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Analysis on human and organizational factors regarding initial responses of shift teams and field workers to the Fukushima Daiichi NPP accident

TECHNICAL MEETING ON MANAGING THE UNEXPECTED — 1

Hiroko KOIKE Takaya HATA Ryuji KUBOTA

Japan Nuclear Energy Safety Organization (JNES)

FROM THE PERSPECTIVE OF THE INTERACTION BETWEEN INDIVIDUALS, TECHNOLOGY AND ORGANIZATION 25–29 June, 2012 IAEA Headquarters Vienna, Austria

Table of Contents

1.Introduction 2.JNES classification 3.Investivation approach step 1 : Make a chronology of event

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step 2 : Identify the problems related to human errors step 3 : Identify direct causes step 4 : Identify human and organizational factors 4.Results of approach 5.Conclusion

• JNES has developed taxonomy of human factors and

“JNES Organizational Factor List” named JOFL. These are event analysis tools for DCA and RCA. A purpose of them is to review PSFs, good practices and lessons learned to be reflected to the regulatory activity.

• JNES analyzed on human and organizational factors
• 1. Introduction

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• JNES analyzed on human and organizational factors

regarding initial responses of the shift teams and field workers to the Fukushima Daiichi NPP accident in order to improve these analysis tools.

DCA : Direct Cause Analysis RCA : Root Cause Analysis PSFs : Performance Shaping Factors

We use two classifications:

• Taxonomy of Human Factors
• The classification of Organizational

Factors named JOFL 2.JNES Classification

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Factors named JOFL

Taxonomy of Human Factors

• Task difficulties
• Work load inadequacies
• Working time inadequacies
• Parallel / Unexpected tasks
• Team structure/organization
• Inadequacies in instruction and supervision
• Communication
• Team work / Workshop moral
• Compliance

Task Factors Organizational Workplace Factors

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Individual Factors

• Psychological stressor
• Physiological stressor
• Subjective factors
• Work performance incapability

Site Environmental Conditions Factors

• HMI inadequacies
• Work place inadequacies
• Work condition inadequacies
• Special equipment

Administrative Factors

• Education and training
• Provisions/Procedures
• Regulation/Work planning

Human Factor Organizational Factor

JOFL classification

No. Key factors No. Intermedeate classification

1-1 economic status 1-2 regulatory response policy 1-3 external communication 1-4 general reputation 2 Organizational Psychological Factors 2-1

• rganization climate

3-1 top management commitment 3-2

• rganizational administratin

3-3 human resource management 3-4 company policies and compliance criteria / standards 3-5 communication between head office and power station 3-6 self-evaluation (or the third party evaluation) 4-1 division-manager level organization administration 4-2 conformance to rules 1 3 4

External Environmental Factors Operational Management Factors Intermediate Management Factors

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4-3 continuous education of organization 4-4 personnel management 4-5 communication 4-6 procurement management 4-7 human resources management related to organizational structure 4-8 engineering control 4-9 work control 4-10 change control 4-11 non-conformance control 4-12 corrective action 4-13 documentation control 5-1 inter/intra-party communication 5-2 knowledge / education 5-3 groupthink and decision-making based on principle of individuality such as a senior manager 6-1 knowledge / skill 6-2 leadership 6-3 ambitiousness / carefulness for safety 6-4 ambitiousness for management 6-5 concern about field staffs 6-6 motivations, stress

Individual Psychological Factors

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Collective Factors

Step 1 : Make a chronology

• f event

Step 2 : Identify problems related to human errors

Reference material 1.TEPCO’s Report 2.The Interim Report of investigation Committee on the Accident at Fukushima Nuclear Power Stations

3.Investigation approach

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Step 3: Identify direct causes Step 4: Identify human and

• rganizational factors

3.The proceedings of the Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) 4.Press release which the regulatory body and our group conducted the on-site investigation.

