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HeonOetting-AnAppliactionOfMachineLearningToTheBoardGamePentago

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An Application of Machine Learning to the Board GamePentagoGreg HeonLilli OettingDecember14,2012AbstractWe present an application of machine learning to the two-player strategy game Pentago.We have explored two different models through which to train our program-a feature-based model and a reinforcement learning model.This paper discusses the relative merits of each,as well as the obstacles we encountered using each model.IntroductionIn the last century,intelligent gameplay has become a classic problem in artificial intelligence. Computers have an unmatched ability to solve problems with brute force,but games often con-tain too many possibilities for a computer to calculate the best move in a reasonable amount of time.To play a game well in a reasonable amount of time,a computer must transcend brute force andfind a smart move without considering every single possible move made in the future; in essence,it must start to understand the game.Pentago is a two player strategy game composed of four quadrants containing a three by three grid each.A players turn consists of placing one piece in an open space and then rotating one of the quadrants90degrees in either direction.Each player must complete both of these actions on a given turn.Play continues until a player achieves a consecutive sequence offive of his or her own pieces or the board isfilled,resulting in a tie.Thefive-in-a-row sequence can be contained in any row,column,or diagonal on the board.We considered several games before settling on Pentago.It is feasible for a machine learn-ing application because it is deterministic,strategic,and unsolved.We avoided games that involved aspects of randomness,like dice or many card games,since we thought that given our limited computing power we would not be able to run enough training trials to average out the randomness.We ultimately implemented a feature-based model that trains the weights on each feature, and a reinforcement learning model that trains a policy.Both models are trained through self-play.The details of each are discussed below.Feature-Based ModelThefirst model we implemented was based on parameterized features and a greedy policy that evaluated board positions and chose the move that would lead to the most highly valued result. Because Pentago is a deterministic game,this strategy can lead to near perfect results if it is able to look an unlimited number of moves into the future when deciding which move to make. Our implementation is based on a large number of pre-defined features and associated weights that are built up based on game results.The ModelFeature SelectionA variety of features associated with success in Pentago are used to evaluate potential moves. Thefinal model contained35different features of gameboards,ranging from features obviously linked to success(i.e.number of4-in-a-row sequences)to those whose importance we were unsure of(i.e.number of corner pieces).We decided to include a large number of features and allow the weights developed during self-play determine the relative importance of each feature and downplay features that are not shown to have a strong affect on the game result.Starting with a wide variety of features limits the affect of our personal bias in the eventual performance of the program and allows the relevant features to be selected through the weights determined during gameplay.Weight DeterminationThe success of this model is based upon its ability to develop weights that accurately reflect a feature s correlation with success in the game.Weights are initialized according to reasonable estimates of which features we suspect to be correlated with success and refined through self-play.This process involves two instances of the program playing against each other.In each game,one player uses the current set of weights and the opponent uses this set adapted by a slight random deviation.The two instances play a game,and the winning players weighting set becomes the current set in the next round.Through this process,we hoped to converge on an optimal set of weights.Results and SetbacksIdeally,this model would be able to look an unlimited number of games into the future when determining a move.Unfortunately,limits on our computing power make this impossible.We reduced this model to a minimax strategy that evaluates all possible moves for the active player, then all possible moves his or her opponent could make in response,andfinally the moves that the active player would be able to make after the opponent has played.The objective is tominimize the threat posed by the opponent on his or her next move.Given that there are more than250possible moves per turn in the beginning of the game,evaluating15.6million boards in order to make a single move was too computationally intensive for the computers available to us.Even looking only three moves ahead was too slow to run the number of games necessary for weight convergence.We eventually switched to a model which evaluates only the immediately reachable boards and doesnt have information about any future moves.This strategy still produced a program intelligent enough to beat a random move generator but much less intelligent than a model which can examine future moves.The fact that the program must evaluate every possible board based on such a large feature set causes it to run slowly even when examining only a single move.In order tofind a more efficient alternative we turned to a reinforcement learning model.Reinforcement LearningThe ModelOur reinforcement learning model uses a Markov decision process(MDP)approach.The num-ber of board positions,however,is too large for the computing power we had,so we hashed board positions into buckets and ran the MDP model on these buckets instead of the much larger state space that is all board positions.On each turn,the obtainable boards are hashed into buckets,and the move associated with the highest valued bucket is chosen.The state transition probabilities are initialized such that there is an equal probability of being able to move between all buckets and built up by seeing what moves are made during self-play. HashingHashing into buckets made reinforcement learning a feasible way of approaching Pentago. Choosing the correct number of buckets and the correct hash function were two of the most difficult problems we encountered with the reinforcement learning approach.Choosing the number of buckets consisted of balancing time constraints,computing power limitations,and the program s performance.As we increased the number of buckets,each game took longer and more memory was used.Even implementing a sparse array for the transition probabilities matrix didn t stop our program from using up all the application memory on an iMac with1000buckets and less than5000training games.On the other hand,having too few buckets meant too many different states would be hashed into the same bucket.If the value of the two boards was significantly different for the two states within the same bucket,the value associated with that bucket is unrepresentative of the boards it contains,which causes poor gameplay.One solution to this collision problem is a smart hash function.Hash function choice is a time and intelligence tradeoffthat we never found a good middle ground for.The hash function we created originally takes the sum of the product of the the piece placed in each spot(0for empty,1for player1,and2for player2)and primes(2,3,5,and7)raisedto the power of the piece s spot in the quadrant(0through8).It then takes the sum mod-ulo numBuckets-2and sets that as the states bucket number.Buckets0and1are reserved for player1wins and player2wins respectively.This essentially hashes boards into buckets randomly since there is no effort to group similarly valued boards together.The benefits of randomly hashing is that it is very fast,but the collisions do detract from gameplay.The alternative to a random hashing is a hashing based on features.Unfortunately,there were no easily calculable features that indicated who was winning,so we implemented a hash function that counted the sum of cubes of streaks(a four in a row would be a streak of four)of each player and taking the sum of thefirst player s andfive times the second player s.1While this would hash similarly valued states together,it was prohibitively slow.To create a brilliant pentago program,one would need a smart and quick hash function,but the game of Pentago is arguably too complex for such a function to exist.At the writing of this paper,the authors have been unable tofind such a function.Self-playThe training of our program consisted of playing itself repeatedly,learning from a win or loss each time.Because states for both players are hashed into the same buckets,but can be unrelated in terms of value,we thought it best to train two side-by-side models;thefirst learns to playfirst,and the second learns to play second.Each has its own probability matrix and value vector.Exploratory MovesTo ensure that the two computers learned a more universal strategy,we programmed each to make random moves some percent of the time during training.These exploratory moves forced the computer to consider states it would not see otherwise and also kept the computer fromfinding what is essentially a local maximum.Some of the data we took was trying to find the best in terms of performance against our baselines.This is discussed in the Results section.UpdatesUpdates on the transition probabilities matrix and the value of each bucket were made after each game ended.Rewards were given only at the end of games.Wins were awarded10and losses-10.ResultsFinding the best parametersWe did tests on the following parameters:the number of buckets hashed into,the number of games,the discount factorγ,the convergence toleranceτ,and the percentage of exploratory 1Five was chosen because a streak offive means the game is overmoves .The best parameters we found given our computing limitations were1500buckets, 2000training games,γ=0.9,τ=0.001,and =20%.Performance against a baselineWe tested reinforcement learning performance against two baselines.Thefirst was a computer that made random moves and the second was our feature-based algorithm.Since the feature based-algorithm is so slow,fewer test games were played when testing against it.Our results with the optimized parameters were winning about96%of the time against random and30% of the time against the greedy algorithm,when it made itsfirst three moves at random.While we wished to see better performance against the greedy algorithm,the96%against random is a clear indicator of intelligent play.The only other baseline we used was occasional human testing,when we wouldfirst train the program and then the authors would play it.While it never won,there were games where it exhibited intelligence in the moves it chose.ConclusionAlthough neither model yielded ideal results,we were able to successfully implement two meth-ods of developing intelligent computer play that performed significantly better than a random-move generator.Based on our results,we believe that our models would result in much more sophisticated play with more time and computing power in order to run a larger number of training games,increase the number of buckets in our reinforcement learning model,and in-crease the number of future moves evaluated by the greedy parameter-based model.This project is significant because it explores fundamental questions of machine learning and the power of computers that extend into much more socially significant realms.The basic aspects of this project teaching a program without human input,solving a problem with unknown parameters,and exploring whether a computer can develop a system of complex strategy are important for a wide variety of applications in machine learning.。

