Nuclear Safety

Hi to all readers,

Now, I will explain about nuclear safety… how about you? Do you think it is safe to build nuclear power plant in Malaysia? Basically, the three primary objectives of Nuclear Safety Systems as defined by the Nuclear Regulatory Commission are to shut down the reactor, maintain it in a shutdown condition and prevent the release of radioactive material during events and accidents. There are many aspects we should consider. One from them is defense-in-depth approach. To achieve optimum safety, nuclear plants in the western world operate using a 'defense-in-depth' approach, with multiple safety systems supplementing the natural features of the reactor core. Key aspects of the approach are:

-         high-quality design & construction,

-         equipment which prevents operational disturbances or human failures and errors developing into problems,

-         comprehensive monitoring and regular testing to detect equipment or operator failures,

-         redundant and diverse systems to control damage to the fuel and preventsignificant radioactive releases,

-         provision to confine the effects of severe fuel damage (or any other problem) to the plant itself.

How about nuclear safety when earthquake occur? According to nuclear world website, we find that nuclear power plants are designed with sensors to shut them down automatically in an earthquake, and this is a vital consideration in many parts of the world. Below is the example other country take when earthquake occur:-

-         Japanese, and most other, nuclear plants are designed to withstand earthquakes, and in the event of major earth movement, to shut down safely.

-         In 1995, the closest nuclear power plants, some 110 km north of Kobe, were unaffected by the severe Kobe-Osaka earthquake, but in 2004, 2005, 2007 and 2009 Japanese reactors shut down automatically due to ground acceleration exceeding their trip settings.

-         In 1999, three nuclear reactors shut down automatically devastating Taiwan earthquake, and were restarted two days later.

Nuclear facilities are designed so that earthquakes and other external events will not jeopardize the safety of the plant. Below are the safeties that other countries take into considerations:-

-         In France for instance, nuclear plants are designed to withstand an earthquake twice as strong as the 1000-year event calculated for each site.

-         Because of the frequency and magnitude of earthquakes in Japan, particular attention is paid to seismic issues in the siting, design and construction of nuclear power plants. The seismic design of such plants is based on criteria far more stringent than those applying to non-nuclear facilities. Power reactors are also built on hard rock foundations (not sediments) to minimize seismic shaking.

-         Japanese nuclear power plants are designed to withstand specified earthquake intensities evident in ground motion. These used to be specified as S1 and S2, but now simply Ss, in Gal units. The plants are fitted with seismic detectors. If these register ground during the motions of a set level (formerly 90% of S1), systems will be activated to automatically bring the plant to an immediate safe shutdown.

-         The December 2004 tsunamis following a magnitude 9 earthquake in Indonesia reached the west coast of India and affected the Kalpakkam nuclear power plant near Madras/Chennai. When very abnormal water levels were detected in the cooling water intake, the plant shut down automatically. It was restarted six days later.

One more thing we must take into considerations about nuclear safety is passive safety system. One major feature Japan has in common (beyond safety engineering already standard in Western reactors) is passive safety systems, requiring no operator intervention in the event of a major malfunction. The main metric used to assess reactor safety is the likelihood of the core melting due to loss of coolant. These new designs are one or two orders of magnitude less likely than older ones to suffer a core melt accident, but the significance of that is more for the owner and operator than the neighbours, who - as Three Mile Island showed - are entirely safe also with older types.

Other than that, the Emergency Core Cooling System (ECCS) is one more safety thing to the nuclear. Emergency Core Cooling System (ECCS) comprises a series of systems which are designed to safely shut down a nuclear reactor during accident conditions. Under normal conditions heat is removed from a nuclear reactor by condensing steam after it passes through the turbine. These systems allow the plant to respond to a variety of accident conditions and at the same time create redundancy so that the plant can still be shut down even if one or more of the systems fails to function. In most plants ECCS is composed of the following systems; High Pressure Coolant Injection System (HPCI), Depressurization System (ADS), Low Pressure Coolant Injection System (LPCI), Isolation Cooling System and other else.

