Reactor Accident Monitoring Software Package example essay topic

TABLE OF CONTENTS 1. Introduction... 2 2. Nuclear Plant Monitoring and Risk Analysis System...

2 a. The Remote Monitoring System... 3 b. Reactor Accident Monitoring Software Package... 3 i. DEW...

4 ii. EALM... 4 . RAP...

4 iv. Support software... 5 3. Accident in Chernobyl, Ukraine... 5 a. Health-related impact...

6 b. Agricultural, ecological and economic impact... 8 c. Social and political impact... 8 4. Accident at Three Mile Island, U.S...

9 a. Causes of the accident at TMI... 10 b. Economic impact on individuals, businesses, and society as a whole... 11 5. Social responsibilities of computer professionals and users of the monitoring software packages...

12 6. Conclusions... 13 Bibliography... 14 1 1. Introduction On every May 1st, like many communists countries, we celebrated Labor Day in Poland. On that day adults as well as children were required to attend a parade organized by the Communist Party followed by dancing, various contests, and sporting activities for children.

Each time we waited all year long for this day to come. May 1st, 1986 was different from other years. I was 15-years old back then. I remember that we gathered in front of the school and waited impatiently for the activities to start. Suddenly, sirens went off in the whole town.

People panicked because it never happened before. Without any explanations we were told to go to the nearby hospital. Each child was given some brownish liquid to drink. I will never forget the bitter and awful taste of it.

Many children were crying from not knowing why they were forced to drink this unpleasant liquid. Some of my schoolmates even fainted. After receiving a dose we were told by the teacher to go home as quickly as possible, close the windows and stay inside. My parents explained to me that something horrible happened in nearby Ukraine. They were very disturbed. One word caught my attention: Chernobyl.

Later on, I learned that this bitter, brownish liquid was diluted iodine that was supposed to protect us from radiation. Being only a child it was difficult for me to understand the enormity and consequences of the accident. Chernobyl is the example of the worst nuclear plant accident in the history of mankind. Having an efficient, reliable and up-to-date monitoring system is essential to all nuclear plants to ensure safety to the surroundings. Failure in functioning of such a system can have enormous social, economic and health related consequences. 2.

Nuclear Plant Monitoring and Risk Analysis System In this paper, I focused my research on the power plant monitoring and risk analysis system implemented by the Illinois Department of Nuclear Safety (IDNS). The goal of IDNS is to provide an adequate and sufficient early warning to the off-site public surrounding each nuclear reactor in the state of Illinois. To achieve this goal, a tree-element Remote Monitoring System, an integrated suite of software analysis packages, and a set of analytical procedures have been developed. 2 a.

The Remote Monitoring System The Remote Monitoring System consists of three sub-systems: the Reactor Data Link (RDL), the Gaseous Effluent Monitoring System (GEMS), and the Gamma Detector Network (GDN). Data from each sub-system is sent to both the primary Radiological and Environmental Assessment Center (REAC) and the alternate REAC via a self-healing communications network. The RDL sub-system receives about 1000 data points from each reactor every two or four minutes. The frequency of transmission is plant-specific. Every six months the current point selection is reviewed and a new catalog of points is implemented. IDNS does not access the nuclear plant's process computers.

The RDL gives REAC vital information on the operational state of each reactor. This information is used to determine the actual or likely failure of the clad, the primary coolant system boundary, and the containment barriers to off-site radiological releases. The GEMS sub-system monitors the plant's engineered release points for radiological releases. The sampling time is changed manually or automatically.

The GEMS provides REAC with information on any release and this information is used to assessing the effects of the release, including dose projections. These projections provide the bases for off-site protection recommendations such as relocating affected populations and restricting access to the contaminated areas (Parker 1). b. Reactor Accident Monitoring Software Package An integrated suite of procedures and software packages has been developed to rapidly assess the operational state of each reactor using data from the RMS. There are currently three major software packages available to the Reactor Analyst. The first is the IDNS Early Warning System (DEW), designed to monitor key areas of operation and alert the analyst whether key systems are challenged or fail to perform their design function. The second is the Emergency Action Level Monitor (EALM).

The third is the Reactor Analyst Procedures (RAP), series of hard copy and computerized flowcharts, which guide the analyst in determining fission product release barrier integrity. Both DEW and EALM run continuously and feed a summary screen. The RAP software is not running all the time, but is used during the event to guide the analyst in reaching conclusions regarding the level of risk to the public and attendant protection action decisions (Parker 1). 3 i. DEW DEW, this software package, using predefined rules, continuously monitors data, primarily from the RDL, to determine if an event is leading to, or can lead to, core damage, a breach of containment.

