Q7 Q and A is meaningless as well as dealing with a vast subject , so lightly. Meaningless Q & A is a misleading factor. Reactors of any kind can be turned off in emergency and other situations; this extract is from a science diary as a sketch; turning off was done at jet speed in Chernobyl. Now how?" A reactor shutdown may occur under these principal situations: •
A reactor may trip due either to fault conditions or to conditions arising that require the reactor to be tripped. • Controlled shutdown where there is no urgency to complete the sequence and prior consideration can be given to each step. • Emergency shutdown where it is essential to close the reactor down but does not warrant the manual trip button being operated to give immediate shutdown. Where possible the controlled shutdown is preferred for two reasons, firstly, it is not good practice to thermally cycle the cores and structures of reactors since this accelerates wear and tear, and secondly, a controlled shutdown gives the operator more time to prepare and think out his course of action thus averting any mistakes which may have an adverse effect on plant and machinery. 7.3.1 Reactor trips Reactor trips can be caused for two reasons, firstly, by the operation of safety circuits because some parameters have been exceeded and identified by the safety circuit logic to warrant a trip, and secondly, if the operator sees a condition occurring which is ou of control and decides that it warrants tripping the reactor by the trip button. In either case, operator action is the same. In the trip condition the reactor operator relies on all automatic systems functioning correctly and during the early stages of the shutdown phase he will closely monitor their correct operation. Reactors and their systems are designed to shut down safely without intervention from the operator, although there is still a large amount of work for him to do to tidy things up and ensure safety-unrelated plant is shutdown and ‘put to bed’ in an appropriate way. An automatic trip may be caused in several ways and the following gives the features built into the safety (guard) lines: • High reactor temperatures <https://www.sciencedirect.com/topics/engineering/high-temperature-reactors>. Fuel has thermocouples <https://www.sciencedirect.com/topics/engineering/thermocouples> attached to it which are fed to the safety lines. • Rapid decrease in reactor gas pressure or high and low gas pressure. • Operation of excess neutron flux <https://www.sciencedirect.com/topics/engineering/neutron-flux> channels. • Failure of a sensing channel or safety circuit equipment. All safety circuit equipment is designed to fail to a trip condition thereby eliminating faults on safety lines preventing a reactor trip. • Failure of the control rod system that drops control rods into the core thereby causing the reactor to shutdown rapidly. During the shutdown of the reactor unit the operator must give vigilance to a number of things on a first priority. Listed below are those items which come into this category: • The operator must establish the cause of the trip and if a loss of coolant is suspected immediately put into action those procedures for loss of coolant. • Check that all control rods have fallen into the core and, if not, take appropriate action. • Maintain a check on the rate of reduction in reactor temperatures, particularly if a loss of coolant is suspected. This check also applies to the pressure vessel temperatures. • Ensure that the temperature scanners are in operation and the alarm presentation is functioning correctly. • Suspend all fuel charge/discharge operations on the reactor. • Ensure that when gas circulators <https://www.sciencedirect.com/topics/engineering/circulators> run down the appropriate pony motors start. • Ensure that feed pumps are running or emergency feed pumps have come into operation. • Monitor BCD data to ensure that fuel is sound. The operator must ensure that all other plant is shutdown in a safe and methodical way, such that when the cause of the trip is known and providing it is feasible start-up preparations can commence. 7.3.2 Controlled shutdown Although under a controlled shutdown automatic systems are operating, the operator can plan and in some instances intervene in the shutdown sequence. The controlled shutdown has the following advantages: • Staff can be allocated their duties and take up appropriate positions on the plant. • Fuelling operations will have ceased at an appropriate time and the charge face cleared of plant and equipment. • All monitoring equipment for the reactor (temperature scanners, BCD, alarm analysis) may be set up ready for the event. • The shutdown does not have to be hurried and no fault condition exists on the reactor. The operator will monitor reactor conditions as the shutdown progresses to ensure that excessive temperatures do not occur and that boiler feed and circulator <https://www.sciencedirect.com/topics/engineering/circulators> pony motors are available. Steam dump systems may already be warmed through to accept steam as soon as conditions permit. Although it is stressed that unhurried conditions do exist, there is also pressure not to waste time since downtime <https://www.sciencedirect.com/topics/engineering/downtime> does have a commercial impact and this also should be considered. 