Nuclear spent fuel management

The production of nuclear electricity results in the generation of spent fuel that requires safe, secure and efficient management National strategies for the management of spent fuel vary, ranging from reprocessing to direct disposal. This indicates that spent fuel is regarded differently by countries - as a resource by some and as a waste by others. Appropriate management of the resulting spent fuel is a key issue for the steady and sustainable growth of nuclear energy .For the example, at the end of 2005, 443 nuclear power reactors were operating in 30 countries worldwide, providing 16% of the global electricity supply. Over 10 000 t of heavy metal (t HM) are unloaded from these reactors each year, which will increase to ~11 500 t HM by 2010. This is the largest continuous source of civilian radioactive material being generated, and needs to be managed appropriately. At the moment most spent fuel is in storage at nuclear power plants, at a few centralized storage sites and at reprocessing facilities. Originally all spent fuel was expected to be reprocessed within a few years and the remaining fuel material recycled into new fuel. The waste from reprocessing was intended to be disposed of in geological repositories. The next steps towards the disposition of spent fuel are either reuse, through reprocessing, or disposal in geological repositories. Some countries are continuing the recycling route, while others have decided to regard the spent fuel as a waste intended for direct disposal .Because progress on implementing these strategies is slow in most countries; the amounts of spent fuel in storage are increasing. The prospect of a revival of the nuclear power industry in the next decades indicates that even more spent fuel could go into storage. On the other hand, spent fuel has been successfully and safely stored in wet and dry conditions for several decades without serious problems, but without decisions on more permanent solutions there could be the prospect of continued storage for times of up to and beyond one hundred years. The management of spent fuel is, for strategic, economic, safety and security reasons.

Reprocessing of spent fuel used

The used fuel dry storage process

Nurkilan nusantara berangan....

Nuclear Fuel Cycle (3)

Other steps in nuclear fuel cycle is Milling...

Uranium milling is the process of extracting uranium from mined ore. The ore is crushed into sand size particles and the uranium is leached out. The uranium then is precipitated out of the leaching solution and dewatered, dried, and packaged. Through the extraction process, uranium is concentrated into a product referred to as "yellowcake." In situ leaching is a combined mining and milling operation.

The picture show the milling process:

     1. Mined ore is crushed

     2. Crushed ore ground into fine sand

     3. Slurry pumped into leach tanks

     4. Acid dissolves uranium

     5. Uranium filtered from waste

     6. Purified & Concentrated

     7. Uranium extraction

     8. Moisture Removed

Yellowcake is a kind of uranium concentrate powder obtained from leach solutions, in an intermediate step in the processing of uranium ores. Yellowcake concentrates are prepared by various extraction and refining methods, depending on the types of ores. Yellowcake is used in the preparation of uranium fuel for nuclear reactors, for which it is smelted into purified UO₂ for use in fuel rods for pressurized heavy-water reactors and other systems that use natural unenriched uranium.

Nuclear Fuel Cycle (2)

There are many steps nuclear fuel cycle…There first step is mining.

 

Uranium mining is the process of extraction of uranium ore from the ground. As uranium ore is mostly present at relatively low concentrations, most uranium mining is very volume-intensive, and thus tends to be undertaken as open-pit mining. 

There are 3 types of mining which are:

1.      Open cast mining

2.      Underground mining

3.      In situ leaching.

1.      Open cast mining

It’s means mining at the surface rather than underground. Coal, iron ore, and phosphates are often extracted by opencast mining. The mineral deposit is covered by soil, which must first be stripped off, usually by large machines such as walking draglines and bucket-wheel excavators.

 

2.      

      Underground mining

Underground mining is a technique used to access ores and valuable minerals in the ground by digging into the ground to extract them.

 

3.      

       In Situ Leaching

In situ leaching (ISL), also known as solution mining, or in situ recovery (ISR) in North America, involves leaving the ore where it is in the ground, and recovering the minerals from it by dissolving them and pumping the pregnant solution to the surface where the minerals can be recovered.

 

 From 3 types of mining I prefer underground mining. This is because it have their advantages compared to other type. Advantages of underground mining are:

·         It allows minerals to be extracted from deep underground

·         It doesn't create a mess like open cut or surface mining

·         Does not affect the physical environment as much as surface mining




References:
http://en.wikipedia.org/wiki/Nuclear_fuel_cycle
http://en.wikipedia.org/wiki/Open_cast_mining
http://en.wikipedia.org/wiki/Underground_mining
http://en.wikipedia.org/wiki/In-situ_leach

Nuclear Fuel Cycle (1)

Hello……

Today, we all study about nuclear fuel cycle…..

You all know about Uranium??? Ok…Before I go further let me explain definition of the Uranium…

Uranium is a very dense, radioactive metallic element, naturally occurring in most rocks, soil, and even in the ocean.

Uranium, a radioactive element, has existed since our planet was born.

²³⁸U – 99.29% and half life, λ= 4.47 x 109years

²³⁵U - 0.711 % and half life, λ= 7.04 x 108years

²³⁴U - 0.005 %

Its most stable isotope, Uranium 238 (92 protons + 146 neutrons), has a half-life of about4.5 billion years, or the age of the Earth.

