Spring 1996 € Volume 1 € Number 1

A Walk on the Wild Side

Virtual reality allows designers, engineers and operators to safely explore potentially dangerous nuclear facilities.


By David Blanchard



One of the major benefits of virtual reality (VR) is that it allows designers and engineers to "walk through" an environment that would normally be too difficult, too expensive or even too dangerous to enter. A nuclear facility certainly falls into all three categories, and in recent months a number of these plants worldwide have begun implementing 3-D visualization systems to achieve a level of efficiency heretofore undreamed of, while protecting personnel from safety hazards as diverse as radioactivity and poisonous snakes.

The Research and Development Division of Electricite de France (EDF), for instance, is using VR software from Division Ltd. of Bristol, U.K., to investigate a range of applications for VR in designing and testing the operating procedures of a nuclear power plant.

One application involves the maintenance of nuclear reactors, which can be a lengthy and complicated procedure. The potential hazard to real maintenance engineers is obvious: the more time spent in close proximity to the reactor itself, the greater the overall radiation exposure received by the operator. While the dosages are still minute in comparison to health safety levels, the total lifetime exposure of an operator limits how long they can work in a nuclear environment, and thus how long the skills they have can be utilized.


EDF uses virtual reality to model a nuckear reactor
(photo courtesy of EDF and Division).

EDF has built a virtual environment to model the interior of the reactor building. This model includes all the major reactor components, including piping and ductwork, multi-level scaffolding, control points, and even the lifts which move engineers between levels around the reactor itself. Finally, on top of the physical models in the virtual world, a radiation plan is overlaid, giving the radiation dosage received per second in any particular part of the building.

Using this complex model, the maintenance engineer puts on a VR headset, and "enters" the reactor building. Using the control on a 3-D mouse, along with natural human motions, the engineer moves around the virtual building, following the paths and actions proposed for the maintenance activity. While this happens in the virtual world, the system continuously computes the theoretical radiation which would have been received had the engineer performed the actual operation.

With the "virtual radiation dosage" information, operators can plan safer and more efficient procedures. While still experimental, EDF sees substantial value in this approach for the development of operating procedures in a nuclear plant.


Maintenance Operations
Similarly, engineers at the Chalk River Laboratories division of Atomic Energy of Canada Ltd. (AECL) in Chalk River, Ont., Canada, are prototyping VR software to improve maintenance operations of reactors during outages, to minimize radiation exposure to maintenance crews, and as a training/demonstration tool for new plant designs or procedures. The AECL is using the PC-based Superscape VRT software from Superscape Ltd. (Aldermaston, U.K.). The AECL maintains three nuclear reactors throughout Canada, which produce about 20 percent of that nation's electricity.

The AECL is using VR software to simulate outage maintenance activities inside a reactor vacuum structure. Maintenance operators "walk through" the facility, making necessary repairs or upgrades. This not only limits the operators' exposure to radiation during real outages, but also helps speed them through reactor repair or improvement tasks.

"Working with the VR software is proving to be a much more expedient process than what is currently used," explains Peter Lirvall, human factors engineer for the Safety Management and Resource Training Branch of Chalk River Labs. "For instance, when an outage occurs, operators typically study paper engineering drawings to familiarize themselves with the area. For larger maintenance tasks, these drawings can be confusing to find and use, so operators have to build a mock-up of the equipment. This full-scale mock-up allows the operators to practice the maintenance procedure, such as taking a valve apart, prior to entering the reactor facility. With the VR software, the agency can build situation-specific 3-D images off of desktop PCs by importing engineering drawings and borrowing from an object library which includes standard valves, pipes, nuts and bolts."

Lirvall believes that VR can potentially save the nuclear power industry billions of dollars by minimizing downtime on reactors. Among the other benefits he cited are: Operators at the AECL have developed a VR model of a typical reactor control room for training purposes, Lirvall notes. "A virtual control room can be used to offload the control room simulator, lower maintenance costs and provide 24-hour unlimited access," he says. "The interactive instruments in the virtual control room can be used to visualize control room operation's effects on the reactor and field equipment."

New training programs can also be integrated into the virtual control room, he continues. "Cross reference skills, for example, can be improved between layout of control room instrumentation and their layout on engineering drawings by being able to bring up related drawings next to the instrument of concern."

According to Lirvall, the VR software may have the most benefit to AECL engineers and operators in the coming years for a proposed one-month outage of the four reactors at the Darlington facility. This outage typically costs the power plant several hundred thousand dollars in lost revenue each day. It is anticipated that a VR system can significantly shorten the outage duration.