7.3.3 Emergency shutdown The operator may be faced with fault conditions that require him to shut the reactor down very quickly but which do not warrant a reactor trip. These conditions may not give him very much time to prepare and to a great extent he is following the same route as the reactor trip condition. The following are some events which may cause him to adopt the emergency shutdown procedure: • Failure of a standpipe <https://www.sciencedirect.com/topics/engineering/standpipe> assembly or of a control rod actuator assembly to seal after insertion. • Incorrect insertion of a standpipe assembly indicating a fault on the assembly or the possibility of misplaced fuel. • A dropped fuel element located either in a channel or on the charge plates in the reactor giving concern that fuel is damaged. • Rising BCD signals which give concern as to the integrity of fuel cladding. • Loss of BCD signals due to failure in the BCD equipment, i.e., failure of the BCD system. • Gross moisture ingress to the coolant circuit from the failure of a boiler tube. • Indications that there may be a gross CO <https://www.sciencedirect.com/topics/engineering/carbon-monoxide>2 coolant leakage. The basic intent of an emergency shutdown or a fast controlled shutdown is to ensure that the unit is taken off as quickly as possible in a safe and efficient manner, without damage to fuel cladding or plant and equipment, and to ensure that boiler feed is controlled such that an unacceptable boiler regime is prevented or water carry-over does not occur. The shutdown sequence to be carried out is similar to that of the reactor trip except that control rods are not tripped-in to commence the sequence of events. The fault still has to be investigated and it is essential that the true cause is found as soon as possible, since this may introduce a problem into the shutdown sequence. KR IRS 14922 On Wed, 14 Sept 2022 at 13:27, 'gopala krishnan' via iyer123 < [email protected]> wrote: > *CULTURAL QA 09-2022-14* > > *BEING A COMPILATION THERE MAY BE ERRORS* > > *Q1 Is food available for below 5 years kids in the Rajdhani > Express train?* > > A1 Prasanna Bhalerao, Knows about trains.23h > > Short TLDR answer: Yes (unless catering is not opted). > > Children 2 or below are considered infants and do not require a ticket, > reservation, etc. They must occupy the same berth/seat as by one of the > parents. Such an infant does not get any food or even milk on the > Rajdhani Express. > > *Children between the age of 2 to 12 are charged at half-ticket*. Only > the base ticket price is half. Reservation charge, superfast charge, > catering charge is full. Such children, on the Rajdhanis and similar trains, > are entitled to and will get the full adult meal. All other ages are > considered as adults. > > My note- I have learnt if berth is required, children are to be taken full > ticket. I do not know whether Rajadhani is exempted. > > *Q2 How can you tell if something is made of stainless steel or > just coated with it (galvanized)?* > > A2 Jason Spenny, 10+ years in the auto industry as an engineer > Sun > > *It's not 100% reliable, but they look different.* > > Stainless steel has almost a yellowish tinge to it. (note, sometimes steel > with a yellowish tinge is nickel plated. *Stainless can sometimes look > more pure silver with no tinge*.) > > *Electroplated galvanized steel (light coating) will have a shiny bluish > tinge*. Zinc galvanized bolts always have a bluish tinge. > > *Hot dip galvanized steel (heavy duty, outdoor rated) will have a dull > gray appearance* with a spackled appearance where you can see the > enormous grains of zinc. > > Beyond that you'd have to do chemical analysis. MAYBE a microscope would > do it. > > *Q3 How can I protect my house from termites?* > > A3 Rentokil Pest Control India, India's Leading Pest Control > Company Updated Sep 5 > > Termites are particularly troublesome pests as they can cause severe > damage to your home or workplace and are notoriously difficult to get rid > of. > > *Have you ever come back home only to find small piles of wood dust > accumulated under your sofa?* *This might be a cause of termite > infestation.