Here we are

Three of us

from leftt Yen, Mathanraj and Suguna

A quiz for you  >>>                  Can you guess what this picture implies?

 

Well, Our pose depicts our motif  in conveying our message to the public and to create awareness among them upon Nuclear Technology. The messages are :

We would like the public to HEAR the advantages of the nuclear not the bad myths of nuclear.

We would like the public to SEE the benefits of nuclear and foresee the benefits it has stored for the future of the world not the disadvantages it holds. 

We would like the public to TALK about the true facts and advantages about Nuclear Technology not spreading myths surrounding this technology.

HEAR GOOD! SEE GOOD! TALK GOOD! reject the bad ones and most importantly

THINK GREEN! THINK NUCLEAR!

Additional info on Safety Details of a NPP

Hi everybody, it is nice to able to post a message again! This time I would like cover more details on safety measures present at a NPP. In previous blog, we did saw what are the safety measures and precautions taken to control the reaction, to control the radiation at the containment chamber itself in case of explosion and etc. Now, we are going to look into external environment configuration of a Nuclear Power Plant (NPP).

First we are going to look into the structure itself, where it will be built. Basically NPP will be built at much more deeper level below the land compared to other structures. The main reason behind this move is too minimise the seismic vibration caused by earthquakes. Whenever there is a presence strong earth quake, the NPP opeartion will be SCRAMed ( will be shutdown immediately ASAP). But at the first stage of selecting place for NPPs, we would look for areas which not prone to earthquekes. This explains, the extra safety measures that a NPP pose in order to overcome problems related to earthquakes. Picture below depicts the earthquake safety measures at a NPP.

Secondly, we would look into the most afraid form of attack, which is the plane crash. Eventhough, we believe one would not make such attack upon a NPP because it will somehow reflect to them back but we don't know how human changes. So let's get prepared for such attack. Talking about plane crashes, in order to fully convert the force of plane at certain speed, it need larger medium. Let's compare the size of Empire State Building and a NPP. Empire State Building collapsed due to its larger size where it absorbed the energy from the planes, while NPP has smaller size and it would not absorbs much energy and the containment wall is strong enough to withstand a plane crash onto it. Here is a link where you can find the facts about it. http://www.nei.org/newsandevents/aircraftcrashbreach/

Thirdly, we would look into the cooling towers and also the tertiary water pump system. Basically, they are made for one main function. Which is to cool the water vapor from turbine and feed it into the reactor. At colling tower, these vapors are condensed at normal temperature in a open space, where it might appear like dangerous gases coming out from the cooling tower. well, actually they are just water vapors.....

If there is no presence of cooling tower, the vapor will be cooled at nearby sea or river. But, the question is will the heat liberated to the nearby sea or river will threaten the living organism there? for example, if the heat from the NPP gives rise to the sea water temperature, it will kill the microorganism which is the food source for fishes. But research shows that, heat exchanged from the NPP will not harm underwater creatures.



AND there is new info for guys, there have been great advancements in Nuclear Technology and it leads the Russians especially to build new type of NPP, which is floating NPP! it is not joke but it have been developed since the year 2000. The stations are to be mass-built at shipbuilding facilities and then towed to the destination point in coastal waters near a city, a town or an industrial enterprise. Many have opened up their doubts upon this type of NPP especially about its hinderance on terrorist attacks. Where it is much more vulnerable compared to NPP built at land site.

But it also pose some advantages in terms of overcoming land constraints, and overcoming problems like having a NPP at my backyard and etc...But guys what do you think about this???

Course summary

         Well, finally exam time is coming near to us. I guess you guys are working very hard for your papers. Our last nuclear class was on Tuesday 12nd October. That is a short course, lasting for three months more or less. But we have learnt a lot about Nuclear engineering, from the simplest thing like what a nuclear power plant (NPP) is, what are components in a NPP...until the very detailed topic in atomic physics like neutrons, microscopic cross section, reactivity coefficient..etc. It can be said that we have been exposed to every aspect of Nuclear engineering concepts. The course broadens our mind and knowledge about another method of producing electricity. We have also learnt about current nuclear technology situation globally. Well, thank to Mr. Shamsul for well organized and prepared lecture notes. Those materials are relevant and exactly what we need for this course. They provide basic concepts and fundamentals in nuclear engineering. They are very helpful for us when we want to refer back or use as reference. I guess Mr. Shamsul took a lot of efforts in preparing these lecture notes for UNITEN students.

