Nuclear diving demands unwavering safety measures. Every action, from meticulous planning to employing advanced technology, prioritizes the divers' well-being. While water offers a natural shield against radiation, divers operate in a realm where the invisible poses the greatest threat. Dive deeper with us as we answer questions about the intricacies of nuclear diving, where safety protocols are paramount both in and outside the water.
What is nuclear diving?
Nuclear diving involves performing dives in radiologically contaminated water and areas of nuclear power plants. Similar in concept to other contaminated diving (biological, chemical, or industrial), the key difference is that the hazards encountered during nuclear dives are invisible and only detectable by specialized radiation measurement tools.
Why perform nuclear dives?
Water acts as an excellent natural shield from radiation. This is the primary reason why nuclear dives are performed. Divers can perform tasks underwater with minimal radiation exposure compared to the exceedingly high doses workers would face in a dry environment.
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Nelosca's nuclear-trained commercial diver gives a thumbs up once fully suited.
Why is nuclear diving essential?
Nelosca offers nuclear diving as a specialized capability to support our nuclear clients' needs fully. Beyond performing dives in radiologically contaminated environments, we are actively developing programs to expand our qualifications for diving on safety-related systems within nuclear plants. These services include inspections, welding, and coating repairs.
Nuclear diving projects present unique technical challenges due to the strict adherence to federal codes and site procedures. Additionally, they require intense staffing support, often involving large crews working around the clock to meet the tight project schedules during refueling outages.
Types of work we perform during nuclear dives:
- Underwater VT-1 and VT-3 Surface and Component Visual Examinations
- 10 CFR 50 Nuclear Quality Assurance (NQA1 Program) Appendix B
- Condensate Storage Tank Inspection and Repair
- Fuel Transfer System Maintenance and Repairs
- Coating Application
- Reactor Component Repairs
- Valve and Seal Inspection, Repairs, and Complete Replacement
Who is involved in nuclear dives?
Nuclear power plant operations rely on dedicated radiation protection (RP) technicians whose primary responsibility is safeguarding workers from radiation and contamination exposure. These technicians perform work area surveys, monitor contaminated tools and equipment, and implement measures to minimize worker exposure to radioactive sources and contamination.
While workers can monitor their own radiation exposure through electronic dosimeters during regular tasks, RP support is crucial for remotely monitoring divers underwater as they cannot access these sensors within their suits.
Nelosca's nuclear diver is sprayed with demineralized water as he enters the water.
A designated team of RP technicians supports monitoring the diver and any equipment entering and exiting the water. The RP supervisor collaborates with the dive supervisor to communicate the diver's location, dose fields in the work area, and work area survey information. Divers themselves must conduct surveys as RP personnel cannot access the work area directly.
Another RP technician is stationed with the dive tender to monitor equipment like the dive umbilical, tools, and the diver entering and exiting the water. This technician checks for the presence of hot particles or radioactive sources emerging from the water, assessing the potential for exposing support workers to high radiation doses or contamination.
How do nuclear diving safety measures differ?
Nuclear diving safety precautions are similar to those employed in other contaminated diving scenarios, utilizing familiar equipment and techniques. Dry suits with mated helmets and gloves are used to keep the diver completely isolated from contamination. A key difference lies in the requirement for divers to wear internal suit sensors to measure radiation exposure during dives. Additionally, dive tenders working in the contaminated area wear dose-monitoring equipment and protective clothing.
Even small movements underwater can significantly impact the diver's radiation exposure. When working near spent fuel or other high-radiation sources, divers may be positioned very close but still be in a low-dose field. While the water provides substantial shielding, minimizing the immediate dose received, even slight movements closer to the source can lead to overexposure, triggering dose rate alarms and necessitating retreat or complete dive termination.
Nelosca nuclear diver is performing an initial leak check upon entry.
Is nuclear diving worth the risk?
Despite the inherent risks associated with nuclear diving, the primary justification for its continued practice lies in the significant reduction of radiation exposure for workers. In many situations, performing tasks underwater reduces both cost and project duration. Ultimately, divers can access areas that are simply not radiologically safe when drained and decontaminated for dry-land work.
While conceptually similar to other forms of contaminated diving, nuclear diving presents unique challenges due to the invisible nature of radiological hazards. Safety precautions necessitate specialized equipment and techniques, including the use of in-suit radiation exposure sensors.
Despite the inherent risks, nuclear diving plays a vital role in minimizing worker radiation exposure and enabling the underwater execution of critical tasks, ultimately supporting the needs of nuclear clients and facilitating complex marine industry projects.
About Nelosca Technologies
Nelosca Technologies, Inc. (Nelosca) is a fourth-generation, family-owned marine construction firm specializing in environmental remediation, dam construction, commercial dive, harbor management, and submarine cable services. Working closely with public and private owners of water-based infrastructure since 1919, Nelosca operates nationwide throughout coastal and inland waterways.
