INCIDENT SHARING

INCIDENT SHARING INCIDENT 1 Date - 5th August 07 Location - Workshop in Nongbon, Thailand Incident - A furnace module to be sent to Nigeria was being fabricated. The company was doing a pneumatic coil test at approximately 100 bar. An employee from other project was walking pass the pressure test area. The testing flange blew off and struck the employee on the head.

Causal Factors The area around the pressure test had not been identified in any way. Area not barricade. No warning signage. No standby person keeping watch to warn passers-by. There had been no general warning of any testing taking place.

Chernobyl Disaster

Chernobyl Built in 1978-1979 Chernobyl

Ukraine

Background Reacktor Bolshoy Moshehnosty Kipyashiy RBMK, a Russian acronym translated roughly means “reactor cooled by water and moderated by graphite”

RBMK Reactor

Control Rods The Control Rods: long metal rods which, in the Chernobyl reactors, contain boron; they help control the chain reaction

Reactor Plant Scenario As the reaction occurs, the uranium fuel becomes hot The water pumped through the core in pressure tubes removes the heat from the fuel The water is then boiled into steam The steam turns the turbines The water is then cooled Then the process repeats

April 25, 1986 01:00 The preparation for the test 13:47 Lowering of the reactor power halted at 1,600 MWt 14:00 The ECCS was isolated 23:10 The power reduction resumed

April 26, 1986 24:00 Operation shift change 24:28 Power level is now 500 MWt and kept decreasing to 30 MWt 24:40 The operator withdrew some control rods 01:00 Power had risen to 200MWt 01:03 Connecting the fourth main cooling pump to the left loop of the system 200MWt 01:07 Connecting the fourth main cooling pump to the right of the loop system - this was a violation of NOP

April 26, 1986 (cont.) 01:19 Increased feed water flow to the steam drums and removed more control rods -violation of NOP 01:23 The test was started 01:23:10 Automatic rods withdrawn from the core 01:23:21 Two groups of automated control rods were back to the core

April 26, 1986 (cont.) 01:23:30 Power kept increasing 01:23:40 Emergency button pushed 01:23:44 Power is at 300000 MWth 01:23:48 1st thermal explosion 01:23:55 2nd explosion

Power Chart

Direct Casualties 31 employees and firefighters died 134 emergency workers suffered from acute radiation sickness

Indirect Casualties By the year 2000 there were 1800 case of thyroid cancer in children and adolescent High number of suicide and violent death among Firemen, policemen, and other recovery workers

Radiation

Radioactive Fallout

System Analysis Use of graphite as a moderator Lack of a well-built containment structure Inadequate instrumentation and alarms for an emergency situation There were no physical controls that prevented the operators from operating the reactor in its unstable state

Human Errors Isolation of the emergency core cooling system Unsafe amount of control rods withdrawn Connection of the four main cooling pumps to the right and left of the system

Human Errors (cont.) Mental model Overconfidence Beta too high The operator did not have a good mental model of the system itself Overconfidence By having an electrical engineer on site for an electrical test No confirmation of cues obtained from the system Beta too high Many missed signals before the accident

Accident Prevention

Recommendations Have proper Standard Operating Procedures (SOP) for both normal and emergency situations Have scheduled trainings and practices for normal and emergency situations

Recommendations (cont.) Always have a reactor expert on site Have operators confirm any cues from the system before making hypothesis or take action Have a team work kind of environment such that every body is involved

Bhopal Gas Tragedy Worst industrial disaster in history 2,000 people died on immediate aftermath Another 13,000 died in next fifteen years 10-15 persons dying every month 520,000 diagnosed chemicals in blood causing different health complications 120,000 people still suffering from Cancer Tuberculosis Partial or complete blindness, Post traumatic stress disorders, Menstrual irregularities Rise in spontaneous abortion and stillbirth India, the second most populated country of the world is one of the most disaster prone countries of Asia.

Second generation effect ICMR, IMA, AMA studies show Children born with genetic defects Growth retardation in boys Hormonal chaos among girls Ground water contamination with high level of mercury, lead, nickel, VOCs and HCH High prevalence of skin and gastro-intestinal diseases Bioaccumulation of toxins found in vegetables and breast milk

Background The plant produced pesticides An intermediate compound in the process is methyl iso-cyanate (MIC) MIC is an extremely dangerous compound MIC is reactive, toxic, volatile and flammable Reacts isothermally with water. Although the reaction is slow, with inadequate cooling the temperature will increase and the MIC will boil

Methylamine (1) reacts with phosgene (2) producing methyl isocyanate (3) which reacts with 1-naphthol (4) to yield carbaryl (5)

How it happened December 3-4, 1984: 40 tonnes of methyl iso-cyanate (MIC) released from Union Carbide plant at Bhopal Accidental release caused by leakage of water into MIC storage tank None of the six safety systems worked Safety standards and maintenance system ignored for months Complete absence of community information and emergency procedures Public alarm system operated after the gas had leaked for nearly four hours

THE END THE END