Three Mile Island

Prepared by: Group 2 (4BENC)

Prepared for: Engr. Siva Kumar A/L Subramaniam

Subject: BENU4583 - Engineering Ethic

The nuclear accident case study

Content

Members• Latifah (Leader)• Marhaizan• Sin Ni• Sabta Ali• Basha Abas• Muhamad Syakir• Safiy Hafifi

1. Introduction

2. Violation Code of Ethics

3. Guidance to Prevent The Event From Happening

4. Ethical Theories

5. Analysis of Issues

6. Flowchart

7. What Should People Involved Do Differently?

8. Conclusion

Introduction

• Name of power plant: Three Mile Island Power Plant (TMI)• Location: Susquehanna River in Pennsylvania, USA , 16 km from the state capital, Harrisburg, a city of 90000

• Type of source energy: Nuclear

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• Power capacity: 1, 700 Megawatts or enough to supply 300,000 homes

• Others: TMI consist of two nuclear plants TMI-1 and TMI-2

Nuclear power plants generate electricity by using steam turbines. The function of the nuclear fuel is to heat water and convert it to steam.

Both plants is 900 MW(e) unit with pressurised water reactors designed by Babcock and Wilcox. The second unit of the site started commercial operation on December 30, 1978.

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What happened to TMI-2?

• Accident began about 4.00am on March 28, 1979 when failure in secondary building.

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TMI-2

TMI-1

What happened to TMI-2?

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• Main feedwater pump stop running caused by electrical and mechanical failure

• Pressure in primary system increased• PORV is opened to reduce the pressure by supply the coolant water

from pressurized relief tank• Once the pressure is stabilized, the PORV should closed to stop the

supplied coolant. But it did not

• There for the coolant was suck back to pressurized relief tank and coolant was overflow caused the reactor to overheated• There are no indicator to show the coolant level in reactor core

• Operator just judge the coolant level by level in pressurizer, since was high they assumed the coolant is fully covered

• Instead the core is experiencing a lost of coolant accident• Nuclear fuel overheated, zirconium cladding ruptured fuel pallet

making ½ of core melted• Failure in secondary building

STOP FUNCTIONING

PRESSUREINCREASED

PORVOPENED

PORVFAILED TO CLOSE

PRESSURESTABILIZED

CORE AREEXTREMELY OVERHEATED

Violation Code of Ethics (NSPE)

Engineers shall undertake assignments only when qualified by education or experience in the specific technical fields involved. (2a)• In the case, the operators are not trained to understand the

nature of the PORV indicator and to look for alternative confirmation that the main relief valve was closed. There was a temperature indicator between the PORV and the pressurizer that could have told them the valve was stuck open, but this temperature indicator was not part of the "safety grade" suite of indicators, and the operators had not been trained to use it. It is located at the back of the desk also meant that it was effectively out of the operators’ sight.

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Violation Code of Ethics (NSPE)

If engineers’ judgment is overruled under circumstances that endanger life or property, they shall notify their employer or client and such other authority as may be appropriate. (1a)• In this case, critical human factors problems were revealed in the

investigation about the industrial design of the reactor control system's user interface. A lamp in the control room, designed to illuminate when electric power was applied to the solenoid that operated the pilot valve of the PORV, went out, as intended, when the power was removed. This was incorrectly interpreted by the operators as meaning that the main relief valve was closed, when in reality it only indicated that power had been removed from the solenoid, not the actual position of the pilot valve or the main relief valve. Because this indicator was not designed to indicate the actual position of the main relief valve, the operators did not correctly diagnose the problem for several hours.

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Violation Code of Ethics (NSPE)

Engineers may express publicly technical opinions that are founded upon knowledge of the facts and competence in the subject matter. (3b)• The NRC officials believed (without concrete

analysis) that the hydrogen bubble could explode, through such an explosion was never possible since there was not enough oxygen in the system. They had ordered evacuation and that a meltdown was conceivable.

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Guidance to Prevent The Event From HappeningSection III (9)(e)

Engineers shall continue their professional development throughout their careers and should keep current in their specialty fields by engaging in professional practice, participating in continuing education courses, reading in the technical literature and attending meeting and seminars.

• The TMI management system

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Guidance to Prevent The Event From HappeningSetion III (1)(a)

Engineers shall acknowledge their errors and shall not distort or alter the facts.

