Proceedings of the International Symposium on Engineering Lessons Learned fromthe 2011 Great East Japan Earthquake, March 1-4, 2012, Tokyo, JapanDAMAGES OF MACHINES AND STRUCTURES IN
GREAT EAST JAPAN EARTHQUAKE AND LESSONSFROM THE DISASTER
Masaki SHIRATORI
Professor, Center for Risk Management and Safety Science, Yokohama National University
Chairman of the JSME Investigation Committee on the Great East Japan Earthquake
masaki@ynu.ac.jp

ABSTRACT:The Japan Society of Mechanical Engineers (JSME) has constituted an investigation committee on
damages of machines and structures caused by the Great East Japan Earthquake and the following
tsunami. The committee consists of the following seven working groups:
WG1: Damages of machines and devices, and effectiveness of the earthquake-proof technologies
WG2: Mechanism of damages of machines and structures due to tsunami
WG3: Applications of robots at the disaster area
WG4: Traffics and logistics
WG5: Damages of energy infrastructure
WG6: Review of codes and standards in NPP.
WG7: Risk management against the earthquake and accidents in NPP.
The committee started its activity from the end of March, 2011, and expects to publish the final reportat the end of March, 2013. Each WG works aggressively and there are many data about damages andlessons learned from the good practices. This paper provides an interim report on the overview of the
JSME activities.
Key Words: Great East Japan Earthquake, Tsunami, Machines and Structures,
Earthquake-proof Technology, Applications of Robots, Traffics and Logistics, Energy
Infrastructure, Codes and Standards in NPP, Risk Management, NPP Accident

INTRODUCTION
The “Tohoku Region Pacific Coast Earthquake followed by the vast tsunami ”, which attacked Japanon March 11th ,2011, caused unprecedented disasters in Japan, especially in Tohoku and North Kanto
prefectures. Further, the accident at the Fukushima Daiichi Nuclear Power Plant(NPP), caused by theearthquake and tsunami, resulted in the meltdown of the fuels in the reactor core, collapse of thenuclear reactor buildings due to the hydrogen explosion and the large scale spread of the radioactive
materials to the environment, and continues to menace the people living in that area. We are facing to asevere situation that we have never experienced.
Here again, we would like to present our condolence to those who have passed through the disaster,138

and send our massage that “We are always with you.” to those who are suffering from the disaster.
Further, we would like to send the same message to the engineers and workers who risk their own
lives to tackle with the accident to put an end of it.
The Japan Society of Mechanical Engineers has settled the following two committees just after theearthquake:- Committee on emergent damage analyses, surveys and proposals- Committee on long range proposals
The members of both committees have been working aggressively from the viewpoint of :- What the engineers and researchers, who are engaged in the mechanical engineering, have toreconsider and learn from the disaster?
- What they can do towards the future?
The characteristics of the present earthquake are :- The scale of the earthquake was very large, that is, M9.0.
- The scale of the tsunami following upon the earthquake was enormously huge.
- The disaster area is extensively wide, and there are so many people who suffered from thedisaster.
- We meet new difficulties to deal with the NPP accident and the spread of the radioactive
materials.
There are many items to be surveyed and many subjects to be investigated. In order to do this job
effectively, JSME settled 7 WG’s in the first committee while 4 in the second. In this paper the author
focuses the attention to the activities done by the first committee, that is,’ the Investigation Committee
on the Great East Japan Earthquake’.
The committee started its activity from the end of March, 2011, and expects to publish the final reportat the end of March, 2013. The investigation policy is such that- Investigation should be fair, right and open.
- Investigate damages due to earthquakes and/or tsunami.
- Questionnaire and hearing investigations are recommended as well as information published bygovernment, companies, etc..
- Find out good practices.
- Send messages to the public as well as JSME members as quick as possible.
Each WG works aggressively and there are many data about damages and lessons learned from thegood practices. This paper provides an interim report on the overview of the JSME activities.

WG1: DAMAGES OF INDUSTRIAL FASCILITESSeismic Damage Distribution in Industrial Facilities
Figure 1 shows the seismic damage distribution of industrial facilities, as of July 5th, 2011, caused by
the Great East Japan Earthquake. Red mark indicates the industrial facilities with damage, whilegreen mark without damage. It is confirmed that the seismic damage is located over a wide area inJapan.
Statistics Results of Seismic Damage Investigation by JSMEWG1 carried out questionnaire investigation about seismic damages among companies, including
member companies, research institutes and universities during the period of May, June and July, 2011.
Total number of answers is 233, of which 118 were with seismic damage, while 115 were without one.
Details of the statistic results are shown in the appendix, and they are summarized as follows:
Damage of Machines and Devices: As for the damage by the strong motion, buckling of tanks,
failure of hook bolts or run off of overhead cranes, and failure of the utility pipes or air ducts were139

commonly observed. As for the damage by the tsunami, equipments, tanks, and unloaders weredestroyed by floating objects, or washed out by buoyancy force. Tsunami also caused the short circuitdamage of the electrical equipments. On the other hand, there are some cases which seemed to be
reduced seismic damages by the earthquake resisting methods taken in advance.