Step1:Main Sequence of the accident of Fukushima Dai-ichi NPS (Friday,11 March)

14:47 Start-up of emergency power generation 15:37～ ～ ～ ～15:42 All emergency Core cooling system not using AC power

(Unit1:IC(isolation condenser), Unit2: RCIC(reactor core isolation cooling system), Unit3: RCIC and HPCI (high pressure core injection system)

Stop of core cooling system 14:46 Loss of external power supply due to earthquake

(1) The manual stopping of IC at Unit 1 (2) Switching off the HPCI system manually at

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diesel power generators stopped except for one generator in Unit6 due to tsunami 15:37 Loss of all AC power supply except for Unit6 And Loss of DC power supply For Unit1,2 Stop of core cooling system not using AC power Alternative water injection from a FP line after decreasing RPV pressure During this time without cooling, the fuel was exposed and core melt started, generating hydrogen

(Unit 5 took power supply from Unit6 on 13 March).

manually at Unit 3 (3) Insufficient recovery activities related to power-supply vehicles and fire engines.

Investigation approach

Step 1 : Make a chronology

• f event

Step 2 : Identify problems related to human errors

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Step 3: Identify direct causes Step 4: Identify human and

• rganizational factors

• 15:03, The return pipe

isolation valves(MO-3A,MO- 3B) of the IC were fully closed.

• 17:50, An operator found the

indication lamps of MO-3A and MO-2A were closed state.

• 18:18, An operator performed

the opening action of MO-3A

Step2: (1)The manual stopping of IC at Unit 1 (Friday, 11 March )

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Problem No.1 Lack of knowledge of IC functions and lack of experience in its operation

the opening action of MO-3A and MO-2A .

• 18:25 , Considering that the

piping needed to supply water for the shell side had not been formed, an operator set the return pipe isolation valve (MO-3A) to a “closed” state .

Step2:(2)Switching off the HPCI system manually at Unit 3

Control

• f flow

CST PCV Main Steam Line Turbine Stop Valve regulating valve RPV

11 March

• 16:30 ,Reserve the reactor water

level by using the RCIC and the HPCI 12 March

• Alternative spraying of the S/C

using DDFP was studied.

• 12:35 HPCI started up

automatically (reactor water

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HPCI system diagram DDFP: diesel-driven fire pump

Injection line Minimum flow Bypass valve Steam Line Suppression Chamber Water Source Switching Line Supply water system Minimum flow line

Problem No.2 A failure to reduce pressure

• f the RPV for the alternative

water injection method using the FP system, etc. after switching off the HPCI system manually at Unit 3.

automatically (reactor water level low). 13 March

• 02:00 ,The reactor pressure that

had remained stable at approx. 1MPa began to decline.

• 02:42, An operator halted the

HPCI.

• 02:45, DDFP had failed.

As a result, water level went down, and the core was exposed.

Date Time Event Problem 11-Mar 17:12

Site Superintendent ordered staff to study a method for water injection through the FP line through fire engines.

12-Mar Before dawn

Licensees and workers from a contractor company started clearing debris to find the outlet

• f the FP line .

Step2:(3)Insufficient recovery activities related to power-supply vehicles and fire engines

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• f the FP line .

2:00

The power generation team and fire brigade headed for the target area to find the outlet of the FP line outside the building. Several operators who had been refueling the DDFP with light oil joined the work teams to find the outlet of the FP line, but were unable to do so.

Problem No.3 Insufficient recovery activities related to fire engines for water injection services.

Date Time Event Problem

11-Mar 22:00

It was confirmed that one initially dispatched HVPS car had arrived at the Power Station site. 10:15 It was confirmed that 72 HVPS cars had arrived at Fukushima NPS.

13-Mar

A backhoe was used to clear

• bstacles that had washed onto

the road before parking a HVPS

Problem No.3 Insufficient recovery activities related to power-supply vehicles for power source restoration work Step2:(3)Insufficient recovery activities related to power-supply vehicles and fire engines

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car.