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令人折服的BAUER德国宝华氦气回收系统

令人折服的BAUER德国宝华氦气回收系统

Circuit: from helium liquefaction via recovery to reutilisation 封闭循环利用回路：从氦气回收、液化、 到二次利用 BAUER convincing helium recovery: tailor-made & absolutely gastight令人折服的宝华氦气回收系统：量身订造 + 100%气密性A company working for more than 60 years successfully in the field of high pressure system engineering for air for respiration, industrial air and technical gases has been intensivelyengaged in the process of helium condensation for many years. As a result, the companysupplies complete recovery systems, mostly to research laboratories of universities andinstitutes, worldwide - tailor-made and absolutely gastight. The system offered comprises gas compressor plants as well as the gas balloon and gas processing and storage.60多年高压压缩领域的历史，从呼吸空气到工艺气体，德国宝华压缩机系统工厂多年来致力于氦气回收系统研发。

在宝华，这里有完备的气体回收系统，其客户遍及全球各个大学和科研院所的实验室和检测工厂。

宝华提供系统定制服务，保证100%的气体密封性。

哈佛案例翻译

哈佛案例翻译

酸雨：南方公司1992年年初，南方公司的经理们正在重审应对《空气清洁法案》1990修订案酸雨条款的战略。

南方公司是一个控股公司；它的经营机构是佐治亚州、阿拉巴马州、密西西比州和佛罗里达州的电力公司。

它最大的南方子公司---佐治亚电力和阿拉巴马电力，其所在州大部分的电力都分别由这两家公司提供。

自《空气清洁法案》于1990年通过以来，南方公司的很多主管都致力于研究的遵行策略，但是现在研究分析的时间差不多结束了。

因为安装控制污染的设备需要一段较长的提前期，最终的遵行策略必须在1992年做出以便与1995年法案的生效日相适应。

佐治亚电力鲍恩火力发电厂所面对的选择正好代表着《空气清洁法案》给南方公司带来的两难处境。

鲍恩发电厂位于佐治亚州亚特兰大市西北部泰勒斯维尔县附近的埃托华河岸。

它于1975年建成，当四部发电机都满载发动时，将能为100万居民的家用、商业和工业之需提供足够的电力。

鲍恩发电厂的规模非常大，但却是具有代表性的火力蒸汽发电厂。

煤在巨大的容器中燃烧，蒸汽经由管道穿过这些容器，并且被燃烧的煤加热。

附近的漩涡机将蒸汽能转换成机械能，之后又在发电机中转换成电能。

像鲍恩这样的大型火力发电厂都有很高的固定成本和很低的可变成本，并连续不断运营。

电力公司将这些火力电厂用于基载发电，而在用电高峰期，则用油和天然气发电来补充。

鲍恩电厂的运营是超大规模的。

每天从肯塔基州运来几百个车厢的煤，其煤炭库存达到100万吨。

1990年，鲍恩电力厂的发电机共消耗煤8.338百万吨，发电量215.51亿千瓦时。

电力价格实际上在市场上有所波动，但是在1990年南方公司实现平均每千瓦时5.6美分的收益。

同样在1990年，鲍恩电力厂的烟囱平均每小时也排放了30吨以上的二氧化硫。

这种污染物是酸性沉淀物、酸雨的重要源头，将对湖泊、森林生态系统和金属、涂料等人工材料造成伤害。

为控制酸雨，新立法于1990年被国会通过，并由布什总统签发，将在1995年开始调节排污。

HAF601英文版

HAF601英文版

Supervision and Management Regulations for Civilian Nuclear Equipment (HAF601)PDF Print Email Friday, 28 May 2010 17:30Page 1 of 3Supervision and Management Regulations for Civilian Nuclear Equipment (HAF601)Contents∙Chapter 1: General Provisions∙Chapter 2: Permits∙Chapter 3: Quality Management and Control∙Chapter 4: Reporting and Filing∙Chapter 5: Supervisory Inspection∙Chapter 6: Legal Responsibilities∙Chapter 7: Supplementary ArticlesChapter 1: General ProvisionsArticle 1 – In order to strengthen the supervision and administration of the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, the present regulations are promulgated in accordance with the Regulations on the Supervision and Management of Civilian Nuclear equipment.Article 2 – These Regulations shall be applicable to business units engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment.Where maintenance is carried out for any civilian nuclear equipment outside of civilian nuclear facilities, the regulations relating to the manufacturing of civilian nuclear equipment shall be complied with.Article 3 – The catalogue of civilian nuclear equipment is compiled and released in batches by the nuclear safety administration department and relevant departments of the State Council.Article 4 – Any business unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment is required to obtain a permit for the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment and to carry out the activities with regard to the design, manufacture, installation and non-destructive testing ofcivilian nuclear equipment in line with the types, scope and conditions of activity specified in the permit.Article 5 – The operational units of the civilian nuclear facilities shall conduct the quality management and process control of the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, and will handle the supervision of manufacturing, inspection and acceptance of such equipment. Furthermore, they are to undertake the inspection, testing and repair of civilian nuclear equipment in service and take full responsibility for the application of the present regulations and the operational safety of the equipment.Article 6 – The nuclear safety administration department of the State Council, also known as China’s National Nuclear Safety Administration (hereinafter abbreviated as “NNSA”), shall implement the supervision and management of activities such as the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment.Chapter 2: PermitsArticle 7 – Any unit applying for a permit to design, manufacture, install or conduct non-destructive testing of civilian nuclear equipment shall submit an application to the NNSA according to the type of activities, category of equipment and level of nuclear safety considered. Any unit applying for the permit to conduct non-destructive testing of civilian nuclear equipment shall submit an application to the NNSA according to the methods of non-destructive testing that are being considered. Methods of non-destructive testing include the following: radiographic test (RT), ultrasonic test (UT), magnetic powder test (MT), eddy current test (ET), penetrant test (PT), leakage test (LT), visual test (VT), etc.Article 8 – Any unit applying for a permit to design, manufacture, install or conduct non-destructive testing of civilian nuclear equipment shall meet the following conditions:1. Be a legal person;2. Have been engaging in work connected with or similar to the activity considered for more than five years;3. Have on its staff one or several professional technician(s) suitable for the activity it is planning to engage in and will be certified to conduct. Professional technician(s) engaged in welding andnon-destructive testing of civilian nuclear equipment should have obtained the corresponding permits;4. Have available the workplace, facilities and equipment needed to conduct the proposed activity;5. Have in place a complete management system and a sound quality assurance system in conformity with the regulations on the supervision and management of nuclear equipment.The specific technical requirements for unit(s) applying for a permit to design, manufacture, install or conduct non-destructive testing of civilian nuclear equipment of different types and levels of nuclear safety shall be stipulated by the NNSA.Any unit applying for a permit to manufacture or install civilian nuclear equipment shall produce a typical prototype based on the type of equipment, level of nuclear safety, scope of activity, manufacturing and installation technique, material trademark and structure, etc. as shown in its application.The specific requirements for producing such a prototype shall be stipulated by the NNSA.Any unit applying for permits to design and manufacture civilian nuclear equipment at the same time shall have to complete the corresponding verification tests during the process of producing the prototype.Article 9 – Any unit applying for a permit to design, manufacture, install or conduct non-destructive testing of civilian nuclear equipment shall submit the application and the certificates in compliance with the conditions specified in Article 8.Any unit applying for a permit to manufacture or install civilian nuclear equipment shall also submit the production scheme, quality plan and other documentation in relation to the prototype. Any unit applying for a permit to design and manufacture civilian nuclear equipment at the same time shall also submit a verification test outline and all necessary related documentation.Article 10 – The nuclear safety administration department shall undertake the formal examination of applications submitted and accept all applications that meet requirements.Article 11 – In the process of examining a permit application, the nuclear safety administration department shall call on experts to undertake technical assessments, and seek comments from the State Council’s c ompetent department for nuclear industry activities and other relevant departments. The methods of technical assessment include the inspection of documentation, discussion following inspection and onsite checks, etc.Where a prototype needs to be produced, the technical assessment shall also include the inspection of the prototype’s production scheme, quality plan and other documentation, and the onsite supervision and observation of the production process, etc.The NNSA shall complete the inspection within forty-five working days following acceptance of the application, grant the permit to any qualified unit and make a public announcement with regard to the permit granted. It shall send a written notice to any unit whose application has failed to meet requirements and explain the reasons for the rejection of the application.It shall arrange for the technical assessment to be carried out in accordance with the provisions of Paragraph 1 and Paragraph 2, and not account for the technical assessment in the period specified in Paragraph 3.Article 12 – Any unit that has been granted a permit to design, manufacture, install or conduct non-destructive testing of civilian nuclear equipment can engage in the relevant activities at the lower level of nuclear safety within the same type of activity, category of equipment, type and scope of equipment, except otherwise specified in the permit.Article 13 – The permit for the design, manufacture, installation and nondestructive test of civilian nuclear equipment shall contain the following information:1. The name, address and legal representative of the unit;2. The type and scope of activities the unit will be allowed to engage in;3. Period of validity;4. The issuing authority, issuance date and permit number.Article 14 – To engage in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment without a permit, or not in accordance with the type and scope of activities specified in the permit is prohibited.One may not entrust any unit with the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment if the unit does not hold the corresponding permits to engage in such activities.The forgery, alteration and transfer of a permit are not allowed.Article 15 – The period of validity of a permit for the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment is five years.Article 16 – Any unit