Fig.1

Seismic damage distribution of industrial facilities (As of July 5, 2011)

WG2: MECANISM OF DAMAGES OF MACHINES AND STRUCTURES
DUE TO TSUNAMI
WG2 investigates combined damage mechanisms of machines, equipments and structures caused due totsunami. Generation and propagation mechanisms of tsunami should be studied primarily by Japan
Society of Civil Engineers and Japan Association for Earthquake Engineering and so on. The Japan
Society of Mechanical Engineers would like to understand the combined damage mechanisms of tsunami
from a viewpoint of loss of functions of machines, equipments and structures, together with the generationand propagation mechanisms of tsunami. Based on such understanding, we, as members of WG2, wish toestablish failure simulations of machines, equipments and structures caused due to tsunami, andsimulation-based methodology for tsunami-proof machines, equipments and structures.
Tsunami has various kinds of potential powers causing damages of machines, equipments and structures,
including getting water, invasion of sea water containing sand, massive water crashing, debris collision. In
the Great East Japan Earthquake and Tsunami, we often observed deformation and failure of machines andstructures crashed by ships and/or containers carried by the tsunami as shown in Figure 2a. In WG2, we
focus on not only failure of single component, but also combined failures of multiple mechanisms. As one
of examples of our investigation, Figure 2b shows a snapshot of simulation of building attacked by debris
carried by tsunami. In addition, we need to consider more complex scenarios such that structures are firstdamaged by earthquake loading and liquefaction and are then attacked by tsunami.
In general, tsunami height is a primal concern. However, to quantitatively evaluate effects of tsunami
ascending and drawing, lifting force causing falling moment, getting water and collision-based failure,large-scale and precise simulations will be needed. We discuss what phenomena current simulation
technology can solve, and what are missing in it. We would like to propose what R&D we should performfrom now on.

140

Figure 2a A factory attacked by a large ship carried by tsunami（Yahoo! JAPAN East Japan Earthquake Picture Record Project,
http://archive.shinsai.yahoo.co.jp/entry/61926/ ）Figure 2b A snapshot of ASI-Gauss-based simulation of building attacked
by debris carried by tsunami (Lynn, K. M. and Isobe, D. (2007). “Finite Element Code for Impact
Collapse Problems of Framed Structures”, International Journal for Numerical Methods in Engineering,Vol. 69, No. 12, 2538-2563.)

WG3: APPLICATION OF ROBOT TECHNOLOGIES TO THE DISASTER SITE
In the Great East Japan Earthquake many robot technologies have been used and tested in Sanriku
Coast and Fukushima Daiichi NPP. In Sanriku Coast, they were used for the investigation of missing
persons driven by tsunami under the sea, debris removal in the disaster sites and the inspection of a
gymnastic hall in danger of collapsing in Hachinohe. In Fukushima Daiichi NPP, they are now being
used for the removal of debris indoor and outdoor of the nuclear reactor buildings, radiation
measurement and inspection in the buildings. In the evacuation centers, therapeutic robots “Paro” wereintroduced into more than 20 centers for providing psychological support to sufferers. The applied
robots and robot technologies to the disaster achieved a certain result. The results of practicalapplications and trials of them, however, present new issues about the operations of these robot
technologies.
Sanriku Coast
The devastated area of the tsunami disaster is extensively wide. A tele-operated mobile robot “Kohga
3” developed by Prof. Matsuno with Kyoto University was used for inspecting the damage of a
gymnastic hall in danger of collapsing in Hachinohe just after the tsunami, but it couldn’t be used forfinding survivors because most of victims died by drowning. Therefore, the robots were mainly used
for the investigation of underwater and the removal of debris in the disaster area on land.
Investigation of underwater: After one month from the earthquake, some underwater robots wereapplied for underwater investigation in order to avoid the danger of divers. “AC-ROB”, “SARbot”,

