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Weld leaks

Before the start of the operational testing of JACADS, the Senate Committee on Governmental Affairs received an allegation that JACADS air filtration system did not meet industry standards. The air filtration system was one of the last systems the contractors had to test and accept before the plant could go operational. Initially the filter system could not pass the test because of welding leaks, inadequate filter clamps, and gaps in the charcoal trays. The operations and maintenance contractor and the air filtration contractor corrected these problems, and the system has performed according to the Army s specifications with no breakdowns affecting destruction rates. The air filtration contractor has also won the contract to provide similar systems for the follow-on facilities in the continental United States. [Pg.50]

The tube-to-tubeplate weld leaks in the PFR evaporators necessitated the development of a repair method by fitting sleeves to bypass defective welds 3000 sleeves were installed in each end of the 500 tubes of each of the three evaporators. The success of the method was demonstrated by the fact that no further leaks have occurred. [Pg.3]

The BR-5/10 reactor pump level indicators sensors are made of stainless steel tube 20 mm in diameter and with wall thickness of 0.2 mm. They are divided into sections to which current collectors are welded. Leaks took place through cracks formed in joint welds of these sections. After improving the joint welding technology of current collectors there were no cases of level indicating sensors. On the rest of the reactors the level indicators of other design are used. No leaks due to such cause occurred. [Pg.121]

Corrosion problems on process units often first show up as weld leaks. More precisely, the failures occur in the heat-affected zone adjacent to the weld. The welding procedure lowers corrosion resistance at the metal grain boundaries in the heat-affected zone. Stress relieving and improved welding techniques will not necessarily mitigate the problem. Use of low-carbon steels or Type 321 stainless (contains titanium) and Type 347 stainless (contains columbium) for replacement piping subject to frequent weld leaks will minimize the rate of failure. [Pg.205]

Following extensive laboratory trials, four experimental sleeves were first fitted to operational evaporators towards the end of 1980. A further 11 evaporator weld leaks occurred in 1981 and a fUrther 41 sleeves were fitted to by-pass defective and suspect welds. In parallel, work was in progress to examine whether the sleeving technique could be applied on a routine basis. A trial installation of 200 sleeves was conducted on the spare evaporator tube bundle in the latter part of 1982. A decision was then made to sleeve all the 3000 tube-to-tubeplate junctions in the three evaporators. Work on two of the units was completed in 1983 and the third unit was sleeved by March 1984. It was installed in the summer and PFR operated for the first time with three fiilly-sleeved evaporators in August 1984. [Pg.42]

N2 - Fail, visible damage to the container rib, stacking feature. Weld leak at the rib, stacking feature. No damage to the gasket. Tiny leak at the top. [Pg.17]

Techniques for handling sodium in commercial-scale appHcations have improved (5,23,98,101,102). Contamination by sodium oxide is kept at a minimum by completely welded constmction and inert gas-pressured transfers. Residual oxide is removed by cold traps or micrometallic filters. Special mechanical pumps or leak-free electromagnetic pumps and meters work well with clean Hquid sodium. Corrosion of stainless or carbon steel equipment is minimi2ed by keeping the oxide content low. The 8-h TWA PEL and ceiling TLV for sodium or sodium oxide or hydroxide smoke exposure is 2 mg/m. There is no defined AID for pure sodium, as even the smallest quantity ingested could potentially cause fatal injury. [Pg.168]

After almost 20 years of service, many leaks developed throughout the mill water supply system. Upon inspection, it was found that perforations had occurred beneath large tubercles. Some tubercles were up to 6 in. (15 cm) in diameter. Accessible pipe was water blasted to remove tubercles, and the deepest metal-loss areas (several thousand) were weld repaired. Perforations ceased. [Pg.58]

A weeping leak developed in a carbon steel emergency service water pipe at a circumferential weld emplo3nng a weld-backing ring. A rubberized saddle clamp was used to plug the leak temporarily. After several weeks the section was cut out of the system and the failure was examined. [Pg.147]