engaging in the design, manufacture, installation and non-destructive testing of civilian nuclear equipment shall apply to the NNSA for a permit extension and submit the extension application and supporting documentation at least six months prior to the permit’s expiry date, in cases where the unit:1. Has engaged in the design, manufacturing, installation or non-destructive testing of civilian nuclear equipment throughout the period of validity of the permit, and plans to continue undertaking the same activities beyond the permit’s expiry date;2. Has been engaged in the design, manufacturing, installation or non-destructive testing of civilian nuclear equipment, and cannot complete related projects by the permit’s expiry date.Any unit that has not engaged in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment during the period of validity of the permit held shall have to re-apply for a permit in line with the procedure specified in this article.Article 17 – In cases where an application to extend the period of validity of a permit has been made by a unit engaged in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, the NNSA shall decide on whether to approve the extension before the expiry date of the permit. Should no decision have been explicitly made by such date, the extension of the permit will be deemed granted.Article 18 – Should any unit engaged in design, manufacturing, installation and non-destructive testing of civilian nuclear equipment change its name, address or legal representative, it will have to apply to the NNSA for the amendment of its permit within twenty working? days following such changes, and submit the application for permit amendment, documentation of its registration with the Administration for Industry and Commerce, a description of the changes involved and the relevant change certificates.The NNSA shall verify the authenticity of the application for permit amendment. Once the application has been verified, the permit can be reissued. The period of validity of the original permit shall re-apply to the amended permit.Article 19 – Should a unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment wish to change the type or scope of activities specified in its permit, it shall have to re-apply to the NNSA for a new permit.Chapter 3: Quality Management and ControlArticle 20 – Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall enhance its safety awareness, establish and effectively implement a quality assurance system, ensure the quality and reliability of the civilian nuclear equipment produced, and submit itself to inspection by the relevant supervisory authorities. Article 21 – Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall prepare a sub-outline of its project quality assurance plan in accordance the requirements of the operating unit of the civilian nuclear facilities where the equipment produced will be used before it starts any relevant activities. The sub-outline of the unit’s project quality assurance plan will have to be [applicable, co mplete and definite regarding interface relation], reviewed and approved by the operating unit of the civilian nuclear facilities using the equipment produced.Any unit engaging in the manufacturing and installation of civilian nuclear equipment shall prepare the corresponding quality plan for the specific activity and provide it to the operating unit of the civilian nuclear facilities using the equipment produced for review and approval.Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall control the whole process as required by the sub-outline of its project quality assurance plan, and investigate and rectify any problem uncovered.Article 22 – Any unit engaging in the design of civilian nuclear equipment shall, before engaging in such activities, first ensure that its designers have analyzed and understand the design requirements proposed by the operating unit of the civilian nuclear facilities where the equipment will be used. The unit must also ensure that it is fully aware of and has specified the requirements for design input, and that it has determined the design interface control measures, methods and content of design verification, and design change control measures.The design unit shall undertake the design verification with regard to its design using approved methods of design verification at each stage of the design process. The staff in charge of design verification shall have a certain level of experience in design, the ability to perform verifications and a relative degree of independence.The design unit shall take the control measures for the design change during the design, which are equal to those for the original design.After the design is completed, the design unit shall continue to provide design services as needed to the unit operating the civilian nuclear facilities using the equipment designed.Article 23 – Any unit engaging in the manufacturing and installation of civilian nuclear equipment shall, before engaging in such activities, first ensure that its relevant personnel analyzes and understands the technical requirements proposed by the design unit, prepares the manufacturing and installation execution plans in accordance with these technical requirements, and strictly implements the execution plans.The manufacturing or installation unit shall complete the necessary technical tests and technical assessments for the approved special technique.The manufacturing or installation unit shall strictly implement the quality plan reviewed and approved by the unit operating the civilian nuclear facilities using the equipment produced.The manufacturing or installation unit shall test the quality of the civilian nuclear equipment manufactured or installed. Any equipment that has been untested or that has failed testing shall be not handed over for acceptance.Article 24 – Any unit engaging in the non-destructive testing of civilian nuclear equipment shall prepare and strictly implement the non-destructive testing procedure followed to undertake the specific testing proposed, based on the structure and material features of the equipment to be tested.The non-destructive testing unit shall issue a non-destructive testing report in an objective and accurate manner.Non-destructive testing of civilian nuclear equipment shall be conducted under the lead of non-destructive testing operators with Class II or above qualification.The non-destructive testing report shall be prepared and examined by non-destructive testing operators with Class II or above qualification, who shall handle the relevant approval procedure. Article 25 – Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall not subcontract the critical technical link as determined by the NNSA to other units.The list of critical technical tasks shall be prepared by the NNSA.Article 26 – The operating unit of the civilian nuclear facilities where the nuclear equipment is used shall take full responsibility for the safe operation of civilian nuclear equipment. Before starting activities such as the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, the operating unit of the civilian nuclear facilities where the nuclear equipment is used shall examine and approve a sub-outline of the project quality assurance plan prepared by any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment.The operating unit of the civilian nuclear facilities where the nuclear equipment is used shall supervise the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment by overseeing or observing these activities as they are being carried out, and handling the inspection and acceptance of the equipment involved. The equipment shall be not accepted if any of the following were to occur:1. Where the quality control cannot be verified to have been carried out as required by the quality assurance plan;2. Where any serious quality problems have not been resolved.Article 27 – Both the unit engaged in manufacturing, installation and non-destructive testing of civilian nuclear equipment and the operating unit of the civilian nuclear facilities where the nuclear equipment is used shall hire personnel holding welder, welding operator and non-destructive testing operator permits to carry out the welding and non-destructive testing of civilian nuclear equipment.The welders, welding operators and non-destructive testing operators of civilian nuclear equipment shall carry out their activities in strict accordance with operational specifications.Chapter 4: Reporting and FilingArticle 28 – Any unit engaging in the design of civilian nuclear equipment shall submit the following documentation to the NNSA for filing within thirty days prior to starting work on the design activities:1. List of sub-outlines and outlined procedures for the design project’s quality assurance plan;2. Contents and schedule of the design work to be carried out;3. List of standards and regulations complied with and list of computer software used in the process;4. List of design verification activities.Article 29 – Any unit engaging in the manufacturing and installation of civilian nuclear equipment shall submit the following documentation to the NNSA for filing within thirty days prior to starting work on the manufacturing and installation activities:1. List of sub-outlines and outlined procedures for the manufactu ring and installation project’s quality assurance plan;2. Technical specifications of the manufacturing and installation work to be carried out;3. List of sub-contracted work;4. Manufacturing and installation quality plan.Article 30 – Any unit engaging in the non-destructive testing of civilian nuclear equipment shall submit the following documentation to the NNSA for filing within fifteen days prior to starting work on non-destructive testing:1. List of sub-outlines and outlined procedures for the non-destructive testing project’s quality assurance plan;2. Contents and schedule of the non-destructive testing to be carried out;3. The standards, regulations, directory and acceptance rules the non-destructive testing process will complying with.Article 31 – Any unit engaging in the design of civilian nuclear equipment shall submit, within seven working days of each quarter-end, an activity report for the previous quarter to the NNSA, including mainly:1. The list of completed designs and list of designs planned for launch and for completion over the next quarter;2. The list of design alterations put through;3. The design verification completion list.Article 32 – Any unit engaging in the manufacturing and installation of civilian nuclear equipment shall, within seven working days of each quarter-end, submit an activity report for the previous quarter to the NNSA, including mainly:1. The list of completed products and installation work, and a list showing product output and installation work planned for launch and for completion over the next quarter;2. The list of quality plans for completed products and installation work;3. A statistic chart showing non-conform products and installation work.Article 33 – Any unit engaging in the non-destructive testing of civilian nuclear equipment shall report the contents and results of the non-destructive testing to the NNSA within ten working days of having completed the non-destructive testing.Article 34 – Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall report to the NNSA in accordance with the following regulations:1. Any major activity conducted in relation to nuclear safety, such as important meetings or discussions, etc. shall be reported seven working days prior;2. Any serious quality problem noted shall be reported within twenty-four hours;3. The condition that the operating unit of civilian nuclear facilities commands to stop the activity due to its impact on the quality of nuclear equipment and nuclear safety shall be reported within 3 working days.Article 35 – Any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment shall carry out an annual assessment of its design, manufacturing, installation and non-destructive testing activities and submit the assessment report for the previous year to the NNSA before April 1st of each year.The assessment report shall include the description of:4. All changes to the un it’s workplace, facilities, equipment, staff, etc.;1. The implementation of the unit’s quality assurance system;2. Any serious quality issues uncovered and their resolution;3. The implementation of requirements for rectification proposed by the operating unit of civilian nuclear facilities where the equipment is used;4. The implementation of requirements for rectification proposed by the NNSA and its subsidiary inspection agencies.Chapter 5: Supervisory InspectionArticle 36 – The NNSA and its subsidiary inspection agencies shall have the right to supervise and inspect a unit’s activities in design, manufacturing, installation and non-destructive testing of civilian nuclear equipment.The inspected unit shall cooperate in the supervisory inspection process carried out by the NNSA and its subsidiary inspection agencies, present true facts, provide necessary documentation and not reject or impede the inspection. The inspected unit shall carefully implement all requirements for rectification proposed during the supervisory inspection.Article 37 – Civilian nuclear equipment shall be supervised and inspected in accordance with: 1. The Regulations on the Supervision and Management of Civilian Nuclear Equipment and other regulations on the supervision and management of nuclear safety;2. The conditions and scope specified in the permit granted for design, manufacturing, installation and non-destructive testing of civilian nuclear equipment;3. The national standards, industry standards and the standards approved by the NNSA with regard to civilian nuclear equipment;4. The quality assurance plan outline and outlined procedures examined and approved by the NNSA.Article 38 – Personnel in charge of supervising and inspecting civilian nuclear equipment shall meet the following conditions:1. Have graduated from junior college, or received higher education or an equivalent level of education;2. Have more than five years of engineering experience with civilian nuclear equipment or more than three years of nuclear safety management experience, master the relevant professional know-how, have good communication skills and be able to make correct judgments independently;3. Be familiar with the relevant laws, administrative regulations and rules on the supervision and management of nuclear safety;4. Be honest and upright, handle affairs in a fair manner, work carefully and have an appropriate attitude.Article 39 – The supervisory inspection of civilian nuclear equipment includes ensuring the following:1. Compliance with conditions specified in the permit;2. Qualifications of personnel involved;3. Implementation of quality assurance plan outline;4. Conformity with the adopted technical standards and relevant technical documentation;5. Implementation of critical processes in the design, manufacturing, installation or non-destructive testing of civilian nuclear equipment;6. Investigation and resolution of serious quality issues, and implementation of requirements for their rectification issued by the NNSA and its subsidiary inspection agencies;7. Acceptance and verification by the NNSA and its subsidiary inspection agencies of the design, manufacturing, installation or non-destructive testing of civilian nuclear equipment;8. Manufacturing supervision of the operating unit;9. Other necessary supervision tasks.Article 40 – Upon receiving the documentation submitted in accordance with these Regulations by any unit engaging in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, the NNSA and its subsidiary inspection agencies shall work out the corresponding supervision plan and notify the unit applying for a permit. This unit shall then prepare to submit itself to supervisory inspection in line with the requirements specified in the supervision plan.The unit engaging in the design, manufacture, installation and nondestructive test of civilian nuclear equipment shall notify the NNSA and its subsidiary inspection agencies in writing based on the actual progress of the relevant activity ten working days before implementing the activity specified in the supervision plan.Article 41 – The supervisory inspection of civilian nuclear equipment can be classified in two sub-categories: routine inspection and non-routine inspection. Non-routine inspection may not be notified in advance to the unit inspected.Supervisory inspection can be further classified into: comprehensive inspection, special inspection and checkpoint inspection mainly carried out by means of site inspection, documentation inspection, record verification or interviews, etc.:1. Comprehensive Inspection: includes quality assurance inspection and technical inspection. Quality assurance inspection mainly focuses on whether the quality assurance plan outline has been implemented effectively. The technical inspection primarily includes a spot check on whether the process of designing, manufacturing, installing and non-destructive testing civilian nuclear equipment meets the requirements set by the current standards, regulations and relevant technical documentation.2. Special Inspection: refers to the inspection for special purposes carried out by the NNSA and its subsidiary inspection agencies on a unit with respect of any issues uncovered or likely to emerge. It mainly involves inspecting the implementation of any technical item or any part of thequality assurance plan outline, as well as the implementation of requirements for rectification issued by the NNSA and its subsidiary inspection agencies.3. Checkpoint Inspection: refers to the inspection carried out on site, at specific check points. Whenever necessary, the NNSA and its subsidiary inspection agencies can carry out the verification independently by means of recomputation or inspection verification.While carrying out the comprehensive inspection or checkpoint inspection of any unit engaged in the design, manufacturing, installation and non-destructive testing of civilian nuclear equipment, the NNSA and its subsidiary inspection agencies shall review the adequacy of the personnel in charge of supervising the manufacturing of civilian nuclear equipment and the implementation of such supervisory task.Article 42 – While carrying out supervisory inspection, the NNSA and its subsidiary inspection agencies shall record the contents of each inspection, the issues uncovered and their resolution, and have the record signed and approved by the personnel in charge of supervisory inspection and the relevant personnel in charge of the unit being inspected. Objective evidence shall be kept if necessary.Should the personnel in charge of the unit under supervision and inspection refuse to sign the record, the supervisory and inspection personnel will take note of this refusal in the record.The NNSA and its subsidiary inspection agencies shall prepare the supervisory inspection report with regard to the information of each supervisory inspection carried out and the corresponding rectification requirements issued, and send it to the inspected unit and other units concerned. The inspected unit shall implement the rectification measures against issues uncovered during the supervisory inspection requested by the NNSA and its subsidiary inspection agencies, and submit a rectification report to the NNSA and its subsidiary inspection agencies. The NNSA and its subsidiary inspection agencies shall examine the rectification report and undertake to verify the implementation of the requirements for rectification during a follow-up supervisory inspection.Article 43 – The personnel in charge of conducting the supervisory inspection of civilian nuclear equipment shall have the right to take the following measures:1. Investigate and gather information from the legal representative of the unit inspected and other people involved;2. Enter the inspected unit’s premises for onsite investigation or verification;3. Consult and duplicate relevant documentation, records and other relevant materials;。

