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Title: US Efforts in Support of Examinations at Fukushima Daiichi – 2016 Evaluations

Although it is clear that the accident signatures from each unit at the Fukushima Daiichi Nuclear Power Station (NPS) [Daiichi] differ, much is not known about the end-state of core materials within these units. Some of this uncertainty can be attributed to a lack of information related to cooling system operation and cooling water injection. There is also uncertainty in our understanding of phenomena affecting: a) in-vessel core damage progression during severe accidents in boiling water reactors (BWRs), and b) accident progression after vessel failure (ex-vessel progression) for BWRs and Pressurized Water Reactors (PWRs). These uncertainties arise due to limited full scale prototypic data. Similar to what occurred after the accident at Three Mile Island Unit 2, these Daiichi units offer the international community a means to reduce such uncertainties by obtaining prototypic data from multiple full-scale BWR severe accidents. Information obtained from Daiichi is required to inform Decontamination and Decommissioning activities, improving the ability of the Tokyo Electric Power Company Holdings (TEPCO) to characterize potential hazards and to ensure the safety of workers involved with cleanup activities. This document reports recent results from the US Forensics Effort to use information obtained by TEPCO to enhance the safety of existingmore » and future nuclear power plant designs. This Forensics Effort, which is sponsored by the Reactor Safety Technologies Pathway of the Department of Energy Office of Nuclear Energy Light Water Reactor (LWR) Sustainability Program, consists of a group of US experts in LWR safety and plant operations that have identified examination needs and are evaluating TEPCO information from Daiichi that address these needs. Examples presented in this report demonstrate that significant safety insights are being obtained in the areas of component performance, fission product release and transport, debris end-state location, and combustible gas generation and transport. In addition to reducing uncertainties related to severe accident modeling progression, these insights are being used to update guidance for severe accident prevention, mitigation, and emergency planning. Furthermore, reduced uncertainties in modeling the events at Daiichi will improve the realism of reactor safety evaluations and inform future D&D activities by improving the capability for characterizing potential hazards to workers involved with cleanup activities.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [6] ;  [8] ;  [9] ;  [2] ;  [10] ;  [11] ;  [12] ;  [13] ;  [10] ;  [14] ;  [9] ;  [15] ;  [16] more »;  [10] ;  [10] ;  [17] ;  [8] ;  [18] ;  [19] ;  [20] « less
  1. Exelon Corp., Chicago, IL (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. WWBX Consulting, Crofton, MD (United States)
  4. Southern Nuclear. Birmingham, AL (United States)
  5. Univ. of Wisconsin, Madison, WI (United States)
  6. GE-Hitachi, Wilmington, NC (United States)
  7. Argonne National Lab. (ANL), Argonne, IL (United States)
  8. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  9. Jensen Hughes, Baltimore, MD (United States)
  10. Fauske and Associates, LLC, Burr Ridge, IL (United States)
  11. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  12. Nuclear Energy Inst., Washington, DC (United States)
  13. Exelon Corp., Chicago, IL (United States); PWR Owners Group
  14. Lutz Nuclear Consulting, Asheville, NC (United States)
  15. Inst. for Nuclear Power Operations, Atlanta, GA (United States)
  16. CANegin & Associates
  17. Rempe and Associates, Idaho Falls, ID (United States)
  18. AREVA Federal Services, Charlotte, NC (United States)
  19. Electric Power Research Inst. (EPRI), Palo Alto, CA (United States)
  20. Tennessee Valley Authority, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States