141

“LBV-300” and “Seamor ROV” were used for searching victims and inspecting obstacles, underwater
portions of piers and bridges for assessment of damage at Minami Sanriku-cho and Rikuzen Takata-shi
on 19th -20th and 21st -23rd April respectively. “Anchor diver 3” was used at Warati-cho on 19th -20th.
These missions were done in collaboration with IRS( International Rescue System Institute ) and
CRASAR( Center for Robot-Assisted Search and Rescue ).
“SARbot” and “LBV-300” are developed by SeaBotix Inc. and the “SARbot” was mainly used
due to the portability and rapid setup/deployment. It is equipped with an enhanced color video camera,
the Tritech Gemini 720i multibeam imaging sonar, an accurate GPS system and a limb graspingmechanism. “Seamor ROV” is a product of Seamor Marine Ltd., and it is equipped with highresolution sonar and a grasper. “AC-ROB” is a small robot driven by a battery and just takes movies. It
is like a video camera with a thruster. It was mainly used for investigating tight places like under thefloating houses. “Anchor Diver 3” is developed by Prof. Hirose with Tokyo Institute of Technology. It
is equipped with a high resolution video camera and a 2D-sonar, and driven by two thrusters. It isconnected to the operation site by a cable and can keep its own position in tidal streams by the cabletension and the thruster control. The time SARbot was under water is 38minutes on 19th and189minutes on 20th, and Seamor 178minutes on 20th. Anchor diver 3 investigated about 100m2 in twodays. No victim was found in the mission, but the situations of the bottom of the ports were made clear.
Prof. Ura with the University of Tokyo also investigated the bottom of Otsuchi bay and Shizukawa bay
by two underwater robots RTV on 29th April-1st May and 15th-16th May, and found 2 victims. The
investigation of victims and the inspection of the debris on the bottom of the sea by underwater robots
have continued until now.
Removal of debris: A new construction machine ASTACO NEO with two robotic manipulatorsdeveloped by Hitachi Construction Machinery Co. Ltd. was applied for the removal of debris at
Ishinomaki in May and June which revealed the high efficiency of the robot.
Fukushima Daiichi NPP
There was no robot in Japan applicable to the disaster site of Fukushima Daiichi NPP just after theaccident caused by the tsunami, but now, many robots are used mainly for the removal of debris
indoor and outdoor, the monitoring of radioactivity or other physical parameters and the inspection of
the damage of the nuclear reactors and buildings. Much more robot technologies related to theconstruction machines or rescue systems will be developed and used for the tasks necessary for thedecommissioning of nuclear power units 1-4.
Removal of debris: As to the removal of debris around the nuclear reactor buildings, sometele-operated construction machines modified for the disaster site came into use. At first, a backhoe
attached with an iron fork at the tip, a crawler dump truck, a monitoring car with a camera and an
operation car were introduced. The backhoe, dump truck and monitoring car are tele-operated byoperators in the operation car. The technologies installed into the tele-operation system were originallydeveloped for unmanned construction almost 20 years ago and they have been improved as
construction robots until now. The system worked very well and the removal of debris outdoors isalmost completed. From June, cleaning up of indoor was also started by the military robot “Warrior”
developed by iRobot Corp.. A cleaner is attached to the manipulator tip of the “Warrior” as shown in
Fig.3a.
Inspection and monitoring: As to the monitoring and inspection, two military robots “Packbot”(Fig.3b) which is a commercial product by iRobot Corp. were introduced for investigating the damage
situation of the indoor of the nuclear reactor buildings after the middle of April. One robot is
controlled as a monitor robot and takes the images of the other robot by its camera, and the other one
is wireless controlled by the operator and measures radioactivity, temperature, moisture and so on. The
robot also has a manipulator with (up to) 8 degrees of freedom(d.o.f.) which can open or close a door.
These robots got much valuable data about indoor environment, but they couldn’t go upstairs becauseof the steep stairs. The rescue robot “Quince”(Fig.3c) developed by IRS(International Rescue System
Institute) was also introduced from July, whose mobility capacity is very high, and it can go upstairs.
The “Quince” has a unique crawler mechanism which has two flippers with crawlers at the front and142the rear sides respectively like arms and legs besides the main two crawlers embedded in the body.
“Quince” is also equipped with a 6 d.o.f. manipulator and is wired controlled by operators. By using
the “Quince”, the damage of the building and the nuclear power plant became much clearer. For theinspection of the building from the air, a micro air vehicle “T-Hawk” was used from April. T-Hawk is
a commercial product developed by Honeywell Inc. for surveillance of combat fields and can easily be
operated by single person.
As mentioned above, in Fukushima Daiichi NPP, there was no robot applicable to the disastersite at first because of the difficulties of the task environments. The site was radiation-contaminatedand also like a heap of debris. Therefore, both the tele-operation function and the mobility on debris
are required for the robots. Professional operators and the robustness of the robots are also essential.
However, such robots didn’t exist in Japan because of the political and economical reasons. On theother hand, there are many robots and operators in USA for military industry. That is the reason why
many robots are introduced into Fukushima NPP from USA. In Japan, it is strongly desired for thegovernment to technically and economically support the anti-disaster robotics technologies.

