BWR FUEL ASSEMBLY INSPECTION SYSTEM (FAIS)

Improved Performance of Refuel Activities

The FAIS system significantly improves the reliability and performance of various refuel activities, including cell to cell fuel shuffles, fuel loading & off-loading, and core verification.  By improving the reliability and timing of various refuel activities, the FAIS system significantly reduces the overall duration of critical path evolutions, enhances procedural compliance and establishes the opportunity for heightened management overview. 

Identification of Installation Anomalies Prior to Core Placement

The FAIS system is most often associated with core verification and critical path savings, however it is important to note that the FAIS system has frequently identified misoriented and/or out of sequence fuel assemblies as well as double blade guide installation anomalies prior to placement in the core.

 

Remote Control Location Maximizes ALARA Concepts.

The remote location of the control station, in concert with system’s CCTV interface capability and wireless video transmission technology, provides enhanced plant management oversight capability and maximizes ALARA concepts.

The equipment is operated remotely from video control consoles equipped with many diverse features including the capability to video record and/or provide still photographs of all activities for permanent record, as well as to export the video signals to remote monitors.

Fuel Window Optimization

In addition to core verification activities, our Fuel Assembly Inspection System (FAIS) can be (and is during most utility usage) instrumental in critical path savings through "Fuel Window Optimization".  By Fuel Window Optimization, we refer to minimizing the time allotted for in-vessel activities, including actual refueling, that are scheduled and must be completed prior to vessel reassembly.  In our largest customer's fleet, R.O.V. Technologies provides FAIS Refueling Services at twelve (12) BWR Reactors.  With information taken from their refueling history files and data base, our customer’s management has determined that the FAIS system saves an average of six (6) hours critical path time during each core verification / assembly height check / FME search and another Twenty Four (24) hours of critical path in Fuel Window Optimization.
NOTE:  References can be supplied upon request.

Fuel Window Optimization Components:

• Close-up views, provided by the FAIS system, of both the installation and removal of the steam plugs have proven to accelerate tooling connection and installation accuracy.
• Periodic close-up inspection of Steam Plug seating for leak detection.
• Close-up views of Blade Guide moves for process control and accuracy.
• “Real Time” verification of Control Rod full-in positioning (for the control room operators).
• Video support during Control Rod Blade changes.
• Video support during Fuel Cell disassembly / reassembly, i.e. Fuel Support Piece, Rem Tac II Tool, etc.
• Orientation and correct cell verification for the fuel assembly in transition, prior to placement.
• Enhanced refueling operation during poor visibility due to water clarity.  There have been occasions when refueling would have stopped without the camera views.
• FME inspection / recovery.
• Video clearance views of the Steam Dryer and Separator removal and reinstallation.
• Video support for LPRM and SRM replacement.
• Video support for Guide Tube vacuuming.
• Video support for emergent refueling mast inspection / repair.
• Accurate placement of 1000 watts of lighting and video support for planned or emergent in-vessel inspection.

In-Vessel Equipment Consists Of:

Reactor Vessel Flange Stud Mounted Camera Systems (2)

The primary function of the stud cameras is to provide oversight viewing of all activities in the vessel.  The full pan and tilt capability of the high-resolution, color, zoom cameras and independently controlled high power underwater lighting provides clear and concise viewing of all in-vessel refuel, inspection, and tooling activities.

During actual reactor core loading, these cameras, installed on reactor vessel head studs (180º apart), are utilized to verify fuel assembly orientation, insertion and seating.  An electronic character generator is added to provide identification and orientation of each camera and to superimpose an arrow that points to the cell that is to receive the fuel assembly currently in transition.

Each unit is comprised of a sturdy cylindrical mounting platform and a pan, tilt and zoom (PTZ) camera system fabricated from aluminum and then hard black anodized.  The motorized pan and tilt unit is secured to the platform and provides 270º of rotational and 180º of directional viewing adjustment.  Each PTZ features a high resolution, color, 25X-zoom camera supplied with two independently controlled high intensity underwater lights.