          Except Engineering in society course which invited several speakers, I've never attended any class with more than two lecturers. But in this class, we have been taught by four lecturers and I love them all..^^.. hehe...I've admired them by their kindness, commitment, expertise and their personality. They had to come all the long way to uniten after working in TNB in order to deliver lectures to us. Wasn't it tired ? Also, during fasting month, it was even worse. Our class was taught by Mr. Azrudi from 6 to 7: 30 pm when lectuers and students were very hungry and tired after one day fasting. However, our class was never cancelled before. It was just late due to traffic jam (which is a pity ). I noticed that he looked tired of speaking continously one and a half hour but he never complained about it. Mr Syukri is a caring lecturer who even provided us drink and food during fasting month. I felt very touched because of all these things... Mr. Azrudi said they are not trained to be lecturers but in my opinion, they are teaching as well as real lecturers or even much better..^^..You've successfully led the class and left good impression to us.

            After all, the nuclear class was fun and interesting, one of my favourite subject. I've never skipped any class (although I often came late) ^^. That is my record!!! hahaha...However, I did not have enough time to study for this subject. I have been distracted with my FYP and other subjects' project. That's why I still have some unclear things I wanna ask lecturers...maybe later since I'm very busy this time. 

          I am thankful for taking this course...although the course content is kind of heavy, making me sometimes hurry like crazy ^^ but as Mr. Syukri and Mr. Shamsul said "it is good for us". So I think yeah it is definitely good for us.

           Lastly, I would like to thank to our beloved lecturers, Mr. Syukri, Mr. Azrudi, Mr. Shamsul and Mr. Azlan for teaching and giving guidance to us so far. You all did an amazing job in transfering knowledge and inspiration to us. I hope Nuclear Malaysia is going much more better with engineers like you all.

All the best !!!

PS: I would love to have some pictures with our beloved lecturers..it is the last class of my degree here. Hopefully I will remember to bring a camera hehe ^^ 

"Nuke is our friend " videoclip republish

Hi guys, first of all, thanks for your support for my video...I am so happy that you guys love it !! I 'd like to republish it for better view since texts in previous video are so small. Sorry for any inconvinence. Hope you enjoy it !!!
http://www.youtube.com/watch?v=FXMz_4K_M2Y

Further discussion on THINK GREEN BECAUSE NUCLEAR IS GREEN!

Allright folks, previous post got many comments, which made me so motivated to write a new post on asked questions. First of all I feel quite relieved that fellow future engineers from UNITEN agreed to the fact that NUCLEAR ENERGY is clean, green and beneficial.

There was one funny question, so the answer is, if we know an alternative source is green, why we wanna go and look into how green it is compared to other green alternatives. knowing that Nuclear Energy is green is very sufficient for us.

Talking about the safety features present in NPP which is austounding, we can see that they are protected layer by layer. Look at the pictures below, you can understand the whole safety structure of it.



Courtesy of MR.Syamsul, TNB NUCLEAR UNIT



Apart from this there few factors included while designing safety measures inside a NPP. They are redundancy and diversity. Redundancy means the safety system is designed such way so that safety measures or sensors placed repetatively such that if one fails, other will sense the problem and rectify it. Diversity in the other hand means, the plant does not depend only on source of solution but many. For example, if moderator inside the reactor begin to deplete, the system can supply water from normal water supply or else from spare water tank. If any one of this fails, the other can solve the problem.

Some interesting facts:

For current existing reactors: core meltdown can occur as much as 1 incident in 10,000 years.

(assuming the if the reactor works for 10000 years)

For future reactors: core meltdown can occur as much as 1 incident in 100,000 years.

(assuming the if the reactor works for 100000 years)

Aren't this facts are mindblowing? think about it!

Well, to talk about the duration of time taken for planning till commissioning takes around 9 to 10 years. to make it simple I post the picture below, it explains what was the effort by government to initiate the nuclear energy programme. Yet folks, it is subjected to changes. Take it as a reference!

I would like add something here, looking at the picture above we know that it takes nearly a decade to operate our own NPP. Talking about a decade of time, don't you feel that we have more than enough of time to learn and acquire more skills on operating a NPP? So my point here is, we don't have worry about our people's level of expertise, we just need to put trust on them, so that they learn and train themselves well enough before they are ready to operate a Nuclear Power Plant.

some quotes by 'some' people:

All the waste in a year from a nuclear power plant can be stored under a desk.
Ronald Reagan

Almost every way we make electricity today, except for the emerging renewables and nuclear, puts out CO2. And so, what we're going to have to do at a global scale, is create a new system. And so, we need energy miracles.
Bill Gates



THINK GREEN BECAUSE NUCLEAR IS GREEN!

HA HI, i'm back with a new topic to discuss here. It is all about our good friend, MR.NUCLEAR!

well, there are many many and many perspective among us on nuclear energy. From a kid to elderly peoples their perspectives varies accroding to their level of understandings. But it is our team's utmost responsibility to enlighten them by providing advantages and also disadvantages to them. Then they will definitely choose the best option for the country!

