21.5 Conclusions
In 1FNPS, fuel debris conditions in the three damaged reactors are still unknown
and uncertain. The water issue also affects criticality control, as the coolant water is
not borated. Although fortunately no sign of criticality has yet been seen, the
subcritical condition is not secured. There are options of principles to pursue a
certain critical control of the fuel debris: prevention of criticality by poison, by dry
process, or by monitoring, and prevention of the severe consequences resulting
from criticality. Engineering research and development is to be conducted regarding any of these options.
Open Access This chapter is distributed under the terms of the Creative Commons Attribution
Noncommercial License, which permits any noncommercial use, distribution, and reproduction in
any medium, provided the original author(s) and source are credited.
References
1. Japan Atomic Energy Research Institute (2005) Working Group on Nuclear Criticality Safety
Data. Nuclear criticality safety handbook, version 2. JAERI-1340. Japan Atomic Energy
Research Institute (in Japanese)
2. Stratton WR (1987) Review of the state of criticality of the Three Mile Island Unit 2 core and
reactor vessel. DOE/NCT-01, Lawrence Livermore National Laboratory, California, United
States of America
3. Tonoike K et al (2013) Major safety and operational concerns for fuel debris criticality control.
In: Proceedings of the GLOBAL 2013: International nuclear fuel cycle conference, Salt Lake
City, UT, September 29–October 3, 2013
4. Suyama K et al (2012) OECD/NEA burnup credit criticality benchmark phase IIIC. Nuclide
composition and neutron multiplication factor of BWR spent fuel assembly for burnup credit
and criticality control of damaged nuclear fuel. OECD/NEA/WPNCS/EGBUC, Paris, France
5. Nishihara K et al (2012) Estimation of fuel composition in Fukushima-Daiichi nuclear power
plant. JAEA-Data/Code 2012–018, Japan Atomic energy Agency (in Japanese), Ibaraki, Japan
6. Akers DW et al (1992) TMI-2 examination results from the OECD-CSNI Program. NEA/CSNI/
R(91)9. Committee on the safety of nuclear installations, Organization for Economic Cooperation and Development, Paris, France
7. Tokyo Electric Power Company, Inc. (2011) Status of Fukushima Daiichi nuclear power station.
http://www.tepco.co.jp/en/nu/fukushima-np/index-e.html
8. Okuno H et al (2009) Second version of data collection part of nuclear criticality safety
handbook (Contract Research). JAEA-Data/Code 2009–010, Japan Atomic Energy Agency,
Ibaraki, Japan
9. Izawa K et al (2012) Infinite multiplication factor of low-enriched UO 2 -concrete system. J Nucl
Sci Technol 49(11):1043
21 Options of Principles of Fuel Debris Criticality Control in Fukushima. . .
259
In 1FNPS, fuel debris conditions in the three damaged reactors are still unknown
and uncertain. The water issue also affects criticality control, as the coolant water is
not borated. Although fortunately no sign of criticality has yet been seen, the
subcritical condition is not secured. There are options of principles to pursue a
certain critical control of the fuel debris: prevention of criticality by poison, by dry
process, or by monitoring, and prevention of the severe consequences resulting
from criticality. Engineering research and development is to be conducted regarding any of these options.
Open Access This chapter is distributed under the terms of the Creative Commons Attribution
Noncommercial License, which permits any noncommercial use, distribution, and reproduction in
any medium, provided the original author(s) and source are credited.
References
1. Japan Atomic Energy Research Institute (2005) Working Group on Nuclear Criticality Safety
Data. Nuclear criticality safety handbook, version 2. JAERI-1340. Japan Atomic Energy
Research Institute (in Japanese)
2. Stratton WR (1987) Review of the state of criticality of the Three Mile Island Unit 2 core and
reactor vessel. DOE/NCT-01, Lawrence Livermore National Laboratory, California, United
States of America
3. Tonoike K et al (2013) Major safety and operational concerns for fuel debris criticality control.
In: Proceedings of the GLOBAL 2013: International nuclear fuel cycle conference, Salt Lake
City, UT, September 29–October 3, 2013
4. Suyama K et al (2012) OECD/NEA burnup credit criticality benchmark phase IIIC. Nuclide
composition and neutron multiplication factor of BWR spent fuel assembly for burnup credit
and criticality control of damaged nuclear fuel. OECD/NEA/WPNCS/EGBUC, Paris, France
5. Nishihara K et al (2012) Estimation of fuel composition in Fukushima-Daiichi nuclear power
plant. JAEA-Data/Code 2012–018, Japan Atomic energy Agency (in Japanese), Ibaraki, Japan
6. Akers DW et al (1992) TMI-2 examination results from the OECD-CSNI Program. NEA/CSNI/
R(91)9. Committee on the safety of nuclear installations, Organization for Economic Cooperation and Development, Paris, France
7. Tokyo Electric Power Company, Inc. (2011) Status of Fukushima Daiichi nuclear power station.
http://www.tepco.co.jp/en/nu/fukushima-np/index-e.html
8. Okuno H et al (2009) Second version of data collection part of nuclear criticality safety
handbook (Contract Research). JAEA-Data/Code 2009–010, Japan Atomic Energy Agency,
Ibaraki, Japan
9. Izawa K et al (2012) Infinite multiplication factor of low-enriched UO 2 -concrete system. J Nucl
Sci Technol 49(11):1043
21 Options of Principles of Fuel Debris Criticality Control in Fukushima. . .
259