Shutdown definition

The number and severity of failures experienced by the equipment under study must be related to the operations of the facility. It would be inappropriate to assign the same operating histories to a continuously operating system and a system that operates intermittently. The number of hours in different operating modes (for example, 100% production versus shutdown) affect failure rate calculation and service description for taxonomy definition. 

The torque requirements of the driven equipment determine the torque specifications of the motor from initial start to shutdown. NEMA definitions are adapted as follows ... 

Develop timetable for shutdown The management team should establish a macro-level schedule for the outage. Without complete planning, a definitive timeline can not be established, but the team should establish specific milestones that must be met. 

The first phase is a clear definition of the scope of work that is to be performed during the shutdown or maintenance outage. This definition must be more than a macro-level listing of the major tasks that are to be performed. Instead, each of these major or macro-level tasks must be fully defined. The purpose of this procedure is to provide an effective method of planning, material control, and follow-up of repetitive, non-repetitive, and capital shutdown work. 

An understanding of basic definitions about safety and toxicity is crucial. First, all compounds, no matter how salutary, can be ingested in some manner or in some quantity that will cause toxicity. Toxicity is the capacity of a substance to produce some adverse effect or harm. Even essential components such as water and vitamins can be consumed at toxic levels. Too much pure water can cause renal shutdown excessive vitamins can cause minor problems such as flushing or nausea or major problems such as liver damage, teratogenicity, and death. The 1538 Paracelsus motto, Only the dose makes the poison, operates for food components (Jones, 1992). 

The quantity of work to be done must be defined by the appropriate time period, which could be by as little as a 15-minute interval for cashiers and as long as a day for paper mills. For continuous process industries, such as chemical plants and some mining processes, the definition of what is needed is relatively easy to determine. Even so, the work must be defined by the hour and day of the year to allow for maintenance and shutdowns for holidays. There are many other industries that also have a well-known stable demand for work profile—for example, prisons, long-term health care facilities, and many manufacturing systems, such as assembly lines. At the other end of the scale are situations such as retad outlets and telephone operators, that have a demand that varies constantly during the day, and from day to day, and from season to season. Many of the organizations with such a fluctuating demand pattern have a detailed data bank of historic data, usually by the 15-minute interval. These data can be used to predict the work requirements for future time periods. 

Between the start of fuel loading in July 1985 and the start of definitive shutdown operations in July 1998, the Superphenix reactor which powers the Creys-Malville NPP has been effected by 101 anomalies and incidents. These events are analysed based on different characteristic criteria. In particular, we noted ... 

We will not discuss here cases pertinent to startup or shutdown of typically continuous dryers but concentrate on three common cases of batch dryers. In batch drying the definition of drying rate, i.e.,... 

For the purposes of this assessment, the emergency is determined to be complete when energy input has been removed from the process unit, major equipment has been secured from damage, and the environment is protected from an uncontrolled hazardous release. The process unit may not be totally secure at this point however, it is considered safe. In some cases, this definition may reduce the primary emergency shutdown requirements. 

The first definitive shutdown decree was published on 30 December 1998 [29]. This decree authorizes the following operations ... 

After the declaration to the French National Assembly on 19 June 1997, of the decision to finally shut down the Creys power plant, and after 6 months of alternating hopes and disappointments as to a possible restart in order to complete the use of the 1st core, and perhaps even the 2" core, the first structured strategic reflection for definitive shutdown began in February 1998. One of the main aims of this reflection was to prove the technical feasibility of this dismantling based on the assumption of reasonable costs and time limits. In this context of technical doubt, fuelled by the media, a very determined attitude had to be adopted. 

The decree of the 31 December 1998 finalized the immediate and definitive shutdown of Creys nuclear power station and authorized unloading of the fuel. It also covers sodium removal and storage operations and the dismantling of the non-nuclear installations within the framework of a safety report and general rules for monitoring and maintenance approved by the DSIN (French Nuclear Installations Safety Authority). 

Generally speaking, all these improvements lead to a significant reduction in the overall risk of core meltdown in cold shutdown conditions, and to uniform accident sequences and relatively moderate impact on long term accident phases. Specifically, the design of automatic makeup adequately reduces shutdown mode risks (aim of risk reduction linked to short term sequences achieved), and other preventive hardware improvements have proved to be adequate. However, discussions are currently taking place with the French safety authorities to definitively conclude this issue. 

The definition tells us that a SIS may be responsible for shutdown functions, permissive functions, and even consequence reduction (mitigation) functions. AU these functions have a common attribute — they aU reduce risk. One common interpretation of a SIS definition is, therefore, "automatic risk reduction systems." In some cases the function is designed to reduce risk by decreasing the likelihood of a potential hazard. In some cases the function will decrease risk by reducing the magnitude of the consequence. 

Definition of safety functions required to achieve and maintain a controlled or safe shutdown state. 

For the social criteria, two methods are applied in this study. A more detailed safety-related discussion of the bioethanol process can be found in the open Hterature [45]. In the first method, safety during operation, operability of the plant, safe startup and shutdown, and location-specific demands are selected as four soft indicators for sustainability assessment. The evaluation and justification of each indicator are provided in Table 6.13, where standard definition and scaling system can be found in Othman et al. [1]. In this approach, the process with the higher score is more desirable. Again the dry grind process is found to be superior. 

An operations manager extends a unit shutdown to await definitive evidence that a thin-walled vessel is safe to operate. ... 

Confirmation of current integrity status and definition of the probability and consequence of failure are essential plant management requirements. The following sections of this chapter deal with the approaches that can be made, both during the production period and at shutdown by utilising plant assessment technology to provide this information. Previous reviews (Brear, 1997 Brear and Townsend, 1997) have detailed the individual assessment techniques and the overall phased approach to component life assessment. 

The cause and effect method (see API RP 14C guideline) is one of the easier, proven, and extremely effective ways for the description of safety functions and shutdown conditions. No special programming knowledge is required for this. So, process specialists can also directly define their requirements. The causes are defined in the rows and probable effects are shown in columns. The linking of several causes and the definition of the relationship between causes and effects is carried out at the intersections of the rows and columns. 

A partial proof testing strategy requires the definition of two or more proof test intervals, as shown in Fig. X/2.2.2-1 [10,23]. Normally, this is defined as a more frequent partial test followed by a less frequent full test (typically to fit in with normal plant shutdown periods). 

Evaluation criteria The criteria based on which evaluation is to be carried out are defined at the beginning as part of problem definition. The criteria normally cover the total cost, system performance, and effectiveness. The system performance characteristics (like availability, maintainability, and SIL of shutdown, etc.) and the effectiveness (like production capacity, product quality, etc.) shall be covered. In many cases regulation, codes, and standards specification play a great role at this point. 

Because of the fire in a main turbogenerator in October 1989, the Spanish Ministry of Industry ordered the definitive shutdown of Vandellos 1 NPP. 

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