* Once they invade your home and start feeding on your > house's foundation or your expensive furniture, it becomes tough to get rid > of them, primarily because of their minuscule size. Often, they thrive > discreetly and in inaccessible spots, making termite control even more > difficult. > > Here is a list of things you can do to prevent termites from spreading and > ensure that the treatment is successful: > > *1. Get Rid of Moisture: Moisture is one of the main* reasons that > attract all kinds of pests, including termites, into your home. Getting rid > of excess moisture in your home will help in keeping termites at bay. > > 2. Fix Leaks: Pay attention to any leaks or decay in your house. Decayed > roofs and moisture-laden walls work as perfect hosts for termites. > > 3. Declutter Your House: Pay special attention to useless papers, > cardboard, old magazines, and newspapers since these things can provide an > excellent environment for pests like termites to thrive. Whether you have > hired professionals for a termite or bed bug treatment, it is essential to > carry out a decluttering drive in your house. > > *4. Maintain a Safe Distance Between Soil & Wood: If* you have a garden, > ensure some distance between the soil and wood. This will help discourage > any attack from termites on the foundation of your home and the furniture. > > Getting termite treatment from an expert pest control brand is the best way to > remove termites from your property and safeguard your precious belongings > > *Q4 What is the type of AC voltage stabilizer?* > > A4 Gopala Krishnan, Former Assistant General Manager 1996-2004 > at Department of Telecom (1966–2004)Just now > > *Voltage stabilizer capacity is depend on the tonnage of air- conditioner.* > This means a stabilizer suited to 1.5 ton AC is not fit for 2 ton AC. The > other way, *stabilizer of 2 ton AC is not safe for 1.5 ton AC.* Some > stabilizers comes with booster. These type of stabilizers are used where > the AC voltage goes very low so that the air conditioner is not able to > function. > > *In India, the suppliers of air conditioner themselves suggest the best > type and capacity of the stabilizer required and wired by them, in most > cases.* > > *Q5 How do you choose the right windows and doors for your home?* > > A5 Gopala Krishnan,Former Assistant General Manager 1996-2004 at > Department of Telecom (1966–2004)Just now > > I am answering this question with respect to south India. > > *The type and size of windows vary depend on the rooms were they are used*. > Doors with bottom frame is used in the doors opening to outside to home. > Present day inner doors are without bottom frame. > > They type of wood depend on the affordability. Teak wood is best. In > Kerala Jack wood is more used. *Inner doors are mostly processed wood > readymade while frame is locally made mostly.* > > Window panes can be wood or wooden frame- work with glass. *Again depend > on affordability.* Mostly the window panes are half sized in bed room so > that bottom portion can be closed during dressing etc. > > *Halls will have wider windows*. *Entrance door to hall can be slightly > wider*. Outer door frames and door plank are made of strong wood. Some > places like Bangalore have wider windows in halls both length wise and > breadth wise*. It is least suited to Chennai or to any place in Kerala.* > > Make sure insect screen in metal meshing is provided in windows for more > safety not only from insects but also from snakes etc. and ensure they > are closed. > > *Q6 Can you eat unripe grapes? Do unripe grapes have any > nutritional value?* > > A6 Lucia Garcia, Worked at Hospitals Mon > > Unripe grapes appear crisp, aqueous, pale green, and contain highly acidic > juices with a very acidic flavor. > > During the ripening process of grapes, the sugar content increases > continuously, while the acidity decreases content continuously. > > *Some experts believe that The Nutritional Value of Unripe Grape is Much > Higher Than That of Ripe Grape.* > > Unripe grapes contain almost no sugar, but are rich in natural organic > acids and other health-promoting components. > > Natural organic acids have a very important role in the human body, and > they have significant biological activities.Clinical experience shows that > natural organic acids have antibacterial, anti-inflammatory, anti-viral, > anti-mutation and anti-cancer effects. > > *In some Asian countries, it is common to eat unripe grapes, which are not > only eaten directly, but also mixed with different kinds of juices and > salads to increase their tartness.* > > *Q7 Why can't you simply "turn off" a nuclear reactor in the same > way traditional engines are switched on and off?* > > A7 James Flack, Growing our own food for taste, pleasure and > saving money Updated Sep 7 > > *What kind of traditional engine?* > > *A steam engine is traditional, and takes hours to get up to heat. You > can’t just turn it off and on with the flick of a switch.* > > I chose a steam engine deliberately, as a Nuclear power station is just a > big steam engine. > > Just instead of burning coal, it ‘burns’ atoms. ( For naval reactors, the > difference is the turbines generally spin the propellers, not generators. ) > > If you turn it on/up ( via the control rods) it takes some time to heat > up, and so generate steam for the turbines. Similarly, turning it down/off > cuts the supply of heat, but you still have lots of stored heat you need to > use up. > > *Q8 Why does Indian Railways (IR) not increase the number of > coaches on a particular route when it has more passengers than seats > available (waiting list)?