Actually it reminds me a quote by Helen Keller, first deafblind person to earn a Bachelor of Arts degree and also the one who developed braille method for blind peoples. She has given a superb message to the world, the one which motivated me the most!

"I long to accomplish a great noble task, but it is my chief duty to accomplish small tasks as if they were great and noble."

In our context, our ultimate goal is to reduce global warming. It leads to adopting nuclear power plants(NPP) which doesn't emits any global warming gases. But before building any NPP, we have to learn the technology, must educate the public, send engineers to learn the technology and believe in ourselves. Hence these small (literally big) tasks must be accomplished in order to operate NPP in Malaysia.

Ok let us move on into today's topic, which is Nuclear energy is the cleanest, greenest electricity!

We can argue about this topic with various of subtopics. I would like to discuss this topic in terms of globally, economically, socially and safety. Bare with me guys, this is going to interesting.

Ok let us start to discuss, looking in terms of globally, why do we say nuclear energy is the cleanest, greenest electricity? Well, I would say and also the facts says that nuclear is clean in many terms. How about we list down them in point forms?

• One of them would be, it doesn't emit any green house gases like carbon dioside and sulfur hexafluoride.
• It is also clean because it doesn't occupy much area compared to hydro power plant, where massive area needed to built a damn for a hydro power plant (can see how much of habitat will be in jeopardy if we change the structure of the original surroundings)
• NPP only consumes 3 tonnes of uranium per year, while coal powered plants uses 3 million tonnes of coal. (don't you see how much area will be used to operate for mining purposes and also the amount of energy used to transport them?
• it is green because the fuel, uranium can be recycled (can we do that for coal based power plants?)

The basic concept of green would be sustainability of a NPP to continously generate electricity while maintaining the balance of the ecosystem. I'm very sure that nuclear power plants are clean and green. ANY DOUBTS?

ok let us look it in terms of economically. Economy = Money. Does having a NPP provides any advantage to the country? First of all, I would say that adopting nuclear technology shows that our country is also advanced technologically and Malaysians are capable of adopting and handling such technology. Do you wish to be left out in the NUCLEAR RENAISSANCE which is happening now?

By the way, having NPP has more advantages besides potraying ourselves as one of the best in the eyes of the world. The benefits are:-

• fuel of uranium costs mush more lower than the amount that our country spents for importing fossil fuels and coals
• operating a NPP creates various kind of job oppurtunity in the job market and at vasities, where we can offer courses related to nuclear technology
• who knows one day, we can even develop our own type of NPP and built it around the world

Isn't it economically saves the cost of our government in purchasing fossil fuels, coals, and building damns such as BAKUN? Apart from then that, isn't there are many propects revolving adopting this amazing technology? Despite our growing demand of power, I believe we should invest in building a NPP and operating it at a lower cost. As to accomplish our vision 2020, we have to set new stragies to become an advanced country. One of them is by powering nation with Nuclear Energy!

Alright, moving into the context of socially, a NPP can bring many changes in the way of our community can think and react. It brings the awareness of saving the planet and its habitats from extinction due global warming. Besides that, we can raise to the challenge of handling new technology and also later develop it like what countries like Japan and Korea are progressing. Nuclear technology will bring healthy competition among countries to reduce the effect of global warming and also in developing nuclear technology into a new paradigm.

In fact, at other part of the world, people treat NPP as a common building; a common sight of their society. It is also will be possible as such change to occur in our country too. Pictures below are the proofs of such event.



So you must be thinking it is CLEAN and GREEN in fact. But wait, is it safe? YES IT IS!

will you adopt a technology is will harm yourself and others? will you design a power plant which is harmful to you and others. NO! NO! and NO!!!!!!

A NPP is designed in a significant way so that it has the safest systems to cater any faulty events. And it is the safest design embarked so far! This provides an oppurtunity for a NPP to stand clean and green along the environment! One with the nature!

so guys, having a NPP brings more benfits and we have seen why do others call nuclear energy CLEAN and GREEN! the time has come my friends for us to change and raise for the global challenges. One might think that they might play a part in reducing greenhouse gases by using electric vehicles. But they must understand that the electricity supply that they use to charge their electric car is not GREEN as their car. The electricity might be generated by coal or fossil fuel powered power plants. Is that GREEN my friend? THINK ABOUT IT!

THINK GREEN! THINK NUCLEAR!

GIVE NUCLEAR A CHANCE!



"Nuke is our friend " videoclip

Hello guys, how are you doing this weekend? Hope you guys have an awesome weekend with your friends and beloved ones. Oh by the way, I should discuss a little bit about our Nuclear midterm test. It was so so so long...I've never ever taken such a long exam before. It was 4-hour test. Can you imagine? I thought I could finish it before time's up but it turned out that I did not have enough time..haha. It was not diffifult..I personally think the questions are good, comprehensive, covering everything we studied.It was just long..and I was very tired after the test. I wish we could have two tests in stead of one. Well, I think I performed ok, neither excellent nor so poor. How about u guys?