Hazard Identification and Risk Assessment

Hazard Identification and Risk Assessment

Hazard Identification and Risk Assessment by N.C.Nigam,A.K.Maheshwari & N.P.Rao .INTRODUCTIONFor any industry to be successful, it has become essential to identify the Hazards ,to assess the associated risks and to bring the risks to tolerable level. Recognising this, IFFCO-AONLA is continuously putting efforts for controlling the risks which are arising from various Hazards such that loss to Human life and property is negligible or zero. Its continuous best efforts to identify the Hazards and to bring the risk levels to tolerable level in the organization are recognised by several Government and safety regulating bodies. This paper describes briefly about various types of Hazards and their associated risks, how they are being controlled effectively through risk analysis at IFFCO – Aonla unitIn all plants, hazards and risk are identified time to time by using modern techniques. IFFCO Aonla unit is OHSAS –18001 certified company. So in all departments /section risk and hazards are find out by proper risk assessments. During this severity at various levels matched with probability level. And find out the case of intolerable, substantial, moderate and tolerable risk. Accordingly control measures at the place checked. Documentation done and records are maintained. .At IFFCO Aonla unit, HAZOP, HAZAN study, Dow index, Risk Analysis, FMIA, Fault Tree Analysis are carried out at its inception level..At IFFCO Aonla unit, various risk assessment procedures are followed. This has been done by Dow Index method and Consequences methods. At the same time when any process modification done/needed, then also proper HAZOP studies and any other risk analysis studies are carried out to assess the risk due to the effect of modification.Now as IFFCO Aonla unit is OHSAS –18001 certified company, in all sections/plants proper hazard and risk assessment procedures and documentation done. Time to time, plant/section updates of this done and audited by other sectional persons. And again compliance incorporated.1.0.0 To effectively implement the safety systems , a structured approach has been drawn out to minimizethe hazards and risks . This involves the following :¾ REPORTING/INVESTIGATING/ANALYSIS OF ACCIDENTS, DANGEROUSOCCURRENCES AND NEAR MISSES.When any accident occurred in plant premise, the concern area shifts in-charge informed his higher officers as well as fire and safety section regarding this. Immediately accident/dangerous occurrence investigation committee consisting of senior officers from affected area, fire and safety section, factory safety officer and medical person set up. This committee starts immediately investigation without delay. It also preserves all facts and finding and reports of for future reference.IFFCO AONLA UNIT131.05.200008.06.200231.12.200222.08.200415.02.2006Accident Free Man days Accident Free Period026.10.1997-31.05.200002.06.2000-08.06.200201.09.2002-31.12.200201.01.2003-22.08.200428.08.2004-15.02.200624681012141615.0612.271.97.8313.00Y-AXIS ACCIDENT FREE MILLION HOURS X-AXIS ACCIDENT FREE PERIOD31.05.200008.06.200231.12.200222.08.200415.02.2006Accident Free Million Man hours Accident Free Period IFFCO AONLA UNITNow we see what type of risks and how they are being handled through some models of risk analysis in IFFCO –AONLA unit.¾PROCESS & SAFETY–RELATED DATA FOR INDIVIDUAL PROCESS STAGES :Physical and Health Occupational Hazards in any large scale Chemical /Hydrocarbon Processing Industry (CPI/HPI) like our can be broadly classified into the following categories:i. Mechanical Risks ii. Electrical Risks iii. Fire/Explosion Risks iv. High /low Temperature Exposure Risks v. Toxic/Carcinogenic Chemicals Exposure Risks vi. Corrosive/Reactive/Radioactive Chemicals Exposure RisksThe first two types of risks are of universal nature associated with any industrial activity and not specific to a particular plant or process. Mechanical risks which are generally encountered are injuries to the head, Limbs, eyes, etc usually as a results of negligence on the part of operating/maintenance personnel in the use of improper tools, bypassing prescribed safety procedures neglect of personal protective wear and risks associated with rotating machinery as well as risks associated with high-energy release from compressed gases. Electrical risks which result in shock and/or burns are most often a consequence of poor maintenance, ingress of dust or moisture, handling by unauthorized personnel and use of improper/substandard hardware.Other categories of risks associated with specific plants are detailed here under.Ammonia Plant :The manufacture of anhydrous liquid ammonia involves processing of hydrocarbons under high temperature, high pressure conditions in the presence of various catalysts, chemicals etc. Typical risks are as follows:Fire /Explosion¾ Glands/seal leaks in valves, pumps, compressors handling hydrogen, natural gas, naphtha, synthesis gas etc.¾ Hose/pipe failure, leakage from flanged joints carrying combustiblegases, vapours, liquids.¾ Fire box explosions in furnaces.High/Low Temp.Exposure RisksToxic ChemicalsExposure Risks¾ Burns due to contact with hot surfaces of pipelines, equipments, etc. or leaking steam lines, process fluids at high temperature. ¾ Frost bite due to contact with anhydrous liquid ammonia at -33 deg. C ¾ Burns due to contact with pyrophoric catalyst. ¾ Asphyxia due to inhalation of simple asphyxiants like CO2 , N2, H2, CH4, naphtha etc. and chemical asphyxiants like CO, NH3, Nickel carbonyl, V2O5, Hydrazine, NOx, SOx, H2S etc. ¾ Acute toxicity due to inhalation of catalyst dusts containing heavy metals like Ni, Cr, CO, Mo, Fe, Zn, Alumina etc. and silica gel molecular sieves, insulation fibers/dusts.1000020060080026.10.1997-31.05.200002.06.2000-08.06.200201.09.2002-31.12.200201.01.2003-22.08.200428.08.2004-15.02.2006947400737122700Y-AXIS –ACCIDENT FREE MAN DAYSX-AXIS ACCDIENT FREE PERIOD 910Urea PlantThe manufacture of urea involves reaction of Ammonia and Carbon dioxide under high temperature & pressure and subsequent recovery and concentration of the solution at various pressure stages. Typical risks are as follows :Fire / Explosion Risks¾ Ammonia leaks from glands / seals Risks involves, pumps orflanged joints piping resulting in formation explosive mixtures in air.Accumulation of H2 may take place in HP Section in case CO2 purity from Ammonia Plant is not within allowable limits. Ignition of this accumulated H2 can occur due to dissipation of static charge.High / Low Temperature Exposure Risks¾ Refer to risks in Ammonia Plant Toxic Chemicals Exposure Risks ¾ Asphyxia due to inhalation of simple Exposure Risks asphyxiants like CO2 and N2 and chemical asphyxiant, NH3. Solution of Urea, Ammonium carbamate and ammonium carbonatecontaining high NH3 content.