Global Nuclear Power

Now in global, we have 436 commercial nuclear power reactors (+ 28 under construction). However 30 countries have their own nuclear power. Nowadays, 16% of world electricity supplied by nuclear as base-load. The total worl power capacity is 370000 MWe. To improve this nuclear power, 56 countries operate a total of 284 research reactors and a further 220 reactors power ships and submarines.

Uranium Requirements

•Principal demand is for nuclear fuel.

•Current Demand:

~ 441 reactors worldwide

Total output ~ 376,000 MWe

Each requires ~ 170 tonnes UOC per year

UOC requirement ~ 70,000 tonnes per year

•Current Production (2009):

Current UOC output = 50,772 tonnes per year

Nuclear Properties of Uranium

•U isotopes all alpha emitters.

•Some spontaneous fission (SF).

•Specific activity of U low due to long half-lives, but they can decay through chain of

  daughter products, ultimately leading to lead or bismuth.

•At secular equilibrium, all decay rates are same throughout the chain. Daughter product

  concentration in proportion to half-life. More or less, 95% of specific activity (Bq/kg) is

  due to daughter products.

Reference: Nuclear Fuel Cycle Lecture 

Nuclear Test

Salam..

First of all, Thank to Allah because give me the opportunity writing on this blog. Yesterday, on shadow by really nice date, 10.10.10, our country have been shocked with tragic accident at Susur Simpang Empat, Alor Gajah, Melaka. Takziah to victim’s family, Al-Fatihah..

Ok, let’s continue to our topic, The introduction of Nuclear Technology. Actually, today (11.10.10) is our test on this subject. Alhamdulillah..thanks to our beloved lec, Sir Syukri, Sir Azzrudi and Sir Shamsul because of the tips!!hehe

After a busiest weekend ever, have a talk on Friday evening, then continue with the revision until 7pm o’clock and having 2days to cover 4-5 chapters, the effort of students and lecturers needs to be proud!yes, i can conclude that, I’m ready to become one of the expertise on Nuclear in Malaysia.haha. : D

This test is contain two part, Part A and Part B. Part A is held on 6pm and finished around 7.40 pm and continued with Part 8 on 8pm O’clock. The Part A is covered from Chapter Atomic Number and essay which is come from the talk given by Pn Sherryl and Mr Azzrudi last Friday. Meanwhile, the Part B is covered from Chapter 4 and 5 that, have been lectured by Mr Shamsul a few weeks ago.

Since this subject doesn’t have a Final Examination, we need to give more than 110% efforts to score on this test. And now, we need to make a video and have a presentation before during the final week of study. And also now, I am really confident that, one day, i will become one of the expertise about the Nuclear Technology. InsyaAllah..hehe

Please remember, the energy nowadays is more reduced and we need the alternative energy for our next generation. And, The Nuclear energy is the best answer! I know that, a lot of people related this Nuclear energy with military, not as an alternative fuel rite? Besides, many people scare and worried about the radiation. For your information, there is too little of radiation that have been produced by a Power Plant ( around 0.0075 miliemeter ). We as a human can accept, the maximum of radiation around 5,000 miliemeter per year.

TALK SUMMARY

Hi to fellow friends,

We meet again in this column and at this time I want to share what I got from the talk lecture series by Mrs. Sheriffah Noor Khamseah Al-Idid binti Dato’ Syed Ahmad Idid from Nuclear power Division, Malaysia Nuclear Agency, Bangi and Mr. Azrudy from TNB Nuclear Unit.

Our first speaker is Mrs. Sheriffah Noor Khamseah Al-Idid binti Dato’ Syed Ahmad Idid. From what she explained, lots of knowledge we get and let says before this we don’t know about nuclear fact, we just got from her explanation.

His title talk series is Global Overview of Nuclear Power Programme (NPP).

So, let me summarize this lecture series to give you an easy way to understand. From 1850 until now, there a lot of energy uses in our life. Coal, oil, gas, and lately nuclear have been uses as the energy source. But, until year 2015 oil remains the dominant energy source. From Mr. Nabuo Tanaka qoute, Executive Director, International Energy Agency (IEA), he stated that the current energy that we used is unsustainable. Therefore, it does will affect the global warming and can give the effect to the people.

With the oil price always unstable and sometimes price are high give the big impact to us. So, we need to find the solution to find the green energy sources. So, nuclear are the green energy that we find?? For your information, uranium with fast breeder reactors have lifetime energy resources is higher with more than 3000 years we can uses with coal is 155 years and gas with 65 years only.

Remove to other part which is status of nuclear power as the end of 2009. This part is very important for me because we can know how much country uses nuclear as their energy sources and how many countries to follow this step. For whom who know, let me tell you that 30 countries(436 nuclear power plants) already have nuclear power plant and it’s generate about 15% of world energy electricity and will be more increase year by years. From these 30 countries, many of them use PWR (Pressurized Light-Water-Moderated and Cooled Reactor) as the reactor types.

