update on fukushima daiichi npp 1 – preparations for core debris removal

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Update on Fukushima Daiichi NPP 1 – Preparations for Core Debris Removal. Robert Kury Vice President, Nuclear Liabilities D&D Program Management 1 March 2013 Presented to Colorado State University Health Physics Graduates. Fukushima Core Debris Removal. Fukushima Core Debris Removal. - PowerPoint PPT Presentation

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Update on Fukushima Daiichi NPP 1 Preparations for Core Debris RemovalRobert KuryVice President, Nuclear Liabilities D&D Program Management

1 March 2013Presented to Colorado State University Health Physics Graduates

Copyright [insert date set by system] by [CH2M HILL Entity] Company ConfidentialCopyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris RemovalBWR Mark I Containment

Copyright by CH2M HILL Company ConfidentialPhases of Mid-to-Long Term Roadmap55Step 1, 2

-Condition equivalent to cold shutdown

-Significant suppression of emissionsPhase 1Phase 2Phase 3Period to the start of fuel removal from spent fuel pool (Within 2 years)Period to the start of fuel debris removal (Within 10 years)-Commence the removal of fuels from the spent fuel pools (Unit 4 in 2 years)

-Reduce the radiation impact due to additional emissions from the whole site and radioactive waste generated after the accident (secondary waste materials via water processing and debris etc.). Thus maintain an effective radiation dose of less than 1 mSv/yr at the site boundaries caused by the aforementioned.

-Maintain stable reactor cooling and accumulated water processing and improve their credibility.

-Commence R&D and decontamination towards the removal of fuel debris

-Commence R&D of radioactive waste processing and disposal-Complete the fuel removal from the spent fuel pools at all units

-Complete preparations for the removal of fuel debris such as decontaminating the insides of the buildings, restoring the PCVs and filling the PCVs with water. Then commence the removal of fuel debris (Target: within 10 years)

-Continue stable reactor cooling

-Complete the processing of accumulated water

-Continue R&D on radioactive waste processing and disposal, and commence R&D on the reactor facilities decommission-Complete the fuel debris removal (in 20-50 years)

-Complete the decommissioning (in 30-40 years)

-Implement radioactive waste processing and disposalPeriod to the end of decommissioning (After30-40 years)Actions towards systematic staff training and allocation, improving motivation, and securing worker safety will be continuously implementedPresent (completion of step 2) Within 2 years Within 10 years After 30-40 yearsCopyright by CH2M HILL Company Confidential5Circle prep for fuel debrisFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialSummary of Pathways Evaluated

Dose Rates in mSv/hr12Copyright by CH2M HILL Company ConfidentialKeys to Success Elimination and Shielding of High Radiation Sources

13Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialCamera insertion route15Fukushima Core Debris Removal

Copyright by CH2M HILL Company ConfidentialFukushima Core Debris Removal

Copyright by CH2M HILL Company Confidential3. Measurement of Accumulated Water Level andAtmosphere dose17Summary of Pathways Evaluated

Dose Rates in mSv/hr18Copyright by CH2M HILL Company ConfidentialFactors Considered for the Pathways19

Copyright by CH2M HILL Company ConfidentialQualitative Comparison Results

20Copyright by CH2M HILL Company ConfidentialKeys to SuccessConfirmation of Existing ConditionsElimination of High Rad SourcesDebris Cleanup and RemovalDecontamination MethodsTechniques can be performed remotely, semi-remotely, or manually, depending on habitability21Copyright by CH2M HILL Company ConfidentialUse of remote cutting and removal of highly contaminated equipment and piping that would provide significant reduction to the dose rates at each locationUse of a Brokk or similar equipment when placing contaminated material into shielded waste containersProvide appropriate shielding to pathways to reduce general area dose rates to the workersUse of temporary and pre-engineered shielding walls and blanketsUse of floor shielding after initial pathway decontamination

21Keys to Success Decontamination Methods

Note: Initial survey data show moderate levels of removable Cs-137 contamination, which is not a major contributor to the general area dose rates. Therefore, general decontamination activities should be performed after installation of shielding to reduce dose rate to a target of < 5 mSv/hr.

22Copyright by CH2M HILL Company ConfidentialThe following decontamination techniques can be performed remotely, semi-remotely, or manually, depending on the general area dose rates.

Performance of large area wipe-downs to remove loose surface contaminants.Use of high-pressure washing/jet blasting with integrated vacuum capabilities to maximize the effectiveness of gross contamination removal.Use of floor shaving and/or scabbling of highly contaminated surfaces to remove embedded contaminants.Use of applied fixatives and/or coatings, as appropriate, to ensure that contaminants remain fixed.

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