¾ Irritation due to inhalation of urea dust.Corrosive / Radioactive Chemicals Exposure Risks¾ Severe burns, damage to eyes, skin and body tissues due to contact with anhydrous ammonia, conc. Urea and Ammonium carbamate solutions.Power PlantThe captive Power Plant involves generation of steam in N.G./Naphtha-fired boilers and utilizing the steam in Urea and Ammonia plants. Typical risks are as follows :Fire / Explosion Risks ¾ Explosion and fire risks associated with storage and handling of B Class (Naphtha) and Natural gas handling pipelines (Referoff site Facilities).¾ Fire Box explosion in BoilerFlammable Material Lower Upper Temp. °C High / Low Temp. Exposure Risks ¾ Burns due to contact with hot surfaces of pipelines, equipments, etc. or leaking steam lines. Toxic Chemical Exposure Risk¾ Asphyxia due to inhalation of SOX and Nox.¾ Irritation due to inflammation caused by inhalation of Natural gas and the Naphtha vapors.The permissible exposure limits for cyclohexylamine coal dust / fly-ash are given below :Offsite FacilitiesThe offsite facilities, as already described at the very outset, consist of integrated units for water and effluent treatment, inert gas generation, cooling towers, storage of petroleum products and ammonia, supply / distribution of utilities like compressed air, water, etc. Potential risks in the above offsite facilities are essentially on account of handling of corrosive, toxic and reactive chemicals as well as inflammable petroleum products.Fire / Explosion Risks ¾ Gland / Seal leaks in valves, pumps, compressor, handling naphtha,N.G., ammonia hydrogen, syngas etc.¾ Hose / pipe failure, leakage from flanged joints in pipes conveying petroleum products, ammonia, hydrogen, syngas, etc.¾ Leakage of petroleum products during tanker unloading operations. ¾ Overflow from storage tanks.¾ Overheating / pressurization of storage tanks.¾ Improper earthing / lightning protection of storage tanks and pipelines.¾ Improper sealing of floating roof tanks.¾ In adequate / improper breather valves leading to tank failures. ¾ Fire Box Explosion in cracker Furnace.Critical data for flammable materials stored / handled in off sites has already been furnished under Ammonia Plant and Power Plant.High / Low Temp. Exposure Risks ¾ Burns due to contact with hot surfaces of pipe lines, equipments, etc or leaking steam lines.¾ Heat radiation burns from high intensity flames from the flare stack. ¾ Frost bite due to contact with anhydrous liquid ammonia at – 33 °CToxic Chemicals Exposure Risks ¾ Asphyxia due to inhalation of simple asphyxiants like N2, H2, Naphtha, etc. and Chemical asphyxiants like Cl2, NH3, NOx, Sox,etc.¾ Toxicity due to inhalation of catalyst dust containing heavy metals like Ni, Pd, Alumina etc. and perlite / insulation fibers, silica gel dust.Data on Threshold Limit Values Limits for most of the above toxic Chemicals and dusts encountered in off sites has already been furnished under Ammonia Plant. Data for Cl2 are as follows :Corrosive Chemicals Exposure Risks ¾ Severe burners, damage to eyes, skin & body tissues due to contact with corrosive chemicals like anhydrous liquidAmmonia, Sulphuric acid, Hydrochloric acid, etc.Bagging PlantThe bagging plant encompasses storage, packing, loading and dispatch activities for product urea via road or rail. Typical risks in this plant are as follows :Fire Risks¾ Fire hazards due to storage of bulk quantity of polyethylene – lined jute bags or HDPE bags which are easily combustible. Chemicals Exposure Risks ¾ Irritation due to inhalation of urea dust and jute fibers.S.No Name of Chemical Form under normal condition Expected form ofChemical under abnormal condition1. 2. 3. 4. 5. 6.AmmoniaChlorineNaphthaHydrochloric AcidSulphuric AcidNatural GasLiquid state at – 33 °C temp. & atmospheric pressure.Liquid at ambient temp. & 17.0 Kg/cm² pressure.Liquid at ambient temp. & pressure.Liquid at ambient temp. & pressure.Liquid at ambient temp. & pressure.Gaseous at ambient temp &PressureVapour / Gaseous form.Vapour / Gaseous form.Vapour Acid fumes Acid fumes Gaseous Form¾INFORMATION ON THE PRELIMINARY HAZARD ANALYSISTypes of AccidentIt is clear that during the course of Urea manufacture, furnaces, reactors, moving machineries, material handling, cranes, chain, pulley blocks, wire ropes, chemicals, Rail wagons, etc. are involved. Past reportable accidents are related to these agencies.Type of personnel injuries indicates burn, cut, bone fracture burn injury etc. A brief resume of types of accidents may happen are as follows ;-1. Burn injury due to handling cleaning of burners in furnaces.2. Fire accidents in furnaces leading to property damage.3. Burn injury accident due to attending electrical faults.4. Burn injury accidents due to handling of acids / alkalies.5.Hit / cut type accidents due to various maintenance jobs. For reference purposes and internal report titled “Safety Performance at a glance” is enclosed as Annexure 5.System Elements or Events that can lead to a major AccidentAll the section / plants of IFFCO Aonla unit are constructed and designed taking care of all relevant safety measures possible. However the system elements such as Ammonia storage, Naphtha storage, Chlorine tonners, Ammonia Plant area, Urea Plant HP section are some of them which can lead to a major accident.Although, Fire, explosion and release / leakage of toxic chemicals may lead to major accident, all necessary safety measures have been duly incorporated in the plant design and regular up gradation of safety appliances is carries out.Hazards Urea manufacturing process involves many chemicals such as NG, as feed stock, Ammonia as anintermediate product and chlorine, hydrochloric / sulfuric acids, as water treatment chemicals.Furnaces, High pressure vessels, Reactors, pipe lines, storage tanks are also involved in thecourse of Urea and Ammonia manufacturing. Handling and storage of these Hazardous chemicals and their use in the process may leak to a hazardous situation.Failure Mode AnalysisThere are various modes in which flammable and toxic chemicals can leak into atmosphere causing adverse affects. It may be small leaks from gaskets of the flanged joints, or guillotine failure of a pipeline of even catastrophic failure of the storage tank. Some typical modes of failures and their possible causes are discussed below :S.No. Failure Mode Probable Cause Remarks1. Flange / Gasket failure Incorrect gasket Incorrect installation. Attention to be paid during selectionand installation of gaskets. 2Weld failureIt is normally due to poor quality of welds Welding to be done by certifiedwelders with right quality of weldingrods. Inspection and radiography must also be done.3 Pipe corrosion erosion or failure due to stress Some times fabrication or installation leaves stress in the pipes. Erosion or corrosion also are sometimes the cause. Pipes material of constructionshould be selected correctly. Design should take care of erosioneffects. And installation of pipes should not leave any stress.4 Over pressurization of pipeline Over pressurization can occur due to failure of SRV or incorrect operation.Necessary procedures should bethere to prevent.5 Deficient installation of pipes Pipes design and installation is sometimes not as per appropriate standard.It must be ensured that installationis as per correct standardscompletely. 