We design and implement customer-oriented and high-quality solutions in areas such as machine, production system, vehicle and steel structure design. In addition, we carry out structural and flow analyses, strength calculations, simulations and structural optimizations related to mechanical design. We also design and implement on a turnkey basis a machine or device that fits the need, where efficiency, technology and the technology used meet the needs. We also help customers with new innovations, from feasibility studies, pre-planning and conceptualization all the way to product implementation. Documentation is always part of our service.

We produce all the documents required for the CE marking of machines and equipment: spare parts, operation and maintenance manuals, risk analyzes and manufacturing and assembly instructions. If necessary, we also take overall responsibility for the development and maintaining of documentation. We choose the software used according to the work and the need. Our designers have efficient and appropriate tools at their disposal. If necessary, we can also use the customer’s software and systems. We assemble a team of Enmac professionals in such a way that it serves the customer in the best possible way. Please don´t hesitate to contact us if you have questions about our services!”

More about mechanical engineering:
Mika Lehtonen Director, Pirkanmaa Business Unit
mika.lehtonen@enmac.fi
p. +358 40 536 8884