"The idea is to use VR to train the operators before they get into the plant since many have not been in reactor facilities for many years, if ever," Lirvall explains. "The operators can use the VR system to perform their tasks, assess the potential problem areas, and get a good feel for the amount of time that will be necessary for each task."

Engineers have developed a virtual prototype of the 80 x 40 meter reactor structure to demonstrate lighting requirements. Future plans call for a virtual environment connected to a database containing equipment documentation. "Design engineers, operators, maintenance personnel and regulators can use the virtual facility to zoom in on an area of interest, locate the equipment and select it to retrieve all available documentation about the equipment," Lirvall points out. "Equipment can be taken apart by, for example, finding and clicking on nuts and bolts to take a cover off and then explore the function of the components. Such a facility may be made available for an operator to communicate with and instruct maintenance personnel in an efficient manner about the problem at hand. Planners will be able to identify potential complications in performing the tasks and reduce both risks and outage delays."

As far as safety, training on a VR system could help improve crane handling or forklift driving in tight environments. VR training can also help a user deal with collision surfaces in areas that cannot be accessed with a forklift or other larger maintenance tools. Such a system could help plant personnel shorten exposure time by identifying the best access/egress routes for people and equipment, Lirvall notes.

The virtual environment facility may be applied so that radiation fields may be visualized to help the planning of access routes. "Colored clouds surrounding field equipment may visualize radioactive areas and let operators familiarize themselves with the radioactive environment before entering it," Lirvall says. "The operator can then choose an access route and plan task procedures to take advantage of locals areas that are shielded from the radiation source. Alternative placements of radiation shields may be explored depending on the access. A mannequin in the virtual environment that is controlled by an operator's body movements may be used to predict the exposure of radiation when walking through the task."


Decommission, Decontaminate, Dismantle
A United States-based company, TRW of Redondo Beach, Calif., is using VR to decontaminate nuclear facilities. The company has developed a system called CAPS (Characterization Analysis Planning System) that uses VR technology to generate information needed to decommission, decontaminate and dismantle old buildings once used for producing radioactive materials for atomic bombs during the height of the Cold War.

Decontaminating radioactive buildings is a very hazardous process, as the radioactivity levels can be so high that a person can spend no more than 15-20 minutes in the building before receiving a maximum yearly exposure. These old facilities present other dangers, too, such as decaying structures. Many have been shut down, and have no power or lights. One dark site encountered by TRW engineers had a large hole in the floor. In another, the roof had rotted away and the bird droppings in the building were highly toxic. Yet another building was infested with poisonous snakes.


A virtual world simulation by TRW of an actual radioactive site
(photo courtesy of Sense8 Corp.).

Thanks to CAPS, photogrammetry and solid modeling, clean-up personnel now have a way to create a model of the interior of a facility. VR then allows workers to "walk through" that model before they are sent in for the actual clean-up.

TRW's system combines advanced VR features with photography to visualize facility models. First, information is gathered by taking photos using a 35mm hand-held camera, with only minimal measurements taken for scale. This method helps reduce the time spent at the actual site gathering data. If radioactivity is too high for humans, a telerobot can be used to operate the camera.

The photos and other information are loaded into the computer. Using a process called photogrammetry, engineers create a model of as-is conditions. A photogrammetric analysis calculates the camera location and allows the user to obtain 3-D coordinates. 3-D solid models are built directly on top of the photos using TRW-developed software and commercially available CAD and plant design packages. The TRW software automatically adds texturing from the source photos to the models.

Models are then imported into WorldToolKit, a VR software package from Sense8 Corp. (Mill Valley, Calif.) that can accept information from multiple sources and formats. Once a virtual environment is created, engineers "walk through" the site, looking for hazards and planning the actual decontamination process, including determining what types of tools to use. Since the site is computer-generated, radioactivity is of course not a concern, allowing workers to practice the demolition before they ever see the actual site.

"The use of VR can make clean-ups cheaper and faster, and more importantly, safer," says Jim Cracraft, TRW's associate investigator for CAPS. "Virtual walkthroughs mean better preparation, both in terms of planning and actual familiarity with a site, while the phototextures add incredible vibrancy and accuracy to the virtual world."

TRW works closely with its clients to get the correct level of detail and make sure that the end product will be as useful as possible. The idea is to make the process as interactive as the virtual environment.

The future of the nuclear power industry "is dependent on safety and stringent quality control practices in construction and operation," observes AECL's Lirvall. Thanks to the implementation of virtual reality-based systems, the considerable health risks in operating nuclear facilities are being minimized, while performance and efficiency are being enhanced.

David Blanchard is an associate editor of CiME and the editor of two newsletters, Intelligent Systems Report and Intelligent Manufacturing. His E-mail address is:

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