This weekend I have been doing the video about Nuclear. I want to bring something fresh and fun in the video. Not about academic things because we have been watching and listening to our excellent presentations from our beloved lecturers, Mr Shamsul and Mr Azrudi. So I don't want to present repeated things. There are a lot of meanings behind the videoclip, from the characters design, their personality to their behaviours. I hope you can find them. So, let's enjoy it.  

Please feel free to drop your comments and suggestions about the video.

Your time is very much appreciated.
Please set FULL SCREEN to enjoy it!!!
http://www.youtube.com/watch?v=FXMz_4K_M2Y

URANIUM AS NUCLEAR FUEL SOURCE

The fuel most widely used by nuclear plants for nuclear fission. In nuclear fission atoms are split apart to form smaller atoms, releasing energy. Nuclear power plants use the heat from nuclear fission to produce electricity.

Uranium Is Abundantly Found in Nature but Must be Processed into Fuel.

Uranium is nonrenewable, though it is a common metal found in rocks all over the world. Uranium occurs in nature in combination with small amounts of other elements.

Nuclear plants use a certain kind of uranium, U-235, as fuel because its atoms are easily split apart. Though uranium is quite common, about 100 times more common than silver, U-235 is relatively rare.

Economically recoverable uranium deposits have been discovered principally in the western United States, Australia, Canada, Africa, and South America. Once uranium is mined, the U-235 must be extracted and processed before it can be used as a fuel. Mined uranium ore typically yields one to four pounds of uranium concentrate (U3O8 or "yellowcake") per ton, or 0.05% to 0.20% U3O8.

Typical Conventional Uranium Mill

Most of Our Uranium Is Imported

Owners and operators of U.S. civilian nuclear power reactors purchased the equivalent of 53 million pounds of uranium during 2008. Uranium delivered to U.S. reactors in 2008 came from six continents:

• 14% of delivered uranium came from the United States
• 86% of delivered uranium was of foreign-origin:
  • 42% was from Australia and Canada
  • 33% originated in Kazakhstan, Russia and Uzbekistan
  • 11% came from Brazil, Czech Republic, Namibia, Niger, South Africa, and the United Kingdom

Enrichment

Because less than one percent of uranium ore contains uranium-235, the form used for energy production, uranium must be processed to increase the concentration of uranium-235. This process—called enrichment—increases the percentage of uranium-235 from one to five percent.

It typically takes place at a gaseous diffusion plant where the uranium hexafluoride is pumped through filters that contain very tiny holes. Because uranium-235 has three fewer neutrons and is one percent lighter than uranium-238, it moves through the holes more easily than uranium-238. This method increases the percentage of uranium-235 as the gas passes through thousands of filters.

Fuel Fabrication

The enriched uranium is taken to a fuel fabrication plant where it is prepared for the nuclear reactor. Here, the uranium is made into a solid ceramic material and formed into small barrel-shaped pellets. These ceramic fuel pellets can withstand very high temperatures, just like the ceramic tiles on the space shuttle. Fuel pellets are about the size of your fingertip, yet each one can produce as much energy as 150 gallons of oil. The pellets are sealed in 12-foot metal tubes called fuel rods. Finally, the fuel rods are bundled into groups called fuel assemblies.






Uranium Fuel Cycle:




Nuclear Reactor


The uranium fuel is now ready for use in a nuclear reactor. Fissioning takes place in the reactor core. Surrounding the core of the reactor is a shell called the reactor pressure vessel. To prevent heat or radiation leaks, the reactor core and the vessel are housed in an airtight containment building made of steel and concrete several feet thick. The reactor core houses about 200 fuel assemblies. Spaced between the fuel assemblies are movable control rods. Control rods absorb neutrons and slow down the nuclear reaction. Water also flows through the fuel assemblies and control rods to remove some of the heat from the chain reaction. The nuclear reaction generates heat energy just as burning coal or oil generates heat energy. Likewise, the heat is used to boil water into steam that turns a turbine generator to produce electricity. Afterward, the steam is condensed back into water and cooled. Some plants use a local body of water for cooling; others use a structure at the power plant called cooling towers.

Used Fuel Storage

Like most industries, nuclear power plants produce waste. One of the main concerns about nuclear power plants is not the amount of waste created, which is quite small compared to other industries, but the radioactivity of some of that waste. The fission process creates radioactive waste products. After about three cycles, these waste products build up in the fuel rods, making the chain reaction more difficult. Utility companies generally replace one-third of the fuel rods every 12 to 18 months to keep power plants in continuous operation. The fuel that is taken out of the reactor is called used fuel. The used fuel contains both radioactive waste products and unused fuel. The used fuel is usually stored near the reactor in a deep pool of water called the used fuel pool. The used fuel cools and loses most of its radioactivity through radioactive decay. In three months, the used fuel will lose 50 percent of its radiation; in one year, 80 percent; in 10 years, 90 percent. The used fuel pool was intended as a temporary method for storing used nuclear fuel.

