Assignment 1 (a) - 4 Marks 1. Identify at least 10 types of hazards that are to be found in your workplace/industry. Hazard: potential source of harm .. a state or set of conditions of a system ... that, together with other conditions in the environment of the system ..., will lead inevitably to an accident (incident) Accident: an undesired and unplanned (but not necessarily unexpected) event that results in (at least) a specified level of loss .. ~ the loss event 2. Describe the way in which the hazard manifests itself (e.g., failure mode / types of machinery, equipment or activity in which it is to be found). 3. Identify engineering and other control measures for the hazards (describe prevention / control / mitigation measures). Hint: See Table 4 given in Efficiently Managing Risk, Chapter 2 - Reader Book 2.1 Occupational Health and Safety, Derek Viner (1988). 1. Hazard 2. Manifestation of the Accident (incident) 3. Control Measures (Engineering and others) 13 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 1(b) - 4 Marks Consider an Energy System (ES) consisting of only the following three Units: (i) Energy Generation Unit (EGU): Generates energy from fuel inside. (ii) Energy Control Unit (ECU): Controls energy generation according to requirements. (iii) Energy Transport Unit (ETU): Transports energy to distribution network The system would fail if failure of any of the three units occurred. Each unit would fail due to any of its own failure modes or common modes. Other relevant data are as below: What Can Go Wrong? Likelihood Frequency of the event happening The Potential Effect Financial Consequence $ Per Incident EGU generates too little power 1 time/year Does not satisfy customer requirements $5,000 EGU generates too much power to be controlled by ECU 0.005 times/year System damage caused by explosion due to accumulated energy $1,000,000 ECU fails to control power output accurately 2 times/year Does not satisfy customer requirements $5,000 ECU completely loses control 0.001 times/year System damage and possible casualties (Catastrophic failure) $10,000,000 ETU fails to transport energy to the network (pollution released to environment instead) 0.02 times/year Environmental impact $500,000 Complete loss of ETU 0.005 times/year System damage caused by explosion due to accumulated energy $1,000,000 1. Table the Energy Systems failure modes (What Can Go Wrong) and determine any potential cause(s) for each (make fair and sound engineering assumptions and write them down). 2. Draw a Fault Tree Diagram for the Energy System failure modes (loss of energy) based on the What Can Go Wrong items given above only. 3. Determine a quantitative measure of the potential financial risk (in $/year) associated with operating this Energy System. 14 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 1(c): 4 Marks Discuss the following three items (two page each - supported by a short literature review): 1. In your opinion, what degree of safety risk is acceptable and why? 2. Give your understanding and opinion on the validity of the idea of keeping risk ALARP? 3. What is your understanding of the SFAIRP principle? Is there any difference between ALARP and SFAIRP? Assignment 1(d): 4 Marks The following scenario is for a nuclear power plant system. The Initiating Event (IE) for the Event Tree is a pipe break in the cooling sub-system that begins the scenario, with a frequency of once every thousand years. The barriers that are relevant (in the sequence they will be activated) are as below: 1. Electricity: The probability of Electricity being available is 99 out of hundred times. 2. Emergency Core Cooling: The likelihood of Emergency Core Cooling being available is 0.85. 3. Fission Product Removal: The chance of Fission Product Removal failure is 10% of the times. 4. Containment: The probability of Containment fails is 1 out of ten times. You are required to: Calculate the probability for a Large & Very Large Fission Release, Calculate the probability for a Medium Fission Release Calculate the probability for a Small & Very Small Fission Release 15 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 1(e): 4 Marks The causes of a Vehicle headlamp to fail (No Light) are as below: Either there is No Power; or Lamp Failure = 1.00E-04/hr; or Switch Failure = 1.00E-03/hr. If either Battery Fails = 1.00E-04/hr or Contact Fails = 1.00E-04/hr, then there would be No Power 1. Draw A Fault Tree for the No Light as the Top Event. 