Offsite estimating

Woods, D. R. et al. have published a series of papers on estimating offsites ... 

Consequence Phase 3 Develop Detailed Quantitative Estimate of the impacts of the Accident Scenarios. Sometimes an accident scenario is not understood enough to make risk-based decisions without having a more quantitative estimation of the effects. Quantitative consequence analysis will vary according to the hazards of interest (e.g., toxic, flammable, or reactive materials), specific accident scenarios (e.g., releases, runaway reactions, fires, or explosions), and consequence type of interest (e.g., onsite impacts, offsite impacts, environmental releases). The general technique is to model release rates/quantities, dispersion of released materials, fires, and explosions, and then estimate the effects of these events on employees, the public, the facility, neighboring facilities, and the environment. 

The following items are usually included in the offsite estimate ... 

Once the battery limits have been summed, the offsite (the difficult part) must be estimated. Since there is so much variation from site to site, and between grassroots plants and construction at existing sites, the use of factors is not recommended. 

Total Offsite Costs. The offsite costs can range from 20% to 50% of the total cost of the project. If a preliminary built-up estimate of the offsites is less than 30% of the total costs, it should be suspect. Unless the offsites are very well defined, it would be better to use a factor of 50% to 75% of battery limits estimate as the offsite figure. 

Utilities are very expensive and highly variable from plant to plant. Great care must be exercised to get the proper steam and electrical loads, not only in the process areas, but also in the offsite areas to make sure the cost estimate for the utilities is complete. 

The cost of utilities is one of the most significant, yet difficult chores encountered in estimating operating costs. As discussed earlier, the amount of utilities required for both the process and the offsite areas must be estimated as accurately as possible. If utilities are generated in the project, the utilities required to operate the utility area must be included. Any increase in the project requires re-estiraating the utilities consumed in the utility area. This can result in a trial and error calculation to get the total cost of utilities. 

Loss of offsite power at nuclear power plants is addressed in EPRI NP-2301, 1982 giving data on the frequency of offsite power loss and subsequent recoveiy at nuclear power plants. Data analysis includes point estimate frequency with confidence limits, assuming a constant rate of occurrence. Recovery time is analyzed with a lognormal distribution for the time to recover. 

The materials leaving containment are source terms for offsite convective-diffusion transport calculations. Codes. such as CRAC-2 calculate atmospheric diffusion with different probabilities of meteorological conditions to estimate the radiological health effects and costs. 

In April 1982, a data workshop was held to evaluate, discuss, and critique data in order to establish a consensus generic data set for the USNRC-RES National Reliability Evaluation Program (NREP). The data set contains component failure rates and probability estimates for loss of coolant accidents, transients, loss of offsite power events, and human errors that could be applied consistently across the nuclear power industry as screening values for initial identification of dominant accident sequences in PRAs. This data set was used in the development of guidance documents for the performance of PRAs. 

Had the new heat exchanger been an addition to an existing plant that did not require investment in electrical services, utilities, offsites, buildings, site preparation or working capital, then the cost would be estimated from ... 

According to the Toxics Release Inventory, in 1996, atotal of 16,938,957 pounds (7,683,382 kg) of lead was released to the environment from 1,494 large processing facilities (TRI96 1998). Table 5-1 lists amounts released from these facilities. In addition, an estimated 47,886 pounds (21,721 kg) were released by manufacturing and processing facilities to publicly owned treatment works (POTWs), and an estimated 350,783,734 pounds (159,112,825 kg) were transferred offsite (TRI96 1998). The TRI data should be used with caution because only certain types of facilities are required to report. This is not an exhaustive list. 

Cadwell, L.L., R.G. Schreckhise, and R.E. Fitzner. 1979. Cesium-137 in coots (Fulica americana) on Hanford waste ponds contribution to population dose and offsite transport estimates. Pages 485-491 in Low-Level Radioactive Waste Management Proceedings of Health Physics Society. Twelfth Midyear Topical Symposium. February 11-15, 1979, Williamsburg, VA. 

Offsite Facilities/Cooling Tower Estimates Made Easy Uchiyama, T. 

Table 8.3 summarizes the actual or estimated prices to build a variety of chemical and refinery process plants. The stated costs do not include associated tankage, utilities, effluent treatment, service roads, general-purpose buildings, spare parts, or all the other components required to complete a major project. These additional offsite facilities are typically considered to add 50% onto the cost of a project. [1, 2]... 

Other utility systems. Other utility systems required in a refinery are electric power distribution, instrument air, drinking water, fire, water, sewers, waste collection, and so forth. Since these are difficult to estimate without detailed drawings, the cost is normally included in the offsite facilities. 

Offsites. Offsites are the facilities required in a refinery that are not included in the costs of major facilities. A typical list of offsites follows. Obviously, the offsite requirements vary widely between different refineries. The values shown here can be considered typical for grassroots refineries when estimated as outlined in this text. 

Special costs. Special costs include land, spare parts, inspection, project management, chemicals, miscellaneous supplies, and office and laboratory furniture. For preliminary estimates, these costs can be estimated as 4% of the cost of the process units, storage, steam systems, cooling water systems, and offsites. Engineering costs and contractor fees are included in the various individual cost items. 

An extensive effort is being made to collect current cost data from the first quarter (June 1976) to 1979. Particular attention has been paid to accurate representation of the effect of different plant locations (land costs, labor productivities, labor costs, construction difficulties, etc.) and date of construction (escalation of the cost of construction material and labor, and installation material and labor, etc.). Also, great care has been given to the proper estimation of the cost of offsites, since they represent a significant fraction of the cost of a new plant, particularly for large coal-conversion plants. 

Operators of facilities that are subject to the EPA s RMP must perform offsite consequence analyses to determine whether accidental releases from their processes could put nearby populations at risk. In performing a consequence analysis it is assumed that all or part of a hazardous substance escapes from a process at a given facility. It is then estimated how far downwind hazardous gas concentrations may extend. 

Facilities that must prepare and submit RMPs must estimate the offsite consequences of accidental releases. This can be done using tables (such as those provided in CAA 112(r) Offsite Consequence Analysis) or a computerized model. There are a number of commercially available computer models. Submitters are expected to choose a tool that is appropriate for their facility. 

These estimates are prepared when the basic process design is essentially complete and the scope of the offsite and waste treatment facilities has been established but not completely defined. Preliminary estimates are normally used to prepare firm project execution plans, to complete the project economics, and, frequently, for appropriation purposes. The Phase 1 design package, described in Chapter 6. contains the necessary information for the preparation of a preliminary estimate. In fact, a thorough Phase 0 package could also be used for this purpose. Appendix L illustrates a preliminary estimate. 

The definitive estimates are prepared after the project has been totally defined, including offsites, waste treatment, site conditions, equipment arrangements, etc. This stage of definition requires the involvement of an engineering contractor to complete the so-called basic engineering referred to in Chapter 12. 

Note of caution When checking estimates, it must be remembered that on sizes 2 1/2 in. and above, the process area pipe is usually prefabricated away from the field and some estimates would show pipe fabricated offsite as material cost. In that case, the cost will include ... 

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