However, there is no permanent storage solution yet for used nuclear fuel, and fuel pools space is running out. The nuclear industry has designed dry cask storage as another temporary solution. Now, the used fuel stays in the pool for five to seven years. Then, it is moved elsewhere on the nuclear power plant site to be stored in vaults or dry casks. Each of these methods for managing used nuclear fuel puts the fuel into airtight, steel and concrete structures. The U.S. Nuclear Regulatory Commission has stated that it is safe to store used fuel on site for at least 120 years. Eventually, the used fuel will be reprocessed and/or transported to a permanent federal disposal site.

Image of an used fuel storage pool




Reprocessing
Used fuel contains both radioactive waste products and unused nuclear fuel. In fact, about one-third of the nuclear fuel remains unused when the fuel rod must be replaced. Reprocessing separates the unused nuclear fuel from the waste products so that it can be used in a reactor again.Currently, American nuclear power plants store the used fuel in used fuel pools—without reprocessing. Reprocessing is more expensive than making new fuel from uranium ore. If uranium prices rise significantly or storage becomes a bigger problem, reprocessing may gain favor.

GREEN LECTURE SERIES SUMMARY PART 2

Alright friends, the second speaker also our nuclear technology lecturer gave an eye opening talk. He made everyone present on that day to be fascinated by the beauty behind nuclear technology. Thank you Mr. Azrudi.

The introduction part was somehow rather similar with the previous speaker. Both of them spoke on the depleting energy source of the world and the distribution of energy in related fields. One interesting point I noted during his talk was, from the 100% energy generated, only 42.8% is used by us! The rest? yes, the rest just lost to the surrounding! I hope you know now, why is it getting hot in Malaysia, literally why the world gets hotter. In addition to that more and more greenhouse gasses (GHG) are been released to the surrounding. This worsen the situation more. now please think about this. How can we meet the escalting demandof power without releasing more GHG into the atmosphere?

Absolutely, the answer is by adopting any kind of green energy source. One of them is Nuclear Power Plant (NPP). Here the speaker stressed what does GREEN means? It means alternative energy that can bring a solution to global warming problem and also can sustain its ability to preserve the environment. I am very confident, NPP able to do it without any flaws.

Talking about flaws, relates our interest into safety area present in operating a NPP. Basically a NPP has 3 or 4 or 5 terrain safety system. Each layer starting from fuel pallets till the containment chamber are protect well enough to prevent any sort of problems. As I mentioned earlier in the reactor technology posts, current reactors safety system are designed based on passive safety concepts. Where it is dependent on natural forces such as natural convection, stored energy in a spring, gravity and etc with minimal dependent on humans. If anything goes wrong in a NPP, one could not say, " Oh, I'm sorry. Gravity didn't work well this morning, that's why the control rods got stuck!" It will be a total absurd if one says that, because natural forces occurs naturally without any breaks in between!

In simple words, safety inside NPP has :

NO RELIANCE on human action!

NO RELIANCE on outside power!

NO RELIANCE on active mechanical equipment!



Courtesy of Mr.Azrudi Mustapha, TNB

That's all guys for today. More posts on safety will be coming soon. Don't miss it!

GREEN LECTURE SERIES SUMMARY - PART 1

wow, what a memorable day it is today 10/10/10. It is gift from god and man made calenderical system makes us to witness such wonders. Guess, I have to wait another 100 years to witness it again.

Alright, last week friday, 8th Oct 2010 UNITEN organised Green Lecture Series with outstanding speakers from Malaysian Nuclear Agency and TNB Nuclear Unit. The speakers were respectively Madam Sheriffah Noor Khamseah Al-Idid and Mr. Azrudi Mustapha.

The first talk was delivered by Madam Sheriffah Noor Khamseah Al-Idid on Gobal Overview of Nuclear Power Programme (NPP).

The speaker gave an overview of increasing energy demand from last century till current date. She also  briefed us on the protion of energy demand required by other fields. For example, commercial sector uses 19% of power, residential uses 22%, industrial uses 31% and transportation sector uses 28% of total power demand.

As technology develops vastly and the urge to become a developed country, triggers countries around the world to raise them up to the challenge. As development takes place, need for energy development also increases exponentially. Hence, an utility provider in a country has to cater the increasing demand for power.