Additional information from the GEMS and GDN sub-systems supplies IDNS-derived measurements of radiological parameters to confirm and supplement plant data. DEW monitors reactors for a number of categories: fuel cladding, primary coolant system boundary, containment integrity, emergency core cooling status, electric power status, residual heat removal system status, balance of plant status, and plant environmental radiation status. DEW is written to provide a user-friendly environment by adopting a layered approach to data analysis. A main alarm summary screen is available for each site indicating which category of rules for which reactor, at dual unit sites, is in alarm. From the summary screen, the user can access the detailed logic to determine the exact cause of the trip within each category. Each logic screen shows the logic, the setpoint, and real-time data.

A graph of the data can easily be displayed on the screen or printed. To aid in the analysis, tow types of event logs are available: a chronological log for all DEW trips showing site, reactor, category, and rule number fired, and second log that allows the analyst to summarize all trips from a given site for any time period, in hours, up to seven days. The detailed logic for DEW is derived from a variety of sources like the extensive collection of plant-specific and plant-controlled documentation including plant drawings, normal and emergency procedures, system descriptions and technical specifications (Parker 2). ii. EALM The EALM consists of the four main categories: abnormal radiation levels / effluents, fission product barrier degradation, system malfunctions, hazards, and other conditions. The first two categories are easily encoded with the RMS data available to the IDNS. Two latest categories are most difficult to program, as many conditions do not have corresponding RMS data..

RAP Taking Boiling Water Reactor (BAR) Emergency Operating Procedures as a point of departure, IDNS developed flowcharts based upon available RMS plant data to guide in the analyses for release barrier failure. There are flowcharts for determining failure of the 4 cladding, the primary coolant system, and the containment boundaries with additional flowcharts for Pressurized Water Reactors (P WRs). A computerized version of these flowcharts was developed using live RMS data. As plant conditions worsen, highlighting flowchart conditions that are met indicates progress through the flowchart. A feature unique to these is the on-screen display of actual plant operating curves. These curves, updated every two to four minutes, include core / clad damage versus time after shutdown, sub cooling limits, fuel damage versus core exit temperature, suppression pool heat capacity temperature limits, and primary containment pressure limit (Parker 3-5). iv.

Support software IDNS has developed a software package, DISPLAY that forms the backbone of the analysis structure. This software is a Fortran-based program that allows the analyst to develop logic using simple text files. These files can then be viewed with real-time data using DISPLAY. Line graphs and data history windows are also available. Another program developed by the IDNS is MESSAGE. This program interfaces the analyses software with an alarm screen in the 24-hour-per-day dispatch center in Springfield, IL.

Alarms in any analysis program can be routed to the dispatcher to have appropriate response personnel notified. New alarms show in reverse video and must be manually reset. The software package developed by IDNS for monitoring nuclear plant has been proved more than adequate during plant accident exercise. During normal plant operations, the software has reliably detected plant operations outside plant technical specifications and conditions defined by utility emergency plans. Malfunctions in any part of the software package designed to monitor nuclear plant could cause a disaster on a massive scale. Two examples described below show how either human error or equipment malfunction lead to an accident.

Each of these accidents had an enormous social, economic, and health-related impact (Parker 6). 3. Accident in Chernobyl, Ukraine Christopher Flavin describes the accident in his book "Reassessing nuclear power: The fallout from Chernobyl". At 1: 00 a.m. on April 26, the operators at the fourth and newest nuclear reactor at Chernobyl was one full day into a special test. They wanted to see 5 whether the residual energy of a spinning turbine could provide sufficient power in case of an emergency shutdown with loss of offsite power. In the course of the test, operators disconnected safety systems and violated operating procedures in order to press the test forward.

Each adjustment caused further departures from the plant's intended performance, making it unstable. By 1: 23 a.m. the reactor's power output had fallen to just 6 percent of its normal level. The fission reaction in the core had been slowed by the buildup of xenon gas. The emergency core cooling system had been shut down; other safety mechanisms had been disconnected. All of the control rods that moderate fission in the reactor's core had been at least partially pulled out in order to keep the reactor going. The operators pushed ahead, apparently oblivious to the fact that the reactor had become dangerously unstable.

Slowly, the reactor's power output began to rise - to the intended level and then far beyond. Operators pushed the emergency button known as AZ-5 that sends the control rods back into the core to stop the fission reaction. But the control rods failed to fall fully into the already deformed core. A few seconds later, shocks were felt in the control room, followed almost immediately by two large explosions (Flavin 8-9). The accident at Chernobyl is the example where human error, equipment malfunction and poor judgment combined, created a disaster on a massive scale. The course of the accident was compounded by the existence of significant drawbacks in the reactor design, which made the plant potentially unstable and easily susceptible to loss of control in case of operational errors. a.