2. Calculate the likelihood of the top even happening per hour. 16 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 2A: 20% of the total mark Assignment 2 Note: Please submit your assignment only as ONE MS Word document. Please copy and paste any Excel or other format materials into your Word document. Assignment 2(a): 4 Marks In the event of loss of the main feed water in a Pressurised Water Reactor the reactor system turns to the backup system, the Auxiliary Feed Water (AFW) supply system, to provide water to the steam generator. By neglecting other components such as piping, valves, control systems, etc, a simplified model of the AFW supply system is shown in the figure below: ? Steam Generator The success of the AFW system requires the following: At least one of three of the Storage Tanks At least one of the three pumps. One of the pumps is steam-turbine driven, whereas the other two are electric pumps that depend on the functioning of electric power supply from diesel generators. Assume the following probability data for the initiating event and the system responses: Event Description Probability Frequency of Occurrence IE Loss of main feed water P(IE) 0.2/year E1 No water supply from three storage tanks P(E1) 0.00001/year E2 Failure of both electric pumps, including failure caused by malfunction of the electric power supply P(E2) 0.002/year E3 Failure of turbine pump P(E3) 0.01/year (IE = Initiating Event; E1 = First Event; E2 = Second Event; E3 - Third Event) 17 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 2(a).1: Construct a Fault Tree diagram for the loss of AFW supply system. 2(a).2: Construct an event tree for loss of main feed water as an initiating event. 2(a).3: From the Event Tree, calculate the likelihood of the loss of the main feed water and AFW supply system failure. Assignment 2(b): 4 Marks A reactor effecting an exothermic reaction is at risk of thermal runaway in the event of coolant failure. Its protective trip system is intended to open a dump valve, which empties the reactor if low coolant flow or high reaction temperature is detected. 2(b).1: Draw a fault tree, which summarises the failure logic analysis given below. 2(b).2: Calculate the likelihood of the runaway reaction. 2(b).3: Identify the primary failures that the system is most sensitive to (explain)? Failure Logic Analysis: Runaway reaction occurs if cooling water failure occurs whilst the protective system is inoperative. Cooling water failure can occur because of pump failure, line blockage or an exhausted water supply. The protective system may be inoperative when either the shutdown system fails because the dump valve fails shut, or because the detection system fails; the detection system fails when both low coolant flow trip and high temperature trip fail. Assume a low demand mode of operation for the safety instrumented functions. Failure Failure Rate Pump failure Line blocked Supply tank empty 0.2/year 0.01/year 0.1/year Failure Mode Probability of Failure (on demand) Dump valve fails shut Low flow trip failure High temperature trip failure 0.001 0.01 0.01 18 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 2(c): 4 Marks For an electric motor: 1. Draw a fault tree diagram for when the motor Overheats. The motor overheats either because of a Primary Motor Failure Over heated), or an Excessive Current Thru Motor. The Excessive Current Thru Motor happens when both the Fuse fails to Open and an Excessive Current in Circuit. The Fuse fails to Open due to the Primary Fuse Failure Closed. The Excessive Current in Circuit is due to either Primary Wiring Failure Shorted or Primary Power Failure Surge. 2. What is the likelihood of a motor Overheats if knowing that: Primary Motor Failure Over heated: Rate = once a year Primary Fuse Failure Closed: Probability = 0.01 Primary Wiring Failure Shorted: Rate = once every hundred years Primary Power Failure Surge: Rate = once in ten years Assignment 2(d): 4 Marks The following situation is an example for a fire detection and suppression system in an office building. The Initiating Event (IE) for the Event Tree is fire starts, with a frequency of once every hundred years. The barriers that are relevant (in the sequence they will be activated) are as below: 1. Fire flame/rise in temperature detection: The probability of fire flame/thermal (rise in temperature) detection system to work is 95 out of hundred times. 2. Fire Alarm system: The likelihood of the Fire Alarm system to work is 0.8. 3. Fire Sprinkler System: The chance of Fire Sprinkler (protection) System to work is 85% of the times. You are required to: Draw an Event Tree to demonstrate the above scenario. Calculate the probability for Death/Injury (extensive damage) Calculate the probability for limited damage. 19 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 2(e): 4 Marks Figure below shows a typical fault tree modelling the loss of Fire Water Deluge System. The loss arises from the failure of a pump, a motor, the combined detection system (UV fire detector / detection panel), and the combined failure of both power sources. Evaluate the frequency of the top event (lambda / failure rate) and MDT for the failure logic modelled. You are required to show all the working outs (calculations). Assume the following basic event data: 20 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Notes: The failure rate output of an AND gate: (failure rate_1) x (failure rate_2) x (MDT_1+MDT_2) The MDT output of an OR gate is the weighted average of the two MDTs weighted by failure ate: [(MDT_1 X failure rate_1) + ((MDT_2 X failure rate_2)]/[ (failure rate_1) + (failure rate_2)] The MDT output of an AND gate is multiple of individual MDTs divided by their sum: [(MDT_1 X MDT_2]/[MDT_1 + MDT_2)] [If interested more, please refer to Reliability, Maintainability and Risk by Dr David J Smith.] 