Reactor refueling system

Besides it was required to develop and modify core components (fuel sub-assemblies, control rod guide tubes and control rods), to explore and modify electrical drives of sodium pumps, to modify a reactor refuelling system, to construct advanced failed fuel detection systems, to design and construct advanced reactor vessel integrity inspection systems, reactor vessel and auxiliary primary sodium pipeline displacement measurement systems, to remarkably improve water-sodium reaction detection systems of the water-sodium steam... 

Operating Experience from Reactor Refuelling System... 

The FFTF refueling system (Cabell, 1980 FFTF, 1983) includes facilities for the receipt, conditioning, storage, installation in and removal from the core of all core components (driver fuel assemblies, control assemblies) and test assemblies that are routinely removable. The reactor refueling system handled three types of core assemblies 12-ft assemblies such as driver fuel 40-ft assemblies such as fuels open test assemblies and 40-ft assemblies such as materials open test assemblies. 

CRBRP, 1983, Clinch River Breeder Reactor Plant System Design Description, Reactor Refueling System, SDD-41, Rev. 27, July. 

FFTF, 1983, Fast Flux Test Facility System Design Description, No. 41, Part P. Reactor Refueling System, Rev. 11, April 6. 

Reactor refueling systems. A series of systems associated with the reactor and reactor vessel are required for refueling. Outside the reactor vessel these include three fuel transfer ports, eight test position spool pieces, two floor valve ad ters and the test transfer port, and the reactor containment building cranes. Inside the reactor vessel are three in-vessel handling machines (IVHMs) and three invessel storage modules. Three IVHMs are required because of the mission of the FFTF that requires closed test loops in the reactor core which interfere with direct access to die entire core with one machine. 

The reactor refueling system (RRS) provides the means of receiving, storing, transporting, and handling reactor core assemblies. Fuel, control, shield, reflector, and ultimate shutdown assemblies are handled by the RRS for all core configuration operations. 

FAILSAFE OPERATION OF A PES IN A LIQUID METAL FAST BREEDER REACTOR REFUELLING SYSTEM... 

Reactor vessel height / diameter Primary coolant systems Primary coolant sodium mass Inlet / outlet reactor temperature Primary coolant flow rate Primary coolant flow velocity Secondary coolant systems Secondary coolant sodium mass Inlet / outlet IHX temperature Secondary coolant flow rate Secondary coolant flow velocity Water - steam systems Feed water flow rate Steam temperature (turbine inlet) Steam pressure (turbine inlet) Type of steam generator Refueling system... 

As it is mentioned above 36 reactor reloads have been carried out since the power unit has been put into operation. In general the refuelling system performance during this period of time was sufficiently reliable - in fact no failures which would have caused the delay of making the reactor critical occurred. It is the refuelling system mechanism position indication and control system that has mostly been a trouble contributor. As far as the mechanical part is concerned the following operating results can be noted ... 

The design of the reactor, including its control, coolant, and refueling systems, shall be such as to limit all possible sources of reactivity addition to a magnitude of the order of that required to bring the reactor to its hot operating condition. 

On-power refuelling provides the principal means for controlling reactivity in the CANDU 3. Additional reactivity control, independent of the safety system, is achieved through use of reactivity control mechanisms. These include absorber rods, mechanical zone control units, and adjuster rods all are located between fuel channels within the low pressure heavy water moderator and do not penetrate the heat transport system pressure boundary. The overall reactor control system is described in Section 5.8.2.3. 

The reactor building is an embedded structure of high seismic class. It contains the reactor, secondary system, steam generator, coast down control system, power switch board and refueling pits as shown in Fig. 2. The dimensions of the building are 26mxl6m,... 

A specific feature of the VKR-MT is the refuelling that is performed without opening the reactor vessel cover. Such refuelling is due to a pebble bed arrangement of micro fuel elements in the reactor core. A principal scheme of the refuelling system is shown in Fig. X-13. 

The refuelling is assumed to be performed in a shut down reactor at atmospheric pressure. However, the refuelling system makes it possible to discharge a specified amount of the micro fuel elements even when the reactor operates at low power level. 

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