Workers at UKAEA are helped to don PPE in a controlled area before work commences, and are also helped to remove it in a designated safe area when work is complete.
The United Kingdom Atomic Energy Authority (UKAEA) is responsible for restoring the Windscale nuclear site, situated on the west coast of Cumbria, to brownfield status. By 2015, UKAEA plans to have all remaining nuclear facilities in a passively safe regime requiring minimal intervention, with all associated buildings demolished to ground level. When looking to improve the safety and protection of protective garments worn in the Post Irradiation Examination Facilities, and demonstrate compliance with stringent EN 1073-2 requirements for protection against radioactive dusts, UKAEA chose to work with DuPont.
Model for reactor decommissioning
In 1981, the Windscale Advanced Gas-cooled Reactor (WAGR) was shut down and all fuel was removed. WAGR is now a demonstration product for reactor decommissioning. The WAGR post irradiation and examination facility houses a suite of concrete shielded caves. The shielded caves, originally built for processing fuel out of the reactor and loading new fuel into it, now contain remaining operational wastes that are being repacked and removed as a precursor to the decommissioning of the caves themselves.
Radioactive materials can be viewed from a safe area (or cave face) through 4ft thick windows, each containing 700 liters of zinc bromide to protect workers from radiation. Engineers in the cave face operate “master-slave manipulators” to move components within the caves for cutting before they are removed for packing and storage. The risk of radiation exposure on the cave face is extremely minimal – in fact, less than would occur naturally, in some cases.
Gary McMinn, Safety Advisor at UKAEA Windscale for the past ten years, explains, “In the Post Irradiation Examination (PIE) facilities, personal protective equipment is worn by health physics surveyors, general decommissioning operatives, engineers, electricians and fitters. Although site workers have always worn protective coveralls, safety shoes, respirators and gloves, the continual monitoring and user feedback indicated that the current equipment was not performing to the new, more stringent standards required. Analysis revealed that donning and doffing procedures and garment design could be improved upon.”
Tailor-made Tyvek® solution
Through working closely with DuPont Personal Protection, a solution to all UKAEA’s protective clothing requirements was found: the DuPont™ Tyvek® 600 Plus with socks and thumb loops was designed. In addition, new dressing and undressing procedures were developed and introduced.
Tyvek® was selected due to its high level of barrier protection in addition to being tough, tear and abrasion resistant and comfortable to wear. It is also non-linting, antistatic, chemical splash resistant up to 0.12 bar, repellent to a range of low concentration inorganic water-based liquids and its smooth surface discourages solid particles from adhering. Tyvek® is made of millions of fine, continuous fibers of high-density polyethylene that are flash-spun and heat-bonded into a breathable fabric.
Site trials of the Tyvek® 600 Plus with thumb loops and socks and the new dressing and undressing procedure commenced at Windscale in November 2004. Feedback soon indicated that the new garments provided a much better fit, and the workers’ confidence and acceptance of the product far exceeded that of the previous equipment used.
Gary adds, “Ongoing feedback from Safety Representatives and users continues to confirm the performance of the Tyvek® 600 Plus with Thumb Loops and Socks. DuPont is still on hand to help resolve technical issues or further modifications we may have, to help with protective clothing solutions for other applications, and to suggest future innovations that help to continually improve people’s protection in the workplace.”
UKAEA operates five sites in the UK dedicated to nuclear plant decommissioning, technology, research and development. Following the success of the new Tyvek® 600 Plus with thumb loops and socks at Windscale, the new garment has been selected as the single use protective suit for all UKAEA sites.
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