Plant specificity

Centralized processing plants specifically designed to handle regional aquaculture crops are estabUshed in areas where production is sufficiently high. In coastal regions, aquacultured animals are often processed in plants that also service capture fisheries. 

Values are for normal power operation. Conductivity, pH, and concentrations of lithium and boron are plant specific and vary over the fuel cycle according to the control scheme used. See Fig. 3. 

The quantity of boric acid maintained in the reactor coolant is usually plant specific. In general, it ranges from ca 2000 ppm boron or less at the start of a fuel cycle to ca 0 ppm boron at the end. Most plants initially used 12-month fuel cycles, but have been extended to 18- and 24-month fuel cycles, exposing the materials of constmction of the fuel elements to longer operating times. Consequendy concern over corrosion problems has increased. 

The pH is plant specific, depending on additive used and secondary system materials. Feedwater generally should be equivalent to pH = 9.3 at 25°C for ammonia and carbon steel equipment. 

Organics related to use of amines for pH control. Value is plant specific. 

For caustic crevice environment, a plant-specific chemical impurity molar ratio <0.5 is defined, eg, Na Cl molar ratio <0.5. ... 

Corrective action should be initiated when value is > — 0.23 V against the standard hydrogen electrode (SHE). Plant-specific values should be estabUshed for protection of stainless steels and nickel-based critical components. 

Plant specific. In range of 200 ppb without H2 addition and in range of 10 ppb with H2 addition. 

Values depend on plant-specific design and operating procedures for steam plant. 

Reduction and recycling of waste are inevitably site- and plant-specific, but a number of generic approaches and techniques have been used successfully across the United States to reduce many kinds of industrial wastewaters. 

In some instances, plant-specific information relating to frequencies of subevents (e.g., a release from a relief device) can be compared against results derived from the quantitative fault tree analysis, starting with basic component failure rate data. 

Direct-Liquefaction Processes Figure 27-8 presents a simph-fied process flow diagram of a typical direct coal liquefaction plant. Specific processes are described in the following paragraphs. 

The principal applications for furan resins are in chemical plant. Specific uses include the lining of tanks and vats and piping and for alkali-resistant tile cements. The property of moisture resistance is used when paper honeycomb structures are treated with furan resins and subsequently retain a good compression strength even after exposure to damp conditions. 

The PRA procedures guide, NUREG/ CR-23(X), partitions human reliability analysis (HRA) into four phases (Figure 4.5-1). The familiarization phase, evaluates a sequence of events to identify human actions that directly affect critical process components. From plant visits and review, this part of HRA identifies plant-specific factors that affect human performance such as good or bad procedures used in the. sequence under consideration. The familiarization phase notes items overlooked during systems evaluation. 

Human reliability [lata NJUREG/CR-1278 was supplemented by judgment of system analysts and plant personnel. Human error probabilities were developed from NUREG/CR-12 8, human action time windows from system analysis and some recovery limes from analysis of plant specific experience. Data sources were WASH-1400 HEPs,Fullwood and Gilbert assessment ot I S power reactor Bxp., NUREG/ CR -127K. and selected acro ptice li.it.j... 

Avalanche Excluded by siting considerations Flooding Plant specific requires detailed. Mudy... 

Fire Plant specific requires detailed study Pipeline accident Site specific requires detailed study... 

Fog Po.ssiblc cause of plant impact by surface vehicles or aircratc Release of chemicals Plant specific requires detailed stiuJy... 

Of course, such generic data only give an idea of the importance of the problem. Actual plant-specific data must be developed, using plant models. 

The nuclear equipment failure rate database has not changed markedly since the RSS and chemical process data contains information for non-chemical process equipment in a more benign environment. Uncertainty in the database results from the statistical sample, heterogeneity, incompleteness, and unrepresentative environment, operation, and maintenance. Some PSA.s use extensive studies of plant-specific data to augment the generic database by Bayesian methods and others do not. No standard guidance is available for when to use which and the improvement in accuracy that is achieved thereby. Improvements in the database and in the treatment of data requires, uhstaiui.il indu.sinal support but it is expensive. 

Flood Event Frequency Estimates were developed from flooding events in nuclear power plants with adjustments for plant-specific features and data. The data were from the IPE Surry flood analysis, industry sources, and licensing event reports (LERs). Some plant specific models were developed for the circulating water (CW) and service water (SW) lines... 

On August 8, 1985, the U.S. Nuclear Regulatory Commission (NRCf requested the operators of nuclear power plants in the U.S. to perform Individual Plant Examinations (IPE) on their plants. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events (including internal flooding, but excluding internal fire). Generic Letter (GL) 88-20 was issued to implement the IPE request to identify any plant-specific vulnerabilities to severe accidents and report the results to the Commission. ... 

Plant-specific features and modeling assumptions affecting risk, and Use of IPEs for risk-based regulation. 

Transients (other than station hlaekouts and ATWS) Important contributor for most plants because of rcli.fiicc i>n sup wii sy- iems failure of such systems can defeat redundancy in front-line systems. Both plant-specific design IPii mcdeling assumptions contribute to variability in results ... 

The IPE Program, while identifying few plant-specific severe accident vulnerabilities suseeptible to low-cost fixes, served as a catalyst for improving the overall safety of nuclear pow. e.r plants, Furthermore, improvements at one plant may be applicable to another plant,... 

Based on PRAs and information on containment loading, licensees with BWR Mark I containment were requested to install hardened vents (NRC, 1989). All other licensee were requested to consider the need for other potential enhancements on a plant-specific basis as part of their IPE. 

The accident sequence frequencies are quantified by linking the system fault tree models together as indicated by the event trees for the accident sequence and quantified with plant-specific data to estimate initiator frequencies and component/human failure rates. The SETS code solves the fault trees for their minimal cutsets the TEMAC code quantitatively evaluates ihe cm sols and provides best estimates of component/event probabilities and frequencies. 

The extensive operating data allowed the quantification of the core melt frequency with both plant specific data and commercial fire data (NUREG/CR-4586) using Bayesian updating. (NUREG/CR-4586). 

Joksimovich, V, 1984, "A Review of Plant Specific PRA s," Risk Analysis 4 p 255, December. 

The Hawthorne and Davis analysis is first generalised for the [CBT]i open circuit plant, with fuel addition for combustion,/ per unit air flow, changing the working fluid from air in the compressor to gas products in the turbine, as indicated in Fig. 3.11. Real gas effects are present in this open gas turbine plant specific heats and their ratio are functions off and T, and allowance is also made for pressure losses. 

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