A backhoe was used to clear obstacles that had washed onto the road before parking an HVPS car. To reserve a cable laying route, the team requested a contractor to fetch compressed gas cylinders stored at the technical training facility in the Power Station site. The team then used the cylinders to fuse the closed shutter of the bulk delivery entrance of Unit 3 Turbine Building and the deformed fire door at the walk through of the control building between Units 3 and 4.

HVPS: High Voltage Power Supply

Investigation approach

Step 1 : Make a chronology

• f event

Step 2 : Identify problems related to human errors

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Step 3: Identify direct causes Step 4: Identify human and

• rganizational factors

“Direct cause No.1”, 1.One of the main reasons was that no one in the shift team had experienced the operation of the IC at Unit 1 or had trained or educated, which would have enabled them to make an appropriate action as the situation changes. 2.One of operators stopped the IC because he misinterpreted that a dry-out of the cooling water of heat exchanger in IC induced the rapture

• f steam line of IC and the radioactivity released directly into the

Step3: Identify direct cause

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atmosphere. “Direct cause No.2”, 1.Cause of the result which they failed to reduce pressure for the alternative water-injection method is that the on-duty shift operators underestimated the risk that the batteries depletion even though an effective alternative water-injection method had not been ensured. 2.Operator misinterpreted that turbine rotational speed of HPCI reduce more due to reduce pressure the RPV, and oscillation of turbine occurs damage.

“Direct cause No.3”,

• Employees could not afford to find equipments or cables at the

unfamiliar fields after most of contractor’s engineers and experts evacuated by Tsunami Alarm. Cable work was suspended by evacuation with continued Tsunami Alarm and many aftershocks of a huge earthquake.

• Another reason for the delayed water injection was that there was

no specific section assigned the task of water injection using fire

Step3: Identify direct cause

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no specific section assigned the task of water injection using fire engines that Site Superintendent directed.

• Nobody on site was able to operate the backhoes and other heavy
• machinery. Similarly, for water-injection operations using the fire

engines, the licensee had always consigned all fire engine

• perations to a contractor, and in the early stages of the accident no

employee on the grounds was able to operate them.

• There were a small number of staffs that recovery operation

related to electrical and instrumentation and human resource was lack.

Investigation approach

Step 1 : Make a chronology

• f event

Step 2 : Identify problems related to human errors

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Step 3: Identify direct causes Step 4: Identify human and

• rganizational factors

Extreme conditions such as acute stress

High radiation

Individuals Symptoms

Confirmation bias Confirmation bias affect

• perators to misapprehend
• peration of IC and HPCI.

Step4: Identify human and organizational factors

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Performance anxiety of equipments Event what no one in the shift team had experienced. When we apply it to these direct causes, causes inducing confirmation bias are “High radiation”, “Performance anxiety of equipments”, and “Event that no one in the shift team had experienced”.

Intelligent Customer

Lack of Human resources

Organizational Symptoms

Decline of organizational performance

According to direct cause No.3, we think that licensee declined of organizational performance because licensee has depended on the contractors.

Step4: Identify human and organizational factors

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Fire engines Power- supply vehicles Lack of procedure Lack of training They did not know the storage location of machinery or material and spend time working at the unfamiliar field. When field workers were under lack of procedure, training and human resources about power-supply vehicles and fire engines, they declined

• f
• rganizational performance.

We found two factors by individual approach. 1)Human Factors “No one in the shift teams had experienced the

• peration or had been trained or educated for expected

behaviors under extreme conditions such as acute stress.”

4.Results of approach

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2)Organizational Factors “Licensee did not retained sufficient capability of Intelligent Customer.” These two factors do not include in our taxonomy of human factors and JOFL. We found new attributes of our classification.

• Taxonomy of human factors and JOFL used by JNES do not

consider Licensee’s activities required under severe accident so that there is a need to improve them.

• We will consider whether to introduce new terminology of
• ur taxonomy to conventional JNES classifications.

5.Conclusion

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• ur taxonomy to conventional JNES classifications.
• Based on final report of Japanese Government, we will

conduct our investigation more deeply.

• We will proceed with investigation of stakeholders on this

accident using the same approach.

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