Fig.3a Warrior with cleaner1)

Fig.3b

Packbot2)

Fig.3cQuince3)1) http://www.tepco.co.jp/en/news/110311/images/110630_4.jpg
2) http://www.tepco.co.jp/en/news/110311/images/110429_1f_11.jpg
3) http://www.tepco.co.jp/en/news/110311/images/110630_4.jpg

WG4: TRANSPORTATIONS AND LOGISTICS
Transportations of railways and roads were damaged widely and seriously in Tohoku area by theearthquake and/or tsunami.
Railway Transportation
In the case of railway transportation, infrastructures such as station buildings, railway tracks, catenary
and pillar etc, were widely and seriously damaged by the earthquake and tsunami, as shown in Fig.4aand Fig.4b. The local lines were directly attacked by both of the earthquake and tsunami, but
Shinkansen lines were not attacked by the tsunami. There were not so big damages in the mechanicaldevices compared with civil infrastructures. There were some trains attacked by the tsunami but all thepassengers had evacuated before the tsunami attack.
Although 27 Shinkansen rapid trains were operated in service in Tohoku line during the earthquake, alltrains could quickly slow down and stopped without derailment and any passenger fatalities. The quick
operation could be done by the UrEDAS and FREQL systems which can detect small P-wave before
large S-wave reaches the railways and send the information to the central operation center. These
alarm systems have been developed due to the various experiences of huge earthquake attacks so far,such as, 1995 Kobe Earthquake and 2004 Chuetsu Earthquake.
The derailment prevention guard systems have been developed and deployed to Shinkansen vehicles

143which can directly avoid the derailment by mechanical guard systems. This new safety system has
been developed after 2004 Chuetsu Earthquake.

(a)

Local railway along Pacific coast(b) Tohoku Shinkansen line
Fig. 4 Damages of railways by the earthquake and tsunami

Road Transportation
In the case of road transportation, roads and traffic signals were attacked and damaged by theearthquake and tsunami, moreover many cars and trucks were floated and carried away. Gas stations
were also damaged, so that many cars cannot be driven due to the lack of gasoline.
A few days after the earthquake, Inter-NAVI information systems were open to the drivers through car
navigation systems to know which roads can be used or not. This system was linked by the similarnavigation systems of big companies, such as, Honda, Toyota, Nissan and Pioneer. Fig.5a shows thenavigation map of available roads drawn by blue lines. Similar navigation system worked as well forcommercial vehicles such as trucks.
The “Kushinoha Sakusen” (teeth of comb operation) greatly contributed to the quick recovery of theroad transportation and logistics operation. Fig.5b shows the road map to rescue and recover thedamaged areas after the earthquake and the tsunami attack.

144

Fig.5aNavigation map around Sendai area

Fig.5b Teeth of comb operation map

WG5: DAMAGE OF ENERGY INFRASTRUCTURE
The following four areas were selected to be investigated:+ Nuclear Power Station+ Thermal Power Station+ Other Energy Infrastructures+ Energy Policy.
The view points of the investigation are+ what happened?
+ what was the cause?
+ what is effective to protect machines and structures from severe damage?
through researchers' and engineers' eyes, which may contribute possible improvement for establishing
more robust society. Faced to such severe disasters of nuclear power stations, JSME, as the third party
not involved in the interested parties -- government, electric power companies and thousands ofevacuated people after the emergency --, has a position to give valuable and dignified opinions.
Nuclear Power Station
A field research and a questionnaire survey were performed. Group members visited the Tokai No. 2
nuclear power station of the Japan Atomic Power Company, the Onagawa nuclear power station of the
Tohoku Electric Power Company and the Hamaoka nuclear power station of the Chubu Electric Power
Company. The questionnaires were sent to four research reactors of the Japan Atomic Energy Agency;
the Japan Research Reactor No. 3 (JRR3), the Japan Materials Testing Reactor (JMTR), the Joyo, theHigh Temperature Engineering Test Reactor (HTTR), and the Tokai No. 2 nuclear power station.
These facilities locate on the coast of the north-eastern part of Japan along the Pacific Ocean except
for Hamaoka. The area was suffered from the Great East Japan Earthquake, and then the Onagawa andthe Tokai No. 2 nuclear power station were attacked by the subsequently occurred huge tsunami.
Fukushima Daiichi, although most severely damaged, and Fukushima Daini Nuclear Power Stations
were excluded from the investigation since these are substantially under the control of the Japanese
Government and the accident investigation by the Japanese Government is in progress.
Investigation results at present are summarized as follows;
Against the earthquake:+ S class facilities were not visibly damaged by the earthquake, while B and C class facilities