6 Leaks from valve Leaks from glands, bonnets or failures valves spindle is sometimes the cause.Right selection of valves and theirmaintenance should be ensured. 7 Instruments failure Multifarious instruments are used for control of process parameters. Any such instrument failure can cause mishap.Reliability of instruments workingmust be ensured through proper selection and maintenance. 8 Failures of protective system Protective system like SRV, bursting discs, vent header, drain lines etc. are provided to take care of abnormal conditions.Reliability of protective system mustbe ensured highest throughinspection and proper maintenance. 9 Operational effort Plant operational parameters should not be exceeded beyond the permissible limits.Operating procedures must becomplete and strictly followed. 10 Other failures There are external other reasons causing the failures.Design and operating philosophymust consider all possible reasons. ¾ INFORMATION ON THE HAZARD ASSESSMENTIdentification Of HazardsThe following main hazards may exist in the factory under the situations given below-• High temperature and pressure.• Fire & explosions (due to inflammable / combustible materials). • Toxic and corrosive chemicals.• Toxic and poisonous gases and dust.• Electricity (Receiving / Clue ration / Distribution). • Disposal of wastes. • Work at heights.• Work in confined spaces / vessels / tank etc.• Specific jobs carried under highly hazards atmosphere (CO2, NH3, Naphtha vapours etc.). • Non working of safety devices, inter locks, failure of high RPM machineries. • Failure of boilers etc.• Any other consequences due to leak of Ammonia, Chlorine gases. • Hazards during heavy equipment handling (Crane, etc.) • Road accidentsHowever, the threats posed to the aforesaid hazards may be on account of (i) Fire or (ii) explosion or (iii) Release of toxic or corrosive liquid / gas from their confinement. Causes Of Major AccidentsFollowing Major causes may lead to major accidents :-1. Release of Ammonia in huge quantity from storage tank.2. Release of chlorine due to leakage / rupture in chlorine toner or its valve failure of injection pipe failure feeding to cooling tower.3. Fire / explosion in Naphtha tanks due to leakage, unconfirmed clouds, or boil over, etc.4.Explosion in High pressure equipments, reactors in Ammonia / Urea Plants.5. Fire / explosion in furnaces of Ammonia Plant and boilers in Power Plant.Assessment Of Hazards According To Their Occurrence FrequencyConcurrency frequency (probability failure / year) for each selected failure case is given in table 9.c.1. For most of the cases the probability of failure occurrence is very less. Fire / explosion, sling failure, safety rule failure, and injuries etc. are some cases which are considered as associated hazards.Assessment Of Accident ConsequencesA major accident may cause severe danger to life and properties. The assessment will be based on :• Onsitelosses.losses.• OffsiteThe first one will be loss of life, property damage and injuries to the scene of occurrence where the people are working or combating with the accident control.The offsite losses will include the loss of lives, injuries and properties damages of neighbor hood bases on the affected area of accident or major event, if any.Assessment Of The Possible Release Of Hazardous Chemicals Or Of Energy.Technological Risks posed by this Fertiliser factory constitute threat to :i) Its workersii) To a third party who may be present either in the factory or in its vicinity at the time of accident. iii) Inhabitants living in the immediate neighborhood of the factory and their property.iv) Environmental Conditions around the factory site.The threats posed to the aforesaid entities may be on account of -i) Fire,ii) Explosion,iii) Release of Toxic or corrosive liquids / gas from their confinement. The primary reason why such a disaster may occur, in spite of all precautionary measures is that major type of chemicals handled, are highly hazardous in nature and in substantial quantities, oriv) A combination of more than one of such accidental phenomenon.These risks may manifest due to accidental failures, break down or rupture of processing vessels, equipments, storage tanks or pipelines. They may also arise due to undetected loss of containment because of which liquid or gas contents gradually leak out in sufficient quantities to create a hazardous situation. The loss of containment and associated hazards may be realized in one of the following ways :-Large scale fire in naphtha storage area due to damage to the storage tank.-Naphtha leak from pipeline resulting into fire.-Flash fire due to leakage of flammable gas.-Equipment failure, pipeline failure, flange gasket failure, pump seal failure, safety relief valve failure etc. resulting in leakage of flammable, explosive and toxic material.-Accidents due to human errors.-Acts of nature like earthquake, enemy air attack during war, sabotage, act of terrorism etc.When the scale of such accident is as to cause either –a) Severe destruction of property.b) Multiple fatalities and other casualties and cannot be contained within the premises, a DisasterSituation is said to prevail.However the release of components listed below may cause hazards:-a) Natural Gas, the feed stock for ammonia plant andb) Hydrogen gas produced by reformation process for synthesizing Ammonia andc) Ammonia itself, generated as an intermediate product, constitute the gravest risks both fromtheir nature of properties and the quantities involved.Natural Gas is a highly flammable Gas equivalent to gasoline from fire and explosion hazard angle, having a auto ignition temp. of 482 °C and a flammable range of 3.8 – 17 %.Naphtha is also highly flammable liquid having flash point of -40o C and flammable range between 1 and 6%.Ammonia is highly toxic gas its TLV being 25 ppm. It is also a combustible gas which can explode under certain circumstances, although its lower explosive limit is rather high being of the order of 16%. It is true that two other highly flammable gases viz Carbon Monoxide and Methane are also evolved in of the Ammonia plant. However, as these gases are immediately converted into non-hazardous substances, they at best constitute transient risks. Besides the materials directly involved in the manufacturing process, another extremely toxic gas viz Chlorine.Chlorine (which has a TLV of 1 ppm) is used for treatment of water in the Cooling Towers. In-spite of the fact, that quantity of chlorine held in the plant is almost insignificant, because of its extremely high toxicity a leakage even in a ‘tonner’ holding only 900 Kg of gas can endanger the persons present inside the plant.Assessment of risks posed by industrial accidents has two aspects viz.