While catering for such demand, they have to look into current issues involving several factors and risks. The main question which arise is the sustainability of energy source adpoted by utility provider ( TNB in Malaysia). If a coal powered plant build in Malaysia to cater the energy demand, will it be possible to run at for a longer time with availability of coal supply? will the price of coal, or fossil fuel (petroluem and natural gas) increase dramatically in the future? what are the alternative source we can adopt to sustain power demand in our nation?. Those are questions that a utility provider must ask before adopting any new technology.

Besides that, there are many dillemmas going through around the world which needs as soon as possible. One of those is the global warming issue. It is said that if we don't make a move now, we will loose 20 to 30% species of world by the year 2030. It is not long folks, it is just around the corner. But i guess only the scientist have been cracking their head to find a solution for this problem, I don't see much actions from those who I encounter daily. Ok coming back to nuclear energy, Having a nuclear plant releases no carbon dioxide to the surroundings. Isn't it something that we are looking for? one of the solution to curb global warming. The speaker delivered statistics and many more advantages in adpoting nuclear technology. Some of them, I have covered in frequently asked questions post. Do read them friends.

Tomorrow, we shall see what the second speaker delivered in his talk!



A message from the speaker!



Suggested reactors for Malaysia.

Yes friends, of course! Definitely we will venture into nuclear technology. Or else will be left out in the this nuclear renaissance era. I don't prefer my country to be left out. Do you?

Ok then let's look into the currentlty available GEN 3/3+ reactors. Below here is a table with the available reactors and their details:



Courtesy of TNB Nuclear Energy Unit



 Based on the table above, we can observe that there are ample of factors that can be considered to choose the suitable type and capacity of a reactor. As for a start I would short list the reactors based on one factor which is the reactor capacity factor. I would suggest we use nuclear reactor type with power capacity range of 1300 to 1400 MWe which are ABWR and APR 1400 (PWR).The reason behind the selection is the amount of load that will be connected through one of these reactors to the national grid system to power several areas. Whenener the Nuclear Power Plant (NPP) has to be shut down immediately, huge amount of load will be off the grid suddenly. These condition will lead many problems like damages to power equipments, tripping at many substations, and a possible situation for a blackout throughout the country. Thus the reasonable range of reactor capacity will be 1300 to 1400 MWe.

Secondly, looking into risks that present such as licensing, constructing and life-cycle costs; ABWR and APR 1400 (PWR) has relevant documents and costings. These reactors has been running currently in countries like Japan and Korea gives more advantages in term of exact amount of constructon cost and life-cycle cost. ABWR for instance provides overall good economics, where it has proven costs and scheludes in Asia and US.

Thridly, the safety measure taken to protect the NPP is high in both type of reactors. Both has 3 or 4 terrain safety system which makes breakdown and also radioactive leakage an impossible one. Besides that, upon consturction the major equipments installed on these type of NPP are made from factories and not asssembled at the construction site itself. These equipments from company has longer life and stronger compared to one which is assembled at the constuction site. Main reason behind the assembling of equipments at the site is because of unavailability of technology to commission the equipments once the containment chamber has been built. Now it is not a problem at all, these equipments can be installed using special gadjets inside the containment chamber (thick concrete wall).

Eventhough I have listed 3 advantages of these reactors, which is a Boiling Water Reactor (BWR) and a Pressurised Water Reactor (PWR), there many more areas such as the important ones; public acceptance, economic situation and future demand that we can look into before deciding the type of reactor that we are going to choose.

Types of reactor Part 2

So guys this the continuation of part 1. First of all we are going to look into the summary of part 1. Then we will get to know about currently available reactors. Then I'll post the suggestion of reactors for Malaysia!

Fellow friends, reactors can be classified into few generations. Early prototype reactors are build during the early stages of nuclear adoption by US and Russia. These reactors are called Generation 1 reactors. They were developed and build between the year 1950 to 1970. Example of them are Shippingport,Magnox and Fermi 1.

Generation 2 reactors are the currently operating commercial reactors. They are designed from 1970's based on specific nuclear  safety standards. These reacotrs are extensively used currently in the world. Example of them are PWR, LWR, CANDU, RBMK and AGR. (kindly refer to part 1 for their details)

Generation 3 are the design of evolutionary reactors. These type of reactors are classfied between year 1995 and year 2019. It's main objective is all about safety,safety and safety! It has limited impact on the environment for all impact compared to the previous generation reacotrs. In additional to that they pose extended reliability within extended life time of 60 years. The reactors are the best so far with advanced safety features to protect and internal faults during operation within the plant and external factors such as plane crash or terrorist bombing. Examples of Gen 3 are: Advanced Boiling Water Reactor (ABWR), Advanced Pressurized Water Reactor (APWR), Enhanced CANDU 6 (EC6), and VVER-1000/V-392 (PWR).