145suffered some damages.
+ All devices and plants functioned properly provided only for the shaking due to earthquake.
+ Employees evacuated smoothly by following an emergency manual.
+ Rubbed marks were found on turbine blades.
+ Two additional items are suggested:・The fall of the steel tower of a power transmission cable resulted in the off-site power loss,
and the fire of switchboards led to the blackout.
・The power supply is indispensable to control facilities.
Against the tsunami:+ Once electric devices such as motors and valves were flooded, these devices lost theirfunctions. Power sauces submerged in water could not supply electricity for most of theequipments (Fig. 6a). Even air-operated valves could not be operated since pilot valves were
designed to be driven by electricity.
+ The properly waterproofed area was free from submergence.
+ A diversity of communication tools is essential between the onsite and the offsite.
The most important lesson learned was electricity supply ready for use for power and light electric
equipments in any conditions. Various back-up systems as well as waterproof are indispensable toassure security. There could happen various events beyond human knowledge. Even so, it is requested
to provide the way how to cope with the incident. Continuous check/review and updating on thesystem and system performance is of substantial importance. It is also important to estimate thesurvival-time allowance of nuclear power station when isolated from off-site power. A diversity ofaccess methods to the power station is needed, e.g. from air and sea. These are useful in an emergency.
The organizational governance is of prime importance at an emergency. One bright evidence to be
pointed out is that the waterproofed area was free from flooding (Fig. 6b), which suggests the potentialof modern technology for the robustness against the incidents beyond the human knowledge.

Fig. 6a

Sea water penetration pass at Onagawa No. 2 reactor. Water does not failto notice any tiny cranny to come into inside.

146

Fig. 6b

Sea water penetration was blocked at Tokai No. 2 reactor.
Waterproof treatment is important.

Thermal Power Station
Field researches were conducted for the Hitachi-Naka thermal power station of the Tokyo ElectricPower Company, the Shin Sendai and the Haranomachi thermal power station of the Tohoku ElectricPower Company. Questionnaire surveys were also conducted for the Hirono, Hitachi-Naka andKashima thermal power station of the Tokyo Electric Power Company, the Shinchi thermal power
station of the Soma Kyodo Power Company, the Nakoso thermal power station of the Joban Joint
Power Company, the Sendai, the Shinsendai and the Haranomachi thermal power stations of the
Tohoku Electric Power Company and the Integrated Coal Gasification Combined Cycle (IGCC) power
generation site of the Clean Coal Power R&D Company. All those power stations were located along
the coast of the Pacific Ocean and were involved in the present earthquake and the tsunami. Althoughsome of those were restored, some are still under the restoration process and will be commissioned
again in 2013.
No major damage of main facilities, e.g. boiler and turbine, was caused by the earthquake.
Employees evacuated following an emergency manual and human damage was suppressed only insmall number. Land subsidence occurred at some power stations, which harmed the transportation forrestoration work after the disaster.
Since the thermal power station located close to the sea, all power stations were damaged by thetsunami which followed the earthquake. The degree of the damage depended on the height of thetsunami and was in wide dispersion. A coal hoist collapsed through the severe pitching/rolling of acoal ship. (Fig. 7a) Fuel tanks were crashed and washed-away by the tsunami. (Fig. 7b) The tsunami
invaded into buildings including control buildings (Fig. 7c) and switchboard buildings (Fig. 7d).
Power loss was caused, which harmed the communication between on-site and off-site. An emergency
power source was installed on a turbine floor at some power station and effectively functioned. It isessential to equip various communication tools.

