Piping dynamic effects

Dynamic Effects Design must provide for impact (hydraulic shock, etc.), wind (exposed piping), earthquake (see ANSI A58.1), discharge reactions, and vibrations (of piping arrangement and support). 

The examples for experimental validation of the SMB model are based on the extended model (Figure 6.37) that takes into account the fluid dynamic effect of piping, especially recycle lines and other peripheral equipment such as measurement devices. From point of process simulation these are additional elements of the plant that have to be regarded within the overall flow sheet. 

PROTECTION AGAINST DYNAMIC EFFECTS ASSOCIATED WITH THE POSTULATED RUPTURE OF PIPING. ... 

However, to date, it is generally agreed, by both researchers and practitioners that bottle testing is still a good guide (257). The bottle test is static and does not model closely the dynamic effects of water droplets dispersed or coalescing in the actual equipment such as control valves, pipes, inlet delivery, baffles, water wash, ete. If the point of injection of chemicals is upstream of the settler, then the test approximates the situation better. It is, however, still crucial that the characteristies of the emulsion be understood before the treatment system is selected (273, 274). 

II.2.4 Dynamic effects (segregation of systems with internal energy, pipe whip, compartment pressurization)... 

Determination of Rupture Locations and Dynamic Effects Associated with the Postulated Rupture of Piping... 

Are the pipes made from a material which has an oligo-dynamic effect... 

Excessive deformations are almost inevitably observed (with probability tending to 1) when the constructions or buildings are located within the area of old sinkholes. Typical karst manifestations for such sites (due to loads from constructions, vibratory dynamic effects, leakage from water pipes, etc.) are differential foundation settlement, as well as repeated collapses. The resulting deformations quite often lead to significant economic losses. However, in this case probability of social and environmental losses is relatively low (Kutepov et al., 1997 Muljukov et al., 2006). 

Where the LBB approach cannot be applied effectively, a determination of pipe break locations and dynamic effects is made. These are identified in CESSAR-DC, Section 3.6.2. The criteria used to define pipe break and/or crack locations and configurations are given in CESSAR-DC, Section 3.6.2.1. Postulated ruptures are classified as circumferential breaks, longitudinal breaks, leakage cracks, or through wall cracks. Each postulated rupture is considered separately as a single postulated initiating event. 

The GDC S are specifically addressed in Section 3.1 of CESSAR-DC. Items such as pre-operational vibration and dynamic effects testing on piping, seismic qualification testing of... 

The RPV supports and internals are designed for a postulated 0.1 A leak. The application of the break preclusion concept eliminates the local dynamic effects of postulated guillotine pipe breaks in... 

The application of LBB technology eliminates the local dynamic effects of postulated pipe breaks from the design basis. There are 4 piping systems in which the application of LBB is accepted. Those systems are the reactor coolant piping, the pressurizer surge line, the shutdown cooling system, and the safety injection system. 

Expansion, vibration and dynamic effects testing of high-energy piping and components Control rod drive system testing ... 

NRC Standard Review Plan Section 3.6.2. Determination of break locations and dynamic effects associated with postulated rupture of piping, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulations, 1975. 

Equipment loads include dead weight, restrained thermal expansion and dynamic effect such as pressure transients, changes in momentum, water and steam hammer in the equipment and earthquake. They also may include the effect of the restraint of attached piping. The effect of such phenomena must be considered in the design check. 

As well as these static—essentially geometric—effects that produce depletion at the wall, there are also dynamic effects which enhance the phenomenon. The existence of a shear rate and/or a shear rate gradient in the fluid next to the wall (as in a pipe) results in a further movement of particles away from the wall, towards areas of lower shear rates such as the centre of pipes. Solid particles, emulsion droplets and polymer molecules all show this tendency. 

Above the low-speed ductile plateau, data for tough pipe-grade MDPEs show very clearly the predicted -2/3 power dependence on impact speed (Fig. 2). For this materid f D,min about 2.5 kJ m 2. It is very difficult to achieve the speeds needed to observe such a low fracture resistance in this geometry, the results being widely scattered by dynamic effects. This topic will be discussed further below. 

The analyses that have been used by the commercial nuclear power industry, subject to NRC approval on a case by case basis, make use of the LBB concept to justify exclusion of the dynamic effects of postulated pipe rupture. This concept is based on the ability to detect a fluid system leak- and perform an orderly and controlled plant shutdown before any potential exists for catastrophic pipe failures. Thus, the object of applying the LBB concept is to establish that a postulated crack remains stable under normal operating plus faulted loads or that significant margin exists against unstable crack growth if the postulated crack is predicted to grow with the applied loads. 

The design specifications for the RCSASs should identify high energy pipes in which sudden ruptures are postulated to occur and systems that must be protected from the dynamic effects of such ruptures. For more information, see Ref. [6]. 

Volume of vessel (free volume V) Shape of vessel (area and aspect ratio) Type of dust cloud distribution (ISO method/pneumatic-loading method) Dust explosihility characteristics Maximum explosion overpressure P ax Maximum explosion constant K ax Minimum ignition temperature MIT Type of explosion suppressant and its suppression efficiency Type of HRD suppressors number and free volume of HRD suppressors and the outlet diameter and valve opening time Suppressant charge and propelling agent pressure Fittings elbow and/or stub pipe and type of nozzle Type of explosion detector(s) dynamic or threshold pressure, UV or IR radiation, effective system activation overpressure Hardware deployment location of HRD suppressor(s) on vessel... 

Investigate the effect of the pressure surge on adjacent equipment per the 1997 edition of API RP-521. The design pressure of adjacent equipment and piping may be exceeded during a tube rupture. This is of special concern in cooling water networks. Dynamic simulation can assess the impact of a tube rupture on adjacent equipment and identify corrective measures. 

Pressure design of unlisted components and other piping elements to which the rules in para. IP-3.1 do not apply shall be based on calculations consistent with the design criteria of this Code. These calculations shall be substantiated by one or more of the means stated in (a) through (d) below, considering applicable dynamic, thermal, and cyclic effects in paras. IP-2.1.7 through IP-2.1.8, as well as thermal shock. Calculations and documentation showing compliance with (a), (b), (c), or (d), and (e) shall be available for the owner s approval ... 

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