Generation 3 + are known as Advanced Evolutionary & Passive Reactors. They are based on passive designs offering improved economics with simpler design and less operator actions. Any actions required for emergency conditions are taken by the system itself without need for an operator to trigger the emergency button. For example, if reaction inside the reactor and the temperature of the reactor increases, the control rod will be released as soon as the sytem detects the rise in temperature and reaction. Releasing the control rods are taken care by gravitational force. There is no chance of gravitational force to stop working. In other word, human factor is minimized and natural forces are given task

(Thus, GEN 3 + reactor are very suitable for operators like Homer Simpson...lol)

The futuristic and totally different type of reactors are the Generation 4 reactors. These reactors co produce hydrogen. It is said that hydrogen from the plants will be used to power hydrogen economy that is expected to bloom after the year 2030.




Summary of Nuclear Reactor  Evolution. Courtesy of Argonne National Laboratory

 

Types of Reactor Part 1

What is a reactor?

Well, reactor is actually the heart of the Nuclear Power Plant (NPP). Components inside a reactor are arranged in such way that to control and sustain the fission reaction of the fuel (which uranium-235). There are several arrangement of components inside a reactor which eventually become a particular type of nuclear reactor. We will look at each of the design and technology behind the design.

Type 1:

PRESSURISED  WATER REACTOR (PWR)



COURTESY OF NRC USA

CAPACITY         :250.5 GWe

FUEL                  :ENRICHED UO₂ (URANIUM OXIDE)

MODERATOR  :WATER

COOLANT         :WATER

COUNTRIES     :US,FRANCE,JAPAN,RUSSIA,CHINA

PWR is the most common reactor and most succesful power reactor.



COURTESY OF NUCLEAR WORLD.ORG


Type 2:

BOILING  WATER REACTOR (BWR)

COURTESY OF NRC USA

CAPACITY         :86.4 GWe

FUEL                  :ENRICHED UO₂ (URANIUM OXIDE)

MODERATOR  :WATER

COOLANT         :WATER

COUNTRIES     :US, JAPAN,SWEDEN

COURTESY OF NUCLEAR WORLD.ORG

Type 3:

CANDU REACTOR (PHWR)

 

COURTESY OF NULEAR-WORLD.ORG



CAPACITY          :23.6 GWe

FUEL                   :NATURAL UO₂ (URANIUM OXIDE)

MODERATOR  :HEAVY WATER

COOLANT         :HEAVY WATER

COUNTRIES     :CANADA

CANDU reactor is known as Canadian Deuterium Uranium reactor. It is also known as Pressurised Heavy Water reactor (PHWR).

 

Type 4:

GAS COOLED REACTOR (AGR & MAGNOX)



COURTESY OF NUCLEAR-WORLD.ORG



CAPACITY         :10.8 GWe

FUEL                  :NATURAL ²³⁸U and ENRICHED UO₂ (URANIUM OXIDE)

MODERATOR  :GRAPHITE ₂

COOLANT         :CARBON DIOXIDE,CO

COUNTRIES     :UK

Type 4:

LIGHT WATER GRAPHITE REACTOR (LWGR)

LWGR is a Soviet design, developed from plutonium production reactors. It employs long (7 metre) vertical pressure tubes running through graphite moderator, and is cooled by water, which is allowed to boil in the core at 290°C, much as in a BWR. Fuel is low-enriched uranium oxide made up into fuel assemblies 3.5 metres long.

Constraints asssociated with moderation are largely due to the fixed graphite,where excess boiling simply reduces the cooling and neutron absorbtion without inhibiting the fission reaction. It induces a positive feedback problem,which raises power in exponential factor within seconds. That is why they have never been built outside the Soviet Union.

CAPACITY         :12.3 GWe

FUEL                  :ENRICHED UO₂ (URANIUM OXIDE)

MODERATOR  :GRAPHITE

COOLANT         :WATER

COUNTRIES     :RUSSIA

Type 5:

FAST NEUTRON REACTOR (FNR)

Some reactors (only one in commercial service) do not have a moderator and utilise fast neutrons, generating power from plutonium while making more of it from the U-238 isotope in or around the fuel. While they get more than 60 times as much energy from the original uranium compared with the normal reactors, they are expensive to build.  Further development of them is likely in the next decade, and the main designs expected to be built in two decades are FNRs.  

CAPACITY         :1 GWe

FUEL                  :PuO₂ (PLUTONIUM OXIDE), UO₂ (URANIUM OXIDE)

MODERATOR  :NONE

COOLANT         :LIQUID SODIUM

COUNTRIES     :FRANCE,JAPAN,RUSSIA

Xe Poisoning Effect

As mentioned in the previous post, poison is a type of material used to control the rate of fission reaction. In this post, we are going to discuss on one of the most important poisons in the nuclear reactor which is Xe.

As known, a major contribution to the sequence of events leading to the Chernobyl nuclear disaster was the failure to anticipate the effect of "xenon poisoning" on the rate of the nuclear fission reaction in the Chernobyl nuclear reactor.