Health-related impact The health impact of the Chernobyl accident can be described in the acute health effects such as death, severe health impairment as well as in late health effects such as cancer. The acute health effects occurred among the workers of the nuclear plant as well as among firefighters and medical personnel that came to the site of the accident. A total of 31 people died and more that 140 people suffered various degree of radiation. 100 firefighters from Chernobyl and the nearby town of Pripyat - who immediately went into action, batting desperately to douse the blazing reactor and prevent it from igniting 6 the three others at the plant- and 300 staff members and medical personnel were the heroes of Chernobyl. During the following days these people received an enormous amount of radiation. Many of them lost their lives to radiation sickness or burns.

During the months and years that followed, an estimated 800,000 workers from all over the former Soviet Union took part in cleanup operation and construction of the concrete "sarcophagus" that now covers the destroyed reactor (Balter 360). As far as late health effects are concerned, there has been an increasing number of carcinomas and thyroid cancer among the infants and children in the former Soviet Union. Based on conducted studies, a conclusion is reached that the peak of thyroid cancer has not yet been reached. An important effect of the accident related to health issue is the appearance of widespread status of psychological stress in the populations affected. The severity of this phenomenon, which was mostly observed in the region of former Soviet Union, appeared to reflect the public fears about the unknowns of radiation and its effects, as well as mistrust toward public authorities and official experts (Flavin 9). Children became the first victims of fallout.

Pediatric endocrinologist Larisa Astakhova described a dramatic increase in thyroid cancer among the children. Westerns scientists were skeptical because they claimed that Chernobyl fallout was not expected to show up for at least 6 t o 8 years. The Belarus cases had began to appear only 4 years after the accident. 200 children in Ukraine were diagnosed with cancer and 700 cases in regions of Belarus and Russia. After extensive studies the conclusion was reached that in fact there was a strong correlation between thyroid cancer and radioactive iodine levels measured shortly after the accident (Balter 357). Doctors reported that many of the Chernobyl victims died slowly and painfully from radiation burns.

Bone marrow that produces the body's red blood cells was also damaged in many patients. Within three months from the accident three-quarters of the patients were dead, many killed by infections that overwhelmed their damaged immune systems. The weather helped minimize the impact of the accident in the area around the reactor. Fire carried the fallout high into the air, and the area of Kiev - the capitol of Ukraine, was largely spared because wind blew away from the city during that time. Otherwise, some 2.4 million of people living in Kiev could be affected with radiation. Meteorologists also reported that there was no rainfall, ensuring that most of the fallout would occur outside the Soviet Union, 7 largely over the Atlantic and Arctic Oceans, as well as Scandinavia and Western Europe (Flavin 11).

After Europe learned about the accident, many European countries distributed iodine to the public. Radioactive iodine-131, which has a half-life of eight days, was one of the principal isotopes released by the Chernobyl explosion Swallowing stable iodine a few hours before radiation exposure can prevent this type of cancer by saturating the thyroid gland with iodine, so the radioactive isotope is not absorbed. Although millions of people in Europe were given stable iodine about four days after the Chernobyl reactor exploded on 26 April 1986, it came far too late. b. Agricultural, ecological and economic impact Despite help from the weather, the Ukraine suffered an ecological disaster. The soil in the region is of a type that will retain radioactive particles for a long time, and the food chain may be contaminated for many years. Scientists estimated that between 3 and 4 percent of the radioactive isotopes were released to the environment - about 7,000 kilograms of material containing 50 to 100 million curries of radioactive materials.

Some were inert gases that rapidly dissipated in the atmosphere, posing no significant threat, but others were long-lived, biologically active elements that fell across Europe and around the world (Houts-Cleary-Hu 12). Because of the negative impacts on ecology and agriculture many countries of Western Europe banned imports of food products from countries affected by the accident such as: Soviet Union, Poland, Sweden, Romania, etc. This posed serious economic consequences. In the affected areas, consumption of spring vegetables, berries, and fresh water fish was discouraged.

Most of the cattle were kept in barns until meadows had been approved for grazing. c. Social and political impact Accident in Chernobyl occurred on April 26th, while most countries learned about it on April 30th or May 1st. It was not until 36 hours after the accident that Soviet officials evacuated 49,000 residents living nearby within 10 kilometers from the plant. Later, the evacuation zone was widened to 8 30 kilometers.

