Safety, repair

The categorization of components, structures and systems susceptible to ageing should be based on factors such as importance to safety, repairability or replaceability. One example of such categorization of components is as follows ... 

Recordkeeping A certification record must be generated that includes The date The signature of the person who performed the inspection and A serial number, or other identifier, of the equipment that was inspected. Any equipment defects must be reported to his/her supervisor and the use of the equipment must be discontinued until safety repairs have been completed. 

Journal of Bridge Engineering (1084-0702) http //scitation.aip.org/beo/ (accessed September 1, 2010). American Society of Civil Engineers bimonthly. Publishes research about the practice and profession of bridge engineering covers projects, design, construction, inspection, safety, repair, and rehabilitation. 

Breakdown maintenance is suitable for equipment whose failure does not threaten production, safety or the environment, and where the cost of preventing failure would be greater than the consequence of failure. In this case, the equipment would be repaired either on location or in a workshop. Even with this policy, it is assumed that the recommended lubrication and minor servicing is performed, just as with a motor car. 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

The manufacturing cost consists of direct, indirect, distribution, and fixed costs. Direct costs are raw materials, operating labor, production supervision, utihties, suppHes, repair, and maintenance. Typical indirect costs include payroll overhead, quaHty control, storage, royalties, and plant overhead, eg, safety, protection, personnel, services, yard, waste, environmental control, and other plant categories. However, environmental control costs are frequendy set up as a separate account and calculated direcdy. The principal distribution costs are packaging and shipping. Fixed costs, which are insensitive to production level, include depreciation, property taxes, rents, insurance, and, in some cases, interest expense. 

Hazards that could re.sult in major equipment damage and consequently lengthy plant downtime. No redundancy is normally required for these, although redundancy is always an option. Situations that result in minor equipment damage that can be quickly repaired do not generally require a safety interlock however, a process interlock might be appropriate. 

Markov model A mathematical model used in reliabihty analysis. For many safety apphcations, a discrete-state (e.g., working or failed), continuous-time model is used. The failed state may or may not be repairable. 

It is worrying that a vessel which is safe when it enters service may become unsafe by slow crack growth - either by fatigue or by stress corrosion. If the consequences of catastrophic failure are very serious, then additional safety can be gained by designing the vessel so that it will leak before it breaks (like the partly inflated balloon of Chapter 13). Leaks are easy to detect, and a leaking vessel can be taken out of service and repaired. How do we formulate this leak-before-break condition ... 

These considerations are always relevant to water pipelines, which must have a very long service life. With natural gas, oil, and product pipelines, shorter periods are usually assumed for depreciation. Disregarding the fact that in this case cathodic protection is compulsory for safety reasons and protection of the environment, the costs of repairs resulting from wall perforation after a long service life can exceed the costs of cathodic protection. 

The weights for each component shown indicate that this particular accelerator is suited for mounting on a truck or trailer. The distances between each component are employed to ensure the safety of the workers involved in the repair (see Safety Requirements section). 

Equipment that can be reached for inspection, repair, or monitoring from permanent platforms is more likely to be inspected, calibrated, and replaced than equipment that requires climbing with a safety harness or scaffold. 

More inclusive is Table 3.3.1 -3 which is appropriate at depth into the analysis. The major headings in this table address major hazardous subject areas,. iccideni mitigation, protection and repair. I or example, under the first major heading, "Storage of Raw Materials, Products, Intermediates," listed are confinement measures, release nicclumi.sms (valves), procedures for safe operation and limitations that must be observed for safety. 

The aforementioned reviews and assessments were assimilated to characterize the effect of dielectric, rotational, and mechanical hazards on motor performance and operational readiness. Functional indicators were identified that can be monitored to assess motor component deterioration caused by aging or other accidental stressors. The study also includes a preliminary discussion of current standards and guides, maintenance programs, and research activities pertaining to nuclear power plant safety-related electric motors. Included are motor manufacturer recommendations, responses from repair facilities to a questionnaire, in-service inspection data, expert knowledge, USNRC-IE audit reports, and standards and guides published by the Institute of Electrical and Electronics Engineers (IEEE). 

The failure data for these rates is obtained from maintenance work requests supplemented by incidence reports and Licensee Event Reports from the 1975-1980 time period. The work requests provide a complete history of all repairs performed at Oconee. They are not restricted to safety-related systems, they are written during all modes of unit operation, and they are not produced in response to licensing-based criteria. 

The event or series of events diat will inidate an accident has to be identified. An event could be a failure to follow correct safety procedures, improperly repaired equipment, or failure of a safety mechanism. 

If repairs are not performed by the manufacturer, such repairs should be made in accordance with methods or procedures approved by the manufacturer. Minor cracks or defects, which may be removed without influence on safety or operation of the equipment, can be removed by grinding or filing. Following repair, the part should again be inspected by an appropriate method to ensure that the defect has been completely removed. 

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