• The nuclear power plant’s management should acknowledged their fault on the arisen of misunderstanding problem.

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Guidance to Prevent The Event From HappeningSection II(1)

Engineer shall hold paramount the safety, health, and welfare of the public.

• The NRC has primary responsibility and regulatory authority for health and safety measures as they relate to the operation of commercial nuclear plants.

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Ethical Theories

Utilitarianism Ethics (design deficiency)

• No procedure to identify and manage the meltdown event and the operating staff is not trained for it.

• Global control board weakness in indications of order instead of position without specific warning.

• Existing emergency operating procedure is difficult to use and not suitable.

• The improper maintenance of the pressurizer increased the probability of the malfunction of open valve.

• The closed connecting valves of the steam generators auxiliary feedwater system leads to the complete loss of emergency core cooling system.

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Ethical TheoriesDuty Ethics• NRC officials failed to fulfill their duty – stirred public

fear by making false statement .• The plant operators’ failed to carry out their duty in

handling and mitigating the accident .• The management’s duty is not fulfilled by not providing

proper training to the plant operators (unsystematic management system).

• The local and state authorities’ duty have been carried out by preparing the residents’ evacuation process and cooperate with the NRC authority.

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Ethical Theories

Right Ethics• People that live near the power plant - the right to live in

safe environment.

• The operators’ in the plant - the right to have a safe

working environment and to live.

• The local and state authorities’ right – defend population

safety by questioning nuclear power plant’s safety

procedure.

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Ethical TheoriesVirtue Ethics• The plant operators’ incompetency in accident handling

and not able to make wise decision.

• The power plant’s management does not carry out their

responsibility by ignoring operators’ training which is the

main element in preventing accident.

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Analysis of IssuesFactual issue:

1. TMI-2 reactor's fuel core.2. Gas in containment building was move to waste

gas decay tanks.3. Hydrogen gas is created because chemical

reaction between water and the zircaloy metal. 4. No injuries or obvious health impacts.5. Major of health studies has been conducted since

the accident happened.6. Communications problems.

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Analysis of IssuesConceptual issue:

1. No "China Syndrome" 2. Nuclear Regulatory Commission (NRC)

statement.

Moral issue:

3. Better understanding on the safety nuclear energy.

4. Public awareness increase. 5. Operators disability in making wise decision.

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Flowchart

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Continue

Flowchart

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From previous

What Should People Involved Do Differently?All the people involved in the accident should have done differently in avoiding the accident from happen in the plant, as described below:• Engineers – Participate with continuing education

course and seminars• Management - Identify workers performance, staffing

requirements, revamping operator training, improved instrumentation and controls

• Government – Strengthen and reorganize the safety enforcement.

• Local authority – Enhance emergency respond team.

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ConclusionC

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Accident was caused by EQUIPMENT failure and HUMAN ERROR

to handling the situation

Accident was caused by EQUIPMENT failure and HUMAN ERROR to handling

the situation1 LOSS of coolant to the reactor led to producing heat and melting the fuel

rod. Small amount radioactive RELEASED to

environment

LOSS of coolant to the reactor led to producing heat and melting the fuel rod. Small amount

radioactive RELEASED to environment2But, NO injuries or deaths involved in this accident

and the experts concluded the amount of radioactive

released is NOT hazardous to living thing

But, NO injuries or deaths involved in this accident and the experts concluded the amount of radioactive released is NOT hazardous to living

thing3

To cleanup cost around a BILLION dollars to

company and took almost 10 YEARS to complete

To cleanup cost around a BILLION dollars to company and took almost 10 YEARS to

complete4

After incident, NO new reactors to be built and

leads to a very large evolution to the SAFETY IMPROVEMENT of a

majority of nuclear plants.

After incident, NO new reactors to be built and leads to a very large evolution to the SAFETY

IMPROVEMENT of a majority of nuclear plants.

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Today, nuclear reactors are still important for our

source of energy, but they are SLOWLY becoming

decommissioned until find a secure way to handling

nuclear energy

Today, nuclear reactors are still important for our source of energy, but they are SLOWLY

becoming decommissioned until find a secure way to handling nuclear energy

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Thank You

The Three Mile Island AccidentBy Group 2 (4BENC) 2010/2011 UTeM