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Scientists of the RAS Institute of Machine Science named after A. Blagonravov together with their colleagues from other research institutions of this land have created world's unique micrometer sensor for installation in critical locations prone to emergencies to ward off catastrophes unparalleled in scale and aftermath.
As shown by our recent past, in particular, there is no avoiding technogenic calamities either on land (Chernobyl catastrophe*, railway explosion near Ufa), or on sea (submarines sinking in the Barents Sea) or in space (launch pad accidents)**. To address the problem Russia has adopted the State Technogenic Catastrophe Preventive Research Program-STCPRP "Safety". According to the RAS Corresponding Member Nikolai Makhutov, its gist is as follows.
People are delving deeper and deeper into natural environment, and technology is getting increasingly complex at a mind-boggling pace, thus creating a continuously growing yet inevitable gap between the potential hazards it creates and our capacity of avoiding them. That does not mean, however, that technogenic disasters are to be treated as the judgment of God. No doubt, there is no way to foresee anything under the sun and an absolute safety is practically unattainable. Still, we are to be prepared for all kinds of breakages, accidents, etc. With that purpose, even in the design phase machines and equipment should be applied most drastic requirements, and standard risks are to be put down in their normative technical documents. That should be a law to be abode by designers and engineers.
Moreover, when potentially hazardous technology is manufactured, e.g., space-rocket or nuclear installations, it is not sufficient if the innovation just has high performance factor or low materials consumption. Developers must foresee even hypothetical accident probability and be prepared to eliminate or mitigate the risks***.
Nowadays, due to scientific progress, the feasibility of urgently preventing emergency situations has grown hundred- if not thousandfold. However, the ideal situation is still too remote, when practically simultaneously with accident occurrence a safety system would go off.
* See: V. Subbotin, "Nuclear Power: From the Past into the Future", Science in Russia, No. 6, 1996. -Ed.
** See: Yu. Markov, "Baikonur: Joy with a Smack of Gall", Science in Russia, Nos. 3 - 5, 1998. -Ed.
*** See: V. Subbotin, "Nuclear Power Safety", Science in Russia, No. 1, 1999. -Ed.
There may be multiple causes of a disaster, and they may practically take fractions of a second. To learn foreseeing, projecting, identifying and instantly eliminating those is a most complex task which is not always attainable at present yet. However, while we are unable to completely avoid critical situations, we can substantially reduce their incidence and negative effects.
It is common knowledge, the scientist goes on, that many dynamic processes in machines in transit from standard to emergency situations follow roughly the same pattern. That allows us to identify them and quickly, practically instantaneously, respond to alarm signals and take corrective measures. Take, for instance, a rocket turbine rotor rotating at an enormous speed of a few tens of thousands of rounds per minute. Even a miniscule destruction of a turbine blade-a tiny fragment detached-may cause a lot of harm. We have already learnt to avoid such occurrences: we have sensors which register the emergency situation. Thus, in 27 cases out of 30 the turbine was stalled in time.
Together with colleagues from other institutes our specialists work on the problem of the so-called controlled catastrophes to prevent those or minimize the risk. The respective systems will alert you to what is to be done (e.g., change the design of an NPP reactor). If an accident is still to occur it will take not seconds but at least a few hours to develop. In that case the personnel will have time to analyze the situation and to act.
We also look for different techniques of protecting people working in hazardous areas. Thus, we have created metallized fabric screening off electromagnetic radiation. Some of its types have higher electrical resistivity. An operator (astronaut) clothed in a suit (pressure suit) made of this fabric can stand even hypothermia.
Many sectors today make use of shape memory metals. A coupling made with such technology, should there happen a fire, will under the impact of high temperature somewhat increase in size tightly sealing a hole and preventing the spilling of dangerous liquids or gas.
Or let us take another and unfortunately typical situation. When buildings collapse concrete slabs often pile up and are pressed so tightly against one another that no tool can be inserted in-between, e.g., a lifting jack or a hydraulic booster. Rather the narrow rift can accommodate a
finger-thick piece. When heated up, it "grows" and creates an effort of tens of tons capable of moving the concrete blocks apart.
Finally, perhaps the most perspective of the above designs is a micrometer sensor, i.e., a tenso-, thermo-, vibration sensor, created in our institute. The invention is the implementation of scientists' and engineers' age-old dream: for the first time they got a real chance to obtain reliable information from the focus of accidents as they are developing. The unique instruments operate right in the reactor fissile core, in the thermonuclear plant superconductor systems, on steam turbine rotors, within chemical production lines- in the flows of liquid metal, gas, plasma, in corrosive environment, i.e., in the extreme conditions of radiation, super-high and super-low temperatures and electromagnetic fields.
Sealed in a pressurized foil body, sensors look like a web of wires a few millimeters long and micron-thick, connected with spot welding. Their data are fed to the tensometric center and processed on-line with the help of up-to-date computer programs. Based on that, the center generates a conclusion whether the operation mode of, e.g., a reactor (and that includes, perhaps, thousands of parameters) meets safety requirements, i.e., it outputs information for decision-making and not necessarily in current perspective. It is not only possible to adjust the operation mode of a functioning installation but to make alterations in the design of newly created equipment. Specialists may even compromise efficiency and economy for higher reliability. Thus unit five of the Kozlodui NPP in Bulgaria was equipped with a thousand sensors up to 2 thousand dollars worth each.
It is already half-a-century now that our institute has been involved in the creation of safety technologies, but whatever effective and even unique offered solutions are, they continuously need improvement to keep in pace with the machines and equipment fleet. Therefore, we are networking with specialists of many sectors: metallurgists make new materials for us, software engineers design more and more intricate programs, others develop most sophisticated systems of pulse holography, thermovision, acoustic emission, strain-sensitive coatings facilitating identification of critical areas in certain technological devices. On our laboratory samples we test various extreme mechanical, thermal, electromagnetic, aerohydrodynamic impacts and find precise parameters of resistance to emergency loads. Only together, Dr. Makhutov stresses, shall we ensure the safety of present-day and future technology.
Prepared by Yaroslav RENKAS
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