•How frequently such accidents can occur and•What could be their impact on people, property and environment.Making a technically sound assessment of accident frequency for any individual plant is like walking on treacherous grounds. It is true that there are various structured methods like HAZOP, HAZAN, fault tree, Analysis Event tree Analysis etc. through which an estimate of such frequencies can be attempted. However, no such methods can ensure that all potential accidents or top – events would be identified, that all potential fault paths would be found and all common cause failures covered. More-over, the adoption of such methods need use of Reliability Indices of equipment and components of the system under study. These Reliability Indices are expected to be furnished by the manufacturers, which is seldom the case in actual practice. No doubt generic data could be used as a less preferable alternative. However, besides such data not being available for every component, their use may give an entirely erroneous picture, as the real values of such indices are greatly dependent on conditions of use, standards of maintenance etc. Even if correct Reliability data were available, the results may not be quite accurate as accidents are known to have taken place due to Human errors in operation and maintenance for which no satisfactory models are yet available.A statistical estimate of the risk could have been made if enough operating experience of the facts was available. However, in the present case, the experience is not long enough to predict with any degree of certainly of probability of accidents of different magnitudes, especially of that which may cause Maximum credible loss, as such accidents are incidents of extremely low frequency. All that can be stated with confidence is that since.a) The process carried out in the plant is well tested.b) The design and installation of the plant comply with recognized standards and codes ofpractice andc) All reasonable precautions are followed in respect of operation and maintenance, chancesof a major accident is of low order.HAZARDOUS AREAS OF THE PLANTThe following areas of the IFFCO Aonla Unit are hazardous with respect to nature of materials handled and operating parameters.• Ammonia Plant• Urea Plant• Ammonia storage•Naphtha Storage and Handling• Chlorine storagePLANT WISE HAZARDSThe plant wise hazards due to nature of materials handled there at are given below :Plant Hazardous Material Nature of Hazard Ammonia Plant Urea Plant Ammonia storage Naphtha Storage and handlingD.M. Water plant Cooling TowerNatural Gas Naphtha Process gas containing H2, CO, CH4 Ammonia (liquid or gas) Ammonia Carbon dioxide Ammonia Naphtha Hydrochloric acid caustic lye Chlorine Fire Fire Fire Explosion Toxic Toxic Asphyxiant ToxicFire Corrosive Toxic ASSESSMENT OF THE POSSIBLE DISPERSION OF RELEASED CHEMICALS STORAGE CAPACITY OF HAZARDOUS MATERIALSThe hazardous materials stored in the plant in substantial quantities. The detail of storage capacity for each material is given below:Equipment Nos. Material CapacityNaphtha storage tank (old) 2 Naphtha 6000 KL Naphtha storage tank (new) 1 Naphtha 10000 KL Ammonia storage Tank 2 Liquid Ammonia 10,000 Te * Chlorine Tonners 16 Chlorine 900KG* Though the capacities of Ammonia storage tanks are 10000 Te each , we normally store minimal quantity of liquid Ammonia in our Ammonia storage Tanks. The storage quantity at no times goes beyond 40% in the storage tanks. This conscious decision reduces the hazard potential.FAILURE CASE LISTINGKeeping in view, the inventories of different hazardous material, plant process parameters etc. following are the selected failure case which way be considered for consequence analysis. This includes the worst case scenario i.e. catastrophic failure of Ammonia storage tanks and Naphtha storage tanks, also leakage of ammonia from ammonia storage tank or from the system handling ammonia, chlorine from tonners and fire in the naphtha tanks or from handling systems is identified as the major accident hazards. This can occur as given below:Incident ConsequenceCatastrophic rupture of Ammonia storage tank or major leakage from the ammonia handling system.Refrigerated liquid ammonia or liquid ammonia spill and dispersion. Chlorine leakages from the tonners due to valve getting sheared.Chlorine leakage and dispersion Catastrophic failure of Naphtha/ FO storage tanks and the leakage catching fire. Major fire. Pipeline fracture / Nozzle failure Liquid ammonia spills at hydraulic head or pump deliverypressure and dispersion.Chlorine leakage at tonners pressure and dispersionIf the leakage due to pipeline fracture or nozzle failure in naphtha and catches fire- fire incident.Gasket failure Liquid ammonia spill and dispersion.Chlorine leakage and dispersion.Fire if the naphtha or FO leakage due to gasket failure and theleakage catch fire.System elements or events that can lead to major accident.a. Catastrophic rupture of Ammonia storage tank or major leakage from the ammonia handlingsystem.b. Chlorine leakage from the tonners due to valve getting sheared.c. Catastrophic failure of Naphtha/FO / Diesel storage tanks or major leakage from the handlingsystems of these materials catching fire.d. Pipeline fracture / Nozzle failure.e. Gasket failure leading to flange leakagesHazardsIncident QuantityReleasedConsequences1 Catastrophic rupture ofAmmonia storage tanks. 4000 MT Ammonia Concentration upto 500 ppm indown-wind direction upto 11000 m2 Liquid ammonia line totank failure (20%) 40MT Ammonia concentration upto 500 ppm indown wind direction upto 4700ft downwind& 8000ft cross wind.3 Chlorine leakage fromthe tonners 900 kg Chlorine Concentration upto 30 PPM indown-wind direction upto 1247 m4 Catastrophic failure ofNaphtha storage Tank 10000 KL 12.5 KW/m2 heat radiation level at a distance of 56.35mBurnpool radius : 150ft, Flame height:210ft, Fatality radius upto distance 300ft, First degree/Injury Zone radius upto400ft(approx.)5 10000KL Naphtha tankoutlet line failure (100%) First degree burn upto 300 ft. Fatality radius upto 210ft Burnpool radius: 100ft6 Catastrophic failure ofNaphtha storage Tanks 7000KL 12.5KW/m2 heat radiation level at adistance of 46.53m7 Catastrophic failure ofFuel Oil Storage tank. 1000 KL 12.5 KW/m2 heat radiation level at adistance of 43.5m8 Leakage of synthesisgas from loop 12.5KW/m2 heat radiation due to flash fireextends up to 224.3 m12.5 KW/m2 radiation level due to jet flameoccur till 92.87 mThe over pressure of 0.2068 bar g is up to adistance of 265.6m This over pressure mayresult in extensive damage.Note: 1. The IDLH of ammonia has been taken as 500ppm (NIOSH)2.The IDLH of chlorine has been taken as 30 ppm. (NIOSH)3. The weather is taken as 5 m/s D pasquillHydrogenSynthesis gas (which is hydrogen rich) is produced in the plant for conversion to Ammonia. There is no hydrogen gas holder for storage. Due to high pressure sufficient quantity is present in theprocess vessels and pipings to pose fire / explosion hazard. No off-site effect is envisaged for any synthesis gas fire explosion accidents.。