Customised tooling and handling equipment to address the most complex challenges Waste processing

Applying proven technologies to deliver innovative solutions

Rolls-Royce has developed a robust and automated system to locate fuel failures in CANDU reactors. To test for evidence of a fuel failure, D2O from the system is selectively channelled past neutron detectors. They record the neutron activity for evidence of compromised fuel bundles.

The Rolls-Royce solution features an automatically-controlled rail-mounted overhead crane, which traverses above a series of dry wells mounted in a large D2O moderator tank. Each well contains two sample coils mounted above one another. Each sample coil receives coolant directly from a specific reactor channel.

In operation the overhead crane makes an automatic sweep above these wells. It stops at pre-determined sample points where it lowers neutron detectors into a designated row of wells. This is to a specific depth, sampling either the upper or lower coil. All radiation data are then sampled and archived for future analysis.

Rolls-Royce capabilities for failed fuel location systems include:

  • Seismic qualification of sample coil assembly and moderator tanks
  • Registration with regulatory authorities
  • Manufacture, assembly and testing of overhead crane, sample coil assemblies, moderator tank, carriage and headers.

Rolls-Royce nuclear waste handling experience ensures the long-term wellbeing of vitrified nuclear waste. In some instances it requires canisters holding this waste to remain in interim hot-cell storage for up to 40 years. As the canisters generate heat, adequate and highly reliable cooling is required to avoid unwanted heat build-up during this time.

Proven Rolls-Royce techniques for meeting this challenge include:

  • an advanced package of heat transfer equipment based on a nuclear-qualified fan cooler supplying 300,000 BTU per hour of heat transfer to 10,000cfm of circulation air
  • using axial-type fans and eight rows of fin tube coils
  • the entire assembly is seismically qualified by Rolls-Royce
  • the fan coolers are designed and fabricated  to an ASME NQA-1 quality standard.

The customer benefits Rolls-Royce brings include:

  • Heat transfer analysis to determine optimum heat-exchange geometry
  • Analysis of the fan cooler air circuit to determine the operating parameters of the fan
  • Layout and packaging of the fan and heat exchanger to meet spatial constraints
  • Static analysis of the fan cooler assembly, including shielding, to verify structural integrity during earthquakes
  • Extensive performance testing.

Safely and efficiently handling irradiated fuel bundles

Few reactor operations demand more careful consideration than handling irradiated fuel bundles within the reactor core. Rolls-Royce nuclear knowledge and experience enable us to provide the industry with ultra-precision equipment such as fuel push rods and insertion tooling.

During a variety of reactor core inspection and maintenance activities, these rods provide a customised tool interface. This is between the delicate fuel bundles and the telescopic rams that traverse the reactor channel, pushing the fuel. The fuel push tool attaches to the hydraulic push ram. It uses a bayonet-style connector while the ram end of the tool is fitted with a ball and socket and swivel-pin joint. This provides deflection capability, allowing the tool to traverse through sagged channels.

The cross-sectional flow area at all points of the tool are equal to or greater than that of a fuel bundle. This ensures the channel’s critical cooling flow is not restricted.

This Rolls-Royce unit with its O-rings is designed to operate in radiation fields of 106 rads. It uses bronze bushes to prevent sliding damage to the channel. All fasteners are locked to ensure no loose parts are released into the reactor system.

Oxidising and distilling highly radioactive waste

Rolls-Royce capabilities in the field of nuclear waste processing include:

  • engineering
  • design
  • fabrication
  • testing of two processes for oxidising and distilling highly radioactive waste salts.

First of these is our pyrochemical electric furnace, which first stabilises waste salts by fully oxidising the material. The salt residue is heated until its contents are molten and then stirred to promote oxidation.

The second technique involves a salt distillation furnace that processes radioactive salts after the pyrochemical process. Its two main chambers are linked by a vapour transfer spool. Salt residue is heated under vacuum in an evaporating chamber and migrates through the vapour into a condensing chamber. The distillation process separates and leaves the oxides behind in the evaporating chamber. Water cooling coils restrict the maximum metal temperature of the exposed surfaces.

Rolls-Royce capabilities include:

  • Helium leak testing
  • ASME NQA-1 required for all design and supply activities
  • Fabrication using inconel 625.

Integrating high-efficiency solid/liquid separation systems

Rolls-Royce nuclear waste handling experience ensures the long-term wellbeing of vitrified nuclear waste.

Rolls-Royce brings unique skills and a wealth of experience in the development of integrated solid/liquid separation (SLS) systems to the nuclear industry.

We employ cross-flow filter technology to remove radioactive solids from a mixed supernatant, using a continuous process of concentration. This is instead of the more conventional once-through filtration process. Our designs feature a back-pulse crud removal system. Also an acid/base chemical injection process to provide effective cleaning of the filters and process equipment over time.

The integrated solution includes two inertial filters, a main circulation pump and filtrate storage tank, back-pulse system, chemical tanks and pipes and all process piping. Complete PLC control, instrumentation and monitoring systems are all fully integrated within the design.

Rolls-Royce SLS systems can be mounted inside a weatherproof enclosure on a single skid that houses all piping and components safely for transport and installation. The skid is complete with significant radiation shielding to protect personnel from exposure to the high activity fields result from process concentration.

Rolls-Royce capabilities include:

  • Process engineering and design
  • Structural and seismic analysis including structural integrity under heavy wind loads
  • Functional and performance testing.