Remote maintenance

The American faciUties also differed fundamentally from the British faciUties in regard to maintenance philosophy. The American plants were designed to employ remote maintenance, ie, to remove and replace equipment using shielded cranes operating inside the shielded stmcture. The British developed a contact approach based on simplified designs for equipment downstream of the fission product removal step. The British approach has been used at all commercial faciUties. 

High-level waste reprocessing is the most hazardous operation in the nuclear industry. It is there that the largest quantities of fissionable and radioactive nuclides are handled in aqueous solution. These large-scale operations require both remote control and remote maintenance of the plant to protect the workers from radiation. In addition, the air and water effluents along with the solid refuse must be closely monitored to assure that the public is protected. Finally, the fissionable material requires strict accountability to ensure that it is not diverted to unauthorized uses. 

Although promising data have been acquired for the fluoride volatility process, the technical feasibility has not been demonstrated yet. Aside from chemical problems, many technological problems such as process stability due to powder handling and remote maintenance, are still remained unsolved. In order to solve these problems, head-end process studies as voloxidation have been started. Here, stress is put on the environmental protection of... 

FIG. 21.14. Principle of a reprocessing plant with remote maintenance. 1, canyon with process equipment 2, control room 3, feed preparations 4, feed input 5, cranes 6, piping 7, analytical section. 

In the event of failure of equipment within a radioactive area, three courses of action may be taken (i) switching to duplicate equipment, (ii) replacing or repairing equipment by remote methods remote maintenance, or (iii) repairing by direct maintenance after decontamination. 

Plants were originally constructed for either completely remote maintenance or conq)letely direct maint ance. Figure 21.14 illustrates the principle of a plant for remote maintenance. All equipment is installed in a large canyon with piping in a parallel corridor. The equipment can be replaced by an overhead crane operated from a shielded room ... 

Remote maintenance is more expensive, but may be safer for the personnel and desirable from the standpoint of continuity of operations because equipmrat replacemmts can be carried out quickly and interruption of operation is relatively brief. Modem robot technology simplifies such remote maintenance. 

The principal advantage of remote maintenance is positive and safe repair scheduling. It has several serious disadvantages (1) design is... 

Fig. 10-14. Plan of a remote-maintenance fuel reprocessing plant. Shielded crane with operator runs above the process equipment cells to perform remote maintenance, Courtesy of W. Harty, Chem. Eng. Progr. Symposium Ser. 50, p. 118, 1954.)...

The equipment used in radiochemical plants is, for the most part, similar to that found in other industrial chemical plants. The equipment should be selected for minimum holdup, thus reducing shielding requirements and criticality hazards. For example, thin film evaporators, operating continuously, should be selected instead of pot-type vessels. The method of coupling equipment together and the remote control and handling features of equipment design may be quite different, especially for the remote-maintenance type of plant. 

Remote-maintenance plants will have a capitalized cost about 50 per cent higher than that shown for the direct-maintenance plant. Pyro-metallurgical or fractional-distillation types of plants are in the low range of the costs estimated for direct-maintenance plants. 

Fig. 5.7 Indesit company TO-BE BUG diagrams for the remote maintenance service (level 1)...

To establish remote maintenance concept with rack system, key technologies such as bilateral servo manipulator (BSM), roll-in type rack, remote connector bank, and remote sampling system have been developed. 

Fusion reactor Remote Maintenance Study, EPRI ER-1046, Final Report, April 1979... 

Operation and maintenance (O M) costs of the MSR could be almost the same or less than those of the LWR according to the publications, although the MSR would need remote maintenance because molten fuel salt of high radioactivity circulates outside the reactor vessel. However, the MSR can operate longer than the LWR and save the downtime. 

Remote maintenance The primary fuel salt system has high radioactivity and requires fully remote operation and maintenance. The technologies need to be developed, making use of the recent significant progress in the robotics applicable under high temperatures and radiation conditions. 

Reactor design Reactor mock-up Reactor remote maintenance Reactor construction and operation... 

Approaches such as this are indirect behaviour modification and can be effective where there is extensive employee participation with feedback provided on progress made. Communicahon is critical to success. The objective is to address and influence the behaviour of ffie remote maintenance worker so that he can deal wdth the hazard at ffie time when it becomes a serious risk. 

No remote maintenance software. Especially VNC, NetBus, PCAnywhere, and the like. 

The first generation of security architecture has to evolve in order to deal with new services for airlines such as remote maintenance or paper-less cockpit. An important goal for the design of new security architectures is to keep the costs of their implementation and assessment of security architecture as low as acceptable. 

Today, intelligent technical systems in industrial and consumer domains are often used to increase comfort, efficiency and safety of such systems. Applied technical components are called ubiquitous and/or embedded systems [21]. The composition of real time systems known from industrial domains with standard information technologies (IT) known from conventional office domains of organisations results in heterogeneous technical environments. Examples can be seen in systems for industrial process automation. Motivated by the need of higher efficiency, standard IT network components and/or protocols like Ethernet or TCP/IP are applied frequently [19]. One example of this is the remote maintenance of industrial field components over the Internet. Formerly, these systems are designed to be closed and separated from other external systems, providing... 

Level 1. No network data flow of any kind. Strict outward communications only, which excludes handshake protocols such as TCP/IP. No remote maintenance access. Physical access strictly controlled. All data entry is approved and verified. Level 2. Outward one-way network data flow from level 2 to level 3 systems only. Remote maintenance access may be allowed on a case-by-case basis for limited time only. Physical connections must be strictly controlled. 

Level 3 Outward one-way network data flow from level 2 to level 3 systems only. Remote maintenance access may be allowed on a case-by-case basis for limited time only. Physical connections must be strictly controlled. 

Level 4. Only approved users are allowed. Access to the internet from level 4 systems may be given to users if adequate protective measures are employed. Security gateways are implemented. Physical connections are controlled. Remote maintenance is allowed and controlled. System functions available to users are controlled by access control mechanisms. Remote external access is allowed for approved users. Level 5. Only approved users can make modifications to the systems. Internet access is allowed subject to protective measures. Remote external access is allowed subject to protective measures. 

One of the early DOE objectives for the CFRP was to develop advanced technology which would substantially increase the overall availability (on-line time) of reprocessing fadlities. Increased availability would allow annual throughout criteria to be met with smaller, less costly, hot-cell facilities and processes. This led to development of new technologies for remote operations, remote maintenance systems, remotely operable and maintainable in-cell equipment, in-cell equipment reliability, space-efficient in-cell equipment arrangements, hotcell layouts, and facility layouts. 

Kakudate, S., and K. Shibanuma. Rail Deployment and Storage Procedure and Test for ITER Blanket Remote Maintenance. Fusion Engineering and Design 65, no. 1 (2003) 133-140. 

E.rternal circulation of fuel solution. Removal of the heat from the reactor core by circulating fuel solution, rather than coolant only, through external heat exchangers increases the total amount of fuel in the system and greatly complicates the problems of containment of radioactivity and accountability of fissionable material. The release of delayed neutrons in the fuel solution outside of the reactor core reduces the neutron economy of the reactor and causes induced radioactiviti in the external equipment, resulting in the need for remote maintenance. 

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