A Japan’s View for Creating a Most
Robust Nuclear Energy– Learning the lessons from the accident
Global2011
Makuhari, Chiba, Japan
Monday, 12 December, 2011
President, Japan Atomic Energy InstituteAtsuyuki Suzuki

1Introductory Remarks• Appreciation for great helps and sympathies provided
by international countries and global societies.
• Repentance for global anxieties on radiologicalreleases into environments.
• Identification of the possible vulnerabilities so as todraw lessons as early as possible.
• Re‐thinking for enhancing nuclear safety to protect
external extreme events• Consideration for creation of a most robust system fornuclear energy, nationally and internationally.
• The views given here are little to do with thegovernment.
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The Vulnerabilities Revealed
1. Preparation for immense tsunami following
huge quake,
2. Prolonged loss of all AC powers, i.e., Days‐longstation blackout
3. Operations for unanticipated accident
management,
4. Hydrogen explosion at R/B,
5. Simultaneous emergency planning at multiple
units,
6. Cooling spent fuel stored at pool, and7. Learning new scientific findings.
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How to Deal with Extreme Natural Events• PSA or Defense‐in‐depth‐ Large uncertainties with estimate on
extreme event occurrence‐ Tremendously serious consequences, whenoccurred• Design‐based facility measures orOperational accident management‐ Devastating impediments of vast off‐sitesocial infrastructures
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The Vital Importance of Power Supply• The good examples‐ Kashiwazaki‐Kariwa NPPs, July 16th, 2007, andFukushima Dai‐ni NPPs, March 11th, 2011
‐ Units #5&6 in Fukushima Dai‐ichi, March 11th, 2011
• Emergency power supply‐ Non‐vulnerable EDGs
‐ Diversity with power supply: water‐cooled, air‐cooled, and gas‐turbine (for security)‐ Independent backup power supplies for integrity‐preservation loads
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Need for Learning for Reinforcing Safety• Learning new scientific findings‐ Remarkable progresses in seismic sciences in Japan
since the 1995 Hyogo‐ken Nambu EQ‐ Seismically induced tsunami:
The 869 Johkan EQ., M8.5, 200km dislocation,
The 1960 Chile EQ., M9.5, 1,000km dislocation, andThe 2004 Sumatra EQ., M9.1, 48.9m above sea‐level• Learning operating experiences‐ Accident management since TMI and Chernobyl‐ Individual Plant Examination of External Events , IPEEE‐ Information sharing
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Need for Industrial Collaborations• Competence of licensees‐ Engineering, financial, and management capability‐ Plant operation with safety at the highest priority• Information asymmetry‐ Vendors, operators, regulators and general public‐ The case for the 60’s/70’s Fukushima Dai‐ichi:
General Electric (GE), Toshiba, Hitachi, andTEPCO; Regulator‐ Stakeholders issues, to be managed based ontransparency
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Impacts on Nuclear Energy Policy• Nationally, the highest priority is given to the managementof the Fukushima Daiichi and the environments.
• The most influential is the serious shortage of funds
available for others, governmental or non‐governmental.
• The issue is how to create an avenue enabling us to continue
the program at least costs.
• Internationally, there seem three groups: little affected,much affected and in between.
• The global trend that nuclear energy is growing does notchange but what is important is how to follow the trendinternationally.
• The issue is to create international partnerships enablingeach country to participate in particular in the area of backend of nuclear fuel cycle as well as nuclear safety.
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Substantive and Procedural Safety• The substantive safety: physical protection system, based on
defense‐in‐depth with reasonably conservative redundancy,i.e., in a reasonably robust manner.
• The procedural safety: convincing arguments for regulations
and stakeholder involvement with the highest possible levelof transparency.
• The interaction between the two: feedback to thesubstantive from the procedural so as to actualize the safetyenhancement required or preferred. This is to be deemed
the most robust safety. The introduction of new scientificfindings into the substantive safety, for instance, would befacilitated, with the aid of social measures that arespecifically prepared as a self‐organizational mechanism.
9How to be Robust in the Nuclear Fuel Cycle• Spent fuel management‐ Short‐term and long‐term storage, pool or dry‐ Reuse at LWR or FR, with MA/L‐lived nuclides or not‐ Geological repository with R&R or pilot program• Global partnerships‐ Flexibility, to be adaptive for each nation’s situation‐ Incentives, to be economically attractive‐ Transparency, to give no concerns about proliferation
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Concluding Remarks• A most robust safety system could be achieved, appropriately
learning the lessons.
• As a safety measure, emergency power supply plays a vital role.
• How robust is robust enough could be addressed with the safety
design philosophy of defense‐in‐depth.
• The system should be flexible enough to adapt the new findings,
whenever necessary.
• For that purpose, an initiative should be taken from the industry. Thisis related to information asymmetry issue.
• How to manage the information asymmetry is crucially important forestablishing a robust safety system and the transparency might be akey element.
• In Japan, most crucial is how to create an avenue that enables
continuing the nuclear development program in a most robust
manner.
• Internationally, partnerships are particularly required for a robust
nuclear energy system, pursuing the safe, secure and steadily
expanded use of nuclear energy.
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