21 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 2B: 20% of the total mark Assignment 3 Note: Please submit your assignment only as ONE MS Word document. Please copy and paste any Excel or other format materials into your Word document. Assignment 3(a): 4 Marks Conduct a complete FMEA for the following case: An aluminium beverage can, which all of us have used, may be described as a pressure vessel when it contains a carbonated beverage, especially under accident conditions when it has been dropped or shaken. The can must be designed as carefully against accidental failure by explosion as does a steam boiler or nuclear reactor vessel, which has strict safety design codes. The successful design of a beverage can depend on avoiding the possibility that it will fail. Divide the can into four (4) parts, i.e. side, top, bottom and rivet in the pop-top. Assignment 3(b): 5 Marks HAZOP: Consider an oil vaporiser that consists of a furnace containing a heating coil and burners, which are fired by natural gas. The oil enters the heating coil as a liquid, is evaporated, and leaves the coil as a superheated vapour. The natural gas entering the burners combines with external air and burns in a hot flame. The combustion gases leave through the stack. The oil flow is controlled by a flow control set which includes: a flow control valve (FCV); a flow element (FE), that measures the oil flow; a flow controller (FC); and a low flow alarm (FAL), which alarms if the oil flow reduces below a set point. 22 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 The natural gas flow passes through a self-actuating pressure-reducing valve (PRV) to the main burner control valve (TCV), and a pilot valve (PV). The main burner control valve is actuated by the temperature controller (TC) which receives the signal from the temperature element (TE), which measures the oil vapour discharge temperature. The high/high pressure switch (PSHH) on the natural gas line is interlocked, via 1-4 to close the main burner control valve (TCV), if the gas pressure is too high. There is also a high temperature switch (TSH) on the vaporised oil outlet to close the main burner control valve (TCV), if the oil is superheated above a maximum temperature. Finally, there is a flame detector device (not shown) which will close both gas valves should the flame go out. Select ONLY the vaporiser coil from the oil inlet (before flow measurement), to vapour exit to process (after temperature control) for examination. The design intent for this part is Oil flow from the feed line, heat from the furnace, vaporise, superheat and transfer oil vapour to the process. Apply at least five (5) guide words and examine ten (10) deviations (from the design intent) in order to construct a possible HAZOP output for the material and activity elements. Assignment 3(c): 4 Marks Prepare a FMEA at component level for an Electric coil heat pressure cooker. Operational phase(s): Cooking (after load/close/sealing) Components: Safety Valve (spring-loaded): opens on overpressure. Thermostat Switch: controls temperature, where Switch opens >120 C. Pressure Gage: dark zone indicates overpressure. Lid Clamps: keeps lid sealed and closed Heating coil: heats up the food to cook 23 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Operators Tasks: (1) loads cooker, (2) closes/seals lid, (3) connects power, (4) observes pressure, (5) times cooking at prescribed pressure, (6) offloads cooked food. Assignment 3(d): 4 Marks The following scenario is for an automobile system where the car battery has failed. The Initiating Event (IE) for the Event Tree is Dead Battery that begins the scenario, with a frequency of once every ten years. The barriers that are relevant (in the sequence they will be activated) are as below: 1. Jumper Cables: The probability of jumper cables is available is 75 out of hundred times. 2. Donor Battery: The likelihood of a Donor Battery is available is 0.5. 3. Cables set: The chance of Cables set is connected properly is 90% of the times. 4. Donor Battery: The probability of the Donor Battery starts the Car is 5 out of hundred times. You are required to: Draw an Event Tree Diagram to demonstrate the above scenario. Calculate the probability for Car not started, Calculate the probability for Car Started. Draw a Fault Tree Diagram for the Car not Started to demonstrate potential causes. 24 CRICOS Provider No. 00103D | RTO Code 4909 MREGC 5007 Assignment 3(e): 4 Marks For the Redundant Fire Pumps shown below: Top Event: No Water from fire water system Causes for the Top Event: VF: Valve Failure = 1.00E-02/hr FP1: Failure of Fire Pump 1 = 1.00E-04/hr FP2: Failure of Fire Pump 2 = 1.00E-04/hr EF: Failure of Engine = 1.00E-03/hr 1. Draw a Fault Tree Diagram for the Top Event 2. Calculate the Likelihood of the Top Event happening.

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