Altogether, 135,000 people were moved. Western countries questioned the delays. Soviet officials explained that they moved people as soon as wind conditions indicated, and that prior to the evacuation; exposure was limited by keeping people indoors. Many scientists believe that evacuation of the people in the affected area as well as warning other countries about the accident came too late. On the other hand, Soviet government denied that Western countries suffered significant damage of any kind (Houts -Cleary-Hu 17).

It is essential to mention that the first indication that the nuclear disaster had occur came not from Soviet officials, who for almost three days denied that accident happened, but from Swedish technicians. I find Soviet's government inaction and denial to be highly unethical, so say it mildly. On the eleventh day following the accident, Russian newspaper "Pravda" published its first description of the disaster. Because of Chernobyl, Soviet credibility suffered considerable damage in the eyes of other governments and their citizens. Public opposition against nuclear plants began. Citizens of various countries like Austria, Finland, France, Poland, Sweden, openly criticized Soviet government.

Millions of people strongly protested against nuclear plant. Because of the accident in Chernobyl, Polish government decided against building its first nuclear plant in Zarnowiec. The accident in Chernobyl had a significant impact on human society. Not only did it produce severe health consequences and physical, industrial and economic damage in the short term, but also its long-term consequences, in terms of socio-economic disruption, psychological stress and damage to the image of the nuclear energy, are expected to persist for some time. 4. Accident at Three Mile Island, U.S. Chernobyl was the most serious nuclear plant accident worldwide.

Several years earlier, similar accident occurred within the U.S. On the morning of March 28, 1979, one of two generating units as a little-known place called Three Mile Island experienced an odd sequence of equipment failures and human errors, resulting in the escape of several puffs of radioactive steam. It was a moment of considerable potential danger and uncertainty. When the uncertainty was at its height, the governor of Pennsylvania issued a calm and measured advisory suggesting that pregnant women and preschool children living within five-mile 9 radius of the plant might evacuate, while others within ten-mile distance should consider talking a shelter in their own homes (Erikson 139). a. Cause of accident at TMI Shortly after 4: 00 a. m., several water pumps stopped working in the Unit 2.

It is worth mentioning that the nuclear reactors are designed in a way that they cannot explode like an atomic bomb. The primary danger is the potential release of the radioactive materials produced in the reactor core as a result of fission. The materials are contained within the fuel rods. One of safety measures are fuel rods themselves, which trap and hold radioactive materials. The second protection consists of the reactor vessel and the closed reactor coolant system loop. A nuclear power facility is designed with many ways to protect against system failure.

Each of its systems has an automatic backup system to replace it in the event of the failure. In case of a loss of the reactor's cooling water the Emergency Core Cooling System automatically uses existing plant equipment to ensure that cooling water covers the core. But it can be effective only if plant operators allow it to keep running and functioning as designed. At Three Mile Island they did not (Kemeny 85-88). When the water flow stopped, the temperature of the reactor coolant increased.

The level of the water inside the pressurizer tank rose and the steam in the top of the tank compressed. Then a vault atop a pressurizer, called PORV, opened - as it was designed to do. Pressure continued to rise, however, and 8 second after pump failure, the reactor scrammed. Its control rods automatically dropped down into the reactor core to halt its nuclear fission, but the decaying radioactive materials left from the fission process continued to heat the reactor's coolant water. With the reactor scrammed and PORV open, pressure in the coolant system fell.

Up to this point, the reactor system responded properly to a turbine failure. The PORV should close 13 seconds into the accident but did not. A light on the control panel indicated that the electric power that opened the PORV had gone off, leading the operators to assume the valve has shut. But the PORV was stuck open draining needed coolant water.

Had the valve closed as it was designed to do, the accident in the plant would be only a minor inconvenience (Kemeny 90-92). Throughout the first two hours of the accident, the operators ignored or failed to recognize the significance of several things that should have warned them that they had an 10 open PORV and a loss-of-coolant accident. One was the high temperature at the drainpipe that led from the PORV to the reactor coolant drain tank. About 6: 00 a.m. at least few of the reactor's fuel rod cladding had ruptured from high gas pressure inside them, allowing some of the radioactive gases within the rods to escape into the coolant water. About 6: 30 a. m., the radiation readings increased rapidly. Shortly before 7: 00 a.m. site emergency was declared, required by TMI's emergency plan whenever some event threatens "an uncontrolled release of radioactivity to the immediate environment".