From the Yukiya Amano, Director-General, International Atomic Energy Agency (IAEA), more than 60 countries are interested in exploring nuclear energy. From his speech, he stated that “Nuclear power is accepted by an increasing number of countries as a stable, safe and clean source of energy. The growing attractiveness of nuclear power is due to a number of factors. They include its strong performance and safety records, now totaling more than 14,000 reactor-years; nuclear power´s very low greenhouse gas emissions; surging global energy demand; and concern about energy security”. So, let’s consider this green energy sources as our country energy sources. Can you support that??

Before I finish my summarization, I am very attracted to Mr. Azrudy speech about how to save our Earth on green environment? We support electric car as to save the earth but the electric car uses energy from hydro for example which release carbon dioxide to our environment. So, how to save our environment? Therefore, let’s uses nuclear energy as sources because its green energy and no carbon dioxide are released.

Hello……

We come back again…..Now I will explain about  what I hear during second talk today…The talk discuss about “Nuclear goes green”…

Can you think how different the world would be today if 40 years ago we had replaced all fossil fuel with nuclear power? There would be no power shortages. Our electrical bill would be a fraction of what it is. We would be driving cars powered by hydrogen and nobody would be worrying about global warming...

Since the Chernobyl disaster, many people think badly about nuclear. But now many people are talking about nuclear and advantages. Now, a lot of research was done to build a nuclear power plant. Nuclear is good because they are good at building weapons and powering cities for the benefit of man-kind. The buildings are good to because they are tall and if there is a big explosion, no one gets hurt.

Scared of nuclear power? Well think again.          

Nuclear Power has a higher safety record than any other major industrial technology. It’s clean, safe, economical and environmentally sound, and allows us to desalinate our water, end hunger and poverty, and turn our wastelands into Gardens of Eden. Nuclear power has more than just a little greenhouse gas attached to it, when mining uranium are, refining and enriching fuel, building the plant, and operating it are included.

Nuclear Power also can help us end our dependence on oil, thereby lessening terrorism and our need to engage in oil-based wars. Nuclear Power is the key to reversing global warming. Find out what really happened at Three Mile Island and how despite the media hype, Chernobyl was simply a one-in-a-million occurrence. Environmentalists have distorted the facts and brought down the nuclear industry. Society must be prepared to again bring nuclear power to the forefront, or the human race may not survive the 21st century.

 

Do you know a typical pellet of uranium weighs about 7 grams can generates how much energy?

For your information, it can generates as much energy as 3.5 barrels of oil, as much as 17,000 cubic feet of natural gas and as much energy as 1,780 pounds of coal…

Now, you can feel it’s nuclear is green or not…Think carefully…

Can Malaysia Run Nuclear Power Plant?

Hi fellow friends,

Since the government launch to use nuclear power plant in 2025(from article before, sources from TNB), many people attract to know about what inside nuclear power plant info, and what are the advantages and disadvantages using nuclear power plant to our country. Off course we will give you some info and I hope that you can appraise about this interesting topic.

For your information, nuclear energy has been contributing to 15% of the world’s energy today as can be seen in Figure below. Some nations rely heavily on nuclear, whereas others have a small proportion of nuclear in their total energy portfolio. France has the highest proportion of electricity produced by nuclear sources at a figure of more than 70%. Figure 2 shows the proportion of electricity generated via nuclear energy.  There seem to be about 30 countries around the world with nuclear reactors with total capacity of 372,000 MW[1]. However, many Asian countries are still lagging behind developed nations in terms of nuclear power. So, what are the contributing factors behind this slow adoption of nuclear power?

World electricity generation

Nuclear electricity generation

Below I will conclude about advantages and disadvantages of using nuclear power plant.

In order to determine the feasibility of nuclear power plants in Malaysia, we need to understand the local scenario. First of all, why didn’t we have nuclear plants in the past? A few analyses in the 70s and 80s were carried out, but the Malaysian Board of Energy, Tenaga Nasional Berhad (TNB) decided to build more gas plants following the rapid expansion of the oil and gas field. Now that gas prices are soaring, nuclear seems like a pretty good alternative. Another reason for sceptics to discount this source of energy at that point in time was due to two major nuclear power incidents in Three Mile and Chernobyl. The common cause of these two incidents is human error.

So, from our point of view, if we want to build nuclear power plant, for short term purposes, importing expatriates with the right skill sets can do the job. But in the long term, it is necessary to train people locally in order to sustain locally operated nuclear power plants.

SO, HERE WE ARE TO REALIZE THAT…..

Reference

[1]  World Nuclear Association,” 2009