147

Water Tank

水タンク
(Upside-Down)（津波で流され逆さまに転倒）

Fig. 7bFig. 7a

揚炭機

揚炭機
Coal Unloader

Crashed and washed-away fuel tank

Damaged coal unloader

Floor (Automobile drifted)
2階 2nd（構内の自家用車が流されている）

Fig. 7cSecond floor of control building

Fig. 7d

Switchboard building

Other Energy Infrastructures
Questionnaire surveys were conducted for the Tokyo and Tohoku Electric Power Company and two oilfactories.
The damage to insulators of power transmission lines by the earthquake was reported. The fall of thesteel tower of the power transmission cable was not caused by the earthquake except for only one case,as mentioned in the above section of “ nuclear power station”. The earthquake caused severe damages
to aerial and underground power transmission cables at many places. Liquefaction might be one causeof the break. Circuit breakers were also damaged by the earthquake.
A few buildings were damaged by falling rocks caused by the earthquake at some hydro power
stations. The walls of aqueducts at the hydro power station suffered from cracking by the earthquake.
When the earthquake hit the oil factories, electric power supply was maintained by an emergency
power source or off-site power. Evacuation was executed smoothly. Communication and governancewell functioned. Fire of a liquefied petroleum gas (LPG) tank happened at one oil factory. Fall of tanks
and reactors and also buckling of a high stack were caused by the earthquake.
Many steel towers of the power transmission cable were collapsed by the tsunami. Transformer
substations along the coast were flooded by the tsunami. One oil factory was attacked by tsunami andtanks were washed away. Power supply facilities were also flooded and blackout was caused.
Energy Policy

148

Questionnaire surveys have been performed for JSME members who registere to the Power andEnergy Systems Division. The registered members are approximately 4,400 of which 320 answers arecollected, whose age ranged from 20s to 80s. Occupations were company employees, researchers,
academic professors, students and so on. They are specialist in the energy-related technologies. Their
opinion on the present disasters and resulting events are interesting and valuable to draw and consider
lessons learned from calamities. Analyses on questionnaire survey are in progress. The overall trend of
the answers is that nuclear reactors are indispensable to produce electricity in Japan. In order to be
accepted by the public, it is necessary for engineers and researchers to develop safer and more reliablenuclear technology, otherwise Japan cannot be survived. Most of all members believe that the role ofengineers is to sustain modern society. Energy supply, especially electricity supply, is an essential task
for retain the society. It is not easy to overcome the present difficulty and to solve the stuck problems,
but we, mechanical engineers, are responsible to provide answers.

WG6: NUCLEAR CODES AND STANDARDSThe severe accident and the consequent radioactive material release at the Fukushima Daiichi nuclear
power station was an unprecedented serious disaster the human being have ever experienced. On theother hand, it should also be noted that the other power stations survived the earthquake and tsunami
safely.
Investigation Policy
The WG 6, titled “Issues and future direction of nuclear codes and standards”, recognizing thesesituations and learning from the accident, defined its objectives that include;- To survey damages and their consequences (accident) that the nuclear power stations in Tohoku
region suffered, to the extent JSME can be committed- To gain insights about the (root) causes of the damages and the accident, mainly focusing on the
nuclear codes and standards issues- To analyze effective measures (good practice) against earthquake and tsunami at some nuclear
power stations- To create proposition about a path forward on nuclear codes and standards development related tothe severe accident leading to enhanced nuclear safety
It should be noted that the activity of the WG 6 is underway in a close cooperation with the Main
Committee on Power Generation Facility Codes (MCPGFC) of JSME that develops and maintains
codes and standards for nuclear power plant design and operation.
Overview of Damages and Accidents in NPP’s along the East Japan Pacific Coast
The effects of the earthquake and tsunami that attacked the nuclear power stations located on the
Pacific Coast of Tohoku region can be summarized as shown in Table 1 below.

Table 1 Earthquake / Tsunami Affected Nuclear Power Stations
Station/Unit
Higashidori 1
Onagawa 1-3
Fukushima Daiichi 1-6
Fukushima Daini 1-4
Tokai Daini

Earthquake(gal)*1
17 / 450 *2
573 / 512
550 / 438
277 / 428
225 / 400

Tsunami(m)>4~ 13
14 ~15~7
5.4

149

Plant Safety Functions
Shutdown*3
Cooling*4
Containment
Success
Success
Success
Success
Success
Success
Success
Failure*5
Failure*5
Success
Success
Success
Success
Success
Success

*1
*2
*3
*4
*5

Representative value of maximum acceleration, taken as maximum observed/design ratio
Observed value / Design value
Automated reactor scram due to earthquake
Structural integrity of reactor cooling systems and security of emergency power supply
Units 1 through 3 failed. Units 5 and 6 succeeded in attaining safe cold stand-by. Unit 4 was inoutage.