The video obtained by the cameras is fed through custom control cables to the remotely located control station and then transmitted by wireless to the refuel bridge monitors to assist with expedient and accurate reactor core refueling.

 

Steam Separator Guide Mounted Robotic Arm Camera Systems (2)

The primary function of the robotic arms is to provide capability for strategic placement of cameras to obtain detailed views of fuel assembly orientation, seating and serial number verification.  The two robotic arm units are lowered into the vessel after “flood-up” and mounted 180º apart in the existing steam separator guide pin holes (resting on the shroud flange or the steam dam depending upon vessel design).

Each arm is comprised of two reducing contour struts fabricated from rectangular aluminum tubing, tested for watertight integrity and then hard black anodized.  The strut base is a pin located turret that provides 200º of rotational motion and 90º of vertical rise for the arms.  A motorized tilt fixture joins the two struts and provides 180º more freedom.

 

The camera end can be extended to cover over three quarters of the vessel during core verification, blade cycling, IVVI and other in-vessel activities requiring close, steady and accurate viewing.  The camera’s tilt angle can be adjusted to an additional 315º and provides high resolution, 25X-zoom, color pictures.

 

Lighting is provided by two independently controlled, high intensity underwater lights.

The video data stream, lighting and motor power/control signals are transmitted through a custom under water control cable with individual removable waterproof connectors for each component.  The views for these cameras are transmitted to the Refuel Bridge via the wireless system to two plasma screen monitors, with zoom capability.

A Mobile Submersible Unit Can Be Utilized For Spent Fuel Pool Inspections.

The R.O.V. Technologies, Inc. Submersible is used to audit proper locations of spent and/or new fuel assemblies within the spent fuel pool.  These spent fuel pool inspections are usually scheduled after the first fuel shuffle and again upon completion of fuel moves.

"Submersible" Utilizing the submersible reduces traffic on the refuel bridge and frees it to perform other tasks.  The verifications are monitored and recorded using on-board, high resolution radiation tolerant cameras and independently controlled high power underwater lighting with all controls operated from a remote location.  In addition, FME, which may be discovered while auditing, can be retrieved with an on-board robotic manipulator and placed safely in a receptacle.

Remote Control Station

The remote Operator’s Control Station, generally housed in a “clean area” Kelly Building or other suitable structure, consists of the system control consoles, related monitors and video recording/processing components required to operate each robotic camera system.

To maximize the effectiveness of the FAIS system, a video switching console provides video and audio signals to the floor managers desk and the refuel bridge, providing refueling personnel and the refuel floor manager with switchable camera signals from all four cameras to any suitable monitor, as well as a “push to talk” communications system linked to the refuel bridge and R.O.V. technicians.

The refuel bridge is provided with 2 high definition, 37-inch plasma monitors mounted on adjustable rail brackets and a communication center.  On the bridge, both the monitors and the communications are fed via wireless signals.  The communications system is designed such that listening capability is continuous at all centers, however a “talk” button must be depressed in order to transmit speech from any center.  Video transmission to additional locations such as the OCC or RP can be arranged.

Additional Benefits of the FAIS System:

Continue Working Despite Poor Water Clarity

Once the equipment is installed in the vessel, there are often requests from refueling supervisors for camera views of emergent issues.  Also, the FAIS system has, in the past, proven invaluable for providing uninterrupted views that allowed refueling to continue while non-refueling work in progress caused surface viewing problems eg: divers working in related areas, IVVI equipment, CRD or other system venting or simply water clarity (see Fuel Window Optimization, above).

Leaves the Refuel Bridge Clear

It should be noted that operating the robotic systems described above do not require the use of the refuel bridge other than for initial installation and subsequent removal.  The time for core verification and fuel pool audits normally assigned as refuel bridge activities, therefore, may be used for other scheduled activities eg: steam dryer and separator preparations, IVVI , etc.

Reduces Overall Critical Path

R.O.V.’s involvement in preliminary outage scheduling activities with our customers has allowed us to assist in reducing critical path by several hours and, in some cases, days from overall outage schedules.  Many of our customers are managing less than 15 day outage durations.