Loss of flow

Oriented strandboard (OSB) resins are quite similar to plywood resins, though they tend to be lower in alkalinity and higher in solids. Sinee OSB resins are sprayed onto dry wood in small discrete droplets rather than applied in glue lines, the problems associated with holding the glue on the wood surfaee are not usually issues of coneem. Adhesive dry-out and loss of flow displace over-penetration as major difficulties. 

Emergency Conditions in Integrated Plants - In integrated plants, a process upset in one unit may have an effect on other units (e.g., loss of flow of a pumparound which is used as a source of heat for reboiling other towers). All possibilities such as these must be carefiiUy considered and the potential for resulting overpressure evaluated. 

The low-power-density, low enrichment reactor core uses soluble boron and burnable poisons for shutdown and fuel bumup reactivity control. Low worth grey rods provide load following. A heavy uranium flywheel extends the pump coastdown to allow for emergency action during loss-of-flow transients. 

Core damage can result most likely from heat imbalance. Figure 6.3-3 is an example from the Indian Point PRA that uses heat imbalance to approach completeness. This diagram shows that cote damage may result from either a loss of cooling or excess power (or both). The direct causes of insufficient heat removal may be loss of flow, makeup water, steam flow, or heat extraction by the turbine. Indirect causes are reactor trip or steam line break inside or outside of containment. Cau.ses of excess power production are rod withdrawal, boron removal, and cold water injection. 

No No Flow Excess ammonia in reactor. Release to work area. 1. Valve A fails closed. 2. Phosphoric acid supply exhausted. 3. Plug in pipe pipe ruptures. Automatic closure of valve B on loss of flow from phosphoric acid supply... 

Group 1 Loss of wet gas flow. This grouping of malfunctions is concerned with events leading to the loss of flow through the compressor which draws off the fractionator overhead vapors. 

Loss of flow of cooling medium to/from the reactor... 

The model constants are the product CR2 and Vmax. Fmax is typically in the 0.7-0.9 range, depending on the type of fabric, and it corresponds to a maximum achievable fiber volume fraction that results in complete loss of flow in the slow-flow direction. 

If this problem—the sudden loss of flow, followed by the premature restoration of flow—occurs repeatedly over a period of a few hours, then layers of fouling deposits or coke are accumulated inside the tubes until a heater shutdown becomes unavoidable. This sort of failure is called a stuttering-feed interruption. 

A single instrument or mechanical failure. Pump failure, loss of flow, instrument malfunction, line rupture or leak, loss of cooling. 

Similar to the energy loss of flow gas in case of sudden changes as discussed in Section 3.4.4, various types of valves and fittings in the CVD vacuum pipehnes also produce a head loss, a so-called minor loss. As hsted in Table 3.6, the head loss (hj) associated with these parts and fittings can be expressed in terms of the head loss coefficient (K)... 

Passive safety features for the MHR include ceramic, coated-particle fuel and an annular graphite core with high heat capacity and low power density. Recently, INL has used the ATHENA thermal hydraulic code to model the response of the MHR during loss-of-flow and loss-of-coolant accidents and has confirmed these passivity safety features work to maintain fuel temperatures well below failure thresholds [8]. 

For upset conditions, indicate autoretrigeration, liquid water, wet sour service, carry-over of crack-inducing agents or corrodents, etc. Consider start-ups, shut-downs, regeneration, presulfiding, loss of flow, etc. 

The facility is equipped with an on-line, timed, weight/volume diversion system that diverts the mainstream into the weighing and volumetric tanks while the content of a reserve tank is dumped into the upper holdup tank. In this way, the sudden loss of flow was compensated for and a constant pump head was maintained. The density of the medium can be monitored to within 1 % and was obtained by combining the flow speed and weight readout. A solid weight... 

McLenachan, J.M., Williams, J.K., Fish, R.D., Ganz, P., and Selwyn, A.P. (1991) Loss of Flow-Mediated Endothelium-Dependent Dilation Occurs Early in the Development of Atherosclerosis, Circulation 84,1273-1278. 

Replacement AHXs (RAHXs) were manufactured to an improved design which avoided the problem of gas locks and afforded greater toleration of loss of flow in individual tubes. The following changes were made and are shown in Figure 7.2. 

E-17 Two loop natural circulation heat rejection from initial three loop operation E-18 Two loop natural circulation E-19 Loss of flow in two sodium loops D. Faulted Events F-1 (Deleted)... 

At the start of this event, the temperature gradients are intitially reduced with the loss of flow and power. The temperatures in the blocks become more uniform, gradually increasing. Once the SCS begins operating, the core temperatures are then gradually reduced to shutdown temperatures. 

Teams can sometimes become tangled up when hazards have effects outside the current node. For example, the team may be discussing Low Level in Tank, T-IOO. The cause of low level in the tank may lie within the node itself a leak through the tank base, for example. However, Low Level is more likely to be caused by loss of flow of RM-12 into the tank, i.e., the cause is Low How in an upstream node. Similarly, deviations in the current node can create hazards in other nodes. Low Level in T-lOO could lead to seal failure of P-101 A, which is in the next node. 

An Intermediate Event is an event that is one that has been designated for further development as the analysis progresses. For example, when developing the fault tree to do with the loss of production just discussed, an intermediate event could be Reactor shuts down. It is likely that, as the tree is developed, this simple phrase will be expanded as various reasons for reactor shutdown are considered. The reasons for reactor shutdown could include loss of feed, loss of flow of heating medium, or instrument malfunction. 

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