Fortunately, the accident at Three Mile Island did not end with a serious threat to the health and safety of the workers and to the community. But the gases still existed within the Unit 2's cooling water, and the reactor itself was badly damaged. Periodic releases of low-level radiation continued, and some feared that major radioactive material release is yet to occur. As a precaution, on March 31, the Department of Health, Education, and Welfare, had arranged for a rapid manufacture of nearly quarter million bottles of potassium iodine. The bottles were distributed to all workers on the island and were not given to the public. Unfortunately, the accident had strong social, psychological, and economic impact on the surrounding areas. b.

Economic impact on individuals, businesses, and society as a whole The economic impact on individuals can be divided into two groups: evacuation costs and health-related cost. It was estimated that about 144,000 people evacuated from this area for about 4-5 days. During that time, about 32% lost paychecks resulting from evacuation. The entire cost related to evacuation that includes accommodation and food cost and loses in paycheck amounted to about $7.2 millions. Shortly after the accident there has been an increased number of visit to physicians. People spent money also on sleeping pills, tranquilizers, alcohol, and cigarettes.

The total cost of health-related expanses amounted to about $0.5 million. The Pennsylvania Department of Commerce conducted a survey of businesses and manufacturing industry within a twenty-mile radius from the site of the accident. During the first week, an estimated loss was $7.67 million in value of production in the manufacturing industry. The tourist industry also suffered loss of about $5 million during the first month of the accident. Researches found that there was no negative impact on the property value in 11 the short vicinity of the TMI. There was no evidence of increased mobility within five mile.

Prices of electricity rose but were nor significant. The overall long-term costs of the nuclear accident at Three Mile Island have been substantial. General public Utilities, the owner of TMI, estimated the total cost of cleanup at a billion of dollars. In addition, there were costs resulting from purchasing replacement power at prices above what it would have cost had TMI been operational.

There was a substantial loss in value of the stock of GPU. Stock dropped from $18.00 to $3.38. Worldwide there was a cost in the decreased performance of pressurized water reactors that was estimated to equal the cleanup costs. Most of the listed costs were borne by the insurance companies, the federal and state governments, other electric power companies, and purchasers of the power throughout the U.S. (Houts- Cleary- Hu 33-36). 5. Designing a software package for nuclear plant monitoring is an enormous task that requires an effort, knowledge and time of many professionals.

The software is a joined teamwork of people from various professions: engineers, nuclear physicists, and computer scientists. Computer professionals, as major designers of the software, are responsible the most for proper and efficient functioning of the program. It is expected from them to put their knowledge and professional experience to the best use possible. Any glitch, overlooked mistake can have serious and damaging consequences.

I think that main emphases should be put on ensuring safety, which is critical in such difficult environment like nuclear plant. Most nuclear plant accidents are caused by the human error, not by the equipment failure. Any monitoring software must be designed in a way that prevents any human error. Although, one's may think that personal judgment is the best advisor in making decisions, I strongly disagree. In my opinion, we cannot rely on personal judgment when it comes to solving problem during critical situations in such complex environment like nuclear plant. Nuclear plant is an environment where no emotions, personal judgment and intuitive thinking are allowed.

Any decision, wrongfully made by a plant operator, has to be prevented by the monitoring system. Of course, plant operators - primary users of the software have some degree of responsibility as well. Their main responsibility is to strictly following any 12 procedures in a course of proper functioning of the plant. They also have to obey any rules and regulations given them by the management or by the government.

Of course, they cannot be hold responsible for any failure of the monitoring software. Nuclear plants are expensive to maintain, but in return they provide electricity to many households. The owners of the plant as well as public authorities such government have the responsibility to ensure proper and safe functioning of the plant. Their main responsibility is to provide funds and regulations. As said before, one of their responsibilities is to ensure safety. In case of an accident, public authorities have to organize evacuation to protect general public in the immediate area from radiological materials released during the accident.

Well-coordinated evacuation can be essential in protecting civilians during the accident. 6. Conclusions In today's world nuclear plants are essential providers of the electricity in many developed countries. Although operational and maintenance costs of nuclear plants are enormous, benefits are even greater. They provide power to thousands of households and businesses. Designing, building and operating the plant is a joined effort of many people such: engineers, nuclear physicists, and computer scientists, to name a few.

Thanks to advances in technology, computers and highly advanced equipment do most tasks. In such complex undertaking, accidents can, and often happen. Most of the accidents are caused by the human error usually based on a poor judgment or failure in following rules and regulations. That is why designers of the software must prevent this to occur by limiting human decision-making to the minimum.

Of course, it is obvious that we cannot rely completely on machines but we can make them "smarter" and more efficient. Any accident caused by human error or equipment failure has serious social, economic, and health-related consequences. Computer scientists have to use their knowledge to the extreme in designing monitoring software. By doing so, they will ensure general public that nuclear plant is the safest and most efficient way of producing power.