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UESI is the premier global provider of underwater services to both the commercial and government nuclear industry. We understand that owners and operators expect service providers to aid in achieving goals, maintaining and improving safety, minimizing cost, and facilitating regulatory interaction. As the first commercial diving company to specialize in services to nuclear plants, UESI has set a standard for safety, reliability and cost effectiveness which the industry has come to expect.
UESI maintains a quality assurance program that meets the requirements of 10 CFR 50 Appendix B, N-QA1, ANSI N45.2. UESI is a participating member of the Nuclear Industry Assessment Committee (NIAC) audit program which is similar to the joint audit program operated by utilities through the Nuclear Procurement Issues Committee (NUPIC). We are also audited periodically by NUPIC. Safety related programs for inspection and maintenance meet applicable industry codes and standards as set forth by ASME, ASTM, ANSI, and other industry organizations.
Decommissioning is essentially a two-part process for dealing with the surplus nuclear facilities: deactivation to stabilize each facility and reduce its maintenance costs, and decommissioning when technically and financially appropriate. Facilities that will eventually require deactivation and decommissioning (DandD) include the following: production reactors, research reactors, chemical processing buildings, uranium, plutonium, and tritium production facilities, and gaseous diffusion plants. Divers potentially figure into both strategies.

Diver support for decommissioning work provides many benefits. Both government operated and commercial facilities in DandD process are committed to adhering to the ALARA (as low as reasonably achievable) principle for radiation exposure to workers while at the same time minimizing the cost of a DandD project.” This is essentially the same principal that guides the work at commercial nuclear power plants. Because water serves as an excellent radiation shield, diving has long been recognized by commercial plants as a valuable component of an ALARA program. Commercial plants also recognized that divers are frequently able to perform work at a fraction of the cost and schedule required to design and build remote tools. In addition, the protective equipment worn by divers isolates them from other possible hazards such as asbestos, lead, and certain toxic chemicals. The ability of divers to operate safely in all sorts of hazardous environments is well documented.

UESI’s extensive experience in commercial nuclear power plants and our experience with DandD suggest that the two efforts share common problems and likewise would benefit from the use of our divers for similar reasons. Working within the water shield, divers can approach highly radioactive materials while receiving minimal exposure. At close range, sometimes within arms-reach, divers can perform tasks safely, quickly, and accurately. These tasks are often difficult or impossible to perform using surface workers with long handled tools or complex, expensive remote tooling. UESI divers have a number of cost-effective underwater tools at their disposal. These include underwater video for project documentation, high-efficiency vacuum systems for desludging, and plasma arc cutting systems for rapid segmentation of bulky equipment.

The following summary of a recent DandD project at a DOE facility demonstrates the effectiveness of using UESI divers. These results are consistent with our experience at commercial nuclear plants.

Over 300 dives were performed with no skin contaminations. Radiological conditions were extreme with contact dose rates in the sludge ranging from 0.050 Rem/hr. to 30 Rem/hr. and averaging about 2 Rem/hr. Divers encountered debris with dose rates of up to 600 Rem/hr. on contact. To put this in perspective, high radiation is considered to be a dose rate exceeding 0.100 Rem/hr. An actual whole-body exposure of 400 to 600 Rem can result in acute radiation poisoning causing death within 30 days.

Taking advantage of the shielding provided by the water and other dose mitigation techniques, we were able to keep the diver in a 0.001 to 0.005 Rem/hour field during the majority of the work. Even though brief excursions into high dose areas were necessary, an average exposure rate of 0.006 Rem/hour was maintained for the entire dive team for the course of the project. This includes Divers, Tenders, and support personnel. Divers typically averaged 0.003 Rem/hour during diving operations keeping total exposure well below expected levels.

Over 10,000 pounds of basin debris was managed and relocated. Divers operated a desludging system to collect approximately 1,500 ft3 of sludge in a fraction of the planned task duration. Overall, it was successfully demonstrated that, on a task by task basis, divers could work more efficiently while receiving significantly less radiation exposure than topside workers using remote tools or extension poles. Much of the work performed underwater would not have been possible without the shielding afforded by the water barrier and direct access by the divers.
Please visit our service pages for an overview of UESI’s capabilities. If you have questions, one of our professional engineers, subject matter experts, or technical specialists will be happy to discuss your maintenance issue or project needs to assist in developing an effective approach.