One can observe from the Table 1 that;- While the maximum observed accelerations slightly exceed the design values at Onagawa andFukushima Daiichi, they are well below the design values at other stations.
- All the operating nuclear power plants were successfully shut down automatically sensing
earthquake acceleration.
- Fukushima Daiichi station was attacked by a huge tsunami that was far higher than that of plantsafety design assumption (~5.7 m), while the height of tsunami did not significantly exceed thedesign assumptions at other stations (for Onagawa, about 15 m was assumed in design).
The accident sequence at Fukushima Daiichi station can be outlined as;- The operating units were automatically shut down by the seismograph signal.
- All the offsite power was lost due to the earthquake (a pylon was collapsed).
- The emergency power supply system lost its function by the attack of the tsunami that lead lasting
period station blackout.
- The reactor core cooling capability was lost, which resulted in melting of the nuclear fuel andhydrogen explosion.
- As a result, a large amount of radioactive material was released to the environment.
For other nuclear power stations, the response of the plants can be roughly summarized as below;- The operating units were automatically shut down by the seismograph signal.
- The offsite power was lost due to the earthquake (one line survived at Onagawa station).
- The emergency power supply systems survived the tsunami attack and maintained their function.
- No damage or malfunction is reported for the systems, structure and components important tosafety.
- All the reactors were successfully cooled down to a stable status
Review of Nuclear Codes and Standards
Based on these observations and publicly available information such as the government reports andutilities’ reports, the WG 6 has defined three viewpoints and started its investigation. Studies anddiscussions of the WG 6 from these viewpoints are currently underway, and here are some important
aspects and outcomes of these discussions.
Viewpoint #1: Why Fukushima accident could not be prevented?
While the direct cause of the Fukushima accident is the loss of offsite and onsite power due to theearthquake and tsunami, it was obviously a failure of risk management and there should be underlying
root causes of this failure. These may include issues related to the safety regulatory system and its
operation by the government, regulation and codes and standards issues, issues of (lack of)
implementing the up to date technology in a timely manner and so on. The discussion is now
underway and the insights gained are to be put together for the proposition on “what the regulatory
system should be”, “what the codes and standards should be” and so on.
View point #2: What is needed for the nuclear codes and standards after Fukushima accident?
One of the most important lessons we have learned from the Fukushima accident is that “nuclear

150

plants should be designed and prepared such that a severe accident can be prevented or avoided evenwhen the plant is suffered from severe natural hazards exceeding the design level”. It is a mission of
JSME, as one of the major Standard Development Organization for nuclear power plant design andoperation, to develop relevant standards to implement this lesson learned using the state-of-the-art
technology. Since the nuclear safety consists of a wide spectrum of technology, there are number ofstandards to be developed and they should be developed systematically.
Among these needed standards, a representative one is “a guideline for countermeasure design toprevent severe accident under severe natural hazard conditions”. The purpose of this guideline is theprevention of accidents and provides technical requirements, for example, for the back-up equipment
to be prepared for core depressurization and cooling under a station blackout condition. Anotherrepresentative one is “a guideline for structural integrity evaluation under severe accident conditions”,
The structural integrity of a containment vessel under the severe accident condition is quite importantto mitigate the accident influence by suppressing radioactive material release to the environment, andthis guideline literally provides structural integrity evaluation methods and criteria. Under the
MCPGFC development of these guidelines has already started.
Viewpoint #3: Did current seismic design technology function?
As mentioned earlier, all the operating units were automatically and successfully shut down during theearthquake. No significant damage, failure, or malfunction is reported on the systems, structures, andcomponents important to safety. In this sense, one may be able to argue that the current seismic
design technology functioned and the design rules (except for the definition of design earthquake) areappropriate.
On the other hand, since the possibility of an earthquake larger than the design level can never be
precluded, it is quite important to clarify the ultimate strength of structural components andfunctionality of active components under seismic loading, and quantify the design margin that isincluded in the current seismic design.

WG7: RISC MANAGEMENT AGAINST THE EARTHQUAKE AND ACCIDENTS IN NPP
Essential Viewpoint
In WG7 we investigate how people, who are responsible to the management, respond against the crisis
caused by the earthquake and tsunami. The validity of the decision at the crisis is discussed. When we
found a wrong decision we discuss the reason why and how the wrong decision was made. The factorsof the wrong decision could be-lack of information-imperfection of organization and/or laws
-sense of values and ethics of people working in the organization
The items of the inspection is focused to-accidents in NPP’s-railway transportation ~Tohoku Shinkansen and JR at the metropolitan area~-Pet-bottle drink (especially focused to the robustness of the cap)
Results Currently Obtained
Fukushima Daiichi NPP:
1. Even if the total power supply was shut down, the melt down of the fuels in the reactor core
could be prevented if they could have prepared the power supply due to the power source
vehicles or if they could have done the cooling water supply by the fire engines in a few

151hours after opening the vent valves.
The lack of the preparation and the training for the above two items is pointed out.
2. One major reason why they did not do the preparation and training leis in the regulation
enacted by the government where the total power loss is neglected. Engineers had been in
the situation of stop thinking.
Tohoku Shinkansen and JR at the Metropolitan Area:-The points of reflection and the intrinsic problems against the criticism done after the accident
・Is it wrong to give the first priority to the safety issues?
・Which should be criticized, decision or preparation?
-Subjects for the future
・Development of simulation technologies for the emergent situations.
・Improvement of information management where how quick the correct information can becollected.