General description. Porosity refers to cavities formed within the weld metal during the solidification process. Such cavities may form due to decreased solubility of a gas as the molten weld metal cools or due to gas-producing chemical reactions within the weld metal itself. At times, cavities can form a continuous channel through the weld metal (worm holes, piping), resulting in leaks (Case History 15.3). [Pg.337]

Operation of this cooling water system was intermittent, resulting in long periods (30 days) of no-flow conditions. After IVi years, leaks were found at welded pipe junctions. Radiographic examinations revealed numerous additional deep corrosion sites at welds that had not yet begun to leak. [Pg.346]

Pressure testing of the finned oil cooler in Fig. 15.29 revealed leaks. Examination of the interior of the cooler after sectioning in the vicinity of the leaks revealed a small cavity in the weld zone in the corner of some fins (Fig. 15.14) and porous areas inside the channel in the welded zone in other fins. Microstructural examinations of specimens cut through the sites revealed interconnected voids resulting from either shrinkage during solidification of the weld or lack of fusion of the base metal and weld metal. [Pg.353]

Signiflcanl new material on welding, electrii al liusign, aiui corrosion has been added It also covers liytirostatic testing, pipeline drying lit uids, [nimps, valves, leak detection and pipeline ni.iinten.7n( e... [Pg.568]

A reactor was prepared for maintenance and washed out. No welding needed to be done, and no entry was required, so it was decided not to slip-plate off the reactor but to rely on valve isolations. Some flammable vapor leaked through the closed valves into the reactor and was ignited by a high-speed abrasive wheel, which was being used to cut through one of the pipelines attached to the vessel. The reactor head was blown off and killed two men. It was estimated that 7 kg of hydrocarbon vapor could have caused the explosion. [Pg.6]

Before a permit to weld or carry out other hot work is issued, it is normal practice to make sure there are no leaks of flammable gas or liquid nearby and no abnormal conditions that make a leak likely. The meaning of nearby depends on the nature of the material that might leak, the slope of the ground, and so on. For highly flammable liquids, 15 m is often used. [Pg.27]

Fires have occurred because a leak in one unit was set alight be welding in the unit next door. Before welding or other hot work is permitted within 15 m, say, of a unit boundary, the foreman of the unit next door should countersign it. [Pg.27]

A similar incident occurred on a boiler. After the No. 1 roof tube had failed several times, it was replaced by a thicker tube, and the change marked on the drawings. Some time later a small leak developed in this tube, and a length had to be replaced. No one looked at the drawings, and a 0.5 m length of standard tube was welded in. The discontinuity caused turbulence, local overheating, and rapid failure [24]. [Pg.56]

Tanks containing liquefied gases that are kept liquid by refrigeration sometimes have electric heaters beneath their bases to prevent freezing of the ground. When such a heater on a liquefied propylene tank failed, the tank became distorted and leaked—but fortunately, the leak did not ignite. Failure of the heater should activate an alarm. As stated in Section 5.2, frequent complete emptying of a tank can weaken the base/wall weld. [Pg.130]

An unusual—and unnecessary—dead-end was a length of 2-in. pipe welded onto a process line to provide a support for an instrument (Figure 9-2). Water collected in the support. Four years after it had been installed, the process line corroded through, and a leak of liquefied gas occuired. [Pg.181]

A leak in another heat exchanger allowed flammable gas to enter a cooling-water return line. The gas was ignited by welding, which was being carried out on the cooling tower. The atmosphere had been tested before work started, five hours earlier (see Section 1.3.2). [Pg.218]


See other pages where Weld leaks is mentioned: [Pg.1488]    [Pg.51]    [Pg.205]    [Pg.208]    [Pg.1488]    [Pg.51]    [Pg.205]    [Pg.208]    [Pg.89]    [Pg.14]    [Pg.98]    [Pg.104]    [Pg.124]    [Pg.290]    [Pg.142]    [Pg.319]    [Pg.949]    [Pg.323]    [Pg.4]    [Pg.41]    [Pg.44]    [Pg.76]    [Pg.256]    [Pg.19]    [Pg.21]    [Pg.134]    [Pg.160]    [Pg.232]    [Pg.257]    [Pg.469]    [Pg.402]    [Pg.821]   
See also in sourсe #XX -- [ Pg.420 ]




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