So, we are going to examine its effect on reactivity of fission reactions through the example of Chernobyl accident.

One of the extraordinary sequences in the operation of a fission reaction is that of the production of I, iodine-135 as a fission product and its subsequent decay into Xe, xenon-135. 6% of the fission products are Iodine-135. It has a rather small probability for absorbing a neutron, so it is not in itself a significant factor in the reaction rate control. But it has a half-life of about 6.7 hours and decays into xenon-135 (half-life 9.2 hours). And Xe-135 likes neutrons very much since it has a very high probability for neutron absorption.

Xenon is produced either by decay chain from Iodine- 135 or direct yield from fission reaction. It is lost by either absorption (burn-up) of a neutron to become Xe -136 which is a weak neutron-absorber. In the normal operation of a nuclear reactor, Iodine-135 is produced, decays into xenon-135 which absorbs neutrons. It establishes the balance of the operating conditions. There is an equilibrium concentration of both iodine-135 and xenon-135.

When a new reactor is started up, it is xenon-free. When the reactor goes critical at low power (low neutron flux), a negligible Xenon is presented. When the reactor is brought up to higher power, Xenon builds up, the operators have to withdraw control rods in order or the reactor to maintain the critical state.

When a reactor is shutdown, the neutron flux is reduced. Xe is no longer produced by fission and is no longer removed by burn up (since no neutrons to be absorbed). So the only operation is I-135 decay to Xe 135 and Xe -135 decays itself.

In the Chernobyl case, there were some failures in understanding in Xenon effect. When the persons conducting the tests on the Chernobyl reactor tried to increase the power at some point in their tests, it would not respond. They apparently did not have the understanding that the failure to increase was due to the absorption of neutrons by the xenon, so they completely removed the control rods to force the increase. The increased power then burned away the xenon and also caused voids in the cooling water, both of which rapidly increased the reaction rate, driving it out of control.

So, it is essentially important for nuclear engineers to have a proper understanding and detailed knowledge as well as careful control in dealing with nuclear reactor.

The Axe-Man of Nuclear Reactor

The story begins with a well. It is called the well of electricity. By some means, it produces electricity from inside and it is very very hot (hundreds of degree)!! There is some kind of rods hung above the well, suspended by a rope. There is a person in charge of this well. His job is to take a fire axe, waiting for the signal. When the ringing bell informs that the well temperature is over the limit, he rapidly cuts the rope, allowing the rods to fall into the well and stop whatever happening in it. As for his good job, he is given a title as SCRAM, or Safety Control Rod Axe Man.

Who is he?

Well, the Axe man is nobody but control rods of nuclear reactor. They are made by neutron-absorbing materials such as Silver (Ag), Indium (In), Cadmium (Cd), Hafnium (Hf) or Boron (B). Their function is to increase or decrease the number of neutrons in the reactor. They are inserted or withdrawn from the core to control the rate of fission reaction (depending on the number of neutrons). In turn, it affects the thermal power of the reactor, the amount of steam produced, and hence the amount of electricity generated.

If the materials absorb all the neutrons coming to them, they are called “Black” neutron-absorbers. If only part of incident neutrons is absorbed, they are called “Grey” neutron absorbers. It is like we tend to absorb a larger amount of sun lights when wearing black clothes than white clothes (simple enough??)

Control rods can operate to serve different purposes. Therefore, they are called different names.

1. Shim rods: To make a coarse adjustment in the reactivity of a nuclear reactor

2. Regulating rods: To make a fine, small adjustment to maintain desired power

3. Safety rods: To provide a very fast shutdown in case of unsafe condition (SCRAM).

Different type of reactors and controls require different type of control rods. They are often combined together to become dual-purpose or triple – purpose rods.

Beside the control rods which control the reactivity of nuclear reactor, another important element which contributes in this job is called Poison.

Although it is called poison but it is good for the nuclear reactor. It is also made of neutron-absorbing materials like control rods. The need of Poisons is explained as following.

After a long time operation, the amount of fuel contained in the core decreases. Therefore, the fuel in excess of that needed must be added when the reactor is built. However, to maintain the normal operation of reactor, we need to decrease the amount of excess power which is generated from excess fuel loaded into the core. One method is to use movable control rods as described above. But control rods alone to balance the excess reactivity may be impractical for a particular core design as there may be insufficient room for the rods or large their mechanisms. That’s why to control a large amount of excess fuel without adding additional control rods. So, we need Poisons.

There are several types of Poisons.

1. Burnable poisons: as their names, they are burned up when absorb neutrons. So, its effect is decreasing over the core life.

2. Fixed burnable poisons: they are burnable poisons which are shaped with the core.

3. Soluble poisons: they are soluble circulated in the coolant during normal operation.