CONCLUDING REMARKS AND AKNOWLEDGEMENTAs already mentioned in the introduction, the investigation committee is now on the way to the final
goal. Therefore, this paper gives an interim report about the subjects to be tackled with. At the
moment the author described the summary of activities in each working groups respectively. In the restof the period the author, as the chairman of the committee, will draw the subjects to be discussed andproposed for the society. These discussions and proposals will be included in the final report.
Finally the author would like to express his sincere acknowledgement for the support of the membersin the committee and WG’s. Without their support this report could not be completed.

APPENDIX
Statistics Results of Seismic Damage Investigation in the JSMEThe following tables show the statistics results of seismic damage investigation carried out by
the Japan Society of Mechanical Engineers (JSME) in the period from May to July, 2011. Total
number of answers is 233 facilities. Of the total, 118 were with seismic damage, and 115 were
without one.
［Maximum seismic intensity・Availability of acceptance for damage investigation・existence or non-existence of photos and reco
damage］
Maximum seismic intensity

Under intensity 3 Intensity 4, 5
7

Availability of acceptance for damag
investigation

Acceptanceexistence or non-existence of photoand records of damage

Existence

Intensity 6, 7
43

Reject19

78
Non-existence

61

38

152

46

（Total number of answers233

Damage situation of mechanical andeuipment

with damage

118

without damage

115

Mitigation of
Damage caused by Damage due toEarthquake andthe lessons
Tunami synergy
learned from past
seismic event

Damage caused
Damage caused by Earthquake
by Tsunami

GroundDeformation

Vibration(1)Foundation・Wall surface・Supporting section

66

23

1

4

10

(2)Large machinery・Generalmachinery・Precision Machinery

52

8

2

2

11

(3)Tank

5

9

1

1

4

(4)Boiler・Cooling machine・Air
conditioning machine

24

8

3

2

4

(5)Pump

13

4

3

2

2

(6)Pipe

54

14

2

8

(7)Electric generation・Electrictransmission, distribution andtransfomation equipment・Access toelectricity

20

7

1

6

(8)Emergency power system

1

2

2

2

(9)Crane2332(10)Elevation machine

17

3

2

1

2

(11)Transportation・Train-related
equipment

4

3

3

1

1

(12)FRP tank

14

4

1

1

(13)Medical equipment21(14)Base isolation・Vibration control
system3(15)Other machinery equipment

23

4

1

3

6

Damage of production network

23

5

6

13

4

＊Power plant facitilies

3

1

3

2

153

Characteristics of the damgae ofmachinery and equipment

Discribed
comment
89［Questions in terms of crisis management］
１．Presence or absence of manualfor emergency assuming seismic
event
２．Useful Effect of emergency
manualPresence

Absence88

Useful25→

31

３．Inconvinience while at work in thenext day and the day afterWith problem

４．Most helpful method to contact
the head office from industrial
facilities

Phone

５．Number of days required to grasp
the reality of the damage

Within a day

Agenda and characteristics of risk
management

Partially presence
1
Useless
47

→

38

10

Without problem
74

Email
61

49
Direct visit

50
5 days

30

Other
16

10 days50

23
10 days - 30 days 30 days - 50 days

11

13

3

Discribed
comment
78

Category of industry of Seismic Damage Investigation in the JSME
Figure A1 shows the percentage in the category of industry of seismic damage investigation in the
JSME.

154

Figure A1

Percentage in the category of industry of seismic damage investigation in the JSME

Major Seismic Damage from Damage Investigation Results• Damage of pipe in the ground• Overflow stream in Liquid storage pool
• Breakage of embedded pipe caused by ground sinking• Damage of shutter• Damage of structure into hoistway• Damage of steel-frame large structure• Inclination of equipment caused by change of center of gravity• Damage by aftershocks• Malfunction in re-operation after emergency shutdown• Equipment failures due to power outage• Damage reduction and improvement of the lessons learned from past seismic damage
Major Seismic Damage from Site Investigation Results• Manifestation of unprecedented damage due to long duration of seismic motion• Seismic interaction between different structures• Damage by seismic input• Plastic deformation of the bolts that hold the overhead crane rails• Fall of piping equipment and suspended structures• Buckling of tank
• Tsunami damage• Outflow of tank
• Flooding of equipment• Damage by collision of floating object•Damage by ground deformation• Deformation of foundation• Inclination of equipment• Deformation of piping supports

155