* > > A8 Madhusudan Kilambi, Works at Indian Railways Sat > > *It does add an extra coach which are numbered as AE ( extra II AC sleeper > coach), BE(extra III AC sleeper coach), SE ( extra II sleeper coach) when > it is operationally feasible.* > > *My note- Chennai- Bangalore trains had to be** booked a fortnight > earlier before the double decker was introduced. Now the trains can be > booked one day before and sometimes the same day. Only thing dynamic fare > in Thatkal. So more trains is the best option. * > > *Q9 What spreadsheet can handle more data than Excel?* > > A9 Jason Hines, Co-founder at Gigasheet; Prev Recorded Future, > Google Updated Aug 3 > > *This is exactly why we built Gigasheet! (Full disclosure - I co-founded > Gigasheet).* Gigasheet is an online spreadsheet with capacity to handle > up to 1 billion rows. It’s free to work with sheets up to 10 gigabytes in > size. You can learn more and sign up at https://gigasheet.com > > *Q10 Is there any biological reason for evolving elongated > skulls?* > > A10 Ken Saladin, Former professor of histology (microscopic > anatomy) Updated 1y > > *Long snouts increase the surface area of the nasal mucosa, which includes > two regions of epithelium—respiratory and olfactory*. Respiratory mucosa > serves just to cleanse, warm, and humidify inhaled air, whereas the > olfactory mucosa is concerned with smell. *The evolution of long > mammalian snouts is thus commonly thought to be driven by its advantage to > the sense of smell.* > > Above: Long-eared elephant shrew and tapir. > > The ability of a long snout to probe into small spaces may be another > evolutionary advantage, as in anteaters. > > As to the olfactory function, shown below is a longitudinal section of a > dog’s nose.[1] The pink tissue is respiratory mucosa with no role in smell; > the more yellowish tissue is olfactory mucosa. But dogs and many (most?) > other mammals also have an accessory olfactory region called the > vomeronasal organ (VNO), in the boxed region just above the anterior teeth. > You can see that also occupies a considerable portion of the snout length. > Bear in mind you’re looking at only the right half of the snout here; all > this is repeated on the left. The VNO also occurs in salamanders, snakes, > turtles, and lizards. > > Dog nasal cavity with VNO boxed. > > *Humans have a much smaller olfactory mucosa than dogs, and our VNO is > just an evolutionary vestige with no function and no separate nerve*. In > other mammals (cats, dogs, rodents, horses, cattle, pigs), the *VNO is > important in detecting the scent of both predators (their enemies) and prey*, > as well as sex and territorial pheromones from their own species. > > *When a snake or lizard flicks its tongues out to touch the ground, then > withdraws it into the mouth, it drags the tongue through the VNO to wipe > off and sense non-volatile chemicals picked up from the ground,* such as > the trail of a prey animal. (Reptiles have no palate separating the oral > and nasal cavities.) That’s what this komodo dragon is doing. Notice how > the forked tip of the tongue is touched to the ground, then taken into the > mouth where it is swiped through the VNO. This individual might be tracking > down an animal to eat, or might be following a pheromone trail left by a > potential mate. This slow-motion video makes the “licking and tasting” > action more noticeable than it is at natural speed. > > You can see that also in this slow-motion snake video, although this is on > an indoor artificial substrate and not as good as the komodo video. > > *Felines, horses, and some other mammals accentuate VNO stimulation with a > flehmen response,[2] shown well by this tiger.* > > Many of this have seen this in our house cats as well; the next video > shows the response in a house cat after sniffing another cat’s butt. > > Here is the flehmen response in a horse.[3] I’ve seen a similar display in > a Florida zoo by a male giraffe that had just tasted a female’s urine in > midstream as she was discharging it. > > *For all I’ve said about dogs and other mammals having more olfactory > mucosa than humans*, plus a functional VNO that we lack, it is > (surprisingly) not true that they have a better sense of smell than we do. > That, in the words of McGann,[4] is “A nineteenth-century myth” that should > be laid to rest…. > > *My note- 2nd reading might find the answer quite interesting and not > tough to understand.* > > *All the above QA are from Quora website on 13-09- 2022.* > > *Quora answers need not be 100% correct answers .* > > *Compiled **and posted by R. Gopala krishnan on 14-09-2022* > > > > -- > You received this message because you are subscribed to the Google Groups > "iyer123" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/iyer123/1972072552.2528726.1663142215924%40mail.yahoo.com > <https://groups.google.com/d/msgid/iyer123/1972072552.2528726.1663142215924%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/thatha_patty/CAL5XZooxkjdJ8AEs-_RCXRhbWTJkbcqxMOmPAhpjRnpOBKqWfg%40mail.gmail.com.
