Canadian Monitoring of the Fukushima Reactor Accident – Multi-Departmental Response

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Multi-Departmental Response

Many federal departments (16) involved, principally:
• Canadian Nuclear Safety Commission (CNSC)
• Environment Canada (EC) – Canadian Meteorological Centre (CMC)
• Health Canada (HC)
• Natural Resources Canada (NRCAN)
• Department of Foreign Affairs and International Trade (DFAIT)
• Public Safety (PS)

Health Canada leads the technical advisory within Canadian Government

Health Canada’s surveillance team contributed operationally to 3 key areas:
1. Plume monitoring – Tracking the plume from Japan as it progressed around the world using both the CTBT network and national means Which leads to…
2. Source term constraints – ability to be less conservative about the worst case scenario to provide better guidance

And allows for…

3. Improving understanding of sequence of events (source term, detection, physical processes

NDC-NDC Cooperation

• All analysis results were shared with other RN NDC
• Allowed for quick confirmation of results, and expert collaboration on in-situ air spectra, and NG systems (dead time on high activity SAUNA systems)

CTBT Data

Supplementary data from the CTBT network was useful to provide official advice to Canadians in Japan, but also helped establish:
• Initial source term assessments and establishment of evacuation zones (DFAIT, HC, EC, CNSC)
• Credible worst case reactor scenarios that reflect educated core hypothesis (CNSC, HC)

Ratio data can provide insight into events occurring inside the reactor

Supplementary data from the CTBT network was useful to provide official advice to Canadians in Japan, but also helped establish:
• Initial source term assessments and establishment of evacuation zones (DFAIT, HC, EC, CNSC)
• Credible worst case reactor scenarios that reflect educated core hypothesis (CNSC, HC)

Ratio data can provide insight into events occurring inside the reactor

Coastal Measurements

Coastal measurements show good agreement between aerial and Richland data (similar elevations/altitude)

• Richland ~ 40 Bq/m2 – Aerial survey ~ 30 – 60 Bq/m3 along path
• Sidney NaI detector shows higher concentrations ~ 95 Bq/ m3
Mountains in Washington, atmospheric transport (around Vancouver Island) may explain the similarities and differences

Summary

• Understanding accident required expertise from many government departments and good collaborative relationships (both nationally and internationally)
• ATM are essential to understand observations and customized models are often necessary
• CTBT data was extremely valuable in assessing accident impacts
• National networks contributed valuable insight for noble gases and source term estimation
• Collaboration with other NDCs was extremely valuable and encouraged for future work
• Ratios of isotopes of Cs and Te possibly relate to water spraying events in the reactor core
• Source term for 133Xe is roughly 10-(18) – 10-(19) Bq

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